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Prognostic Indicators in Invasive Breast Cancer
Breast Cancer: Strategies for the 1990s II
0039-6109/90 $0.00
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Prognostic Indicators in Invasive Breast Cancer Margaret C. Sunderland, MD, * and William L. McGuire, MDt
For an individual patient's breast cancer, the course is still largely unpredictable. Some women die of metastatic disease within a year, whereas others survive several decades. Because of the marked variability in clinical course, there has been considerable interest in identifying the important characteristics predictive of tumor behavior, an interest intensified by the recent advent of promising strategies for adjuvant therapy in patients without involved lymph nodes. 14 Patients with tumor-free nodes who are at high risk for early disease recurrence may benefit from this adjuvant therapy, whereas if they could be identified reliably, patients at low risk for disease recurrence could be spared the toxicity of systemic therapy. Numerous clinical studies have demonstrated statistical relations between certain prognostic factors and two important intervals in the progression of breast cancer: the time from initial diagnosis to the first disease recurrence and the time until death from breast cancer. Besides predicting survival time after diagnosis, prognostic factors also help the clinician by providing information on the likely site(s) of initial recurrence, the clinical course after relapse has occurred, and the expected response to medical therapy. TUMOR SIZE
Knowing the extent of disease at the time of diagnosis is crucial for an accurate assessment of a patient's prognosis. Many studies have documented the relation between tumor size and survival expectations; tumor size is
*Fellow,
Divisions of Oncology and Hematology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas tProfessor, Department of Medicine, and Chief, Division of Medical Oncology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and Clinical Research Professor of the American Cancer Society
This article was supported in part by NIH Grants CA1l378 and CA30l95.
Surgical Clinics of North America-Vol. 70, No.5, October 1990
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the primary basis of the TNM staging system. Larger tumors are associated with shorter intervals before disease recurrence or death. In a representative sample consisting of 24,740 patients, survival data collected by the Surveillance, Epidemiology and End Results (SEER) program of the US National Cancer Institute have confirmed the importance of tumor size. 7 The relation between tumor size and survival at 5 years was linear regardless of nodal status, although for node-negative patients, the adverse effect of size on survival was less than for node-positive patients. Five-year survival rates, adjusted for age-expected mortality, ranged from 45% for tumors more than 5 cm in size with involved lymph nodes to 96% for tumors smaller than 2 cm with no involved nodes. Similar findings were reported by Rosen and colleagues, 55 who gathered data on pathologic features in 644 patients with a median follow-up period of 18.2 years. Tumor size was more important in predicting recurrence than was nodal status or histopathologic grade. A very favorable prognosis was implied for patients with tumors less than 1 cm, for whom the probability of relapse was 12%, compared with 28% for patients with tumors of 1 to 2 cm. When analyzed by decade, however, tumor size was not found to be of significance in disease recurrences after 10 years. (See article by Rosen and associates in the previous issue of this journal.)
AXILLARY NODE METASTASES Axillary lymph node involvement diagnosed pathologically is an important prognostic factor in early-stage breast cancer. The axillary region is the principal lymph drainage area for breast carcinoma, and lymph node involvement proves to be an excellent marker for the metastatic potential of a tumor. The overall prognosis is quite good for patients with node-negative disease: 70% to 75% will have no disease recurrence after primary surgery and should not require further therapy. For node-positive patients, the expected relapse rate is much higher, and only about 25% to 30% of these patients will remain disease free after initial local therapy. For tumors of equal size, women without node involvement have a 20% greater chance of survival at 5 years than those who are found to be node positive. 26 The extent of nodal involvement also is highly prognostic: larger numbers of positive nodes are associated with earlier recurrence and decreased overall survival. There is a sharp drop in the outlook for longterm survival of breast cancer patients with four or more positive lymph nodes compared with those with fewer involved nodes (Fig. 1): women with four or more positive nodes have a 5-year disease-free survival rate about 20% to 30% below those with less involvement. This difference was first noted in an early National Surgical Adjuvant Breast Project (NSABP) trial and has been confirmed in many subsequent studies. 9, 26 Tumor diameter and lymph node status are viewed as independent but additive prognostic factors: an increase in tumor size implies a statistical decrease in survival regardless of nodal status. Likewise, greater lymph
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lime (years) Figure 1. Disease-free (DF) survival according to axillary node status. Number of patients with no nodes = 3103; with 1 to 3 positive nodes = 1414; with 4 to 10 positive nodes = 835; with 11 to 20 positive nodes = 386; with >20 positive nodes = 170. Data are from the San Antonio database; median follow-up = 40 months. (From Clark GM, McGuire WL: Steroid receptors and other prognostic factors in primary breast cancer. Semin Oncol 15:20, 1988; with permission.)
node involvement is associated with decreased survival regardless of tumor size. Despite the prognostic strength of the traditional TNM staging system, women with ostensibly equivalent disease stages often exhibit vastly differing courses and periods of survival. This fact obviously implies the need to differentiate further between clinically aggressive and clinically indolent disease. STEROID HORMONE-RECEPTOR STATUS Estrogen and Progesterone Since 1977, which saw the original publication on the importance of steroid hormones in breast cancer, numerous articles have appeared supporting their value as prognostic factors. 20. 42 An undetectable or low estrogen-receptor value in a tumor is predictive of earlier recurrence and shorter overall survival than in patients with an estrogen-receptor-positive tumor, regardless of the nodal status. . For node-negative patients, estrogen-receptor status assumes a more important role as a prognostic factor. A multivariate analysis of 1647 patients with stage I cancer found estrogen-receptor status, along with tumor size, to be an independent prognostic factor. 10. 47 Even within this group for which the survival outlook is relatively optimistic, estrogen-receptor positivity indicated at least a 10% increase in disease-free survival compared with estrogen-receptor-negative findings. A difference for overall survival also was demonstrated, although the magnitude was smaller (Fig. 2).
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Figure 2. Disease-free survival (DFS) (A) and overall survival (OS) (B) based on tumor size and estrogen receptor (ER) status for patients with node-negative tumors; 4-year actuarial survival rate. (Data from Bellner SE, Clark GM, McGuire WL: Review: Steroid receptors, cellular kinetics, and lymph node status as prognostic factors in breast cancer. Am J Med Sci 31:59, 1988.) ~
Whereas the estrogen-receptor status is important as a prognostic factor in stage I disease, progesterone-receptor status appears to be a more significant indicator for predicting survival in stage II disease. 12 In an adjuvant study of patients with node-positive disease, progesterone-receptor status was as significant as the number of involved nodes in predicting disease recurrence. Estrogen-receptor status and tumor size, although important in univariate analysis, did not exhibit significance when adjusted for progesterone-receptor and nodal status. This survival advantage for patients with progesterone-receptor-positive tumors has been confirmed by others, although primarily it is an advantage for patients treated with adjuvant chemotherapy, hormonal therapy, or bothY For patients not receiving adjuvant therapy, the prognostic significance of tumor progesterone receptors is not as clear. 54 Survival After Relapse After the first recurrence of breast cancer, the median survival time for all patients is approximately 2 years. 30, 38 Patients with visceral metastatic disease or a short disease-free interval have the shortest survival expectations. A positive estrogen-receptor status, on the other hand, predicts longer survival after the initial relapse. In fact, this relation to expected survival has been demonstrated more consistently for recurrent disease than for primary breast cancer. When other prognostic factors are included in the analysis, Clark and
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associates demonstrated that the estrogen-receptor status, node involvement at the time of diagnosis, and the length of the disease-free interval were independently important for predicting survival after relapse. 13 Even for those patients with visceral metastases, women with estrogen-receptorpositive tumors still had a better survival than those with receptor-negative disease. Response to Hormonal Therapy In addition to their usefulness in predicting survival in primary breast cancer and recurrent disease, the beneficial effect of positive estrogenreceptor and progesterone-receptor status has been demonstrated in numerous trials investigating disease response to hormonal therapy. 44 Depending on the receptor concentrations, about 40% to 80% of patients with advanced disease with receptor-positive tumors will benefit from hormonal therapy.2 Patients whose tumors are both estrogen-receptor and progesterone-receptor positive have the highest response rate, whereas those with tumors positive for only one receptor have an intermediate response 51 (Table 1). Patients with receptor-negative tumors have a response rate of less than lO% to hormonal manipulation and can be spared the potential toxicity of these treatments in favor of cytotoxic therapy for advanced disease.
HISTOPATHOLOGY AND NUCLEAR GRADE Several histopathologic features are associated with a more aggressive cancer. A high mitotic rate, nuclear anaplasia, and a poor degree of cellular differentiation have been recognized for many years as predictors of a worse clinical outcome. When determined by a skilled pathologist, increased histopathologic grade or decreased nuclear grade consistently predicts earlier recurrence and shorter overall survival time in breast cancer patients.5. 28 In the Ludwig Trials I through IV of adjuvant therapy for nodenegative breast cancer, tumor grade was determined by two central pathologists.17 For this group of 1537 women, the 5-year overall survival rate was 86% for grade 1 tumors versus 57% for grade 3 tumors, and tumor grade was a statistically Significant factor for predicting disease-free survival or overall survival. Nuclear grade was also a prognostic factor for nodenegative patients entered in NSABP Protocol B_06. 28 Histopathology review Table 1. Response to Endocrine Therapy as a Function of Receptor Status RECEPTOR STATUS
RESPONSES/PATIENTS (%)
ER+/PR+ ER-/PR+ ER+/PRER-/PR-
871113 6113 331121 12/111
(77) (46) (27) (11)
Modified from Osborne CK, Yochmowitz MG, Knight WA, et al: The value of estrogen and progesterone receptors in the treatment of breast cancer. Cancer 46:2884, 1980.
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was performed by one pathologist, and the importance of nuclear grade was shown to be independent of other established prognostic factors. However, the cellular features that define histologic grades often are difficult to identify with consistency; differences in grade assignment are a common result of readings by more than one observer. In a study published by the Eastern Cooperative Oncology Group, agreement between pathologists reviewing the same specimens ranged from 40% to 90%, depending on the feature(s) observed, and the level of interobserver disagreement was directly proportional to the number of reviewers. 29 For the Ludwig trials, although local assessment identified a subgroup of patients with a poor prognosis, local grading agreed with that of the central reviewers in only 54% of the cases. CELLULAR KINETICS AND DNA CONTENT The prognostic value of tumor grading can be enhanced significantly by substituting quantitative measurements for traditional histopathologic features. For example, the proportion of actively growing cells is reflected in the mitotic activity seen on microscopic sections. Similarly, a large chromosome imbalance, measured as the cellular DNA content, is associated with poor cellular differentiation and nuclear pleomorphism. Thymidine-Labeling Index The number of cells in the DNA synthesis (S) phase of the cell cycle can be measured by incubating fresh tissue with radiolabeled thymidine. Actively growing cells incorporate the thymidine into DNA, and the proportion of cells involved in DNA synthesis can then be calculated by autoradiography. This proportion, the thymidine-labeling index, is a measure of the rate of cellular proliferation and has been found to be related to the risk of relapse by several groups. Tubiana and associates prospectively measured the index for 128 patients and correlated this measure with the patient's clinical course over a period of 10 years. 60 The thymidine-labeling index was found to be a better predictor of relapse than was tumor size, the number of axillary nodes, or histologic grade. A larger sample, 514 patients, was studied by Meyer and Province, who also found the labeling index to be strongly prognostic for disease-free survival (P = 0.0052) and overall survival (P = 0.0047).48 Nuclear grade and progesterone-receptor status did not contribute prognostic information for these patients, and estrogen-receptor status had only a moderate relation to overall survival. Unfortunately, although the thymidine-labeling index of a tumor specimen has value as a prognostic factor, the technique is impractical. The assay uses fresh tissue, and exposure to thymidine requires 2 to 3 weeks. Moreover, the actual measurement is cumbersome because cell counting is a manual process, and histopathologic training is needed to identifY carcinomatous cells. For these reasons, this technique has not been readily transported outside specialized research laboratories. Flow Cytometry Flow cytometry measurement of DNA is a faster method to assess the growth characteristics of a tumor. A suspension of single cells prepared
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from a dissociated tumor specimen can be processed by flow cytometry in a few minutes, providing information on as many as 100,000 cells. Flow cytometry also has the advantage of measuring nuclear DNA content by using a different DNA-specific fluorescent stain. Histograms generated by the cytometer allow the simultaneous identification of nondiploid cell populations and estimation of the distribution of cells in a specific clonal group in the various stages of the cell cycle. The DNA index is a quantitative measure of the degree of aneuploidy and can be calculated from DNA histograms; by definition, a cell with the normal diploid (2N) complement of DNA has an index of 1.0. Many breast cancers contain aneuploid cell populations, with a large proportion of these populations showing a simple hyperdiploid amount of DNA. Hypodiploid and tetraploid tumors-DNA index below 1.0 and around 2.0, respectively-are found less frequently. The proliferative capacity of a tumor measured by flow cytometry is defined as the portion of cells in the S phase and usually is reported as the S-phase fraction. A variety of statistical programs are available to calculate the fraction of cells with a DNA content that fall between the 2N and 4N DNA values for a specific clonal group. Because this generally is a static measurement, both cycling and noncycling S-phase cells will be included. After the methodology was developed to allow flow cytometry analysis of paraffin-embedded specimens,34 many institutions with archival material and clinical databases were able to demonstrate prognostic value for these measurements. To assess their importance for tumor behavior, the DNA index and S-phase fraction were compared with other well-known prognostic factors. Although the findings were not entirely consistent, aneuploidy was associated with those characteristics already established as predictors of shorter survival. Thus, aneuploidy has been correlated with increasing tumor size, 22, 35, 63 poor differentiation, 22, 35 and the presence of nodal metastases. 35 There have been conflicting reports on the relation of ploidy to hormone-receptor status: some investigators have reported a higher aneuploidy rate in estrogen-receptor-negative tumors36, 43, 49 and progesterone-receptor-negative tumors,35, 43 whereas others have found no significant relations. 37 Similarly, S-phase values have been associated with histopathology gradeS, 24 and hormone-receptor statuS. 24, 36 In a series of 1331 frozen breast tumor specimens, Dressler and associates were able to determine the DNA index in 89% and the S-phase fraction in 81%.19 The S-phase values were widely distributed; the median value for aneuploid tumors was significantly higher than the median value for diploid tumors, 10.3% versus 2.6%. Aneuploidy was found in 57% of the tumors. When aneuploid tumors were analyzed separately, those from women younger than 50 years and estrogen-receptor- or progesteronereceptor-negative tumors were more likely to exhibit a higher S-phase fraction. In diploid tumors, these features were not associated with significant increases in S-phase fraction. However, in comparing S-phase values in node-negative and node-positive tumors, a highly significant difference was found for diploid, although not for aneuploid, tumors. That is, for diploid tumors, node-negative patients were more likely to have a high S-
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phase fraction than node-positive patients; 38% and 63%, respectively (P <0.0001).
FLOW CYTOMETRY DATA AND SURVIVAL
A number of retrospective studies have been published comparing How cytometry measures obtained on archival specimens with long-term survival for breast cancer patients. Aneuploidy, as a prognostic factor for shorter disease-free survival and overall survival, has 1>een a frequent finding l6. 4O (Table 2). The relation of the S-phase fraction to survival has been less well studied, although it likewise appears to have important predictive value. Among 310 patients with early-stage disease, Ewers and associates found the recurrence rate at 16 months to be twice as high for aneuploid tumors as for diploid tumors.21 An early survival advantage for patients with diploid tumors also was reported by Owainati and colleagues, although this advantage did not remain after 3 years of follow-up. 53 More recent long-term studies indicate that the prognostic value of ploidy remains significant over many years. Van der Linden and colleagues reported on 156 patients with a median follow-up of 44 months in whom DNA ploidy was significantly correlated with the probability of disease recurrence (P <.005) but not with overall survival. 62 With a follow-up of 8 to 13 years, nuclear DNA content also provided independent predictive information for 227 patients reported by Fallenius and coworkers.22 The probability of disease-free survival was strongly correlated with the DNA Table 2. Aneuploidy and Survival PVALUES SOURCE
Clark et al ll Comelisse et al ' · l5 Fallenius et al22
NUMBER OF PATIENTS
345 341 349 98 129
nodenode+ nodenode + node-
MEDIAN FU (MONTHS)
DFS
OS
0.02 0.03 NS 0.011 0.009
0.11 0.002 NS NA NA
59 84 Range 813 yrs
Hatschek et al33
290
NS
NA
60
Hedley et al35 Klintenburg et al41
412 node + 210
0.58 NS
0.57 NS
65.8
Muss et al"" van der Linden et al611 von Rosen et alM
71 node156 170 node + 294 node-
0.23 0.045 NS <0.01
0.92 NA NA NA
COMMENTS
Stage I-III DNA content in 4 histogram categories SPF was related to survival
60
SPF was related to survival
51 44 42
Stage I-III DNA content in 4 histogram categories
DFS = disease-free survival; OS = overall survival; FU = follow-up; NA = not assessed; NS = not significant. Listed P values obtained from multivariate analyses; published studies evaluating ploidy by univariate analyses are not included.
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distribution (P <0.001). This additional prognostic information was found within both the node-positive and the node-negative groups. In a group of 345 node-negative breast cancer patients, Clark and associates found the disease-free survival rate at 5 years to be 88% for patients with diploid tumors and 74% for those with aneuploid tumors (P = 0.02),u In contrast, Comelisse and coworkers, in a recent update of their study on 690 patients with stage I through III disease, reported ploidy to be a significant prognostic factor only for node-positive patients. 1, 15 A few studies have suggested that the utility of flow cytometry as a laboratory tool is confined to the measurement of the proliferative rate. Klintenberg and associates found ploidy to offer no additional prognostic information for 210 patients with early-stage breast cancer.41 At a minimum follow-up of 60 months, the highest relapse-free survival rate was observed for those patients whose tumors were estrogen-receptor positive and had a proliferative index less than 5. Compared with this low-risk group, there was a sevenfold increase in the risk of recurrence for patients with involved nodes, estrogen-receptor-negative tumors, and a high proliferative index. On multivariate analysis, estrogen-receptor status, nodal status, and the proliferative index contributed independent prognostic information. Hatschek and coworkers reported similar results for 290 patients. 33 Those patients with high S-phase tumors had a higher risk of recurrence regardless of tumor size or estrogen-receptor status. This shorter disease-free survival was found for both the node-negative (P = 0.006) and the node-positive groups (P = 0.03). Flow cytometry permits measurement of several features, and an improved prognostic picture might be expected from combining the Sphase fraction and the DNA index. In fact, this has been demonstrated. For the women with node-negative disease reported by Clark and coworkers, those with diploid, low S-phase tumors had a significantly higher rate of disease-free survival at 5 years (90%) than did those with diploid, high S-phase, or aneuploid tumors (70.9%) (Fig. 3). In contrast, S-phase fractions did not define two separate groups of aneuploid tumors. Although the number of patients with diploid, low S-phase tumors was small, only 28% of the number studied, it represents a group of node-negative patients at very low risk for recurrence, and it is appropriate to question the routine use of adjuvant chemotherapy for these women. Kallioniemi and associates have proposed a prognostic test that combines the DNA index and the proliferative rate. 39 Three types of DNA histograms are defined, which are associated with a favorable, intermediate, and poor prognosis. Those authors were able to show an independent importance for the index as a predictor of shorter disease-free survival.
FLOW CYTOMETRY: PROBLEMS AND POTENTIAL
The accurate analysis of a tumor specimen by flow cytometry is dependent on a number of technical factors. Tissue preservation, sample
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0.9 Oipl/Lo-S (n - 97)
0.8 Aneu/AII-S (n - 233)
0.7 0.6
p - 0.006 (O-Lo S vs A)
12
24
36
48
Oipi/Hi-S (n - 16)
60
72
84
Time (months) Figure 3. Disease-free (DF) survival according to prognostic group. Patients with diploid low S-phase tumors had a significantly higher rate of DF survival than did those with aneuploid tumors or diploid high S-phase tumors. The DF survival rates among the latter two groups were not significantly different. (From Clark GM, Dressler LG, Owens MA, et al: Prediction of relapse or survival in patients with node-negative breast cancer by DNA How cytometry. N Engl J Med 320:627, 1989; with permission.)
preparation, and sample processing may influence the quality of the histogram. In addition to the variability introduced by the sample, readings for the S-phase fraction and ploidy will vary depending on cytometer performance and the statistical interpretation of the DNA histogram. 18 Software programs for evaluation of the histogram may differ, especially as there is an ongoing effort to improve the validity of flow cytometry measurements. Contradictory results reported in the literature may be explained in part by this lack of standardization. Despite these problems, flow cytometry should be more easily adapted to most medical centers than the traditional means of measuring cellular differentiation and proliferation. Flow cytometry has potential as an important tool for gathering data in early-stage breast cancer.
ONCOGENES Current dogma in the theory of cancer development suggests that specific genes, called oncogenes, may induce some types of cancer and that normal host genes, proto-oncogenes, that are required for cellular function can be converted to oncogenes. 3 When proto-oncogenes are altered, there appears to be an increased risk of malignancy. The structure or expression of these genes can be altered through a variety of mechanisms: amplification (creation of multiple copies), mutation, deletion, and translocation to regions with different controlling genes have all been implicated experimentally in human cancer. The abnormal occurrence of proto-oncogenes and oncogenes has been described for several breast cancer cell lines, as well as for human ,
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tumor specimens. The most thoroughly studied is the HER-21neu oncogene. Other oncogenes frequently found in human breast cancer tumors are c-myc, int-2, and H-ras. 6 HER-2/neu Growth factors and their cellular receptors are believed to be involved in the abnormal growth characteristics of cancer cells. One such growth factor receptor is encoded by the gene HER-2Ineu, also identified as cerbB-2 and neu. As a member of the tyrosine kinase family, it is closely related structurally to the epidermal growth factor receptor. Amplification of the HER-21neu oncogene, or its overexpression via mRNA transcription, has been reported in a large number of recent studies covering more than 1000 human breast carcinomas. Although there is considerable variation among the studies in the percentage of patients showing the chang~, gene amplification has been found frequently, with an average of 18% of the tumor specimens showing additional gene copies. 57 Whether amplification correlates with a more aggressive cancer is controversial. A number of recent studies have examined the HER-21neu oncogene's value as a predictor of disease-free or overall survival. The earliest report to provide long-term survival data was published by Slamon and colleagues in 1987. 56 Their analyses of an initial group of 103 tumor specimens showed gene amplification to be more common in patients with more than three positive lymph nodes. Another 86 patients with node-positive disease for whom long-term survival data were known were then added to the initial group. Significant correlations were found between the degree of gene amplification and both time to relapse (P = 0.001) and overall survival (P = 0.02) on follow-up at 50 months. This significance was retained when correcting for other features, including tumor size and nodal involvement. Very similar results were obtained by Tsuda and colleagues. 59 In 91 patients with node-positive disease, HER-21neu amplification identified those with earlier disease recurrences and shorter survival. Increasing numbers of gene copies also correlated with a poorer prognosis. When the node-negative patients were included in the analysis, only nodal status and HER-21neu amplification were shown to be significant prognostic factors. Because gene amplification eventually exerts its effect through protein overproduction, the direct measurement of gene product may be more relevant to malignant disease than a gene copy analysis. The potential role for overexpression of the HER-21neu gene product has been investigated by several groups. 57, 58, 64 Tandon and associates examined the HER-21neu protein in 728 primary breast cancer specimens. 58 In 378 node-negative patients, as with gene amplification, protein expression fail6d to predict disease outcome. For the 350 patients with positive nodes, those with higher levels of HER-21neu protein had a significantly shorter disease-free and overall survival thaq patients with less expression of the protein. When other clinical measures were considered, HER-21neu expression and nodal status remained as independent prognostic factors. Even among nodepositive patients, increased HER-2/neu protein expression was able to identify a subgroup of patients with a shorter survival (Table 3). A positive correlation of HER-21neu protein and prognosis has not
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Table 3. HER-21neu Protein Versus Positive Nodes: Effects on 5-Year Survival NO. OF PATIENTS
DISEASE-FREE SURVIVAL (%) ± SD
OVERALL SURVIVAL (%) ± SD
Low High
136 19
60 ± 5 37 ± 13
81 ± 4 46 ± 14
Low High
89 23
48 ± 6 34 ± 10
66 ± 6 39 ± 12
Low High
66 17
20 ± 6 24 ± 12
44 ± 7 36 ± 13
NO. OF POSITIVE NODES
HER-21NEU PROTEIN
1-3 4-10
>10
From Tandon AK, Clark CM, Chamness CC, et al: HER-2/neu oncogene protein and prognosis in breast cancer. J Clin Oncol 7:1120, 1989; with permission.
been demonstrated consistently. For example, van de Vijver and coworkers had noted a trend toward shorter survival for patients with stage II disease and neu overexpression, but this trend did not remain significant after adjustment for tumor size. 61 Of interest, those investigators did note a high percentage of ductal carcinoma in situ, 42%, to have increased expression of the HER-21neu protein. In summary, the HER-21neu oncogene may prove, with further study, to have prognostic value but perhaps only in node-positive patients. Other Oncogenes Other proto-oncogenes have been linked to prognosis in breast cancer. Lidereau and colleagues 45 investigated the oncogene int-2 in 107 patients, finding that amplification of this gene had a highly significant association with subsequent relapse. The proto-oncogene c-myc also appears to be amplified in breast cancer, but a consistent prognostic value has not been associated with the finding. 4 Overexpression of the H-ras protein has been associated with positive nodal status, larger tumor size, and, interestingly, estrogen-receptor positivity. Rare allelles of the H-ras oncogene also are frequent in women with breast cancer. 46 The biologic and molecular consequences of this observation remain unknown.
PERSPECTIVE The study of prognostic factors for breast cancer has become increasingly complex. As the number of prognostic factors grows, determination of their relative importance and prognostic accuracy becomes more difficult. Conflicting results published by respected investigators and the lack of standardization for new techniques and methodologies are two problems not unexpected in an area of rapid growth. These issues aside, interpretation of the data should still be approached with caution. The cytologic and molecular measurements made on a tumor at the time of diagnosis may not remain constant over time as metastases develop.
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The proliferative rate, ploidy, hormone-receptor status,52 and oncogenic profile may alter, changing the tumor's biology and thus its growth and metastatic potential. For example, in one study, 44% of tumors that initially were progesterone-receptor positive were progesterone-receptor negative on a second biopsy performed later. 31 Adjuvant therapy, either cytotoxic or hormonal, may alter the phenotypic expression of the breast cancer. Both macrometastases and micrometastases at the time of diagnosis may have different characteristics than the primary tumor. A recent study by Feichter and coworkers illustrates this point. 23 The DNA index and Sphase fraction were measured in 80 primary breast cancers and in their respective lymph node metastases. The DNA index agreed in 76% of cases and the S-phase fraction in 62%. However, diploid tumors had a higher concordance rate than did aneuploid tumors. For aneuploid tumors, DNA index agreement was 70% and the S-phase fraction agreement was only 56%. Also, animal tumor models have demonstrated that the cellular kinetics of metastatic foci can change abruptly after surgical removal of the primary tumor. 25 Finally, the variability of the disease demands special care in the analysis and manipulation of collected data. 32 Beneficial effects seen early in the course of the disease are not necessarily associated with improved long-term survival but may reflect only a delay of disease recurrence. Similarly, an early adverse effect may obscure an eventual benefit. These phenomena underscore the importance of observing large numbers of patients for many years in any study analyzing prognostic factors.
SUMMARY Tumor size and axillary lymph node involvement are the primary determinants of clinical course for most patients. Receptors for estrogen and progesterone are important additional prognostic factors for diseasefree survival, overall survival, survival time after initial disease recurrence, and the likelihood of response to hormonal therapy. Histologic grading has merit as a prognostic factor, although poor reproducibility limits its broad application. Promising data have been emerging from the use of flow cytometry to analyze DNA content and proliferative rate. Patients with aneuploid tumors are more likely to have a shorter survival time than patients with diploid tumors. A high S-phase fraction also identifies a subset of patients at increased risk for early relapse. A combined index of ploidy and S-phase may be a more useful guide; together, diploidy and low S-phase identify a subgroup of node-negative patients at very low risk for disease recurrence. A number of oncogenes have been identified in breast cancer; amplification of the HER-21neu gene or overexpression of the gene product may be an important prognostic indicator for node-positive patients.
REFERENCES 1. Beerman H, Kluin PM, van de Velde CJH, et al: DNA How cytometry in the prognosis of node-negative breast cancer [letter]. N Engl J Med 321:473, 1989
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2. Benner SE, Clark GM, McGuire WL: Review: Steroid receptors, cellular kinetics, and lymph node status as prognostic factors in breast cancer. Am J Med Sci 31:59, 1988 3. Bishop JM: The molecular genetics of cancer. Science 235:305, 1987 4. Bonilla M, Ramirez M, Lopez-Cuerto J, et al: in vivo amplification and rearrangement of c-myc oncogene in human breast tumors. JNCI 80:665, 1988 5. Bustamante-Montes MA, Clark G, Langone G, et al: Histopathological grading of breast specimens correlates with disease free survival in node-negative breast cancer patients [abstract]. Proc Annu Meeting Am Assoc Cancer Res 30:A1003, 1989 6. Callahan R: Genetic alterations in primary breast cancer. Breast Cancer Res Treat 13:191, 1989 7. Carter CL, Allen A, Henson DE: Relation of tumor size, lymph node status, and survival in 24,470 breast cancer cases. Cancer 63:181, 1989 8. Christov K, Milev A, Todorov V: DNA aneuploidy and cell proliferation in breast tumors. Cancer 64:673, 1989 9. Clark GM, McGuire WL: Steroid receptors and other prognostic factors in primary breast cancer. Semin Oncol 15(2 suppl 1):20, 1988 10. Clark GM, Osborne CK, McGuire WL: Correlations between estrogen receptor, progesterone receptor, and patient characteristics in human breast cancer. J Clin Oncol 2:1102, 1984 11. Clark GM, Dressler LG, Owens MA, et al: Prediction of relapse or survival in patients with node-negative breast cancer by DNA flow cytometry. N Engl J Med 320:627, 1989 12. Clark GM, McGuire WL, Hubay CA, et al: Progesterone receptors as a prognostic factor in stage II breast cancer. N Engl J Med 309:1343, 1983 13. Clark GM, Sledge GW, Osborne CK, et al: Survival from first recurrence: Relative importance of prognostic factors in 1015 breast cancer patients. J Clin Oncol 5:55, 1987 14. Clinical Alert from the National Cancer Institute, May 18, 1988. Breast Cancer Res Treat 12:3, 1988 15. Cornelisse CJ, van de Velde CJ, Caspers RJ, et al: DNA ploidy and survival in breast cancer patients. Cytometry 8:225, 1987 16. Coulson PB, Thornthwaite JT, Woolley TW, et al: Prognostic indicators including DNA histogram type, receptor content, and staging related to human breast cancer patient survival. Cancer Res 44:4187, 1984 17. Davis BW, Gelber RD, Goldhirsch A, et al: Prognostic significance of tumor grade in clinical trials of adjuvant therapy for breast cancer. Cancer 58:2662, 1986 18. Dressler LG, Bartow SA: DNA flow cytometry in solid tumors: Practical aspects and clinical applications. Semin Diagn Pathol 6:55, 1989 19. Dressler LG, Seamer LC, Owens MA, et al: DNA flow cytometry and prognostic factors in 1331 frozen breast cancer specimens. Cancer 61:420, 1988 20. Early Breast Cancer Trialists' Collaborative Group: Effects of adjuvant tamoxifen and of cytotoxic therapy on mortality in early breast cancer: An overview of 61 randomized trials among 28,896 women. N Engl J Med 319:1681, 1988 21. Ewers SB, Langstrom E, Baldetorp B, et al: Flow-cytometric DNA analysis in primary breast carcinomas and clinicopathological correlations. Cytometry 5:408, 1984 22. Fallenius AG, Franzen SA, Auer GU: Predictive value of nuclear DNA content in breast cancer in relation to clinical and morphologic factors. Cancer 62:521, 1988 23. Feichter GE, Kaufmann M, Muller A, et al: DNA index and cell cycle analysis of primary breast cancer and synchronous axillary lymph node metastases. Breast Cancer Res Treat 13:17, 1989 24. Feichter GE, Mueller A, Kaufmann M, et al: Correlation of DNA flow cytometric results and other prognostic factors in primary breast cancer. Int J Cancer 41:823, 1988 25. Fisher B, Gunduz N, Saffer EA: Influence of the interval between primary tumor removal and chemotherapy on kinetics and growth metastases. Cancer Res 43:1488, 1983 26. Fisher B, Bauer M, Wickerman, et al: Relation of number of positive axillary nodes to the prognosis of patients with breast cancer. Cancer 52:1551, 1983 27. Fisher B, Redmond C, Fisher ER, et al: Relative worth of estrogen or progesterone receptor and pathologic characteristics of differentiation as indicators of prognosis in node negative breast cancer patients: Findings from the National Surgical Adjuvant Breast and Bowel Project Protocol B-06. J Clin Oncol 6:1076, 1988 28. Fisher B, Redmond CK, Wickerham DL, et al: Relation of estrogen and/or progesterone
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29. 30.
31. 32. 33.
34.
35. 36.
37. 38.
39.
40. 41.
42. 43.
44. 45. 46. 47. 48.
49.
50.
51. 52.
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receptor content of breast cancer to patient outcome following adjuvant therapy. Breast Cancer Res Treat 3:355, 1983 Gilchrist KW, Kalish L, Gould VE, et al: Interobserver reproducibility of histopathological features in stage II breast cancer: An ECOG study. Breast Cancer Res Treat 5:3, 1985 Goldhirsch A, Gelber RD, Castiglione M: Relapse of breast cancer after adjuvant treatment in premenopausal and perimenopausal women: Patterns and prognosis. J Clin Oncol 6:89, 1988 Gross GE, Clark GM, Chamness GC, et al: Multiple progesterone receptor assays in human breast cancer. Cancer Res 44:836, 1984 Harris JR, Hellman S: Observations on survival curve analysis with particular reference to breast cancer treatment. Cancer 57:925, 1987 Hatschek T, Fagerberg G, Stal 0, et al: Cytometric characterization and clinical course of breast cancer diagnosed in a population-based screening program. Cancer 64:1074, 1989 Hedley DW, Friedlander ML, Taylor IW: Application of DNA How cytometry to paraffinembedded archival material for the study of aneuploidy and its clinical significance. Cytometry 6:327, 1985 Hedley DW, Rugg CA, Gelber RD: Association of DNA index and S-phase fraction with prognosis of node positive early breast cancer. Cancer Res 47:4729, 1987 Helin HJ, Helle MJ, Kallioniemi OP, et al: Immunohistochemical determination of estrogen and progesterone receptors in human breast carcinoma: Correlation with histopathology and DNA How cytometry. Cancer 63:1761, 1989 Horsfall DJ, Tilley WD, Orell SR, et al: Relationship between ploidy and steroid hormone receptors in primary invasive breast cancer. Br J Cancer 53:23, 1986 Huseby RA, Ownby HE, Frederick J, et al: Node-negative breast cancer treated by modified radical mastectomy without adjuvant therapies: Variables associated with disease recurrence and survivorship. J Clin Oncol 6:83, 1988 KallioniemiOP, Blanco G, Alavaikko M, et al: Improving the prognostic value of DNA How cytometry in breast cancer by combining DNA index and S-phase fraction: A proposed classification of DNA histograms in breast cancer. Cancer 62:2183, 1988 Kallioniemi OP, Blanco G, Alavaikko M, et al: Tumour DNA ploidy as an independent prognostic factor in breast cancer. Br J Cancer 56:637, 1987 Klintenberg C, Stal 0, Nordenskjold B, et al: Proliferative index, cytosol estrogen receptor and axillary node status as prognostic predictors in human mammary carcinoma. Breast Cancer Res Treat 7:S99, 1986 Knight WA III, Livingston RB, Gregory EJ, et al: Estrogen receptor as an independent prognostic factor for early recurrence in breast cancer. Cancer Res 37:4669, 1977 Kute TE, Muss HB, Hopkins M, et al: Relationship of How cytometry results to clinical and steroid receptor status in human breast cancer. Breast Cancer Res Treat 6:113, 1985 Legha SS: Tamoxifen in the treatment of breast cancer. Ann Intern Med 109:219, 1988 Lidereau R, Callahan R, Dickson C, et al: Amplification of the int-2 gene in primary human breast tumors. Oncogene Res 2:285, 1988 Lidereau R, Escot C, Theillet C, et al: High-frequency of rare alleles of the human c-Hras-l proto-oncogene in breast cancer patients. JNCI 77:697, 1987 McGuire WL: Prognostic factors in primary breast cancer. Cancer Surv 15:527, 1986 Meyer JS, Province M: Proliferative index of breast carcinoma by thymidine labeling: Prognostic power independent of stage, estrogen and progesterone receptors. Breast Cancer Res Treat 12:191, 1988 Moran RE, Black MM, Alpert L, et al: Correlation of cell-cycle kinetics, hormone receptors, histopathology, and nodal status in human breast cancer. Cancer 54:1586, 1984 Muss HB, Kute TE, Case D, et al: The relation of How cytometry to clinical and biologic characteristics in women with node negative primary breast cancer. Cancer 64:1894, 1989 Osborne CK: Heterogeneity in hormone receptor status in primary and metastatic breast cancer. Semin OncoI12:317, 1985 Osborne CK, Yochmowitz MG, Knight WA, et al: The value of estrogen and progesterone receptors in the treatment of breast cancer. Cancer 46:2884, 1980
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53. Owainati AA, Robins RA, Hinton C, et al: Tumour aneuploidy, prognostic parameters and survival in primary breast cancer. Br J Cancer 55:449, 1987 54. Raemakers JMM, Beex LVAM, Pieters GF, et al: Progesterone receptor activity and relapse-free survival in patients with primary breast cancer: The role of adjuvant chemotherapy. Breast Cancer Res Treat 9:191, 1987 55. Rosen PP, Groshen S, Saigo S, et al: A long term follow-up study of survival in stage I (TlNOMO) and stage II (TlNIMO) breast carcinoma. J Clin Oncol 7:355, 1989 56. Slamon DJ, Clark GM, Wong SG, et al: Human breast cancer: Correlation of relapse and survival with amplification of the HER-21neu oncogene. Science 235:117, 1987 57. Sunderland MC, McGuire WL: Oncogenes as clinical prognostic indicators. In Lippman ME, Dickson RB (eds): Breast Cancer: Cellular and Molecular Biology II. Boston, Kluwer, in press 58. Tandon AK, Clark GM, Chamness GC, et al: HER-21neu oncogene protein and prognosis in breast cancer. J Clin Oncol 7:1120, 1989 59. Tsuda H, Hirohashi S, Shimosato Y, et al: Correlation between long-term survival in breast cancer patients and amplification of two putative oncogene-coamplification units: hst-llint-2 and c-erbB-2/ear-1. Cancer Res 49:3104, 1989 60. Tubiana M, Pejovic MH, Chavaudra N, et al: The long-term significance of the thymidinelabeling index in breast cancer. lnt J Cancer 33:441, 1984 61. van de Vijver, Peterse JL, Mooi WJ, et al: Neu-protein overexpression in breast cancer: Association with comedo-type ductal carcinomas in situ and limited prognostic value in stage II breast cancer. N Engl J Med 319:1239, 1988 62. van der Linden JC, Lindeman J, Baak JP, et al: The multivariate prognostic index and nuclear DNA content are independent prognostic factors in primary breast cancer patients. Cytometry 10:56, 1989 63. von Rosen A, Rutqvist LE, Carstensen J, et al: Prognostic value of nuclear DNA content in breast cancer in relation to tumor size, nodal status, and ER content. Breast Cancer Res Treat 13:23, 1989 64. Wright C, Angus B, Nicholson S, et al: Expression of the c-erbB-2 oncoprotein: A prognostic indicator in human breast cancer. Cancer Res 49:2087, 1989
Address reprint requests to William L. McGuire, MD Division of Medical Oncology The University of Texas Health Science Center at San Antonio 7703 Floyd Curl Drive San Antonio, Texas 78284-7884
0039-6109/90 $0.00
+ .20
Prognostic Indicators in Invasive Breast Cancer Margaret C. Sunderland, MD, * and William L. McGuire, MDt
For an individual patient's breast cancer, the course is still largely unpredictable. Some women die of metastatic disease within a year, whereas others survive several decades. Because of the marked variability in clinical course, there has been considerable interest in identifying the important characteristics predictive of tumor behavior, an interest intensified by the recent advent of promising strategies for adjuvant therapy in patients without involved lymph nodes. 14 Patients with tumor-free nodes who are at high risk for early disease recurrence may benefit from this adjuvant therapy, whereas if they could be identified reliably, patients at low risk for disease recurrence could be spared the toxicity of systemic therapy. Numerous clinical studies have demonstrated statistical relations between certain prognostic factors and two important intervals in the progression of breast cancer: the time from initial diagnosis to the first disease recurrence and the time until death from breast cancer. Besides predicting survival time after diagnosis, prognostic factors also help the clinician by providing information on the likely site(s) of initial recurrence, the clinical course after relapse has occurred, and the expected response to medical therapy. TUMOR SIZE
Knowing the extent of disease at the time of diagnosis is crucial for an accurate assessment of a patient's prognosis. Many studies have documented the relation between tumor size and survival expectations; tumor size is
*Fellow,
Divisions of Oncology and Hematology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas tProfessor, Department of Medicine, and Chief, Division of Medical Oncology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and Clinical Research Professor of the American Cancer Society
This article was supported in part by NIH Grants CA1l378 and CA30l95.
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the primary basis of the TNM staging system. Larger tumors are associated with shorter intervals before disease recurrence or death. In a representative sample consisting of 24,740 patients, survival data collected by the Surveillance, Epidemiology and End Results (SEER) program of the US National Cancer Institute have confirmed the importance of tumor size. 7 The relation between tumor size and survival at 5 years was linear regardless of nodal status, although for node-negative patients, the adverse effect of size on survival was less than for node-positive patients. Five-year survival rates, adjusted for age-expected mortality, ranged from 45% for tumors more than 5 cm in size with involved lymph nodes to 96% for tumors smaller than 2 cm with no involved nodes. Similar findings were reported by Rosen and colleagues, 55 who gathered data on pathologic features in 644 patients with a median follow-up period of 18.2 years. Tumor size was more important in predicting recurrence than was nodal status or histopathologic grade. A very favorable prognosis was implied for patients with tumors less than 1 cm, for whom the probability of relapse was 12%, compared with 28% for patients with tumors of 1 to 2 cm. When analyzed by decade, however, tumor size was not found to be of significance in disease recurrences after 10 years. (See article by Rosen and associates in the previous issue of this journal.)
AXILLARY NODE METASTASES Axillary lymph node involvement diagnosed pathologically is an important prognostic factor in early-stage breast cancer. The axillary region is the principal lymph drainage area for breast carcinoma, and lymph node involvement proves to be an excellent marker for the metastatic potential of a tumor. The overall prognosis is quite good for patients with node-negative disease: 70% to 75% will have no disease recurrence after primary surgery and should not require further therapy. For node-positive patients, the expected relapse rate is much higher, and only about 25% to 30% of these patients will remain disease free after initial local therapy. For tumors of equal size, women without node involvement have a 20% greater chance of survival at 5 years than those who are found to be node positive. 26 The extent of nodal involvement also is highly prognostic: larger numbers of positive nodes are associated with earlier recurrence and decreased overall survival. There is a sharp drop in the outlook for longterm survival of breast cancer patients with four or more positive lymph nodes compared with those with fewer involved nodes (Fig. 1): women with four or more positive nodes have a 5-year disease-free survival rate about 20% to 30% below those with less involvement. This difference was first noted in an early National Surgical Adjuvant Breast Project (NSABP) trial and has been confirmed in many subsequent studies. 9, 26 Tumor diameter and lymph node status are viewed as independent but additive prognostic factors: an increase in tumor size implies a statistical decrease in survival regardless of nodal status. Likewise, greater lymph
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lime (years) Figure 1. Disease-free (DF) survival according to axillary node status. Number of patients with no nodes = 3103; with 1 to 3 positive nodes = 1414; with 4 to 10 positive nodes = 835; with 11 to 20 positive nodes = 386; with >20 positive nodes = 170. Data are from the San Antonio database; median follow-up = 40 months. (From Clark GM, McGuire WL: Steroid receptors and other prognostic factors in primary breast cancer. Semin Oncol 15:20, 1988; with permission.)
node involvement is associated with decreased survival regardless of tumor size. Despite the prognostic strength of the traditional TNM staging system, women with ostensibly equivalent disease stages often exhibit vastly differing courses and periods of survival. This fact obviously implies the need to differentiate further between clinically aggressive and clinically indolent disease. STEROID HORMONE-RECEPTOR STATUS Estrogen and Progesterone Since 1977, which saw the original publication on the importance of steroid hormones in breast cancer, numerous articles have appeared supporting their value as prognostic factors. 20. 42 An undetectable or low estrogen-receptor value in a tumor is predictive of earlier recurrence and shorter overall survival than in patients with an estrogen-receptor-positive tumor, regardless of the nodal status. . For node-negative patients, estrogen-receptor status assumes a more important role as a prognostic factor. A multivariate analysis of 1647 patients with stage I cancer found estrogen-receptor status, along with tumor size, to be an independent prognostic factor. 10. 47 Even within this group for which the survival outlook is relatively optimistic, estrogen-receptor positivity indicated at least a 10% increase in disease-free survival compared with estrogen-receptor-negative findings. A difference for overall survival also was demonstrated, although the magnitude was smaller (Fig. 2).
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Figure 2. Disease-free survival (DFS) (A) and overall survival (OS) (B) based on tumor size and estrogen receptor (ER) status for patients with node-negative tumors; 4-year actuarial survival rate. (Data from Bellner SE, Clark GM, McGuire WL: Review: Steroid receptors, cellular kinetics, and lymph node status as prognostic factors in breast cancer. Am J Med Sci 31:59, 1988.) ~
Whereas the estrogen-receptor status is important as a prognostic factor in stage I disease, progesterone-receptor status appears to be a more significant indicator for predicting survival in stage II disease. 12 In an adjuvant study of patients with node-positive disease, progesterone-receptor status was as significant as the number of involved nodes in predicting disease recurrence. Estrogen-receptor status and tumor size, although important in univariate analysis, did not exhibit significance when adjusted for progesterone-receptor and nodal status. This survival advantage for patients with progesterone-receptor-positive tumors has been confirmed by others, although primarily it is an advantage for patients treated with adjuvant chemotherapy, hormonal therapy, or bothY For patients not receiving adjuvant therapy, the prognostic significance of tumor progesterone receptors is not as clear. 54 Survival After Relapse After the first recurrence of breast cancer, the median survival time for all patients is approximately 2 years. 30, 38 Patients with visceral metastatic disease or a short disease-free interval have the shortest survival expectations. A positive estrogen-receptor status, on the other hand, predicts longer survival after the initial relapse. In fact, this relation to expected survival has been demonstrated more consistently for recurrent disease than for primary breast cancer. When other prognostic factors are included in the analysis, Clark and
993
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associates demonstrated that the estrogen-receptor status, node involvement at the time of diagnosis, and the length of the disease-free interval were independently important for predicting survival after relapse. 13 Even for those patients with visceral metastases, women with estrogen-receptorpositive tumors still had a better survival than those with receptor-negative disease. Response to Hormonal Therapy In addition to their usefulness in predicting survival in primary breast cancer and recurrent disease, the beneficial effect of positive estrogenreceptor and progesterone-receptor status has been demonstrated in numerous trials investigating disease response to hormonal therapy. 44 Depending on the receptor concentrations, about 40% to 80% of patients with advanced disease with receptor-positive tumors will benefit from hormonal therapy.2 Patients whose tumors are both estrogen-receptor and progesterone-receptor positive have the highest response rate, whereas those with tumors positive for only one receptor have an intermediate response 51 (Table 1). Patients with receptor-negative tumors have a response rate of less than lO% to hormonal manipulation and can be spared the potential toxicity of these treatments in favor of cytotoxic therapy for advanced disease.
HISTOPATHOLOGY AND NUCLEAR GRADE Several histopathologic features are associated with a more aggressive cancer. A high mitotic rate, nuclear anaplasia, and a poor degree of cellular differentiation have been recognized for many years as predictors of a worse clinical outcome. When determined by a skilled pathologist, increased histopathologic grade or decreased nuclear grade consistently predicts earlier recurrence and shorter overall survival time in breast cancer patients.5. 28 In the Ludwig Trials I through IV of adjuvant therapy for nodenegative breast cancer, tumor grade was determined by two central pathologists.17 For this group of 1537 women, the 5-year overall survival rate was 86% for grade 1 tumors versus 57% for grade 3 tumors, and tumor grade was a statistically Significant factor for predicting disease-free survival or overall survival. Nuclear grade was also a prognostic factor for nodenegative patients entered in NSABP Protocol B_06. 28 Histopathology review Table 1. Response to Endocrine Therapy as a Function of Receptor Status RECEPTOR STATUS
RESPONSES/PATIENTS (%)
ER+/PR+ ER-/PR+ ER+/PRER-/PR-
871113 6113 331121 12/111
(77) (46) (27) (11)
Modified from Osborne CK, Yochmowitz MG, Knight WA, et al: The value of estrogen and progesterone receptors in the treatment of breast cancer. Cancer 46:2884, 1980.
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was performed by one pathologist, and the importance of nuclear grade was shown to be independent of other established prognostic factors. However, the cellular features that define histologic grades often are difficult to identify with consistency; differences in grade assignment are a common result of readings by more than one observer. In a study published by the Eastern Cooperative Oncology Group, agreement between pathologists reviewing the same specimens ranged from 40% to 90%, depending on the feature(s) observed, and the level of interobserver disagreement was directly proportional to the number of reviewers. 29 For the Ludwig trials, although local assessment identified a subgroup of patients with a poor prognosis, local grading agreed with that of the central reviewers in only 54% of the cases. CELLULAR KINETICS AND DNA CONTENT The prognostic value of tumor grading can be enhanced significantly by substituting quantitative measurements for traditional histopathologic features. For example, the proportion of actively growing cells is reflected in the mitotic activity seen on microscopic sections. Similarly, a large chromosome imbalance, measured as the cellular DNA content, is associated with poor cellular differentiation and nuclear pleomorphism. Thymidine-Labeling Index The number of cells in the DNA synthesis (S) phase of the cell cycle can be measured by incubating fresh tissue with radiolabeled thymidine. Actively growing cells incorporate the thymidine into DNA, and the proportion of cells involved in DNA synthesis can then be calculated by autoradiography. This proportion, the thymidine-labeling index, is a measure of the rate of cellular proliferation and has been found to be related to the risk of relapse by several groups. Tubiana and associates prospectively measured the index for 128 patients and correlated this measure with the patient's clinical course over a period of 10 years. 60 The thymidine-labeling index was found to be a better predictor of relapse than was tumor size, the number of axillary nodes, or histologic grade. A larger sample, 514 patients, was studied by Meyer and Province, who also found the labeling index to be strongly prognostic for disease-free survival (P = 0.0052) and overall survival (P = 0.0047).48 Nuclear grade and progesterone-receptor status did not contribute prognostic information for these patients, and estrogen-receptor status had only a moderate relation to overall survival. Unfortunately, although the thymidine-labeling index of a tumor specimen has value as a prognostic factor, the technique is impractical. The assay uses fresh tissue, and exposure to thymidine requires 2 to 3 weeks. Moreover, the actual measurement is cumbersome because cell counting is a manual process, and histopathologic training is needed to identifY carcinomatous cells. For these reasons, this technique has not been readily transported outside specialized research laboratories. Flow Cytometry Flow cytometry measurement of DNA is a faster method to assess the growth characteristics of a tumor. A suspension of single cells prepared
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from a dissociated tumor specimen can be processed by flow cytometry in a few minutes, providing information on as many as 100,000 cells. Flow cytometry also has the advantage of measuring nuclear DNA content by using a different DNA-specific fluorescent stain. Histograms generated by the cytometer allow the simultaneous identification of nondiploid cell populations and estimation of the distribution of cells in a specific clonal group in the various stages of the cell cycle. The DNA index is a quantitative measure of the degree of aneuploidy and can be calculated from DNA histograms; by definition, a cell with the normal diploid (2N) complement of DNA has an index of 1.0. Many breast cancers contain aneuploid cell populations, with a large proportion of these populations showing a simple hyperdiploid amount of DNA. Hypodiploid and tetraploid tumors-DNA index below 1.0 and around 2.0, respectively-are found less frequently. The proliferative capacity of a tumor measured by flow cytometry is defined as the portion of cells in the S phase and usually is reported as the S-phase fraction. A variety of statistical programs are available to calculate the fraction of cells with a DNA content that fall between the 2N and 4N DNA values for a specific clonal group. Because this generally is a static measurement, both cycling and noncycling S-phase cells will be included. After the methodology was developed to allow flow cytometry analysis of paraffin-embedded specimens,34 many institutions with archival material and clinical databases were able to demonstrate prognostic value for these measurements. To assess their importance for tumor behavior, the DNA index and S-phase fraction were compared with other well-known prognostic factors. Although the findings were not entirely consistent, aneuploidy was associated with those characteristics already established as predictors of shorter survival. Thus, aneuploidy has been correlated with increasing tumor size, 22, 35, 63 poor differentiation, 22, 35 and the presence of nodal metastases. 35 There have been conflicting reports on the relation of ploidy to hormone-receptor status: some investigators have reported a higher aneuploidy rate in estrogen-receptor-negative tumors36, 43, 49 and progesterone-receptor-negative tumors,35, 43 whereas others have found no significant relations. 37 Similarly, S-phase values have been associated with histopathology gradeS, 24 and hormone-receptor statuS. 24, 36 In a series of 1331 frozen breast tumor specimens, Dressler and associates were able to determine the DNA index in 89% and the S-phase fraction in 81%.19 The S-phase values were widely distributed; the median value for aneuploid tumors was significantly higher than the median value for diploid tumors, 10.3% versus 2.6%. Aneuploidy was found in 57% of the tumors. When aneuploid tumors were analyzed separately, those from women younger than 50 years and estrogen-receptor- or progesteronereceptor-negative tumors were more likely to exhibit a higher S-phase fraction. In diploid tumors, these features were not associated with significant increases in S-phase fraction. However, in comparing S-phase values in node-negative and node-positive tumors, a highly significant difference was found for diploid, although not for aneuploid, tumors. That is, for diploid tumors, node-negative patients were more likely to have a high S-
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phase fraction than node-positive patients; 38% and 63%, respectively (P <0.0001).
FLOW CYTOMETRY DATA AND SURVIVAL
A number of retrospective studies have been published comparing How cytometry measures obtained on archival specimens with long-term survival for breast cancer patients. Aneuploidy, as a prognostic factor for shorter disease-free survival and overall survival, has 1>een a frequent finding l6. 4O (Table 2). The relation of the S-phase fraction to survival has been less well studied, although it likewise appears to have important predictive value. Among 310 patients with early-stage disease, Ewers and associates found the recurrence rate at 16 months to be twice as high for aneuploid tumors as for diploid tumors.21 An early survival advantage for patients with diploid tumors also was reported by Owainati and colleagues, although this advantage did not remain after 3 years of follow-up. 53 More recent long-term studies indicate that the prognostic value of ploidy remains significant over many years. Van der Linden and colleagues reported on 156 patients with a median follow-up of 44 months in whom DNA ploidy was significantly correlated with the probability of disease recurrence (P <.005) but not with overall survival. 62 With a follow-up of 8 to 13 years, nuclear DNA content also provided independent predictive information for 227 patients reported by Fallenius and coworkers.22 The probability of disease-free survival was strongly correlated with the DNA Table 2. Aneuploidy and Survival PVALUES SOURCE
Clark et al ll Comelisse et al ' · l5 Fallenius et al22
NUMBER OF PATIENTS
345 341 349 98 129
nodenode+ nodenode + node-
MEDIAN FU (MONTHS)
DFS
OS
0.02 0.03 NS 0.011 0.009
0.11 0.002 NS NA NA
59 84 Range 813 yrs
Hatschek et al33
290
NS
NA
60
Hedley et al35 Klintenburg et al41
412 node + 210
0.58 NS
0.57 NS
65.8
Muss et al"" van der Linden et al611 von Rosen et alM
71 node156 170 node + 294 node-
0.23 0.045 NS <0.01
0.92 NA NA NA
COMMENTS
Stage I-III DNA content in 4 histogram categories SPF was related to survival
60
SPF was related to survival
51 44 42
Stage I-III DNA content in 4 histogram categories
DFS = disease-free survival; OS = overall survival; FU = follow-up; NA = not assessed; NS = not significant. Listed P values obtained from multivariate analyses; published studies evaluating ploidy by univariate analyses are not included.
PROGNOSTIC INDICATORS IN INVASIVE BREAST CANCER
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distribution (P <0.001). This additional prognostic information was found within both the node-positive and the node-negative groups. In a group of 345 node-negative breast cancer patients, Clark and associates found the disease-free survival rate at 5 years to be 88% for patients with diploid tumors and 74% for those with aneuploid tumors (P = 0.02),u In contrast, Comelisse and coworkers, in a recent update of their study on 690 patients with stage I through III disease, reported ploidy to be a significant prognostic factor only for node-positive patients. 1, 15 A few studies have suggested that the utility of flow cytometry as a laboratory tool is confined to the measurement of the proliferative rate. Klintenberg and associates found ploidy to offer no additional prognostic information for 210 patients with early-stage breast cancer.41 At a minimum follow-up of 60 months, the highest relapse-free survival rate was observed for those patients whose tumors were estrogen-receptor positive and had a proliferative index less than 5. Compared with this low-risk group, there was a sevenfold increase in the risk of recurrence for patients with involved nodes, estrogen-receptor-negative tumors, and a high proliferative index. On multivariate analysis, estrogen-receptor status, nodal status, and the proliferative index contributed independent prognostic information. Hatschek and coworkers reported similar results for 290 patients. 33 Those patients with high S-phase tumors had a higher risk of recurrence regardless of tumor size or estrogen-receptor status. This shorter disease-free survival was found for both the node-negative (P = 0.006) and the node-positive groups (P = 0.03). Flow cytometry permits measurement of several features, and an improved prognostic picture might be expected from combining the Sphase fraction and the DNA index. In fact, this has been demonstrated. For the women with node-negative disease reported by Clark and coworkers, those with diploid, low S-phase tumors had a significantly higher rate of disease-free survival at 5 years (90%) than did those with diploid, high S-phase, or aneuploid tumors (70.9%) (Fig. 3). In contrast, S-phase fractions did not define two separate groups of aneuploid tumors. Although the number of patients with diploid, low S-phase tumors was small, only 28% of the number studied, it represents a group of node-negative patients at very low risk for recurrence, and it is appropriate to question the routine use of adjuvant chemotherapy for these women. Kallioniemi and associates have proposed a prognostic test that combines the DNA index and the proliferative rate. 39 Three types of DNA histograms are defined, which are associated with a favorable, intermediate, and poor prognosis. Those authors were able to show an independent importance for the index as a predictor of shorter disease-free survival.
FLOW CYTOMETRY: PROBLEMS AND POTENTIAL
The accurate analysis of a tumor specimen by flow cytometry is dependent on a number of technical factors. Tissue preservation, sample
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0.9 Oipl/Lo-S (n - 97)
0.8 Aneu/AII-S (n - 233)
0.7 0.6
p - 0.006 (O-Lo S vs A)
12
24
36
48
Oipi/Hi-S (n - 16)
60
72
84
Time (months) Figure 3. Disease-free (DF) survival according to prognostic group. Patients with diploid low S-phase tumors had a significantly higher rate of DF survival than did those with aneuploid tumors or diploid high S-phase tumors. The DF survival rates among the latter two groups were not significantly different. (From Clark GM, Dressler LG, Owens MA, et al: Prediction of relapse or survival in patients with node-negative breast cancer by DNA How cytometry. N Engl J Med 320:627, 1989; with permission.)
preparation, and sample processing may influence the quality of the histogram. In addition to the variability introduced by the sample, readings for the S-phase fraction and ploidy will vary depending on cytometer performance and the statistical interpretation of the DNA histogram. 18 Software programs for evaluation of the histogram may differ, especially as there is an ongoing effort to improve the validity of flow cytometry measurements. Contradictory results reported in the literature may be explained in part by this lack of standardization. Despite these problems, flow cytometry should be more easily adapted to most medical centers than the traditional means of measuring cellular differentiation and proliferation. Flow cytometry has potential as an important tool for gathering data in early-stage breast cancer.
ONCOGENES Current dogma in the theory of cancer development suggests that specific genes, called oncogenes, may induce some types of cancer and that normal host genes, proto-oncogenes, that are required for cellular function can be converted to oncogenes. 3 When proto-oncogenes are altered, there appears to be an increased risk of malignancy. The structure or expression of these genes can be altered through a variety of mechanisms: amplification (creation of multiple copies), mutation, deletion, and translocation to regions with different controlling genes have all been implicated experimentally in human cancer. The abnormal occurrence of proto-oncogenes and oncogenes has been described for several breast cancer cell lines, as well as for human ,
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tumor specimens. The most thoroughly studied is the HER-21neu oncogene. Other oncogenes frequently found in human breast cancer tumors are c-myc, int-2, and H-ras. 6 HER-2/neu Growth factors and their cellular receptors are believed to be involved in the abnormal growth characteristics of cancer cells. One such growth factor receptor is encoded by the gene HER-2Ineu, also identified as cerbB-2 and neu. As a member of the tyrosine kinase family, it is closely related structurally to the epidermal growth factor receptor. Amplification of the HER-21neu oncogene, or its overexpression via mRNA transcription, has been reported in a large number of recent studies covering more than 1000 human breast carcinomas. Although there is considerable variation among the studies in the percentage of patients showing the chang~, gene amplification has been found frequently, with an average of 18% of the tumor specimens showing additional gene copies. 57 Whether amplification correlates with a more aggressive cancer is controversial. A number of recent studies have examined the HER-21neu oncogene's value as a predictor of disease-free or overall survival. The earliest report to provide long-term survival data was published by Slamon and colleagues in 1987. 56 Their analyses of an initial group of 103 tumor specimens showed gene amplification to be more common in patients with more than three positive lymph nodes. Another 86 patients with node-positive disease for whom long-term survival data were known were then added to the initial group. Significant correlations were found between the degree of gene amplification and both time to relapse (P = 0.001) and overall survival (P = 0.02) on follow-up at 50 months. This significance was retained when correcting for other features, including tumor size and nodal involvement. Very similar results were obtained by Tsuda and colleagues. 59 In 91 patients with node-positive disease, HER-21neu amplification identified those with earlier disease recurrences and shorter survival. Increasing numbers of gene copies also correlated with a poorer prognosis. When the node-negative patients were included in the analysis, only nodal status and HER-21neu amplification were shown to be significant prognostic factors. Because gene amplification eventually exerts its effect through protein overproduction, the direct measurement of gene product may be more relevant to malignant disease than a gene copy analysis. The potential role for overexpression of the HER-21neu gene product has been investigated by several groups. 57, 58, 64 Tandon and associates examined the HER-21neu protein in 728 primary breast cancer specimens. 58 In 378 node-negative patients, as with gene amplification, protein expression fail6d to predict disease outcome. For the 350 patients with positive nodes, those with higher levels of HER-21neu protein had a significantly shorter disease-free and overall survival thaq patients with less expression of the protein. When other clinical measures were considered, HER-21neu expression and nodal status remained as independent prognostic factors. Even among nodepositive patients, increased HER-2/neu protein expression was able to identify a subgroup of patients with a shorter survival (Table 3). A positive correlation of HER-21neu protein and prognosis has not
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Table 3. HER-21neu Protein Versus Positive Nodes: Effects on 5-Year Survival NO. OF PATIENTS
DISEASE-FREE SURVIVAL (%) ± SD
OVERALL SURVIVAL (%) ± SD
Low High
136 19
60 ± 5 37 ± 13
81 ± 4 46 ± 14
Low High
89 23
48 ± 6 34 ± 10
66 ± 6 39 ± 12
Low High
66 17
20 ± 6 24 ± 12
44 ± 7 36 ± 13
NO. OF POSITIVE NODES
HER-21NEU PROTEIN
1-3 4-10
>10
From Tandon AK, Clark CM, Chamness CC, et al: HER-2/neu oncogene protein and prognosis in breast cancer. J Clin Oncol 7:1120, 1989; with permission.
been demonstrated consistently. For example, van de Vijver and coworkers had noted a trend toward shorter survival for patients with stage II disease and neu overexpression, but this trend did not remain significant after adjustment for tumor size. 61 Of interest, those investigators did note a high percentage of ductal carcinoma in situ, 42%, to have increased expression of the HER-21neu protein. In summary, the HER-21neu oncogene may prove, with further study, to have prognostic value but perhaps only in node-positive patients. Other Oncogenes Other proto-oncogenes have been linked to prognosis in breast cancer. Lidereau and colleagues 45 investigated the oncogene int-2 in 107 patients, finding that amplification of this gene had a highly significant association with subsequent relapse. The proto-oncogene c-myc also appears to be amplified in breast cancer, but a consistent prognostic value has not been associated with the finding. 4 Overexpression of the H-ras protein has been associated with positive nodal status, larger tumor size, and, interestingly, estrogen-receptor positivity. Rare allelles of the H-ras oncogene also are frequent in women with breast cancer. 46 The biologic and molecular consequences of this observation remain unknown.
PERSPECTIVE The study of prognostic factors for breast cancer has become increasingly complex. As the number of prognostic factors grows, determination of their relative importance and prognostic accuracy becomes more difficult. Conflicting results published by respected investigators and the lack of standardization for new techniques and methodologies are two problems not unexpected in an area of rapid growth. These issues aside, interpretation of the data should still be approached with caution. The cytologic and molecular measurements made on a tumor at the time of diagnosis may not remain constant over time as metastases develop.
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The proliferative rate, ploidy, hormone-receptor status,52 and oncogenic profile may alter, changing the tumor's biology and thus its growth and metastatic potential. For example, in one study, 44% of tumors that initially were progesterone-receptor positive were progesterone-receptor negative on a second biopsy performed later. 31 Adjuvant therapy, either cytotoxic or hormonal, may alter the phenotypic expression of the breast cancer. Both macrometastases and micrometastases at the time of diagnosis may have different characteristics than the primary tumor. A recent study by Feichter and coworkers illustrates this point. 23 The DNA index and Sphase fraction were measured in 80 primary breast cancers and in their respective lymph node metastases. The DNA index agreed in 76% of cases and the S-phase fraction in 62%. However, diploid tumors had a higher concordance rate than did aneuploid tumors. For aneuploid tumors, DNA index agreement was 70% and the S-phase fraction agreement was only 56%. Also, animal tumor models have demonstrated that the cellular kinetics of metastatic foci can change abruptly after surgical removal of the primary tumor. 25 Finally, the variability of the disease demands special care in the analysis and manipulation of collected data. 32 Beneficial effects seen early in the course of the disease are not necessarily associated with improved long-term survival but may reflect only a delay of disease recurrence. Similarly, an early adverse effect may obscure an eventual benefit. These phenomena underscore the importance of observing large numbers of patients for many years in any study analyzing prognostic factors.
SUMMARY Tumor size and axillary lymph node involvement are the primary determinants of clinical course for most patients. Receptors for estrogen and progesterone are important additional prognostic factors for diseasefree survival, overall survival, survival time after initial disease recurrence, and the likelihood of response to hormonal therapy. Histologic grading has merit as a prognostic factor, although poor reproducibility limits its broad application. Promising data have been emerging from the use of flow cytometry to analyze DNA content and proliferative rate. Patients with aneuploid tumors are more likely to have a shorter survival time than patients with diploid tumors. A high S-phase fraction also identifies a subset of patients at increased risk for early relapse. A combined index of ploidy and S-phase may be a more useful guide; together, diploidy and low S-phase identify a subgroup of node-negative patients at very low risk for disease recurrence. A number of oncogenes have been identified in breast cancer; amplification of the HER-21neu gene or overexpression of the gene product may be an important prognostic indicator for node-positive patients.
REFERENCES 1. Beerman H, Kluin PM, van de Velde CJH, et al: DNA How cytometry in the prognosis of node-negative breast cancer [letter]. N Engl J Med 321:473, 1989
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2. Benner SE, Clark GM, McGuire WL: Review: Steroid receptors, cellular kinetics, and lymph node status as prognostic factors in breast cancer. Am J Med Sci 31:59, 1988 3. Bishop JM: The molecular genetics of cancer. Science 235:305, 1987 4. Bonilla M, Ramirez M, Lopez-Cuerto J, et al: in vivo amplification and rearrangement of c-myc oncogene in human breast tumors. JNCI 80:665, 1988 5. Bustamante-Montes MA, Clark G, Langone G, et al: Histopathological grading of breast specimens correlates with disease free survival in node-negative breast cancer patients [abstract]. Proc Annu Meeting Am Assoc Cancer Res 30:A1003, 1989 6. Callahan R: Genetic alterations in primary breast cancer. Breast Cancer Res Treat 13:191, 1989 7. Carter CL, Allen A, Henson DE: Relation of tumor size, lymph node status, and survival in 24,470 breast cancer cases. Cancer 63:181, 1989 8. Christov K, Milev A, Todorov V: DNA aneuploidy and cell proliferation in breast tumors. Cancer 64:673, 1989 9. Clark GM, McGuire WL: Steroid receptors and other prognostic factors in primary breast cancer. Semin Oncol 15(2 suppl 1):20, 1988 10. Clark GM, Osborne CK, McGuire WL: Correlations between estrogen receptor, progesterone receptor, and patient characteristics in human breast cancer. J Clin Oncol 2:1102, 1984 11. Clark GM, Dressler LG, Owens MA, et al: Prediction of relapse or survival in patients with node-negative breast cancer by DNA flow cytometry. N Engl J Med 320:627, 1989 12. Clark GM, McGuire WL, Hubay CA, et al: Progesterone receptors as a prognostic factor in stage II breast cancer. N Engl J Med 309:1343, 1983 13. Clark GM, Sledge GW, Osborne CK, et al: Survival from first recurrence: Relative importance of prognostic factors in 1015 breast cancer patients. J Clin Oncol 5:55, 1987 14. Clinical Alert from the National Cancer Institute, May 18, 1988. Breast Cancer Res Treat 12:3, 1988 15. Cornelisse CJ, van de Velde CJ, Caspers RJ, et al: DNA ploidy and survival in breast cancer patients. Cytometry 8:225, 1987 16. Coulson PB, Thornthwaite JT, Woolley TW, et al: Prognostic indicators including DNA histogram type, receptor content, and staging related to human breast cancer patient survival. Cancer Res 44:4187, 1984 17. Davis BW, Gelber RD, Goldhirsch A, et al: Prognostic significance of tumor grade in clinical trials of adjuvant therapy for breast cancer. Cancer 58:2662, 1986 18. Dressler LG, Bartow SA: DNA flow cytometry in solid tumors: Practical aspects and clinical applications. Semin Diagn Pathol 6:55, 1989 19. Dressler LG, Seamer LC, Owens MA, et al: DNA flow cytometry and prognostic factors in 1331 frozen breast cancer specimens. Cancer 61:420, 1988 20. Early Breast Cancer Trialists' Collaborative Group: Effects of adjuvant tamoxifen and of cytotoxic therapy on mortality in early breast cancer: An overview of 61 randomized trials among 28,896 women. N Engl J Med 319:1681, 1988 21. Ewers SB, Langstrom E, Baldetorp B, et al: Flow-cytometric DNA analysis in primary breast carcinomas and clinicopathological correlations. Cytometry 5:408, 1984 22. Fallenius AG, Franzen SA, Auer GU: Predictive value of nuclear DNA content in breast cancer in relation to clinical and morphologic factors. Cancer 62:521, 1988 23. Feichter GE, Kaufmann M, Muller A, et al: DNA index and cell cycle analysis of primary breast cancer and synchronous axillary lymph node metastases. Breast Cancer Res Treat 13:17, 1989 24. Feichter GE, Mueller A, Kaufmann M, et al: Correlation of DNA flow cytometric results and other prognostic factors in primary breast cancer. Int J Cancer 41:823, 1988 25. Fisher B, Gunduz N, Saffer EA: Influence of the interval between primary tumor removal and chemotherapy on kinetics and growth metastases. Cancer Res 43:1488, 1983 26. Fisher B, Bauer M, Wickerman, et al: Relation of number of positive axillary nodes to the prognosis of patients with breast cancer. Cancer 52:1551, 1983 27. Fisher B, Redmond C, Fisher ER, et al: Relative worth of estrogen or progesterone receptor and pathologic characteristics of differentiation as indicators of prognosis in node negative breast cancer patients: Findings from the National Surgical Adjuvant Breast and Bowel Project Protocol B-06. J Clin Oncol 6:1076, 1988 28. Fisher B, Redmond CK, Wickerham DL, et al: Relation of estrogen and/or progesterone
PROGNOSTIC INDICATORS IN INVASIVE BREAST CANCER
29. 30.
31. 32. 33.
34.
35. 36.
37. 38.
39.
40. 41.
42. 43.
44. 45. 46. 47. 48.
49.
50.
51. 52.
1003
receptor content of breast cancer to patient outcome following adjuvant therapy. Breast Cancer Res Treat 3:355, 1983 Gilchrist KW, Kalish L, Gould VE, et al: Interobserver reproducibility of histopathological features in stage II breast cancer: An ECOG study. Breast Cancer Res Treat 5:3, 1985 Goldhirsch A, Gelber RD, Castiglione M: Relapse of breast cancer after adjuvant treatment in premenopausal and perimenopausal women: Patterns and prognosis. J Clin Oncol 6:89, 1988 Gross GE, Clark GM, Chamness GC, et al: Multiple progesterone receptor assays in human breast cancer. Cancer Res 44:836, 1984 Harris JR, Hellman S: Observations on survival curve analysis with particular reference to breast cancer treatment. Cancer 57:925, 1987 Hatschek T, Fagerberg G, Stal 0, et al: Cytometric characterization and clinical course of breast cancer diagnosed in a population-based screening program. Cancer 64:1074, 1989 Hedley DW, Friedlander ML, Taylor IW: Application of DNA How cytometry to paraffinembedded archival material for the study of aneuploidy and its clinical significance. Cytometry 6:327, 1985 Hedley DW, Rugg CA, Gelber RD: Association of DNA index and S-phase fraction with prognosis of node positive early breast cancer. Cancer Res 47:4729, 1987 Helin HJ, Helle MJ, Kallioniemi OP, et al: Immunohistochemical determination of estrogen and progesterone receptors in human breast carcinoma: Correlation with histopathology and DNA How cytometry. Cancer 63:1761, 1989 Horsfall DJ, Tilley WD, Orell SR, et al: Relationship between ploidy and steroid hormone receptors in primary invasive breast cancer. Br J Cancer 53:23, 1986 Huseby RA, Ownby HE, Frederick J, et al: Node-negative breast cancer treated by modified radical mastectomy without adjuvant therapies: Variables associated with disease recurrence and survivorship. J Clin Oncol 6:83, 1988 KallioniemiOP, Blanco G, Alavaikko M, et al: Improving the prognostic value of DNA How cytometry in breast cancer by combining DNA index and S-phase fraction: A proposed classification of DNA histograms in breast cancer. Cancer 62:2183, 1988 Kallioniemi OP, Blanco G, Alavaikko M, et al: Tumour DNA ploidy as an independent prognostic factor in breast cancer. Br J Cancer 56:637, 1987 Klintenberg C, Stal 0, Nordenskjold B, et al: Proliferative index, cytosol estrogen receptor and axillary node status as prognostic predictors in human mammary carcinoma. Breast Cancer Res Treat 7:S99, 1986 Knight WA III, Livingston RB, Gregory EJ, et al: Estrogen receptor as an independent prognostic factor for early recurrence in breast cancer. Cancer Res 37:4669, 1977 Kute TE, Muss HB, Hopkins M, et al: Relationship of How cytometry results to clinical and steroid receptor status in human breast cancer. Breast Cancer Res Treat 6:113, 1985 Legha SS: Tamoxifen in the treatment of breast cancer. Ann Intern Med 109:219, 1988 Lidereau R, Callahan R, Dickson C, et al: Amplification of the int-2 gene in primary human breast tumors. Oncogene Res 2:285, 1988 Lidereau R, Escot C, Theillet C, et al: High-frequency of rare alleles of the human c-Hras-l proto-oncogene in breast cancer patients. JNCI 77:697, 1987 McGuire WL: Prognostic factors in primary breast cancer. Cancer Surv 15:527, 1986 Meyer JS, Province M: Proliferative index of breast carcinoma by thymidine labeling: Prognostic power independent of stage, estrogen and progesterone receptors. Breast Cancer Res Treat 12:191, 1988 Moran RE, Black MM, Alpert L, et al: Correlation of cell-cycle kinetics, hormone receptors, histopathology, and nodal status in human breast cancer. Cancer 54:1586, 1984 Muss HB, Kute TE, Case D, et al: The relation of How cytometry to clinical and biologic characteristics in women with node negative primary breast cancer. Cancer 64:1894, 1989 Osborne CK: Heterogeneity in hormone receptor status in primary and metastatic breast cancer. Semin OncoI12:317, 1985 Osborne CK, Yochmowitz MG, Knight WA, et al: The value of estrogen and progesterone receptors in the treatment of breast cancer. Cancer 46:2884, 1980
1004
MARGARET
C.
SUNDERLAND AND WILLIAM
L.
MCGUIRE
53. Owainati AA, Robins RA, Hinton C, et al: Tumour aneuploidy, prognostic parameters and survival in primary breast cancer. Br J Cancer 55:449, 1987 54. Raemakers JMM, Beex LVAM, Pieters GF, et al: Progesterone receptor activity and relapse-free survival in patients with primary breast cancer: The role of adjuvant chemotherapy. Breast Cancer Res Treat 9:191, 1987 55. Rosen PP, Groshen S, Saigo S, et al: A long term follow-up study of survival in stage I (TlNOMO) and stage II (TlNIMO) breast carcinoma. J Clin Oncol 7:355, 1989 56. Slamon DJ, Clark GM, Wong SG, et al: Human breast cancer: Correlation of relapse and survival with amplification of the HER-21neu oncogene. Science 235:117, 1987 57. Sunderland MC, McGuire WL: Oncogenes as clinical prognostic indicators. In Lippman ME, Dickson RB (eds): Breast Cancer: Cellular and Molecular Biology II. Boston, Kluwer, in press 58. Tandon AK, Clark GM, Chamness GC, et al: HER-21neu oncogene protein and prognosis in breast cancer. J Clin Oncol 7:1120, 1989 59. Tsuda H, Hirohashi S, Shimosato Y, et al: Correlation between long-term survival in breast cancer patients and amplification of two putative oncogene-coamplification units: hst-llint-2 and c-erbB-2/ear-1. Cancer Res 49:3104, 1989 60. Tubiana M, Pejovic MH, Chavaudra N, et al: The long-term significance of the thymidinelabeling index in breast cancer. lnt J Cancer 33:441, 1984 61. van de Vijver, Peterse JL, Mooi WJ, et al: Neu-protein overexpression in breast cancer: Association with comedo-type ductal carcinomas in situ and limited prognostic value in stage II breast cancer. N Engl J Med 319:1239, 1988 62. van der Linden JC, Lindeman J, Baak JP, et al: The multivariate prognostic index and nuclear DNA content are independent prognostic factors in primary breast cancer patients. Cytometry 10:56, 1989 63. von Rosen A, Rutqvist LE, Carstensen J, et al: Prognostic value of nuclear DNA content in breast cancer in relation to tumor size, nodal status, and ER content. Breast Cancer Res Treat 13:23, 1989 64. Wright C, Angus B, Nicholson S, et al: Expression of the c-erbB-2 oncoprotein: A prognostic indicator in human breast cancer. Cancer Res 49:2087, 1989
Address reprint requests to William L. McGuire, MD Division of Medical Oncology The University of Texas Health Science Center at San Antonio 7703 Floyd Curl Drive San Antonio, Texas 78284-7884