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DNA ploidy of ovarian dysgerminomas: Correlation with clinical outcome
GYNECOLOGIC
ONCOLOGY
4,
13-16 (1992)
DNA Ploidy of Ovarian Dysgerminomas: Correlation with Clinical Outcome MARY B. PALMQUIST,M.D.,* *Section
of Gynecologic
Surgery,
MAURICE
J. WEBB, M.D. ,*,l MICHAEL M. LIEBER, M.D. ,t THOMAS A. GAFFEY, M.D. ,$ AND OFER NATIV, M.D.?
TDepartment
of Urology, and SSection Rochester, Minnesota
of Surgical 55905
Pathology,
Mayo
Clinic
and Mayo
Foundation,
Received August 17, 1990
Abnormal nuclear DNA content, as determinedby flow cytometry, when combinedwith conventional prognostic variables such as tumor grade or stageat diagnosis,appearsto identify patientswho are at increasedrisk for recurrenceof disease.The DNA content of ovarian dysgerminoma,a tumor that is homologousto testicular seminomaand is found in young women of childbearingage,wasstudiedto determineif there is a correlation betweenDNA content and outcome.Such information would be useful in selectingtreatment regimensand making possiblethe preservationof childbearingpotential in womenwho are likely to have a goodoutcome.The specimens from 23 casesof ovarian dysgerminomaseenat our institution between 1950 and 1985 wereanalyzed by DNA flow cytometry. Five of the tumors were diploid (21%) and nineteenwere nondiploid (79%). Patient outcomewasnot predictedany better by nuclearDNA content than by conventionalprognosticvariables. D 1~ &d&c PISS, IX.
The nuclear DNA content of certain human genitourinary neoplasms combined with conventional clinical and hist6pathologic staging appears to identify patients who are at increased risk of disease recurrence [1,2]. In the future, DNA ploidy may be helpful in selecting treatment plans for patients. Significant correlation between DNA ploidy, determined by flow cytometry, of genitourinary tumors and clinical outcome of the patients has been reported [3,4]. In particular, with testicular seminoma there is a significant correlation between DNA ploidy and tumor recurrence, local extension, and patient survival. One study at our institution [5] found that 48% of the tumors were DNA diploid and 52% were DNA nondiploid in a group of 102 patients with testicular seminoma. No patient with DNA diploid testicular seminoma presented with or sub-
sequently had advanced-stage disease, and no DNA diploid testicular seminoma proved fatal. The testicular seminoma was DNA aneuploid in all of the patients who presented with advanced-stage disease, experienced recurrence of the tumor, or died of the disease. Because testicular seminoma and ovarian dysgerminoma are homologous tumors, the results of the seminoma study prompted us to analyze a group of Mayo Clinic patients with ovarian dysgerminoma to determine if nuclear DNA ploidy of tumors correlated with biologic behavior. Ovarian dysgerminomas are very radiosensitive and occur primarily in young women [6,7]. Because radiotherapy may ablate childbearing potential in this group of patients or be teratogenic in the next generation, accurate identification of less-aggrgssive ovarian dysgerminomas could avoid the use of rhdiotherapy and preserve fertility in some women. MATERIALS
AND METHODS
Relevant pathology reports were reviewed and the hematoxylin-and-eosin-stained tissue slides were examined in 35 cases evaluated at the Mayo Clinic between 1950 and 1985 [8]. Archival paraffin-embedded tissue blocks were available from 23 cases [the age of patients ranged from 8 to 56 years (mean, 23.2 years; median, 21 years)]. Primary ovarian tumor tissue was analyzed in 22 patients, and 1 case of metastatic tumor to a lymph node was reviewed. Nuclear suspensions were prepared from paraffinembedded tissue blocks by the technique of Hedley and associates [9]. Three 40-pm-thick sections were cut with a standard tissue microtome, deparaffinized with HistoClear (National Diagnostics, Inc., Sommerville, NJ), and rehydrated with progressively decreasing ethanol concen-
’ To whom reprint requests should be addressed at Section of Gynecologic Surgery, Mayo Clinic, 200 First St. SW, Rochester, MN 55905. 13
0G90-8258192$1.50 Copyright 0 1992 by Academic Press, Inc. All rights of reproduction in any form reserved.
14
PALMQUIST
TABLE 1 Stage at Diagnosisand Outcome
At diagnosis
Outcome
Dead
Alive Stage IA IC IIB III IV Total
Disease present
No evidence of disease
Dead
No.
%
No.
%
No.
%
No.
%
9 3 1 7 3
39 13 4 30 13
8 3 1 5 1
35 13 4 22 4
1 0 0 2 0
4 0 0 9 0
0 0 0 0
0 0 0 0
2
9
‘78
3
13
2
9
23
99
18
trations. The tissue was subsequently treated with pepsin (P 7012, Sigma Chemical Co., St. Louis, MO) and centrifuged at 2800 rpm for 10 min to obtain a nuclear pellet. The isolated nuclei were stained with propidium iodide according to the method of Vindelov and associates [lo]. Nuclear suspensions were sequentially treated with trypsin (T 9253, Sigma) and ribonuclease A (R 4875, Sigma) and stained with propidium iodide (P 5264, Sigma). After filtration to eliminate nuclear clumps, the samples were analyzed within 30 min of propidium iodide staining. Nuclear DNA content was measured on a FACS IV flow cytometer (Becton-Dickinson, Sunnyvale, CA) equipped with a 5-W argon ion laser run at a wavelength of 514 nm. Every group of specimens was standardized with Fullbrite Fluorospheres (Coulter Electronics, Inc., Hialeah, FL) set to channel 35 of the FACS IV machine, to control day-to-day channel variations. Histograms of 20,000 nuclei for each specimen were recorded at a maximum scanning flow rate of 1000 nuclei per second. Cell cycle of the DNA histogram derived from flow cytometry was evaluated with a computer program for Dean and Jett mathematical analysis [ 111. To quantitate the number of nuclei normally found in the nontumor 4C (G2) peak, 12 different specimens of normal human ovarian stroma were studied. Nuclei extracted from these 12 formalin-fixed, paraffin-embedded samples gave a mean (&SD) of 4.80 + 2.66% of nuclei in the 4C peak. From these normal tissue control data, 13% of nuclei in the 4C peak (3 SD above the mean) was selected as the upper limit of normal. Tumor DNA histograms displaying fewer than 13% nuclei in the 4C peak were designated as DNA diploid; those with 13% or more were categorized as DNA tetraploid. The tumor DNA content was classified as DNA aneuploid if a third separate peak that was different from the standard 2C and 4C peaks was present. By convention,
ET AL.
the term “aneuploidy” is used to designate an abnormal multiple of the haploid set of chromosomes [12]. A DNA index was calculated as the ratio of the peak channel (corresponding to DNA amount) of the abnormal DNA stem line of cells to the peak channel of the normal DNA cells. By definition, the DNA index of normal DNA diploid cells is 1.0. The Fullbrite Fluorosphere doublet peak appeared at channel 76, and the ratio of doublet to singlet peaks was 2.17 on the FACS IV instrument used. All tissue blocks were analyzed and DNA histograms were classified as DNA diploid, DNA tetraploid, or DNA aneuploid without knowledge of patient clinical outcome. The data are presented in the conventional “diploid” and “nondiploid” groups as previously reported [ 1,5], with tetraploid and aneuploid groups combined. In our study, the FIG0 ovarian tumor classification was used to determine stage of disease at diagnosis (Table 1). Tumor size was the largest linear dimension recorded at the time of the operation. RESULTS Ovarian Involvement
Twelve patients had involvement of the right ovary only, seven patients had involvement of the left ovary only, and three patients had bilateral involvement (location of the primary tumor was not documented in one patient who had widespread metastatic disease at presentation and did not undergo laparotomy). In only 1 of the bilateral cases was tissue available from both tumors, and the 2 tumors were analyzed separately. Therefore, our data include 24 tumors from 23 patients. Peritoneal cytologic studies, obtained for 8 patients, were positive for 2 and negative for 6. Neither of the 2 patients with positive cytologic studies had had relapse of disease at the time of follow-up and both were alive with no evidence of disease. One of these patients had a tetraploid tumor; the other had bilateral tumors, of which one was diploid and one was tetraploid. Ploidy
The DNA ploidy patterns of the tumors were diploid in 5 (21%), tetraploid in 16 (67%), and aneuploid in 3 patients (12%). DNA ploidy did not appear to be related to stage (Table 2). Treatment
The treatments are summarized in Table 3. None of the patients received additional chemotherapy alone. Tumor Size
The largest linear tumor dimension was recorded for all but three of the tumors. It ranged from 7 to 25 cm
DNA PLOIDY
OF OVARIAN
DYSGERMINOMAS
TABLE 2 Distribution of DNA Ploidy by DiseaseStage Diploid
15
TABLE 4 Distribution of DNA Ploidy by Tumor Size
Nondiploid
by DNA ploidy (no.)
No.
%
No.
%
I II III IV
2 0 2 1
8 0 8 4
11 1 5 2
45 4 21 8
13 1 7 3
O-10 11-20 >20 Not recorded
0 3 1 1
1 10 3 2
1 2 0 0
Total
5
21
19
79
24
Total
5
16
3
Stage
Tumor size (cm)
Distribution
Total No.
Diploid
Tetraploid
Aneuploid
a One patient with stage I disease had bilateral tumors, one diploid, and one nondiploid.
(mean, 15.2 cm; median, 15 cm). The tumor DNA content did not appear to be related to the size of the tumor at the time of diagnosis (Table 4). Outcome
Of the five patients with diploid tumors, one presented with stage IV disease with documented metastasis to the neck. This patient underwent biopsy of the neck mass and palliative radiotherapy only, without abdominal laparotomy or debulking of abdominal tumor mass, and subsequently died of her disease. The four other patients with diploid tumors had no relapse of their disease and were alive with no evidence of disease at follow-up (Table 5). Of the 16 patients with tetraploid tumors, 7 (44%) experienced at least one recurrence; 12 (75%) patients are alive with no evidence of disease, 3 (19%) are dead with no clinical evidence of disease at the time of death, and 1 (6%) died from the tumor. All 3 patients with
TABLE 3 Treatment Regimens Treatment”
No.
%
10 10 2 1
43 43 9 4
aneuploid tumors were alive with no evidence of disease at the time of follow-up. Of the eight patients who had tumor recurrence, one (12%) had a DNA diploid tumor and seven (88%) had tetraploid tumors. The recurrence rate was 20% for DNA diploid tumors and 37% for nondiploid tumors (Table 5). The one patient with a DNA diploid tumor and recurrence died from dysgerminoma; this was the patient with stage IV disease treated by palliative radiotherapy. Six (86%) of the seven patients with DNA tetraploid tumors that recurred were either alive with no evidence of disease at the time of follow-up or dead with no evidence of disease; only one (14%) patient with a tetraploid tumor that recurred died of her disease. Of the eight patients who had recurrence of their disease, the five who presented at stage III or lower had a good outcome. They received additional therapy and were either alive at follow-up with no evidence of disease or dead with no evidence of disease, indicating 100% salvage of these patients with recurrences. All of these patients had DNA tetraploid tumors. Of the three patients with stage IV disease that recurred, one with tetraploid tumor was alive with no evidence of disease and two died of their disease, one with a DNA tetraploid tumor and one with a DNA diploid tumor.
Surgical us0 TAH-BSO Biopsy only BSO
TABLE 5 Outcomeby Tumor DNA Ploidy Progression Total
Additional XRT only None XRT and chemotherapy Chemotherapy only
14 6 3 0
” Abbreviations: BSO, bilateral salpingo-oophorectomy; TAH-BSO, total abdominal hysterectomy with bilateral salpingo-oophorectomy; USO, unilateral salpingo-oophorectomy; XRT, radiotherapy.
61 26 13 0
DNA ploidy
Yes
No
No.
%
No.
%
No.
%
Diploid Nondiploid
5 19
21 79
1 7
20 37
4 12
80 63
Total
24”
8
33
16
67
’ One patient presented with bilateral tumor (one diploid and one nondiploid) and these data were analyzed separately.
16
PALMQUIST
DISCUSSION Even though three (60%) of the five DNA diploid tumors were beyond stage I at presentation, only one (20%) patient experienced recurrence and died of disease, and in this case the treatment given was not adequate by today’s standards. In contrast, a smaller percentage (42%) of the nondiploid tumors were beyond stage I at diagnosis, yet 37% of these nondiploid tumors beyond stage I recurred after initial therapy. However, only one (14%) with recurrence of a nondiploid tumor died of disease. There are a number of reasons for the lack of correlation of outcome with ploidy status. First, our study included only 23 patients. Even in a large institution such as ours, ovarian dysgerminoma is a tumor so rare that even many years of experience have not yielded large numbers of cases. The practice of saving paraffin-embedded blocks of tumor in tissue archives at community hospitals is not common and therefore the tumor tissues of the many cases of ovarian dysgerminoma referred to the Mayo Clinic from other institutions for additional therapy were not available for evaluation. Because our sample size was small, we cannot rule out the possibility that a correlation may exist between DNA ploidy of ovarian dysgerminoma and patient outcome. Study of a larger group of patients will be required to confirm this possibility. Second, statistically significant differences in patient outcome are difficult to demonstrate in a tumor such as dysgerminoma because even patients who have recurrence of disease are still salvageable. It is interesting that the DNA ploidy of ovarian dysgerminoma did not correlate with outcome in our study but the DNA ploidy of testicular seminoma has been found to correlate with outcome (with statistical significance) in another study at this institution [5]. Is it possible that the tumors are not embryologically equivalent as is currently believed.?
ET AL.
REFERENCES 1. Britton, L. C., Wilson, T. O., Gaffey, T.A., Lieber, M. M., Wieand, H. S., and Podratz, K. C. Flow cytometric DNA analysis of Stage I endometrial carcinoma, Gynecol. Oncol. 34, 317-322 (1989). 2. Rainwater, L. M., Hosaka, Y., Farrow, G. M., and Lieber, M. M. Well differentiated clear cell renal carcinoma: significance of nuclear deoxyribonucleic acid patterns studied by flow cytometry, J. Ural. I37, 15-20 (1987). 3. Sledge, G. W., Jr., Eble, J. N., Roth, B. J., Wuhrman, B. P., Fineberg, N., and Einhorn, L. H. Relation of proliferative activity to survival in patients with advanced germ cell cancer, Cancer Res. 48, 3864-3868 (1988). 4. Stephenson, R. A. Flow cytometry in genitourinary malignancies using paraffin-embedded material, Semin. Vrol. 6, 46-52 (1988). 5. Winkler, H. Z., Nativ, O., Hosaka, Y., Reiman, H. M., and Lieber, M. M. Testicular seminoma: Nuclear DNA ploidy studied by flow cytometry, in press. 6. Free], J. H., Cassir, J. F., Pierce, V. K., Woodruff, J., and Lewis, J. L., Jr. Dysgerminoma of the ovary, Cancer 43, 798-805 (1979). 7. Stanhope, C. R., and Smith, J. P. Germ cell tumours, Clin. Obstet. Gynaecol. 10, 357-364 (1983). 8. Buskirk, S. J., Schray, M. F., Podratz, K. C., Lee, R. A., Stanhope, C. R., Gaffey, T. A., Weber, F.C., Earle, J. D., Naessens, J. M., and Malkasian, G. D. Ovarian dysgerminoma: A restrospective analysis of results of treatment, sites of treatment failure, and radiosensitivity, Mayo Clin. Proc. 62, 1149-1157 (1987). 9. Hedley, D. W., Friedlander, M. L., Taylor, I. W., Rugg, CA., and Musgrove, E. A. Method for analysis of cellular DNA content of paraffin-embedded pathological material using flow cytometry, J. Histochem. Cytochem. 31, 1333-1335 (1983). 10. Vindelov, L. L., Christensen, I. J., and Nissen, N. I. A detergenttrypsin method for the preparation of nuclei for flow cytometric DNA analysis, Cytometry 3, 323-327 (1983). 11. Dean, P. N., and Jett, J. H. Mathematical analysis of DNA distributions derived from flow microfluorometry, J. Cc12Biol. 60,523527 (1974). 12. Hiddemann, W., Schumann, J., Andreef, M., Barlogie, B., Herman, C. J., Leif, R. C., Mayall, B. H., Murphy, R. F., and Sandberg, A. A. Convention on nomenclature for DNA cytometry. Committee on Nomenclature, Society for Analvtical Cytology, Cancer Genet. Cytogenet. 13, 181-183 (1984).
ONCOLOGY
4,
13-16 (1992)
DNA Ploidy of Ovarian Dysgerminomas: Correlation with Clinical Outcome MARY B. PALMQUIST,M.D.,* *Section
of Gynecologic
Surgery,
MAURICE
J. WEBB, M.D. ,*,l MICHAEL M. LIEBER, M.D. ,t THOMAS A. GAFFEY, M.D. ,$ AND OFER NATIV, M.D.?
TDepartment
of Urology, and SSection Rochester, Minnesota
of Surgical 55905
Pathology,
Mayo
Clinic
and Mayo
Foundation,
Received August 17, 1990
Abnormal nuclear DNA content, as determinedby flow cytometry, when combinedwith conventional prognostic variables such as tumor grade or stageat diagnosis,appearsto identify patientswho are at increasedrisk for recurrenceof disease.The DNA content of ovarian dysgerminoma,a tumor that is homologousto testicular seminomaand is found in young women of childbearingage,wasstudiedto determineif there is a correlation betweenDNA content and outcome.Such information would be useful in selectingtreatment regimensand making possiblethe preservationof childbearingpotential in womenwho are likely to have a goodoutcome.The specimens from 23 casesof ovarian dysgerminomaseenat our institution between 1950 and 1985 wereanalyzed by DNA flow cytometry. Five of the tumors were diploid (21%) and nineteenwere nondiploid (79%). Patient outcomewasnot predictedany better by nuclearDNA content than by conventionalprognosticvariables. D 1~ &d&c PISS, IX.
The nuclear DNA content of certain human genitourinary neoplasms combined with conventional clinical and hist6pathologic staging appears to identify patients who are at increased risk of disease recurrence [1,2]. In the future, DNA ploidy may be helpful in selecting treatment plans for patients. Significant correlation between DNA ploidy, determined by flow cytometry, of genitourinary tumors and clinical outcome of the patients has been reported [3,4]. In particular, with testicular seminoma there is a significant correlation between DNA ploidy and tumor recurrence, local extension, and patient survival. One study at our institution [5] found that 48% of the tumors were DNA diploid and 52% were DNA nondiploid in a group of 102 patients with testicular seminoma. No patient with DNA diploid testicular seminoma presented with or sub-
sequently had advanced-stage disease, and no DNA diploid testicular seminoma proved fatal. The testicular seminoma was DNA aneuploid in all of the patients who presented with advanced-stage disease, experienced recurrence of the tumor, or died of the disease. Because testicular seminoma and ovarian dysgerminoma are homologous tumors, the results of the seminoma study prompted us to analyze a group of Mayo Clinic patients with ovarian dysgerminoma to determine if nuclear DNA ploidy of tumors correlated with biologic behavior. Ovarian dysgerminomas are very radiosensitive and occur primarily in young women [6,7]. Because radiotherapy may ablate childbearing potential in this group of patients or be teratogenic in the next generation, accurate identification of less-aggrgssive ovarian dysgerminomas could avoid the use of rhdiotherapy and preserve fertility in some women. MATERIALS
AND METHODS
Relevant pathology reports were reviewed and the hematoxylin-and-eosin-stained tissue slides were examined in 35 cases evaluated at the Mayo Clinic between 1950 and 1985 [8]. Archival paraffin-embedded tissue blocks were available from 23 cases [the age of patients ranged from 8 to 56 years (mean, 23.2 years; median, 21 years)]. Primary ovarian tumor tissue was analyzed in 22 patients, and 1 case of metastatic tumor to a lymph node was reviewed. Nuclear suspensions were prepared from paraffinembedded tissue blocks by the technique of Hedley and associates [9]. Three 40-pm-thick sections were cut with a standard tissue microtome, deparaffinized with HistoClear (National Diagnostics, Inc., Sommerville, NJ), and rehydrated with progressively decreasing ethanol concen-
’ To whom reprint requests should be addressed at Section of Gynecologic Surgery, Mayo Clinic, 200 First St. SW, Rochester, MN 55905. 13
0G90-8258192$1.50 Copyright 0 1992 by Academic Press, Inc. All rights of reproduction in any form reserved.
14
PALMQUIST
TABLE 1 Stage at Diagnosisand Outcome
At diagnosis
Outcome
Dead
Alive Stage IA IC IIB III IV Total
Disease present
No evidence of disease
Dead
No.
%
No.
%
No.
%
No.
%
9 3 1 7 3
39 13 4 30 13
8 3 1 5 1
35 13 4 22 4
1 0 0 2 0
4 0 0 9 0
0 0 0 0
0 0 0 0
2
9
‘78
3
13
2
9
23
99
18
trations. The tissue was subsequently treated with pepsin (P 7012, Sigma Chemical Co., St. Louis, MO) and centrifuged at 2800 rpm for 10 min to obtain a nuclear pellet. The isolated nuclei were stained with propidium iodide according to the method of Vindelov and associates [lo]. Nuclear suspensions were sequentially treated with trypsin (T 9253, Sigma) and ribonuclease A (R 4875, Sigma) and stained with propidium iodide (P 5264, Sigma). After filtration to eliminate nuclear clumps, the samples were analyzed within 30 min of propidium iodide staining. Nuclear DNA content was measured on a FACS IV flow cytometer (Becton-Dickinson, Sunnyvale, CA) equipped with a 5-W argon ion laser run at a wavelength of 514 nm. Every group of specimens was standardized with Fullbrite Fluorospheres (Coulter Electronics, Inc., Hialeah, FL) set to channel 35 of the FACS IV machine, to control day-to-day channel variations. Histograms of 20,000 nuclei for each specimen were recorded at a maximum scanning flow rate of 1000 nuclei per second. Cell cycle of the DNA histogram derived from flow cytometry was evaluated with a computer program for Dean and Jett mathematical analysis [ 111. To quantitate the number of nuclei normally found in the nontumor 4C (G2) peak, 12 different specimens of normal human ovarian stroma were studied. Nuclei extracted from these 12 formalin-fixed, paraffin-embedded samples gave a mean (&SD) of 4.80 + 2.66% of nuclei in the 4C peak. From these normal tissue control data, 13% of nuclei in the 4C peak (3 SD above the mean) was selected as the upper limit of normal. Tumor DNA histograms displaying fewer than 13% nuclei in the 4C peak were designated as DNA diploid; those with 13% or more were categorized as DNA tetraploid. The tumor DNA content was classified as DNA aneuploid if a third separate peak that was different from the standard 2C and 4C peaks was present. By convention,
ET AL.
the term “aneuploidy” is used to designate an abnormal multiple of the haploid set of chromosomes [12]. A DNA index was calculated as the ratio of the peak channel (corresponding to DNA amount) of the abnormal DNA stem line of cells to the peak channel of the normal DNA cells. By definition, the DNA index of normal DNA diploid cells is 1.0. The Fullbrite Fluorosphere doublet peak appeared at channel 76, and the ratio of doublet to singlet peaks was 2.17 on the FACS IV instrument used. All tissue blocks were analyzed and DNA histograms were classified as DNA diploid, DNA tetraploid, or DNA aneuploid without knowledge of patient clinical outcome. The data are presented in the conventional “diploid” and “nondiploid” groups as previously reported [ 1,5], with tetraploid and aneuploid groups combined. In our study, the FIG0 ovarian tumor classification was used to determine stage of disease at diagnosis (Table 1). Tumor size was the largest linear dimension recorded at the time of the operation. RESULTS Ovarian Involvement
Twelve patients had involvement of the right ovary only, seven patients had involvement of the left ovary only, and three patients had bilateral involvement (location of the primary tumor was not documented in one patient who had widespread metastatic disease at presentation and did not undergo laparotomy). In only 1 of the bilateral cases was tissue available from both tumors, and the 2 tumors were analyzed separately. Therefore, our data include 24 tumors from 23 patients. Peritoneal cytologic studies, obtained for 8 patients, were positive for 2 and negative for 6. Neither of the 2 patients with positive cytologic studies had had relapse of disease at the time of follow-up and both were alive with no evidence of disease. One of these patients had a tetraploid tumor; the other had bilateral tumors, of which one was diploid and one was tetraploid. Ploidy
The DNA ploidy patterns of the tumors were diploid in 5 (21%), tetraploid in 16 (67%), and aneuploid in 3 patients (12%). DNA ploidy did not appear to be related to stage (Table 2). Treatment
The treatments are summarized in Table 3. None of the patients received additional chemotherapy alone. Tumor Size
The largest linear tumor dimension was recorded for all but three of the tumors. It ranged from 7 to 25 cm
DNA PLOIDY
OF OVARIAN
DYSGERMINOMAS
TABLE 2 Distribution of DNA Ploidy by DiseaseStage Diploid
15
TABLE 4 Distribution of DNA Ploidy by Tumor Size
Nondiploid
by DNA ploidy (no.)
No.
%
No.
%
I II III IV
2 0 2 1
8 0 8 4
11 1 5 2
45 4 21 8
13 1 7 3
O-10 11-20 >20 Not recorded
0 3 1 1
1 10 3 2
1 2 0 0
Total
5
21
19
79
24
Total
5
16
3
Stage
Tumor size (cm)
Distribution
Total No.
Diploid
Tetraploid
Aneuploid
a One patient with stage I disease had bilateral tumors, one diploid, and one nondiploid.
(mean, 15.2 cm; median, 15 cm). The tumor DNA content did not appear to be related to the size of the tumor at the time of diagnosis (Table 4). Outcome
Of the five patients with diploid tumors, one presented with stage IV disease with documented metastasis to the neck. This patient underwent biopsy of the neck mass and palliative radiotherapy only, without abdominal laparotomy or debulking of abdominal tumor mass, and subsequently died of her disease. The four other patients with diploid tumors had no relapse of their disease and were alive with no evidence of disease at follow-up (Table 5). Of the 16 patients with tetraploid tumors, 7 (44%) experienced at least one recurrence; 12 (75%) patients are alive with no evidence of disease, 3 (19%) are dead with no clinical evidence of disease at the time of death, and 1 (6%) died from the tumor. All 3 patients with
TABLE 3 Treatment Regimens Treatment”
No.
%
10 10 2 1
43 43 9 4
aneuploid tumors were alive with no evidence of disease at the time of follow-up. Of the eight patients who had tumor recurrence, one (12%) had a DNA diploid tumor and seven (88%) had tetraploid tumors. The recurrence rate was 20% for DNA diploid tumors and 37% for nondiploid tumors (Table 5). The one patient with a DNA diploid tumor and recurrence died from dysgerminoma; this was the patient with stage IV disease treated by palliative radiotherapy. Six (86%) of the seven patients with DNA tetraploid tumors that recurred were either alive with no evidence of disease at the time of follow-up or dead with no evidence of disease; only one (14%) patient with a tetraploid tumor that recurred died of her disease. Of the eight patients who had recurrence of their disease, the five who presented at stage III or lower had a good outcome. They received additional therapy and were either alive at follow-up with no evidence of disease or dead with no evidence of disease, indicating 100% salvage of these patients with recurrences. All of these patients had DNA tetraploid tumors. Of the three patients with stage IV disease that recurred, one with tetraploid tumor was alive with no evidence of disease and two died of their disease, one with a DNA tetraploid tumor and one with a DNA diploid tumor.
Surgical us0 TAH-BSO Biopsy only BSO
TABLE 5 Outcomeby Tumor DNA Ploidy Progression Total
Additional XRT only None XRT and chemotherapy Chemotherapy only
14 6 3 0
” Abbreviations: BSO, bilateral salpingo-oophorectomy; TAH-BSO, total abdominal hysterectomy with bilateral salpingo-oophorectomy; USO, unilateral salpingo-oophorectomy; XRT, radiotherapy.
61 26 13 0
DNA ploidy
Yes
No
No.
%
No.
%
No.
%
Diploid Nondiploid
5 19
21 79
1 7
20 37
4 12
80 63
Total
24”
8
33
16
67
’ One patient presented with bilateral tumor (one diploid and one nondiploid) and these data were analyzed separately.
16
PALMQUIST
DISCUSSION Even though three (60%) of the five DNA diploid tumors were beyond stage I at presentation, only one (20%) patient experienced recurrence and died of disease, and in this case the treatment given was not adequate by today’s standards. In contrast, a smaller percentage (42%) of the nondiploid tumors were beyond stage I at diagnosis, yet 37% of these nondiploid tumors beyond stage I recurred after initial therapy. However, only one (14%) with recurrence of a nondiploid tumor died of disease. There are a number of reasons for the lack of correlation of outcome with ploidy status. First, our study included only 23 patients. Even in a large institution such as ours, ovarian dysgerminoma is a tumor so rare that even many years of experience have not yielded large numbers of cases. The practice of saving paraffin-embedded blocks of tumor in tissue archives at community hospitals is not common and therefore the tumor tissues of the many cases of ovarian dysgerminoma referred to the Mayo Clinic from other institutions for additional therapy were not available for evaluation. Because our sample size was small, we cannot rule out the possibility that a correlation may exist between DNA ploidy of ovarian dysgerminoma and patient outcome. Study of a larger group of patients will be required to confirm this possibility. Second, statistically significant differences in patient outcome are difficult to demonstrate in a tumor such as dysgerminoma because even patients who have recurrence of disease are still salvageable. It is interesting that the DNA ploidy of ovarian dysgerminoma did not correlate with outcome in our study but the DNA ploidy of testicular seminoma has been found to correlate with outcome (with statistical significance) in another study at this institution [5]. Is it possible that the tumors are not embryologically equivalent as is currently believed.?
ET AL.
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