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Risk factors for regional nodal failure after breast conserving therapy: regional nodal irradiation reduces the rate of axillary failure in patients with four or more positive nodes
90
I. J. Radiation Oncology
● Biology ● Physics
Volume 54, Number 2, Supplement, 2002
Materials/Methods: The study population included a total of 5758 patients enrolled in the NSABP B-15, B16, B-18, B-22 and B-25 trials. From the B-18 study, only patients (pts) who had positive lymph nodes (LN⫹) and received postoperative adjuvant chemotherapy were included. Median follow-up without recurrence was 9.5 years (range: 0.04-15.8 years). The distribution of pathologic tumor size was as follows: ⬍⫽ 2cm, 2.1–5cm and ⬎ 5cm in 30%, 52% and 11%, respectively (7% had unknown tumor size). The median number of LN removed was 16. Distribution of number of LN⫹ was 1-3, 4-9 and 10⫹ in 51%, 32, and 16%, respectively. The distribution of the number of LN dissected was 1-5 (108 pts), 6-9 (579 pts), ⬎10 (4849 pts) in 1.9%, 10.1%, and 84.2%, respectively (3.8% had unknown). Patients were treated either by doxorubicin-based chemotherapy (B-15, B-16, B-18, B-22 and B-25: 5199 patients), or CMF (B-15: 559 patients). Results: The 10-year overall crude rate of locoregional failure as first event was 14.3% (821/5758). The majority of recurrences occurred on the chest wall / mastectomy scar (56.7%). Axillary and supraclavicular recurrences represented 11.8% and 22.4% of all loco-regional recurrences, respectively. In the group of patients who had only 1-5 LN dissected, the 10-year cumulative incidence of axillary recurrence was 9.3% compared to 2.2% and 1.5% for the group of patients who had 6-9 and ⬎10 LN removed, respectively (p⬍0.0001). However, the supraclavicular recurrence rate remained similar for the three groups (0.9%, 2.6% and 3.4%, respectively, p⫽0.25). In patients who had 1-3 LN⫹, the rate of axillary recurrence was 8.9%, 1.1% and 0.5% in patients with 1-5, 6 -9 and ⬎10 LN dissected, respectively. In patients with 4-9 LN⫹, the corresponding risk of axillary recurrence was 11.8%, 3.9% and 2.1%, respectively. Furthermore, in the group of patients who had ⬎ 10 positive LN, or ⬎50% of the removed LN found to be positive, the rate of axillary lymph node recurrence remained relatively low (2.6%) as far as the number of LN dissected was 10 or more. The statistical analysis showed that the risk of axillary failure increased significantly with the number of positive lymph nodes (p⬍0.0001), smaller number of LN dissected (p⬍0.0001) or increase proportion of LN⫹ (p⬍0.0001). However, regarding the rate of supraclavicular recurrence, only the number of LN⫹ and the proportion of LN⫹ were found to be significantly predictive for recurrence. Conclusions: For patients with positive axillary LN’s and only 1-5 LN dissected, the risk of axillary failure was significantly higher (9.3%) compared to the axillary risk in patients who had 6-9 or ⬎10 LNs removed (2.2% and 1.5%, respectively). The number of axillary LN removed did not predict the risk for supraclavicular recurrence (p⫽0.25). The proportion of positive LN’s was a significant predictor of axillary, supraclavicular and loco-regional failures.
# of LN dissected
Crude rate of axillary recurrence (# of events / # of pts)
10-year Cumulative incidence of axillary failure (SE)
Crude rate of s/c recurrence (# of events / # of pts)
10-year Cumulative incidence of s/c failure (SE)
1–5 6–9 ⬎ 10
10 / 108 12 / 579 69 / 4849
9.3% (2.8) 2.2% (0.6) 1.5% (0.2) P⬍0.0001
1 / 108 14 / 579 160 / 4849
0.9% (0.9) 2.6% (0.7) 3.4% (0.3) P⫽0.25
151
Risk Factors for Regional Nodal Failure After Breast Conserving Therapy: Regional Nodal Irradiation Reduces the Rate of Axillary Failure in Patients with Four or More Positive Nodes
I.S. Grills, L. Kestin, C. Mitchell, A. Martinez, F. Vicini Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI Purpose/Objective: To determine the incidence of and risk factors for regional nodal failure (RNF), as well as to evaluate the effectiveness of and indications for regional nodal irradiation (RNI) in patients with Stage I and II breast cancer treated with breast-conserving therapy (BCT). Materials/Methods: A total of 1500 cases of stage I/II breast cancer were treated with BCT at William Beaumont Hospital between 2/80 and 12/00. Eleven percent of patients were less than age 40 and 33% were less than age 50. A complete pathologic review was performed in 40% of the patients. All patients underwent excisional biopsy and 925(62%) were re-excised. A level I/II axillary lymph node dissection was done in 93% of patients. Less than 6 lymph nodes were excised in 59 (4%) patients, 6-10 nodes in 343 (25%), and ⬎10 nodes in 982 (70%). Lymph nodes were pathologically involved in 331 patients (22%); 248 with 1 to 3 nodes and 80 with ⱖ4 nodes involved. All patients received whole breast irradiation to a median dose of 45Gy and 97% received a tumor bed boost to a median dose of 61Gy. Treatment included the breast only in 1309 patients (87%) and the breast/regional lymphatics in 191 (13%). RNI films were available for review in 102 patients, 69% of whom received full axillary irradiation and 31% of whom received irradiation to the supraclavicular/level III lymph nodes. Results: With a median follow-up of 8.1 years, 35 patients failed within the regional nodes. Twelve patients who received RNI and 23 patients who did not developed a RNF. The median time to failure was 3.1 years. The 5 and 10 year rates for any RNF were 1.9% and 2.8%, respectively. The 5 and 10 year rates of axillary failure (AF) or supraclavicular failure (SCF) were 0.6% and 1.0%, and 0.9% and 1.6%, respectively. In patients with ⱖ4 positive lymph nodes, RNI reduced the 10 year rate of any RNF from 11% to 2% (p⫽0.024) and the rate of AF from 5% to 0% (p⫽0.019). RNI reduced the rate of SCF, although not statistically significant, from 11% to 2%. RNI did not affect the rate of AF or SCF in patients with 1-3 positive nodes. Patients receiving RNI in this group were significantly more likely to have ⬍6 or ⬍10 lymph nodes excised, a higher percent positive nodes, extracapsular extension, or a nodal metastasis ⬎1 to 2 cm. In node negative patients, the rate of RNF was significantly higher if ⬍6 nodes were dissected. Multiple clinical, pathological, and treatment-related factors were analyzed for association with RNF. On univariate analysis, RNF was associated with the number of nodes excised, the number of positive nodes, the percent of positive nodes, the presence of extracapsular extension, the size of the nodal metastasis, the presence of angiolymphatic invasion, ER status, age, systemic chemotherapy, and RNI. Three subsets of patients, those with ⱖ 67% nodes positive, a nodal metastasis ⱖ2.0cm, or age ’35 years, had an unusually high rate of RNF, approximately 15%. On multivariate analysis, only age (p⫽0.001), the number of nodes excised (p⫽0.04), the number of positive nodes (p⫽0.06), and the presence of angiolymphatic invasion (p⫽0.03) were significant predictors for RNF. RNI did not improve overall survival for any subset of patients but was associated with poorer survival outcomes, likely a reflection of the high-risk characteristics of those treated.
Proceedings of the 44th Annual ASTRO Meeting
Overall survival was impacted by the number of lymph nodes excised, with 10 year survival rates being 33%, 65% and 69% in patients with ⬍6, 6-10, ⬎10 nodes excised, respectively (p⫽0.05). Conclusions: Failure within the regional lymph nodes as an isolated site of first relapse is uncommon in patients with stage I/II breast cancer treated with BCT. RNI can significantly reduce the rate of RNF (AF) in patients with ⱖ4 positive lymph nodes. Young age, inadequate axillary lymph node dissection, the number of positive nodes, and angiolymphatic invasion independently predict for a higher rate of RNF and should be considered when evaluating patients for regional nodal treatment. Excision of ⬍6 lymph nodes may reduce overall survival.
152
History of Prior Pregnancy Confers Better Prognosis in Older Women with Early Stage Breast Cancer Treated with Breast Conservation Therapy
P.R. Anderson, A.L. Hanlon, G. Freedman, N. Nicolaou Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA Purpose/Objective: To compare the pretreatment characteristics and outcome of women with Stage I/II breast cancer treated with conservative surgery and radiation who have a history of prior pregnancy (HPP) with those women who have never had a history of prior pregnancy (NPP). Materials/Methods: From 1979 to 1996, 1358 women with Stage I/II breast cancer underwent lumpectomy, axillary dissection and radiation therapy with or without systemic therapy. The median age was 56 years (range 22-88). 1162 patients (86%) had a history of prior pregnancy (HPP) and 196 patients (14%) had never been pregnant (NPP). The median follow-up was 87 months. The two groups were compared for clinical factors of age, tumor size, menopausal status, method of detection, family history; pathologic factors of histology, extensive intraductal component, lymphatic invasion, final margins, nodal status, receptor status; and treatment-related factors of re-excision, regions treated and adjuvant therapy. Multivariate analysis utilizing Cox regression was used to determine independent predictors of outcome. Outcome was also evaluated for patterns of failure (local, regional and distant), cause-specific survival (CSS) and overall survival (OS). Results: Statistically significant differences between the two groups were observed for age ⬎60 (NPP 34% vs HPP 40%, p⫽0.0002) and median age (NPP 52 yrs vs HPP 57 yrs, p⫽0.0032). There were no significant differences in the 10 yr rates of local or regional failure between the two groups. The 10 yr rate of distant metastases was 18% for women with NPP and 13% for women with HPP (p⫽0.09). Cox multivariate regression models (MVA) demonstrated that NPP was an independent predictor of distant metastases, CSS and OS after adjusting for age. For pts ⬎60 yrs, those with NPP were more likely to present with larger, T2 tumors compared to those with a HPP (38% versus 22%, p⫽0.0035). In pts ⬎60 yrs, 7% of pts with NPP and 10% of pts with HPP received chemotherapy, and 45% with NPP and 43% with HPP received Tamoxifen. In pts ⬎60 yrs, the 10 yr actuarial rate of overall DM was 22% for women who were never pregnant and 10% for women with a history of prior pregnancy (p⫽0.0047). In pts ⬎60 yrs, a statistically significant difference in the 10 yr CSS rates was observed, with a 76% CSS for those women with no prior pregnancy vs 92% CSS for women with a history of prior pregnancy (p⫽0.0017). A statistically significant difference was also observed in the 10 yr OS rates in pts ⬎60 yrs, with a 50% OS for women with no prior pregnancy vs a 76% OS for women with a history of prior pregnancy (p⫽0.0128). MVA for pts ⬎60 yrs demonstrated prior pregnancy status, chemotherapy and physical examination as sole method of detection as independent predictors of outcome. The Cox multivariate regression model for distant metastases (DM), cause-specific survival (CSS) and overall survival (OS) for pts ⬎60 yrs demonstrated that a history of prior pregnancy (HPP) was the most highly significant independent predictor of decreased DM (p⫽0.0010), improved CSS (p⫽0.0015) and improved OS (p⫽0.0110). Conclusions: Women ⬎60 yrs who have never been pregnant experience significantly higher rates of overall distant metastases compared to women ⬎60 yrs with a history of prior pregnancy. In addition, these women ⬎60 yrs and no prior pregnancy experience a statistically worse cause-specific survival and overall survival. These findings support a more aggressive initial treatment approach and adjuvant systemic therapy should be strongly considered in these women ⬎60 yrs with no prior history of pregnancy who have early stage breast cancer.
153
Patterns and Predictors of Locoregional Recurrence in 469 Patients Treated with Post-Mastecomy Radiation
W.A. Woodward, A. Katz, T. Buchholz, M. McNeese, G. Perkins, A. Jhingran, E. Strom Department of Radiation Oncology, MD Anderson Cancer Center, Houston, TX Purpose/Objective: The objective of this study was to examine the LRR (local-regional recurrence) patterns of breast cancer patients treated with post-mastectomy radiation, and to compare them to LRR patterns of breast cancer patients who did not receive radiation following mastectomy. Materials/Methods: 1800 patients were treated with mastectomy followed by doxorubicin-based chemotherapy on 5 prospective clinical trials. The cohort for this study consists of the 469 patients who received postoperative radiation by physician preference. Their results were compared to those of the 1,031 patients who did not receive postoperative radiation, which have been previously reported. Rates of isolated and total LRR (with or without distant metastasis) were calculated using Kaplan-Meier analysis. Median follow-up time for all patients was 10 years. Results: Post mastectomy radiation reduced isolated LRR rates for patients in all nodal categories (4%, 10%, 21%, 22% without radiation vs. 0%, 1.5%, 2.4%, 6.1% with radiation, respectively for patients with 0, 1-3, 4-9, or ⬎10 involved nodes). LRR for patients with involvement of 20% or more lymph nodes was reduced from 27% in patients who did not receive radiation to 11% in those treated with radiation. For patients with fewer than 20% involved nodes this reduction was from 12% to 4.2%. LRR for patients with close or positive margins was decreased from 45% in patients treated without radiation to 13.3% in those who received postoperative treatment (p⫽0.01). The chest wall and supraclavicular fossa remained the most common sites of LRR following radiation. Chest wall recurrences were reduced from 68% to
91
I. J. Radiation Oncology
● Biology ● Physics
Volume 54, Number 2, Supplement, 2002
Materials/Methods: The study population included a total of 5758 patients enrolled in the NSABP B-15, B16, B-18, B-22 and B-25 trials. From the B-18 study, only patients (pts) who had positive lymph nodes (LN⫹) and received postoperative adjuvant chemotherapy were included. Median follow-up without recurrence was 9.5 years (range: 0.04-15.8 years). The distribution of pathologic tumor size was as follows: ⬍⫽ 2cm, 2.1–5cm and ⬎ 5cm in 30%, 52% and 11%, respectively (7% had unknown tumor size). The median number of LN removed was 16. Distribution of number of LN⫹ was 1-3, 4-9 and 10⫹ in 51%, 32, and 16%, respectively. The distribution of the number of LN dissected was 1-5 (108 pts), 6-9 (579 pts), ⬎10 (4849 pts) in 1.9%, 10.1%, and 84.2%, respectively (3.8% had unknown). Patients were treated either by doxorubicin-based chemotherapy (B-15, B-16, B-18, B-22 and B-25: 5199 patients), or CMF (B-15: 559 patients). Results: The 10-year overall crude rate of locoregional failure as first event was 14.3% (821/5758). The majority of recurrences occurred on the chest wall / mastectomy scar (56.7%). Axillary and supraclavicular recurrences represented 11.8% and 22.4% of all loco-regional recurrences, respectively. In the group of patients who had only 1-5 LN dissected, the 10-year cumulative incidence of axillary recurrence was 9.3% compared to 2.2% and 1.5% for the group of patients who had 6-9 and ⬎10 LN removed, respectively (p⬍0.0001). However, the supraclavicular recurrence rate remained similar for the three groups (0.9%, 2.6% and 3.4%, respectively, p⫽0.25). In patients who had 1-3 LN⫹, the rate of axillary recurrence was 8.9%, 1.1% and 0.5% in patients with 1-5, 6 -9 and ⬎10 LN dissected, respectively. In patients with 4-9 LN⫹, the corresponding risk of axillary recurrence was 11.8%, 3.9% and 2.1%, respectively. Furthermore, in the group of patients who had ⬎ 10 positive LN, or ⬎50% of the removed LN found to be positive, the rate of axillary lymph node recurrence remained relatively low (2.6%) as far as the number of LN dissected was 10 or more. The statistical analysis showed that the risk of axillary failure increased significantly with the number of positive lymph nodes (p⬍0.0001), smaller number of LN dissected (p⬍0.0001) or increase proportion of LN⫹ (p⬍0.0001). However, regarding the rate of supraclavicular recurrence, only the number of LN⫹ and the proportion of LN⫹ were found to be significantly predictive for recurrence. Conclusions: For patients with positive axillary LN’s and only 1-5 LN dissected, the risk of axillary failure was significantly higher (9.3%) compared to the axillary risk in patients who had 6-9 or ⬎10 LNs removed (2.2% and 1.5%, respectively). The number of axillary LN removed did not predict the risk for supraclavicular recurrence (p⫽0.25). The proportion of positive LN’s was a significant predictor of axillary, supraclavicular and loco-regional failures.
# of LN dissected
Crude rate of axillary recurrence (# of events / # of pts)
10-year Cumulative incidence of axillary failure (SE)
Crude rate of s/c recurrence (# of events / # of pts)
10-year Cumulative incidence of s/c failure (SE)
1–5 6–9 ⬎ 10
10 / 108 12 / 579 69 / 4849
9.3% (2.8) 2.2% (0.6) 1.5% (0.2) P⬍0.0001
1 / 108 14 / 579 160 / 4849
0.9% (0.9) 2.6% (0.7) 3.4% (0.3) P⫽0.25
151
Risk Factors for Regional Nodal Failure After Breast Conserving Therapy: Regional Nodal Irradiation Reduces the Rate of Axillary Failure in Patients with Four or More Positive Nodes
I.S. Grills, L. Kestin, C. Mitchell, A. Martinez, F. Vicini Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI Purpose/Objective: To determine the incidence of and risk factors for regional nodal failure (RNF), as well as to evaluate the effectiveness of and indications for regional nodal irradiation (RNI) in patients with Stage I and II breast cancer treated with breast-conserving therapy (BCT). Materials/Methods: A total of 1500 cases of stage I/II breast cancer were treated with BCT at William Beaumont Hospital between 2/80 and 12/00. Eleven percent of patients were less than age 40 and 33% were less than age 50. A complete pathologic review was performed in 40% of the patients. All patients underwent excisional biopsy and 925(62%) were re-excised. A level I/II axillary lymph node dissection was done in 93% of patients. Less than 6 lymph nodes were excised in 59 (4%) patients, 6-10 nodes in 343 (25%), and ⬎10 nodes in 982 (70%). Lymph nodes were pathologically involved in 331 patients (22%); 248 with 1 to 3 nodes and 80 with ⱖ4 nodes involved. All patients received whole breast irradiation to a median dose of 45Gy and 97% received a tumor bed boost to a median dose of 61Gy. Treatment included the breast only in 1309 patients (87%) and the breast/regional lymphatics in 191 (13%). RNI films were available for review in 102 patients, 69% of whom received full axillary irradiation and 31% of whom received irradiation to the supraclavicular/level III lymph nodes. Results: With a median follow-up of 8.1 years, 35 patients failed within the regional nodes. Twelve patients who received RNI and 23 patients who did not developed a RNF. The median time to failure was 3.1 years. The 5 and 10 year rates for any RNF were 1.9% and 2.8%, respectively. The 5 and 10 year rates of axillary failure (AF) or supraclavicular failure (SCF) were 0.6% and 1.0%, and 0.9% and 1.6%, respectively. In patients with ⱖ4 positive lymph nodes, RNI reduced the 10 year rate of any RNF from 11% to 2% (p⫽0.024) and the rate of AF from 5% to 0% (p⫽0.019). RNI reduced the rate of SCF, although not statistically significant, from 11% to 2%. RNI did not affect the rate of AF or SCF in patients with 1-3 positive nodes. Patients receiving RNI in this group were significantly more likely to have ⬍6 or ⬍10 lymph nodes excised, a higher percent positive nodes, extracapsular extension, or a nodal metastasis ⬎1 to 2 cm. In node negative patients, the rate of RNF was significantly higher if ⬍6 nodes were dissected. Multiple clinical, pathological, and treatment-related factors were analyzed for association with RNF. On univariate analysis, RNF was associated with the number of nodes excised, the number of positive nodes, the percent of positive nodes, the presence of extracapsular extension, the size of the nodal metastasis, the presence of angiolymphatic invasion, ER status, age, systemic chemotherapy, and RNI. Three subsets of patients, those with ⱖ 67% nodes positive, a nodal metastasis ⱖ2.0cm, or age ’35 years, had an unusually high rate of RNF, approximately 15%. On multivariate analysis, only age (p⫽0.001), the number of nodes excised (p⫽0.04), the number of positive nodes (p⫽0.06), and the presence of angiolymphatic invasion (p⫽0.03) were significant predictors for RNF. RNI did not improve overall survival for any subset of patients but was associated with poorer survival outcomes, likely a reflection of the high-risk characteristics of those treated.
Proceedings of the 44th Annual ASTRO Meeting
Overall survival was impacted by the number of lymph nodes excised, with 10 year survival rates being 33%, 65% and 69% in patients with ⬍6, 6-10, ⬎10 nodes excised, respectively (p⫽0.05). Conclusions: Failure within the regional lymph nodes as an isolated site of first relapse is uncommon in patients with stage I/II breast cancer treated with BCT. RNI can significantly reduce the rate of RNF (AF) in patients with ⱖ4 positive lymph nodes. Young age, inadequate axillary lymph node dissection, the number of positive nodes, and angiolymphatic invasion independently predict for a higher rate of RNF and should be considered when evaluating patients for regional nodal treatment. Excision of ⬍6 lymph nodes may reduce overall survival.
152
History of Prior Pregnancy Confers Better Prognosis in Older Women with Early Stage Breast Cancer Treated with Breast Conservation Therapy
P.R. Anderson, A.L. Hanlon, G. Freedman, N. Nicolaou Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA Purpose/Objective: To compare the pretreatment characteristics and outcome of women with Stage I/II breast cancer treated with conservative surgery and radiation who have a history of prior pregnancy (HPP) with those women who have never had a history of prior pregnancy (NPP). Materials/Methods: From 1979 to 1996, 1358 women with Stage I/II breast cancer underwent lumpectomy, axillary dissection and radiation therapy with or without systemic therapy. The median age was 56 years (range 22-88). 1162 patients (86%) had a history of prior pregnancy (HPP) and 196 patients (14%) had never been pregnant (NPP). The median follow-up was 87 months. The two groups were compared for clinical factors of age, tumor size, menopausal status, method of detection, family history; pathologic factors of histology, extensive intraductal component, lymphatic invasion, final margins, nodal status, receptor status; and treatment-related factors of re-excision, regions treated and adjuvant therapy. Multivariate analysis utilizing Cox regression was used to determine independent predictors of outcome. Outcome was also evaluated for patterns of failure (local, regional and distant), cause-specific survival (CSS) and overall survival (OS). Results: Statistically significant differences between the two groups were observed for age ⬎60 (NPP 34% vs HPP 40%, p⫽0.0002) and median age (NPP 52 yrs vs HPP 57 yrs, p⫽0.0032). There were no significant differences in the 10 yr rates of local or regional failure between the two groups. The 10 yr rate of distant metastases was 18% for women with NPP and 13% for women with HPP (p⫽0.09). Cox multivariate regression models (MVA) demonstrated that NPP was an independent predictor of distant metastases, CSS and OS after adjusting for age. For pts ⬎60 yrs, those with NPP were more likely to present with larger, T2 tumors compared to those with a HPP (38% versus 22%, p⫽0.0035). In pts ⬎60 yrs, 7% of pts with NPP and 10% of pts with HPP received chemotherapy, and 45% with NPP and 43% with HPP received Tamoxifen. In pts ⬎60 yrs, the 10 yr actuarial rate of overall DM was 22% for women who were never pregnant and 10% for women with a history of prior pregnancy (p⫽0.0047). In pts ⬎60 yrs, a statistically significant difference in the 10 yr CSS rates was observed, with a 76% CSS for those women with no prior pregnancy vs 92% CSS for women with a history of prior pregnancy (p⫽0.0017). A statistically significant difference was also observed in the 10 yr OS rates in pts ⬎60 yrs, with a 50% OS for women with no prior pregnancy vs a 76% OS for women with a history of prior pregnancy (p⫽0.0128). MVA for pts ⬎60 yrs demonstrated prior pregnancy status, chemotherapy and physical examination as sole method of detection as independent predictors of outcome. The Cox multivariate regression model for distant metastases (DM), cause-specific survival (CSS) and overall survival (OS) for pts ⬎60 yrs demonstrated that a history of prior pregnancy (HPP) was the most highly significant independent predictor of decreased DM (p⫽0.0010), improved CSS (p⫽0.0015) and improved OS (p⫽0.0110). Conclusions: Women ⬎60 yrs who have never been pregnant experience significantly higher rates of overall distant metastases compared to women ⬎60 yrs with a history of prior pregnancy. In addition, these women ⬎60 yrs and no prior pregnancy experience a statistically worse cause-specific survival and overall survival. These findings support a more aggressive initial treatment approach and adjuvant systemic therapy should be strongly considered in these women ⬎60 yrs with no prior history of pregnancy who have early stage breast cancer.
153
Patterns and Predictors of Locoregional Recurrence in 469 Patients Treated with Post-Mastecomy Radiation
W.A. Woodward, A. Katz, T. Buchholz, M. McNeese, G. Perkins, A. Jhingran, E. Strom Department of Radiation Oncology, MD Anderson Cancer Center, Houston, TX Purpose/Objective: The objective of this study was to examine the LRR (local-regional recurrence) patterns of breast cancer patients treated with post-mastectomy radiation, and to compare them to LRR patterns of breast cancer patients who did not receive radiation following mastectomy. Materials/Methods: 1800 patients were treated with mastectomy followed by doxorubicin-based chemotherapy on 5 prospective clinical trials. The cohort for this study consists of the 469 patients who received postoperative radiation by physician preference. Their results were compared to those of the 1,031 patients who did not receive postoperative radiation, which have been previously reported. Rates of isolated and total LRR (with or without distant metastasis) were calculated using Kaplan-Meier analysis. Median follow-up time for all patients was 10 years. Results: Post mastectomy radiation reduced isolated LRR rates for patients in all nodal categories (4%, 10%, 21%, 22% without radiation vs. 0%, 1.5%, 2.4%, 6.1% with radiation, respectively for patients with 0, 1-3, 4-9, or ⬎10 involved nodes). LRR for patients with involvement of 20% or more lymph nodes was reduced from 27% in patients who did not receive radiation to 11% in those treated with radiation. For patients with fewer than 20% involved nodes this reduction was from 12% to 4.2%. LRR for patients with close or positive margins was decreased from 45% in patients treated without radiation to 13.3% in those who received postoperative treatment (p⫽0.01). The chest wall and supraclavicular fossa remained the most common sites of LRR following radiation. Chest wall recurrences were reduced from 68% to
91