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Breast Cancer Subtype, Lymph Node Involvement, and Age As Predictors of Isolated Local-Regional Recurrence Following Breast-Conserving Therapy
Volume 96 Number 2S Supplement 2016 Author Disclosure: W.H. Hall: Independent Contractor; Peace health St. Joseph Medical Center. Partner; NWWROA. Board Member; Peace health St. Joseph Foundation Board. C. Kaufman: None. K. Huang: None.
2088 Effect of Breast Volume on Toxicity With Hypofractionation M. Marietta,1 A. Zhara,2 and M.P. Mitchell3; 1University of Kansas, Kansas City, KS, 2Univeristy of Iowa, Iowa City, IA, 3University of Kansas Medical Center, Kansas City, KS Purpose/Objective(s): Hypofractionation remains underutilized, despite long term data from multiple randomized trials showing equivalence of hypofractionation to conventional fractionation for early stage breast cancer. Conventional wisdom was to decrease dose per fraction to reduce skin reaction in patients with larger breasts. In our clinic, we have been offering hypofractionation routinely in early stage breast cancer for the past three years, even for posterior separation >25 cm. We sought to assess skin toxicity among patients receiving hypofractionation in relationship to breast size. Materials/Methods: We performed an IRB approved retrospective review of early stage breast cancer patients treated at our institution between 2012 and 2015. Data was collected on contoured breast volume, whole breast dose, use of boost, beam energy, skin toxicity, cosmesis, and dosimetric variables such as max point dose. Results: Charts were reviewed for 82 patients treated for early stage breast cancer with whole breast radiation, using 3D conformal tangents and fieldin-field optimization. Median follow-up was 7 months. 61 patients were treated with hypofractionation and 21 patients were treated with conventional radiation therapy. In the overall group of patients, the percent of patients with > grade 2 skin toxicity at end of treatment was significantly higher in patients undergoing conventional fractionation, 80.9% versus 27.9% (P Z 0.01). In a subset of patients with large breasts, defined as a contoured breast volume of greater than 1000 cc, the percent of patients with > grade 2 skin toxicity remained significantly higher in patients undergoing conventional fractionation, 88.9% versus 33.3% (P Z 0.01). For conventionally defined large breast size (posterior separation >25), the percent of patients with > grade 2 skin toxicity was 18.2% for hypofractionation versus 75% for conventional treatment. Fatigue, pain, infection rate, and patient reported cosmesis were not significantly different between the two groups. Mean hotspot was similar for hypofractionation as compared to conventional treatment, 106.4 versus 106.6. The volume of breast receiving 105% of prescription dose was slightly higher in patients receiving hypofractionation, mean 59.9 cc versus 36.8 cc. Conclusion: Use of hypofractionation decreases acute skin toxicity as compared to conventional schedules, even in patients with large breasts, and does not increase infection rate or impair cosmesis. Author Disclosure: M. Marietta: None. A. Zhara: None. M.P. Mitchell: None.
2089 Breast Cancer Subtype, Lymph Node Involvement, and Age As Predictors of Isolated Local-Regional Recurrence Following Breast-Conserving Therapy L.Z. Braunstein,1 A.G. Taghian,2 A. Niemierko,2 L.W. Salama,3 A. Capuco,4 J.S. Wong,4 R.S. Punglia,4 J.R. Bellon,4 S. MacDonald,2 and J.R. Harris4; 1Harvard Radiation Oncology Program, Boston, MA, 2 Massachusetts General Hospital, Boston, MA, 3Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, 4Dana-Farber/ Brigham and Women’s Cancer Center, Boston, MA Purpose/Objective(s): Advances in breast-conserving therapy (BCT) have yielded local-regional control rates comparable or superior to those of mastectomy. Here, we sought to identify risk factors associated with isolated local-regional recurrence (iLRR) following BCT. Materials/Methods: This study included a multi-institutional cohort of 2,233 consecutive breast cancer patients who underwent BCT between
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1998 and 2007. Patient characteristics and disease parameters were stratified by age and subtype. Biologic subtype was approximated by receptor status and tumor grade. No patients received HER2/neu-directed therapy. The association of clinical and pathologic parameters with iLRR was evaluated using a Cox proportional hazards regression model. Median follow-up time was 106 months. Results: iLRR was observed in 96 patients (4.3%), of which 69 were local events (i.e. in-breast) while 27 involved the ipsilateral regional lymph nodes. Among the overall cohort, 10-year freedom from iLRR was 94.5%. On univariate Cox regression analysis, risk factors associated with iLRR included subtype other than luminal A (hazard ratio [HR] for luminal B Z 3.07, HER2 Z 6.59, triple negative Z 4.71, P<0.0005), younger age (HR of youngest versus oldest quartile Z 2.02; P Z 0.006), regional lymph node involvement (HR for pN1 disease Z 1.93; pN2 Z 3.25; pN3 Z 4.59; P<0.01 for each), positive resection margins (HR Z 2.07; P Z 0.012), presence of LVI (HR Z 1.96; P Z 0.001), and intermediate- (HR Z 2.27; P Z 0.03) or high-grade disease (HR Z 6.64; P <0.0005). Multivariate Cox regression demonstrated an association with iLRR among those with triple-negative subtype (HR Z 3.96; P<0.0005), younger age (HR Z 0.98 per increasing year; P Z 0.02), nodal disease (HR Z 1.06 per involved node; P<0.0005), and tumors >5cm in size (HR Z 4.91; P Z 0.012). Conclusion: BCT yields favorable outcomes for the large majority of patients, although increased iLRR was observed among those with nonluminal A subtype, younger age, tumors >5cm, and increasing lymph node involvement. Risk factors for iLRR following BCT appear to be converging with those following mastectomy in the current era. Author Disclosure: L.Z. Braunstein: None. A.G. Taghian: None. A. Niemierko: None. L.W. Salama: None. A. Capuco: None. J.S. Wong: None. R.S. Punglia: None. J.R. Bellon: None. S. MacDonald: None. J.R. Harris: None.
2090 The Role of Postmastectomy Radiation Therapy for T1-T3, N1 Breast Cancer: Analysis of the National Cancer Data Base A. Brandmaier,1 X. Wu,2 P. Christos,2 D. Nori,2 S. Formenti,2 and H. Nagar2; 1Weill Cornell Medical College/New York Presbyterian Hospital, New York, NY, 2NewYork-Presbyterian Hospital/Weill Cornell Medicine, New York, NY Purpose/Objective(s): Post-mastectomy radiation therapy (PMRT) has been shown to benefit women with pathologic stage N2 or greater breast cancer and is a category 1 recommendation from the NCCN. The role of PMRT in patients with 1-3 positive lymph nodes is more controversial. Prospective and retrospective data suggest a benefit, including EORTC 22922 and a comprehensive meta-analysis which showed improvement in local recurrence and disease specific survival. The data has limitations with some of the clinical trials preceding modern chemotherapy and the use of endocrine and HER2 directed therapy. The purpose of our study was to investigate national practice patterns of adjuvant radiation therapy (RT) and factors associated with receipt of RT and overall survival (OS) in this patient population. Materials/Methods: Women with breast cancer who underwent upfront mastectomy and had pathologic T1-T3, N1 disease from 2004-2013 were identified in the National Cancer Database (NCDB). Patients were stratified by use of adjuvant RT. Multivariable proportional hazards modelling was used to examine the association of treatment and survival adjusting for demographic, socioeconomic and clinicopathologic factors. Results: A total of 22,398 patients met inclusion criteria with a median follow up of 48 months. Within this cohort, 37% of patients received PMRT. OS was associated with facility location, age, race, insurance status, Charlson-Deyo co-morbidity index, grade, number of regional nodes examined, number of positive nodes, T stage, lymphovascular invasion, receptor subtype, and receipt of endocrine therapy, radiation, and chemotherapy (all P < .05). Receipt of PMRT was associated with year of diagnosis, facility location, age, race, income and education level,
2088 Effect of Breast Volume on Toxicity With Hypofractionation M. Marietta,1 A. Zhara,2 and M.P. Mitchell3; 1University of Kansas, Kansas City, KS, 2Univeristy of Iowa, Iowa City, IA, 3University of Kansas Medical Center, Kansas City, KS Purpose/Objective(s): Hypofractionation remains underutilized, despite long term data from multiple randomized trials showing equivalence of hypofractionation to conventional fractionation for early stage breast cancer. Conventional wisdom was to decrease dose per fraction to reduce skin reaction in patients with larger breasts. In our clinic, we have been offering hypofractionation routinely in early stage breast cancer for the past three years, even for posterior separation >25 cm. We sought to assess skin toxicity among patients receiving hypofractionation in relationship to breast size. Materials/Methods: We performed an IRB approved retrospective review of early stage breast cancer patients treated at our institution between 2012 and 2015. Data was collected on contoured breast volume, whole breast dose, use of boost, beam energy, skin toxicity, cosmesis, and dosimetric variables such as max point dose. Results: Charts were reviewed for 82 patients treated for early stage breast cancer with whole breast radiation, using 3D conformal tangents and fieldin-field optimization. Median follow-up was 7 months. 61 patients were treated with hypofractionation and 21 patients were treated with conventional radiation therapy. In the overall group of patients, the percent of patients with > grade 2 skin toxicity at end of treatment was significantly higher in patients undergoing conventional fractionation, 80.9% versus 27.9% (P Z 0.01). In a subset of patients with large breasts, defined as a contoured breast volume of greater than 1000 cc, the percent of patients with > grade 2 skin toxicity remained significantly higher in patients undergoing conventional fractionation, 88.9% versus 33.3% (P Z 0.01). For conventionally defined large breast size (posterior separation >25), the percent of patients with > grade 2 skin toxicity was 18.2% for hypofractionation versus 75% for conventional treatment. Fatigue, pain, infection rate, and patient reported cosmesis were not significantly different between the two groups. Mean hotspot was similar for hypofractionation as compared to conventional treatment, 106.4 versus 106.6. The volume of breast receiving 105% of prescription dose was slightly higher in patients receiving hypofractionation, mean 59.9 cc versus 36.8 cc. Conclusion: Use of hypofractionation decreases acute skin toxicity as compared to conventional schedules, even in patients with large breasts, and does not increase infection rate or impair cosmesis. Author Disclosure: M. Marietta: None. A. Zhara: None. M.P. Mitchell: None.
2089 Breast Cancer Subtype, Lymph Node Involvement, and Age As Predictors of Isolated Local-Regional Recurrence Following Breast-Conserving Therapy L.Z. Braunstein,1 A.G. Taghian,2 A. Niemierko,2 L.W. Salama,3 A. Capuco,4 J.S. Wong,4 R.S. Punglia,4 J.R. Bellon,4 S. MacDonald,2 and J.R. Harris4; 1Harvard Radiation Oncology Program, Boston, MA, 2 Massachusetts General Hospital, Boston, MA, 3Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, 4Dana-Farber/ Brigham and Women’s Cancer Center, Boston, MA Purpose/Objective(s): Advances in breast-conserving therapy (BCT) have yielded local-regional control rates comparable or superior to those of mastectomy. Here, we sought to identify risk factors associated with isolated local-regional recurrence (iLRR) following BCT. Materials/Methods: This study included a multi-institutional cohort of 2,233 consecutive breast cancer patients who underwent BCT between
Poster Viewing
E37
1998 and 2007. Patient characteristics and disease parameters were stratified by age and subtype. Biologic subtype was approximated by receptor status and tumor grade. No patients received HER2/neu-directed therapy. The association of clinical and pathologic parameters with iLRR was evaluated using a Cox proportional hazards regression model. Median follow-up time was 106 months. Results: iLRR was observed in 96 patients (4.3%), of which 69 were local events (i.e. in-breast) while 27 involved the ipsilateral regional lymph nodes. Among the overall cohort, 10-year freedom from iLRR was 94.5%. On univariate Cox regression analysis, risk factors associated with iLRR included subtype other than luminal A (hazard ratio [HR] for luminal B Z 3.07, HER2 Z 6.59, triple negative Z 4.71, P<0.0005), younger age (HR of youngest versus oldest quartile Z 2.02; P Z 0.006), regional lymph node involvement (HR for pN1 disease Z 1.93; pN2 Z 3.25; pN3 Z 4.59; P<0.01 for each), positive resection margins (HR Z 2.07; P Z 0.012), presence of LVI (HR Z 1.96; P Z 0.001), and intermediate- (HR Z 2.27; P Z 0.03) or high-grade disease (HR Z 6.64; P <0.0005). Multivariate Cox regression demonstrated an association with iLRR among those with triple-negative subtype (HR Z 3.96; P<0.0005), younger age (HR Z 0.98 per increasing year; P Z 0.02), nodal disease (HR Z 1.06 per involved node; P<0.0005), and tumors >5cm in size (HR Z 4.91; P Z 0.012). Conclusion: BCT yields favorable outcomes for the large majority of patients, although increased iLRR was observed among those with nonluminal A subtype, younger age, tumors >5cm, and increasing lymph node involvement. Risk factors for iLRR following BCT appear to be converging with those following mastectomy in the current era. Author Disclosure: L.Z. Braunstein: None. A.G. Taghian: None. A. Niemierko: None. L.W. Salama: None. A. Capuco: None. J.S. Wong: None. R.S. Punglia: None. J.R. Bellon: None. S. MacDonald: None. J.R. Harris: None.
2090 The Role of Postmastectomy Radiation Therapy for T1-T3, N1 Breast Cancer: Analysis of the National Cancer Data Base A. Brandmaier,1 X. Wu,2 P. Christos,2 D. Nori,2 S. Formenti,2 and H. Nagar2; 1Weill Cornell Medical College/New York Presbyterian Hospital, New York, NY, 2NewYork-Presbyterian Hospital/Weill Cornell Medicine, New York, NY Purpose/Objective(s): Post-mastectomy radiation therapy (PMRT) has been shown to benefit women with pathologic stage N2 or greater breast cancer and is a category 1 recommendation from the NCCN. The role of PMRT in patients with 1-3 positive lymph nodes is more controversial. Prospective and retrospective data suggest a benefit, including EORTC 22922 and a comprehensive meta-analysis which showed improvement in local recurrence and disease specific survival. The data has limitations with some of the clinical trials preceding modern chemotherapy and the use of endocrine and HER2 directed therapy. The purpose of our study was to investigate national practice patterns of adjuvant radiation therapy (RT) and factors associated with receipt of RT and overall survival (OS) in this patient population. Materials/Methods: Women with breast cancer who underwent upfront mastectomy and had pathologic T1-T3, N1 disease from 2004-2013 were identified in the National Cancer Database (NCDB). Patients were stratified by use of adjuvant RT. Multivariable proportional hazards modelling was used to examine the association of treatment and survival adjusting for demographic, socioeconomic and clinicopathologic factors. Results: A total of 22,398 patients met inclusion criteria with a median follow up of 48 months. Within this cohort, 37% of patients received PMRT. OS was associated with facility location, age, race, insurance status, Charlson-Deyo co-morbidity index, grade, number of regional nodes examined, number of positive nodes, T stage, lymphovascular invasion, receptor subtype, and receipt of endocrine therapy, radiation, and chemotherapy (all P < .05). Receipt of PMRT was associated with year of diagnosis, facility location, age, race, income and education level,