Radiotherapy omission after breast-conserving surgery is associated with reduced breast cancer–specific survival in elderly women with breast cancer

Purpose To evaluate the effect of radiotherapy (RT) omission on survival in older breast cancer patients treated with breast-conserving surgery. Methods Data were analyzed for 4836 women aged 50 to 89 with T1-T2, N0-N1, M0 breast cancer. Tumor and treatment factors, relapse rates, and overall survival (OS) and breast cancer-specific survival (BCSS) were compared between women treated with and without RT in 3 age categories: 50 to 64 (n = 2398), 65 to 74 (n = 1665), and ≥75 years (n = 773). Results Median follow-up was 7.5 years. Rates of RT omission significantly increased with advancing age (7%, 9%, and 26% in age 50–64, 65–74, and ≥75 years respectively, P< .0001). RT omission was associated with significantly reduced local control, BCSS, and OS. Despite similar tumor characteristics and higher rates of systemic therapy use, women aged ≥75 years were observed to have lower 5-year OS and BCSS when RT was omitted. Conclusion These findings support the hypothesis that inadequate local therapy is associated with reduced survival in elderly women treated with breast-conserving therapy.