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 > or = 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 > or = 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 > or = 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.