The omission of radiotherapy (RT) does not affect overall survival at 10 years after breast conserving surgery (BCS) for older women with hormone receptor-positive breast cancer, according to a study that examined the impact of locoregional RT after BCS on long-term outcomes in older patients receiving appropriate systemic therapy. A total of 1,326 patients aged 65 and older with axillary node-negative, hormone receptor-positive breast cancer were randomly assigned to either receive or not receive (658 and 668, respectively) whole breast RT and followed for a median of 7.3 years. At 10 years, ipsilateral breast tumor recurrence rates were 9.8% and 0.9% in the no RT and RT arms, respectively, with a hazard ratio of 0.12 for those receiving RT. Regional recurrence differed significantly (2.3% vs 0.5% with no RT and with RT, respectively), but no differences were seen in contralateral breast cancer or distant metastases. Breast cancer-free survival rates were 12.7% and 6.6% for the no RT and RT arms, respectively. At 10-years, overall survival rates were 80.4% and 81.0% without and with RT, respectively.
