Objective:The present study examined the effect of radiotherapy on recurrence and survival in elderly patients with hormone receptor-positive early breast cancer.Methods:A retrospective analysis of 327 patients aged ≥65 years,with stage Ⅰ-Ⅱ,hormone receptor-positive breast cancer who underwent breast-conserving surgery and received endocrine therapy (ET) or radiotherapy plus endocrine therapy (ET+RT) was performed.Both groups were divided into luminal A type and luminal B type subgroups.Evaluation criteria were 5-year disease-free survival (DFS),local relapse rate (LRR),overall survival (OS),and distant metastasis rate (DMR).Results:There were significant differences in 5-year DFS [hazard ratio (HR)=1.59,95％ confidence interval (95％ CI),1.15-2.19;P=0.005] and LRR (HR=3.33,95％ CI,1.51-7.34;P=0.003),whereas there were no significant differences in OS and DMR between ET group and ET+RT group.In luminal A type,there was no significant difference in 5-year DFS,LRR,OS and DMR between ET group and ET+RT group.In luminal B type,there were statistically significant differences in 5-year DFS (HR=2.19,95％ CI,1.37-3.49;P=0.001),LRR (HR=5.45,95％ CI,1.65-17.98;P=0.005),and OS (HR=1.75,95％ CI,1.01-3.05;P=0.048) between ET group and ET+RT group.In the ET group,there were significant differences between luminal A type and luminal B type in 5-year DFS (HR=1.84,95％ CI,1.23-2.75;P=0.003) and OS (HR=1.76,95％ CI,1.07-2.91;P=0.026).Conclusions:After breast-conserving surgery,radiotherapy can reduce the LRR and improve the DFS and OS of luminal B type elderly patients,whereas luminal A type elderly patients do not benefit from radiotherapy.Without radiotherapy,luminal A type patients have better DFS and OS than luminal B type patients.