Correlation of radiotherapy with prognosis of elderly patients with hormone receptor-positive breast cancer according to immunohistochemical subtyping.

objectiveThe present study examined the effect of radiotherapy on recurrence and survival in elderly patients with hormone receptor-positive early breast cancer.

methodsA 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).

resultsThere 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).

conclusionsAfter 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.