3875 - Correlation of radiotherapy with the prognosis of elderly patients with hormone receptor-positive breast cancer according to immunohistochemical subtyping

Background

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 (HR 1.59, 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 the two groups. In luminal A type, there was no significant difference in 5-year DFS, LRR, OS, and DMR between the ET group and the ET+RT group. In luminal B type, there were statistically significant differences in 5-year DFS (HR 2.188, 95% CI 1.37–3.49, P = 0.001), LRR (HR 5.447, 95% CI 1.65–17.98, P = 0.005), and OS (HR 1.752, 95% CI 1.01–3.054, P = 0.048) between the two groups. In the ET group, there were significant differences between luminal A type and luminal B type in 5-year DFS (HR 1.841, 95% CI 1.23–2.75, P = 0.003) and OS (HR 1.763, 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.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The author.

Funding

National Natural Science Foundation of China (81672623).

Disclosure

The author has declared no conflicts of interest.