Adjuvant Radiotherapy Not Associated with Improved Long-Term Survival in Elderly Male Breast Cancer Patients

Strategic Insights -

A study published in Scientific Reports has found that adjuvant radiotherapy (RT) does not improve long-term survival in elderly male breast cancer patients treated with breast-conserving surgery (BCS). The research, conducted using the Surveillance, Epidemiology, and End Results (SEER) database, included 360 patients with early-stage, low-risk breast cancer (node-negative, hormone receptor-positive) who underwent BCS between 2000 and 2021. The study aimed to evaluate the survival impact of adjuvant RT in this patient population and identify subgroups that may benefit from RT.

Key Takeaways:

  • The study found that adjuvant RT did not demonstrate a significant survival advantage over no RT (NRT) in elderly male breast cancer patients treated with BCS.
  • After propensity score matching (PSM), 15-year overall survival, relative survival, and standardized mortality ratio were 31.8%, 15.2%, and 2.14 for RT versus 34.1%, 21.5%, and 2.25 for NRT (p = 0.36, 0.68, and 0.81, respectively).
  • Machine learning models, including Cox, gradient boosting machine (GBM), and extreme gradient boosting (XGBoost), confirmed the limited contribution of RT to survival prediction, with the Cox model demonstrating the best discrimination (C-index = 0.713).
  • Causal forest analysis revealed notable heterogeneity in treatment effects across subgroups, with younger patients, those diagnosed earlier, or with stage I disease showing relatively higher estimated benefit from RT.
  • The study suggests that RT may be safely omitted in selected individuals, but this decision should be made cautiously in the absence of recurrence data.

Statistics:

  • 360 patients were included in the study following propensity score matching (PSM).
  • 15-year overall survival: 31.8% for RT versus 34.1% for NRT (p = 0.36).
  • 15-year relative survival: 15.2% for RT versus 21.5% for NRT (p = 0.68).
  • 15-year standardized mortality ratio: 2.14 for RT versus 2.25 for NRT (p = 0.81).
  • Cox model showed a C-index of 0.713, indicating good discrimination.

Sources:

  • Survival impact of adjuvant radiotherapy in early stage low risk elderly male breast cancer patients treated with breast conserving surgery. Scientific Reports, 2025,15(1):1-12.
  • Cancer Weekly. September 9, 2025; p 1094.