Omission of adjuvant radiotherapy in low-risk elderly males with breast cancer

Purpose Randomized clinical trials demonstrate that lumpectomy + hormone therapy (HT) without radiation therapy (RT) yields equivalent survival and acceptable local–regional outcomes in elderly women with early-stage, node-negative, hormone-receptor positive (HR +) breast cancer.

Whether these data apply to men with the same inclusion criteria remains unknown.

Methods The National Cancer Database was queried for male patients ≥ 65 years with pathologic T1-2N0 (≤ 3 cm) HR + breast cancer treated with breast-conserving surgery with negative margins from 2004 to 2019.

Adjuvant treatment was classified as HT alone, RT alone, or HT + RT.

Male patients were matched with female patients for OS comparison.

Survival analysis was performed using Cox regression and Kaplan − Meier method.

Inverse probability of treatment weighting (IPTW) was applied to adjust for confounding.

Results A total of 523 patients met the inclusion criteria, with 24.4% receiving HT, 16.3% receiving RT, and 59.2% receiving HT + RT.

The median follow-up was 6.9 years (IQR: 5.0–9.4 years).

IPTW-adjusted 5-yr OS rates in the HT, RT, and HT + RT cohorts were 84.0% (95% CI 77.1–91.5%), 81.1% (95% CI 71.1–92.5%), and 93.0% (95% CI 90.0–96.2%), respectively.

On IPTW-adjusted MVA, relative to HT, receipt of HT + RT was associated with improvements in OS (HR: 0.641; p  = 0.042).

RT alone was not associated with improved OS (HR: 1.264; p  = 0.420).

Conclusion Among men ≥ 65 years old with T1-2N0 HR + breast cancer, RT alone did not confer an OS benefit over HT alone.

Combination of RT + HT demonstrated significant improvements in OS.

De-escalation of treatment through omission of either RT or HT at this point should be done with caution.