He MT, Lu XX, Gou ZC, et al. - In patients with T3N0M0 breast cancers, the therapeutic effect of postmastectomy radiotherapy (PMRT) was found to be associated with age. Improved survival is conferred by PMRT in older patients with T3N0M0 breast cancer, particularly those older than 65 years.

• Participants were 4,840 T3N0M0 patients selected from the Surveillance, Epidemiology, and End Results database.

• Overall survival (OS) did not differ significantly between with and without PMRT in young patients (aged 18–45 and 46–55).

• PMRT’s benefit is limited in T3N0M0 patients of young age.

• A lower hazard ratio (HR) for OS was observed among older patients with PMRT vs those without PMRT, in the multivariate Cox analysis (aged 56–65: HR = 0.67, P = 0.014; aged >65: HR = 0.60, P < 0.001).

• Results indicate the importance of age for T3N0M0 cases when individualized treatment is made.