This study aimed to investigate the role of post-mastectomy radiotherapy (PMRT) in the female aged 70 years or older diagnosed with breast cancer, which is still controversial.

This retrospective study enrolled female breast cancer women aged 70 + years following mastectomy from the Surveillance, Epidemiology, and End Results (SEER) database.

Propensity score matching (PSM) was performed to reduce covariable imbalance. A nomogram was created to predict the 1,3,5-years overall survival (OS) and divide patients into three risk groups.