Objective: Postmastectomy radiation therapy (PMRT) remains controversial for patients with pathologic stage T3N0 (pT3N0) breast cancer. A Surveillance, Epidemiology, and End Results (SEER) database analysis suggested that PMRT might benefit patients older than age 50. However, the relevance between estrogen receptor (ER), progesterone receptor (PR), race, and PMRT in patients younger than age 50 is unknown.
Methods: The impact of PMRT treatment on cause-specific survival (CSS) and overall survival (OS) were analyzed for women in the SEER database from 1998 to 2007. Approximately half (47%) of the 1104 patients who met the study requirements received PMRT. We performed univariate analysis to compare CSS between the PMRT and no-PMRT groups for all patients and further stratified by age, race, tumor size, tumor grade, and ER/PR status.
Results: No difference in CSS or OS was detected between women treated with or without PMRT. Black/other race, ER-, and PR-, all suggested a trend toward decreased CSS. In univariate analysis, PMRT seems to be beneficial in patients younger than age 40 (hazard ratio=0.65; P=0.25; a nonsignificant trend in favor of PMRT).
Conclusions: This SEER database analysis of patients younger than age 50 and with pT3N0 breast cancer showed that PMRT did not significantly affect CSS at 5 years; however, it implied a trend of benefit for patients younger than 40. The findings that patients with African heritage and negative ER/PR status showing decreased CSS warrant further investigation to determine the role of personalized PMRT in these high-risk cohorts.