The different outcomes between breast-conserving surgery and mastectomy in triple-negative breast cancer: a population-based study from the SEER 18 database

Breast-conserving surgery (BCS) including radiotherapy (RT) has been demonstrated to provide at least equivalent prognosis to mastectomy in early-stage breast cancer. However, studies on triple-negative breast cancer (TNBC) patients are relatively scarce. The current population-based study aimed to investigate the distinct outcomes between BCS+RT and mastectomy in patients with TNBC. Utilizing the Surveillance, Epidemiology, and End Results (SEER) database, we enrolled 11,514 female TNBC cases diagnosed during the years 2010-2013. Those patients were subdivided into BCS+RT (5,469) and mastectomy groups (6,045), and we conducted a survival comparison between the two groups. The endpoints were breast cancer-specific survival (BCSS) and overall survival (OS). In the overall cohort, patients with BCS+RT exhibited distinctly better breast cancer-specific survival (BCSS) (log-rank, p < 0.001) and overall survival (OS) (log-rank, p < 0.001) than did mastectomy patients. When stratifying the TNBC patients according to age, histology grade, TNM stage, tumor size, and lymph node (LN) status, most patients in the BCS+RT group presented with better survival than did the patients in the mastectomy group, except for the grade I (log-rank, p = 0.830, both BCSS and OS) and stage I (log-rank, BCSS, p = 0.127; OS, p = 0.093) patients. In addition, after adjusting for confounding variables by multivariable Cox proportional hazard analysis, BCS+RT still tended to present with higher BCSS and OS. In conclusion, from our study on SEER data, BCS+RT displayed elevated BCSS and OS in TNBC patients compared to mastectomy, at least equally. Our study provided further evidence for surgeons that BCS with RT is available for TNBC patients.