Prognostic comparison between breast-conserving surgery combined with radiotherapy and total mastectomy in patients with triple-negative invasive lobular carcinoma: a SEER database-based study

Objective To investigate the prognosis of patients with triple-negative invasive lobular carcinoma (TN-ILC) undergoing breast-conserving surgery combined with radiotherapy (BCS+RT) versus total mastectomy. Methods A retrospective analysis was performed for 2 386 female patients with TN-ILC who underwent surgery in the SEER database from 2006 to 2018, and the baseline characteristics (age, histological grade, AJCC stage, etc.) were balanced by propensity score matching (PSM, 1∶1, caliper value 0.02), and breast cancer-specific survival (BCSS) and overall survival (OS) were compared by Kaplan-Meier method and COX regression analysis. Results A total of 1 056 pairs of patients were obtained after PSM, and the BCS+RT group had significantly better BCSS and OS than the total mastectomy group (both P<0.001). Stratified analyses showed that BCS+RT had a survival advantage in all subgroups except histologic grade Ⅰ and tumor stage Ⅰ. Multivariate analysis confirmed that BCS+RT was an independent protective factor (BCSS: HR=0.682, OS: HR=0.607, both P<0.001). Conclusions BCS+RT significantly improves survival compared with total mastectomy in patients with TN-ILC, supporting BCS+RT as the preferred treatment strategy for eligible patients.