Evaluation of the efficacy of chemotherapy for tubular carcinoma of the breast: A Surveillance, Epidemiology, and End Results cohort study

BACKGROUND: The use of systematic treatment for tubular carcinoma (TC) of the breast remained controversial. This study aimed to explore the efficacy of chemotherapy on TC to develop individualized treatment strategies. METHODS: Using the Surveillance, Epidemiology, and End Results (SEER) database, 6486 eligible cases with TC and 309,304 with invasive ductal carcinoma (IDC) were collected. Breast cancer‐specific survival (BCSS) was assessed through multivariable Cox analyses and Kaplan–Meier analyses. Differences between groups were balanced using propensity score matching (PSM) and inverse probability of treatment weighting (IPTW). RESULTS: Compared with IDC patients, TC patients had a more favorable long‐term BCSS after PSM (hazard ratio = 0.62, p = 0.004) and IPTW (hazard ratio = 0.61, p < 0.001). Chemotherapy was an unfavorable predictor of BCSS for TC (hazard ratio = 3.20, p < 0.001). After stratifying by hormone receptor (HR) and lymph node (LN) status, chemotherapy was correlated with worse BCSS in the HR+/LN− subgroup (hazard ratio = 6.95, p = 0.001) but showed no impact on BCSS in the HR+/LN+ (hazard ratio = 0.75, p = 0.780) and HR−/LN− (hazard ratio = 7.87, p = 0.150) subgroups. CONCLUSIONS: Tubular carcinoma is a low‐grade malignant tumor with favorable clinicopathological features and excellent long‐term survival. Adjuvant chemotherapy was not recommended for TC regardless of HR and LN status, while the therapy regimens should be carefully individualized.