Breast-Conserving Surgery is Oncologically Safe for Well-Selected, Centrally Located Breast Cancer

Objective The aim of this study was to evaluate the long-term survival outcomes of breast-conserving surgery (BCS) in centrally located breast cancer (CLBC) compared with mastectomy in CLBC and BCS in non-CLBC, based on the Surveillance, Epidemiology, and End Results (SEER) database. Methods Female patients aged < 80 years with unilateral T1-T2 invasive ductal or lobular breast cancer undergoing BCS or mastectomy were enrolled. The differences in clinical-pathological characteristics were evaluated using Chi square tests. Multivariate logistic regression was used to measure the relationship between predictive variables and performing BCS in CLBC. Survival outcomes were estimated using the Kaplan-Meier method and compared using Cox proportional hazards models. To overcome the effects of baseline differences on survival outcome in patients treated with BCS in the central and upper-outer locations, a 1:1 ratio propensity score matching method was performed. Results Overall, among 16,522 CLBC patients, 7982 cases (48.3%) underwent BCS between 1998 and 2015. Factors such as older age, Black race, invasive ductal carcinoma (IDC), grade I, small tumor size, none or limited lymph node metastasis, positive progesterone receptor status, and receiving chemotherapy were independently correlated with BCS. BCS was an independent favorable prognostic factor among CLBC patients, based on multivariate Cox analysis. It was also shown that CLBC had similar survival outcomes compared with tumors in the upper-outer quadrant, and had a better breast cancer-specific survival compared with tumors in the lower quadrants, based on multivariate Cox analysis. Conclusions BCS should be an acceptable and preferable alternative to mastectomy for well-selected, early-stage T1 or T2 CLBC.