National trends in contralateral prophylactic mastectomy in women with locally advanced breast cancer.

BACKGROUND AND OBJECTIVES: Women with unilateral early-stage breast cancer are increasingly choosing contralateral prophylactic mastectomy (CPM) despite the absence of survival benefits and increased risk of surgical complications. Data are lacking on whether this trend extends to women with clinically locally advanced nonmetastatic (cT4M0) cancer. This study aims to estimate national CPM trends in women with unilateral cT4M0 breast cancer. METHODS: Women aged ≥ 18 years, who underwent mastectomy during 2004 to 2014 for unilateral cT4M0 breast cancer were identified using the National Cancer Database and grouped as all locally advanced (T4), chest wall invasion, skin nodule/ulceration, or both (T4abc), and inflammatory (T4d) cancer. Poisson regression for trends and logistic modeling for predictors of CPM were performed. RESULTS: Of 23 943 women, 41% had T4abc disease and 35% T4d. Cumulative CPM rates were 15%, 23%, and 18%, for the T4abc, T4d, and all T4 groups, respectively. Trend analysis revealed a significant upsurge in CPM demonstrating 12% annual growth for T4abc tumors, 8% for T4d and 9% for all T4 (all P \u3c 0.001). CONCLUSIONS: Increasing numbers of women with unilateral cT4M0 breast cancer are undergoing CPM. This rising trend warrants further research to understand stakeholders\u27 preferences in surgical decision-making for women with locally advanced breast cancer