Contralateral prophylactic mastectomy improves the outcome of selected patients undergoing mastectomy for breast cancer

BACKGROUND: Risk factors for contralateral breast cancer (CBC) may indicate a benefit for contralateral prophylactic mastectomy (CPM) at the time of u nilateral mastectomy for breast cancer. The purpose of this study is to eva luate the efficacy of CPM in preventing CBC. METHODS: sixty-four patients undergoing CPM and a control group of 182 pati ents not undergoing CPM and matched for age, stage, surgery, chemotherapy, and hormonal therapy were retrospectively compared for CBC rate, disease-fr ee survival, and overall survival. RESULTS: Thirty-six CBCs Occurred in the control group. In the CPM group, 3 CBCs were found at the time of prophylactic mastectomy, but none occurred subsequently (P = 0.005). Disease-free survival at 15 years in the CPM grou p was 55% (95% confidence interval [CI] 38% to 69%) versus 28% (95% CI 19% to 36%) in the control group (P = 0.01). Overall survival at 15 years was 6 4% (95% CI 45% to 78%) CPM versus 48% (95% Ct 39% to 58%) in controls (P = 0.26). CONCLUSIONS: CPM prevented CBC and significantly prolonged disease-free sur vival. Future studies will need to address risk assessment and contralatera l breast cancer prevention in patients treated for early breast cancer. (C) 2001 by Excerpta Medica, Inc.