Abstract 2574: Outcomes of contralateral prophylactic mastectomy in relation to familial history: a decision analysis

Abstract

Abstract Purpose Family history of breast cancer is associated with an increased risk of contralateral breast cancer (CBC) even in the absence of mutations in the breast cancer susceptibility genes BRCA1/2. We compared quality-adjusted survival outcomes after contralateral prophylactic mastectomy (CPM) with surveillance only (no CPM) among women with breast cancer in relation to degree of family history. Methods We created a microsimulation model for women with a first-degree, second-degree and no family history treated for a stage I, II, or III estrogen receptor (ER)-positive or -negative breast cancer at the ages of 40, 50, 60, and 70 years. The model incorporated a 10-year post-treatment period for risk of developing CBC and/or dying of the primary cancer or CBC. For each patient profile, we used 100,000 microsimulation trials to estimate the quality-adjusted life expectancy for two clinical strategies: CPM and no CPM. Results CPM had a minimal improvement on quality-adjusted life expectancy among women age 50 to 60 with no or a unilateral first or second-degree family history (range -.06 to 0.31) and was unfavorable for the majority of women age 70 with stage III breast cancer regardless of degree of family history (range -.08 to -.02). Sensitivity analysis showed the highest predicted benefit of CPM with 95% risk reduction was 0.57 QALY for a 40-year-old woman with stage I breast cancer who had a first-degree relative with bilateral breast cancer. Conclusion Women age 40 years with stage I breast cancer and a first-degree relative with bilateral breast cancer have a QALY benefit from CPM similar to that reported for BRCA1/2 mutation carriers. For the majority of women, having a family history does not improve the minimal effect of CPM on quality-adjusted life expectancy. Citation Format: Kalatu R. Davies, Abenaa Brewster, Isabelle Bedrosian, Patricia Parker, Melissa A. Crosby, Susan K. Peterson, Yu Shen, Robert Volk, Scott B. Cantor. Outcomes of contralateral prophylactic mastectomy in relation to familial history: a decision analysis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2574.