Streamlining decision making in contralateral risk-reducing mastectomy: impact of PREDICT and BOADICEA computations

Introduction. Patients with sporadic breast cancer (BC) have low contralateral breast cancer risk (CLBCR; approximately 0.7% per annum) and contralateral pro- phylactic mastectomy (CPM) offers no survival advantage. CPM with autologous reconstruction (AR) has major morbidity and resource implications. Objective. The aim of this study was to review the impact of PREDICT survival estimates and lifetime CLBCR scores on decision making for CPM in patients with uni- lateral BC. Methods. Of n = 272 consecutive patients undergoing mastectomy and AR, 252 were included. Five- and 10-year survival was computed with the PREDICT(V2) online prognostication tool, using age and clinicopathological factors. Based on family history (FH) and tumor biology, CLBCR was calculated using validated BODICEA web- based software. Survival scores were correlated against CLBCR estimates to identify patients receiving CPM with ‘low’ CLBCR ( \ 30% lifetime risk) and poor prognosis (5- year survival \ 80%). Patients with ‘high’ CLBCR receiving unilateral mastectomy (UM) were similarly identified (UK National Institute of Health and Care Excellence [NICE] criteria for CPM, C 30% lifetime BC risk). Justifications motivating CPM were investigated. Results. Of 252 patients, 215 had UM and 37 had bilateral mastectomy and AR. Only 23 (62%) patients receiving CPM fulfilled the NICE criteria. Of 215 patients, 5 (2.3%) failed to undergo CPM despite high CLBCR and good prognosis. CPMs were performed, at the patient’s request, for no clear justification ( n = 8), contralateral non-invasive disease, and/or FH ( n = 5), FH alone ( n = 4) and ipsilateral cancer recurrence-related anxiety ( n = 3). Conclusion. In the absence of prospective risk estimates of CLBCR and prognosis, certain patients receive CPM and reconstruction despite modest CLBCR, yet a propor- tion of patients with good prognoses and substantial risk are not undergoing CP