A Cochrane review [Abstract] 1 included 61 observational studies with a total of 15 077 subjects with a wide range of risk factors for breast cancer who underwent prophylactic mastectomy (PM). No randomized trials were found. Bilateral prophylactic mastectomy (BPM) studies on the incidence of breast cancer and/or disease-specific mortality reported reductions after BPM particularly for those with BRCA1/2 mutations (21 studies). For contralateral prophylactic mastectomy (CPM), studies consistently reported reductions in incidence of contralateral breast cancer but were inconsistent about improvements in disease-specific survival (26 studies). Seven studies attempted to control for multiple differences between intervention groups and this study showed no overall survival advantage for CPM at 15 years. 20 studies assessed psychosocial measures; most reported high levels of satisfaction with the decision to have PM but more variable satisfaction with cosmetic results. Worry over breast cancer was significantly reduced after BPM when compared both to baseline worry levels and to the groups who opted for surveillance rather than BPM. Case series reporting on adverse events from PM with or without reconstruction reported rates of unanticipated re-operations from 4% in those without reconstruction to 64% in patients with reconstruction.
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