Frequency of bilateral prophylactic and contra-lateral risk-reducing mastectomies in women with germline PALB2 variants.

Germline PALB2 variants confer a moderate/high-risk for breast cancer (BC). Recent reports described an increasing attention in suggesting bilateral prophylactic mastectomy (BPM), for healthy carriers, or contraleral risk-reducing mastectomy (CRRM) and/or therapeutic mastectomy for women with BC. In this study, we aimed to calculate systematically the overall number of these procedures reported in literature. We revised all articles using systematic research through the PUBMED database. Overall numbers, frequencies, geographic distribution, family history, and post-operative histopathological analysis of BPM or CRRM were the main outcomes considered. Among 51 studies, 10 articles fulfilled our aim. All BPM or CRRM were performed in North America. One-hundred and forty-two (6.6%) were PALB2 positive, from 2,135 tested women; a total of 84 women were treated, 35 (41.7%) were healthy carriers and 49 (58.3%) received a CRRM for a previous or contextual diagnosis of BC, respectively. A positive family history was reported in 80% of these groups, and a post-operative tumor was identified in 2.6% of breast specimens. In conclusion, very few studies are reported, only in North America, but about of 2/3 (~ 60%) of the screened women received BPM or CRRM, with a high familial history for BC and a low detection rate of tumor in breast post-operative specimens.