Clinical application of genetic testing on operative procedures for hereditary breast ovarian cancer (HBOC) - An identical twins case

Abstract

　Hereditary breast and ovarian cancer (HBOC) caused by germline pathogenic variant in BRCA 1/2 gene is gaining considerable attention in recent years. Since BRCA1/2 pathogenic variant carriers are at extremely high-risk of developing breast and ovarian cancer, risk-reducing salpingo-oophorectomy (RRSO) and risk-reducing mastectomy (RRM) are recommended.

　In this report, we experienced an extremely rare case of familial breast cancer in an identical female twin pair. First one of twins developed breast cancer, followed by another of twins. The second case was suspected to be HBOC and was confirmed to be BRCA1 pathogenic variant positive, so that total mastectomy and contralateral RRM were indicated and performed.

　BRCA gene testing would be useful to determine the operative methods in case of suspected HBOC. We concluded that HBOC patients should be provided with sufficient information in advance, including the risk of developing breast and ovary cancer and the benefit of risk-reducing surgical procedures.