Trends and timing of risk-reducing mastectomy uptake in unaffected BRCA1 and BRCA2 carriers in Slovenia

Objectives. Risk-reducing mastectomy (RRM) is one of key prevention strategies in female carriers of germline BRCA pathogenic/likely pathogenic variants (PV/LPV). We retrospectively investigated the rate, timing and longitudinal trends of bilateral RRM uptake and the incidence and types of cancers among unaffected BRCA carriers who underwent genetic counseling at the Institute of Oncology Ljubljana in Slovenia. Materials and Methods. Female BRCA carriers without personal history of cancer were included in the study. Clinical data on PV/LPV type, date of RRM, type of reconstructive procedure, occult carcinoma and histopathology results was collected and analyzed. Results. Of the 346 unaffected BRCA carriers (median age 43 years, 70% BRCA1, 30% BRCA2, median follow-up 46 months) who underwent genetic testing between October 1999 and December 2019, 25.1% had a RRM (range 35-50 years, median age at surgery 38 years). A significant difference in time to prophylactic surgery between women undergoing RRM only vs. women undergoing RRM combined with risk-reducing salpingo-oophorectomy was observed (22.6 vs 8.7 months, p=0.0009). We observed an upward trend in the annual uptake in line with the previously observed Angelina Jolie effect. In 5.7% of cases, occult breast cancer was detected. No women developed breast cancer after RRM. Women who did not opt for surgical prevention developed BRCA1/2-related cancers (9.3%). Conclusion. The uptake of RRM among unaffected BRCA carriers is 25.1% and is similar to our neighboring countries. No women developed breast cancer after RRM while women who did not opt for surgical prevention developed BRCA1/2 related cancers in 9.3% of cases. The reported data may provide meaningful aid for carriers when deciding on an optimal prevention strategy