Uptake of breast cancer risk-management strategies among unaffected BRCA 1/2 carriers: a systematic review of international evidence.

Women carrying BRCA1/BRCA2 pathogenic variants face a substantially increased risk of breast cancer and may choose between risk-reducing mastectomy (RRM) or intensive surveillance. This systematic review aimed to synthesise the available evidence on the uptake of breast cancer risk management strategies among unaffected BRCA1/2 carriers. A systematic review was conducted in accordance with PRISMA guidelines. Four electronic databases (PubMed, Scopus, Web of Science, ASSIA) and grey literature sources were searched for studies published since 1995. Eligible studies reported uptake of breast cancer risk management strategies among unaffected BRCA1/2 carriers. Two reviewers independently screened records, extracted data, and assessed methodological quality using Kmet criteria. Due to heterogeneity in study design and outcome definitions, findings were synthesised narratively. Thirty-two studies published between 2002 and 2025 were included. Uptake of RRM ranged from approximately 0% to 81.6%, with higher uptake consistently reported in North America and Norwegian cohorts and lower rates in several Asian and Middle Eastern populations. Intensive surveillance was commonly adopted among women not undergoing surgery, with adherence often exceeding 80-90%. Only a minority of studies explicitly quantified women not adopting any specific preventive strategy, the proportion of whom ranged from 2.8%- to 9.7% CONCLUSIONS: Breast cancer risk management among unaffected BRCA1/2 carriers varies widely across settings. Surveillance was the most adopted strategy in most cohorts, whereas uptake of RRM showed marked international variability. More evidence, standardisation, and longitudinal research are needed to support organization, counselling, adherence, and equitable access to risk management in BRCA1/2 carriers.