Uptake of cancer risk management strategies among women who undergo cascade genetic testing for breast cancer susceptibility genes

Background: Uptake of cancer risk management based on inherited predispositions, which encompasses bilateral mastectomy (BLM), bilateral salpingo-oophorectomy (BSO), and intensified screening, is the primary motivation for cascade testing for hereditary breast and ovarian cancer (HBOC). However, long-term outcome data for cascade testers are lacking. Methods: Medical records were abstracted for all unaffected women with pathogenic variants in HBOC genes from 2 cancer hospitals (2013-2019) with at least 1 year of follow-up to compare the uptake of surgery and screening between cascade and noncascade testers. Results: Cascade testers (79.8%) were younger than noncascade testers (mean age, 37.6 vs 43.5 years; P =.002). Among women aged ≥40 years, 43% underwent BLM, and 71.6% underwent BSO, with no significant difference in uptake between cascade and noncascade testers. The mean time to BSO among cascade testers was shorter among women aged ≥40 years versus those aged <40 years (11.8 vs 31.9 months; P =.04); no such difference was observed among noncascade testers. Mammography and breast magnetic resonance imaging rates were low in the recorded 6 years for both groups after genetic counseling. Conclusions: Management uptake among cascade testers is high with rates comparable to those for unaffected BRCA-positive women. A large proportion of women act on cascade test results, and this represents a novel report of utilization of cancer management strategies.