Uptake of Risk-Reducing Measures, Cascade Testing, and Related Challenges Among Carriers of Breast Cancer-Associated Germline Pathogenic Variants in Mexico.

PURPOSE: Genetic cancer risk assessment (GCRA) provides pathogenic variant (PV) carriers with the invaluable opportunity to undertake timely cancer risk-reducing (RR) measures and initiate cascade testing (CT). This study describes the uptake of these strategies and the related barriers among breast cancer-associated germline PV carriers in Mexico.

METHODS: Carriers who were at least 6 months after disclosure of genetic test results at two GCRA referral centers were invited to answer a survey assessing sociodemographic characteristics, awareness of their carrier status and its implications, uptake of RR measures according to international guidelines by PV, CT initiation, and associated challenges.

RESULTS: Of the eligible carriers, 246/384 (64%) answered the survey (median age: 44 years). Most were female (88%), married/in domestic partnership (66%), and had personal breast/ovarian cancer history (61%). PVs included BRCA1 / 2 (75%), CHEK2 (10%), PALB2 (5%), ATM (5%), NF1 (2%), RAD51C (2%), PTEN (1%), and TP53 (1%). Most (87%) participants were aware of their carrier status. When recommended, 37% underwent RR bilateral mastectomy, 48% RR oophorectomy, 70% annual mammogram, and 20% breast magnetic resonance imaging. Challenges hindering the uptake of RR measures included financial limitations (67%), lack of recommendation by their physician (35%), and fear (24%). Nearly all (98%) claimed sharing their results with their relatives. CT was initiated in 63% of families and was associated with carriers being married/in domestic partnership ( P = .04) and believing GCRA was useful ( P < .001).

CONCLUSION: Despite the resource-constrained setting, relevant rates of RR measures and CT were observed. Targeted interventions to reduce out-of-pocket expenses and improve patient-physician communication and patients' understanding on carrier status are warranted to enhance the overall benefit of GCRA and ultimately improve the provision of patient-centered care to both carriers and their at-risk relatives.