Women with pathogenic variants in moderate penetrance breast cancer genes: How frequently do they meet high penetrance genetic testing criteria?

Abstract

10584 Background: 5-10% of breast cancers are associated with germline pathogenic variants in breast cancer predisposition genes. 2-5% of these variants are in moderate penetrance (MP) genes, conferring a relative risk to develop breast cancer of 2-5. Various personal history (PH) and family history (FH)-based criteria for testing high penetrance genes, such as BRCA1 and BRCA2, have been proposed, but it is unknown to what extent women with pathogenic variants in MP genes may meet such criteria. We evaluated PH and FH of cancer among women with pathogenic variants in MP genes in a diverse and unselected patient cohort in New York City to determine how often they met well-established genetic testing criteria from the National Comprehensive Cancer Network (NCCN). Methods: Exome sequence data from ~16,000 female Bio Me Biobank participants were evaluated for expected pathogenic (per ClinVar, or predicted loss-of-function) variants in ATM, BARD1, BRIP1, CHEK2, NF1, PALB2, RAD51C, and RAD51D. We extracted demographic information, PH and FH of breast, ovarian, and/or pancreatic cancer, and PH and FH of genetic testing from participant questionnaires and electronic medical record review. We then determined which participants met current NCCN criteria (version 1.2023) for high penetrance breast, ovarian, and pancreatic cancer genetic testing. Results: We identified 252 women with expected pathogenic variants in MP genes: 105 CHEK2, 58 ATM, 35 BRIP1, 24 PALB2, 9 BARD1, 8 NF1, 8 RAD51D, and 5 RAD51C. 30% met NCCN criteria, including 30% of those with CHEK2 variants, 36% ATM, 14% BRIP1, 33% PALB2, and 30% with variants in BARD1, NF1, RAD51D, or RAD51C. 36% of those who met NCCN criteria had previously undergone clinical genetic testing. 29 of 33 (88%) women with a PH of breast cancer and 52 of 81 (64%) women with a FH of breast cancer met criteria. Conclusions: Current genetic testing criteria focus on identifying individuals harboring pathogenic variants in high penetrance cancer genes. However, in our study, a substantial portion of women with a pathogenic variant in a MP breast cancer gene also met such criteria, particularly when PH or FH of breast cancer were present. Only a third of those who met NCCN criteria had undergone clinical genetic testing. These findings suggest that the majority of women with genetic risk for breast cancer may be missed in clinical practice. Studies have shown that most physicians would change management strategies for patients with pathogenic variants, including variants in MP genes. As our understanding of genetic risk for breast cancer continues to evolve, we must explore strategies to improve identification and management of individuals with variants in MP breast cancer genes.