Multigene assessment of genetic risk for women for two or more breast cancers.

PURPOSE: The prevalence, penetrance, and spectrum of pathogenic variants that predispose women to two or more breast cancers is largely unknown. METHODS: We queried clinical and genetic data from women with one or more breast cancer diagnosis who received multigene panel testing between 2013 and 2018. Clinical data were obtained from provider-completed test request forms. For each gene on the panel, a multivariable logistic regression model was constructed to test for association with risk of multiple breast cancer diagnoses. Models accounted for age of diagnosis, personal and family cancer history, and ancestry. Results are reported as odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: This study included 98,979 patients: 88,759 (89.7%) with a single breast cancer and 10,220 (10.3%) with ≥ 2 breast cancers. Of women with two or more breast cancers, 13.2% had a pathogenic variant in a cancer predisposition gene compared to 9.4% with a single breast cancer. BRCA1, BRCA2, CDH1, CHEK2, MSH6, PALB2, PTEN, and TP53 were significantly associated with two or more breast cancers, with ORs ranging from 1.35 for CHEK2 to 3.80 for PTEN. Overall, pathogenic variants in all breast cancer risk genes combined were associated with both metachronous (OR 1.65, 95% CI 1.53-1.79, p = 7.2 × 10-33) and synchronous (OR 1.33, 95% CI 1.19-1.50, p = 2.4 × 10-6) breast cancers. CONCLUSIONS: This study demonstrated that several high and moderate penetrance breast cancer susceptibility genes are associated with ≥ 2 breast cancers, affirming the association of two or more breast cancers with diverse genetic etiologies.

Hereditary Cancer Risk Assessment and Genetic Testing in the Community-Practice Setting.

OBJECTIVE: To evaluate the feasibility and results of incorporating routine hereditary cancer risk assessment, counseling, and follow-up genetic testing in the community obstetrics and gynecology practice setting without referral to a genetic counselor. METHODS: This prospective process intervention study was conducted with two obstetrics and gynecology practice groups (five sites). The intervention included baseline process assessment, refinement of clinic-specific patient screening workflows and tools, and training in hereditary cancer risk screening and follow-up. Outcomes related to hereditary cancer assessment and testing were measured during an 8-week postintervention period. Patients and health care providers were surveyed about satisfaction with the process. Data also were collected during the 8 weeks before the intervention to assess the effects of screening process improvements. RESULTS: A total of 4,107 patients were seen during the postintervention period, and 92.8% (3,811) were assessed for hereditary cancer risk. Among those assessed, 906 of 3,811 (23.8%) women met National Comprehensive Cancer Network guidelines for genetic testing, and 813 of 906 (89.7%) eligible patients were offered genetic testing. A total of 165 of 4,107 (4.0%) women completed genetic testing and received a final test result. This represents a fourfold increase over genetic testing immediately before the intervention (1.1%) and an eightfold increase over the previous year (0.5%). Testing identified pathogenic variants in 9 of 165 (5.5%) tested women. All health care providers (15/15) reported that they will continue to use the established hereditary cancer risk assessment process. In addition, 98.8% (167/169) of patients who submitted a sample for genetic testing and completed a patient satisfaction survey stated that they were able to understand the information provided, and 97.6% (165/169) expressed satisfaction with the overall process. CONCLUSION: It is feasible to incorporate hereditary cancer risk assessment, education, and testing into community obstetrics and gynecology practices. As a result, multigene panel testing identified significant cancer risks that otherwise would not have been recognized.

A genealogical assessment of familial clustering of anorectal malformations.

Familial recurrence of anorectal malformations (ARMs) has been reported in single institution case series and in two population-based studies. Here, we investigate the familial aggregation of ARMs using well-established, unbiased methods in a population genealogy of Utah. Study subjects included 255 ARM cases identified from among the two largest healthcare providers in Utah with linked genealogy data using International Classification of Diseases, Ninth Revision (ICD-9) diagnosis codes. The genealogical index of familiality (GIF) statistic, which compares the average pair-wise relatedness of cases to sets of matched controls, was used to test excess familial clustering. We also estimated relative risks (RRs) for ARM and associated phenotypes in relatives of cases adjusting for age-, sex-, and birthplace. Significant excess familial clustering was observed for all ARM subjects (GIF p < 1e-3). Significant RR estimates for ARM (RR = 15.6, p = 3.3e-6), and for almost all co-morbid birth defects previously associated with ARM, were observed among first-degree relatives of ARM case subjects. This genealogically-based population survey of familial aggregation of ARMs confirms the presence of a heritable component to ARMs and provides unbiased risk estimates to relatives of cases, which may have clinical utility.