Population-Level Genomic Screening for Hereditary Breast Cancer
Posted: Monday, November 19, 2018
Based on a cross-sectional study of more than 50,000 adults, population-level genomic screening may better identify BRCA1/2-variant carriers at high risk for hereditary breast cancer than current methods. Detection of these disease-associated gene variants may permit early diagnosis of high-risk individuals, according to Michael F. Murray, MD, of the Department of Genetics, Yale School of Medicine, New Haven, Connecticut, and colleagues. These findings were reported in JAMA Network Open.
“Optimal clinical management of patients identified through sequencing-based screening who do not otherwise meet the criteria for clinical testing is likely to evolve as more longitudinal outcomes data become available from this cohort and others,” the investigators noted.
To identify pathogenic and likely pathogenic BRCA1/2 variants, Dr. Murray and colleagues focused on 50,726 adult volunteers, who underwent exome sequencing at a single health-care system (Geisinger Health System, Danville, Pennsylvania). Clinical data obtained from electronic health records as well as visits were correlated with the variants.
They found that 99.5% of patients had no expected pathogenic BRCA1/2 variants and 0.5% (n = 267) were BRCA1/2 carriers. Of the 267 participants who had pathogenic and likely pathogenic variants, 219 (82%) had no prior clinical testing. Of the variants identified, 35.6% had BRCA1 variants, and 64.4% had BRCA2 variants. Of the 148 variant carriers who were women, 20.9% (n = 31) had a personal history of breast, compared with 5.2% (n = 1,554) of the 29,880 noncarriers. In addition, the study findings showed “considerable clinical underascertainment” of individuals with hereditary breast and ovarian syndrome.
The study investigators noted that compared with previous clinical care, “exome sequencing–based screening identified five times as many individuals with pathogenic or likely pathogenic BRCA1/2 variants.”