Retrospective cross-sectional study of differences in cascade genetic testing among families with hereditary cancer risk

Performing germline genetic testing of family members following the identification of an individual with a pathogenic variant in a cancer predisposition gene (‘cascade genetic testing’) is a critical step in maximizing the preventive benefit of genetic testing for hereditary cancer. A retrospective cross-sectional study at the University of Pittsburgh (PA) analyzed differences in cascade genetic testing among relatives of individuals with hereditary cancer risk. Of 22,932 probands with pathogenic or likely pathogenic variants, 5559 (24.24%) had at least one relative pursue cascade testing, with the highest rate among non-Hispanic White probands and significantly lower rates among African American or Black, Asian, Hispanic, and Middle Eastern probands, even when controlling for socioeconomic status. The availability of free familial variant testing was not associated with a meaningful increase in cascade testing. The authors conclude that cascade testing remains markedly underused, and persistent demographic disparities suggest additional factors at play beyond financial access.