Cascade screening is the process of contacting relatives of people who have been diagnosed with certain hereditary conditions. Its purpose is to identify, inform, and manage those who are also at risk. We conducted a scoping review to obtain a broad overview of cascade screening interventions, facilitators and barriers to their use, relevant policy considerations, and future research needs. We searched for relevant peer-reviewed literature in the period 1990-2017 and reviewed 122 studies. Finally, we described 45 statutes and regulations related to the use and release of genetic information across the fifty states. We sought standardized best practices for optimizing cascade screening across various geographic and policy contexts, but we found none. Studies in which trained providers contacted relatives directly, rather than through probands (index patients), showed greater cascade screening uptake; however, policies in some states might limit this approach. Major barriers to cascade screening delivery include suboptimal communication between the proband and family and geographic barriers to obtaining genetic services. Few US studies examined interventions for cascade screening or used rigorous study designs such as randomized controlled trials. Moving forward, there remains an urgent need to conduct rigorous intervention studies on cascade screening in diverse US populations, while accounting for state policy considerations.
Bibliographical noteFunding Information:
Amy Sturm is on the scientific advisory boards for Genome Medical and Clear Genetics. Heather Zierhut is a senior adviser for GeneMatters, LLC. Heather Hampel is on the scientific advisory board for InVitae Genetics and Genome Medical; has stock in Genome Medical; has been the principal investigator of a study supported by Myriad Genetic Laboratories, Inc.; and has done consulting work for Beacon Lab Benefit Solutions. The authors acknowledge the contributions and efforts of Martha Knuth, of the Stephen B. Thacker CDC Library, in developing and implementing search strategies, deduplicating records, and reviewing the "Study Data And Methods" section of the manuscript for accuracy; and of Stephen D. Morgan in aiding in full-text abstraction of a subset of included articles. The authors are very grateful for the wide-ranging support provided by Siobhan Addie, of the National Academies of Sciences, Engineering, and Medicine, in the development and preparation of the manuscript. The authors appreciate the expert legal support provided by Rachel Hulkower, of the Public Health Law Program of the Centers for Disease Control and Prevention (CDC). Finally, the authors thank Chris Hammond, from the Office of the General Counsel of the Department of Health and Human Services (HHS) for his legal advice and independent review of Pennsylvania laws. The policy search does not constitute a systematic update of state laws related to genetic information privacy. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Agency for Healthcare Research and Quality, the CDC, the National Cancer Institute, or HHS