Delivery Of Cascade Screening For Hereditary Conditions: A Scoping Review Of The Literature

Abstract

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.

Keywords: Cascade screening; Precision medicine; Scoping review.

Exhibit 1. Numbers of cascade screening studies included in the analysis, by publication date since 1990

SOURCE Authors’ analysis. NOTES The latest five-year period (2015–19) has not yet ended, so the data for that period are incomplete. The bar shows data for January 1, 2015–August 1, 2017.