Interventions Facilitating Family Communication of Genetic Testing Results and Cascade Screening in Hereditary Breast/Ovarian Cancer or Lynch Syndrome: A Systematic Review and Meta-Analysis

SIMPLE SUMMARY: In general, 5–20% of all cancers are due to pathogenic variants in cancer genes that are passed down in the family. It is recommended that blood relatives of individuals with such a pathogenic variant have genetic testing, to identify if they also carry the same variant. This information will help their healthcare providers to make individualized cancer screening and prevention plans. However, only around 30% of at-risk relatives have genetic testing, presumably due to a lack of communication about inherited cancer genes among family members. In this paper, we identified interventions that were designed to improve family communication about hereditary cancer and/or genetic testing among at-risk relatives for two common hereditary cancer syndromes. We analyzed the components of these interventions and synthesized outcomes with statistical methods. Although we identified 14 eligible studies, there are still many unanswered questions about clinical and research implications with diverse samples to be addressed in future studies. ABSTRACT: Evidence-based guidelines recommend cascade genetic testing of blood relatives of known Hereditary Breast and Ovarian Cancer (HBOC) or Lynch Syndrome (LS) cases, to inform individualized cancer screening and prevention plans. The study identified interventions designed to facilitate family communication of genetic testing results and/or cancer predisposition cascade genetic testing for HBOC and LS. We conducted a systematic review and meta-analysis of randomized trials that assessed intervention efficacy for these two outcomes. Additional outcomes were also recorded and synthesized when possible. Fourteen articles met the inclusion criteria and were included in the narrative synthesis and 13 in the meta-analysis. Lack of participant blinding was the most common risk of bias. Interventions targeted HBOC (n = 5); both HBOC and LS (n = 4); LS (n = 3); or ovarian cancer (n = 2). All protocols (n = 14) included a psychoeducational and/or counseling component. Additional components were decision aids (n = 4), building communication skills (n = 4), or motivational interviewing (n = 1). The overall effect size for family communication was small (g = 0.085) and not significant (p = 0.344), while for cascade testing, it was small (g = 0.169) but significant (p = 0.014). Interventions show promise for improving cancer predisposition cascade genetic testing for HBOC and LS. Future studies should employ family-based approaches and include racially diverse samples.