Uptake and patient-related outcomes of mainstreaming genetic testing: a systematic review and meta-analysis
Mainstreaming genetic testing refers to genetic testing for cancer susceptibility genes following cancer diagnosis, which is provided by nongenetic health professionals of the cancer-treating team. Mainstreaming can be used to guide cancer treatment and secondary cancer prevention in the patient and to identify carriers in the family members of patients who test positive through cascade testing. We aimed to assess uptake and patient-reported outcomes of mainstreaming genetic testing. We searched PubMed and the Cochrane Library from inception to June 2024. Our population included adult patients offered mainstreaming genetic testing (intervention). Outcomes included testing uptake, satisfaction, decisional conflict/regret, anxiety, depression, and cancer-related distress. We followed a prospective protocol according to Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines (International Prospective Register of Systematic Reviews: CRD42023467312). Qualitative synthesis and random effects meta-analyses were performed. Quality assessment was performed using the Methodological Index for Non-Randomized Studies. Searches yielded 5314 studies; 29 studies (n=13,219) were included, of which 14 were on ovarian cancer (n=6039), 6 on breast cancer (n=4354), 3 on prostate cancer (n=772), 1 on endometrial cancer (n=302), and 5 on multiple cancers (n=1752). There were no studies for colorectal cancer. Pooled genetic testing uptake was 91% (95% confidence interval=86-96, I Mainstreaming genetic testing uptake is associated with high uptake and satisfaction and low decision conflict, regret, and post-test distress. Quality and quantity of evidence across different types of cancers vary significantly.