Prospective Feasibility Trial of a Novel Strategy of Facilitated Cascade Genetic Testing Using Telephone Counseling

Abstract

PURPOSE A powerful consequence of detecting cancer-associated pathogenic variants is the ability to test at-risk relatives (ARRs), termed cascade testing. However, historical studies suggest cascade testing uptake of 30% or less. Here, we tested the feasibility of a novel, streamlined method of cascade testing using telephone genetic counseling and mailed saliva-based genetic testing. PATIENTS AND METHODS Probands with newly diagnosed cancer-associated pathogenic variants were offered facilitated cascade testing whereby the genetics team identified and contacted ARRs by telephone to disclose the familial pathogenic variant and offer telephone counseling and mailed saliva testing. Results and guideline-based recommendations were reviewed by telephone and shared with the primary care physician. RESULTS Thirty probands were enrolled, and 114 ARRs were identified. Twelve ARRs were excluded (lived outside of the United States, n = 5; proband did not approve of contact, n = 7). Among 102 ARRs telephoned, contact was established with 95 (93%). Among 114 identified ARRs, 66 (58%) completed genetic testing. Among those completing testing, 27 (41%) carried the familial pathogenic variant. Surveys of ARRs at the time of genetic testing and 6 months later demonstrated low levels of anxiety, depression, distress, and uncertainty and high levels of satisfaction with testing. At 6 months, 7 ARRs with pathogenic variants had undergone cancer surveillance interventions and 4 had undergone cancer risk-reducing surgery. CONCLUSION Facilitated cascade testing with telephone genetic counseling and mailed saliva kits resulted in high testing uptake among ARRs. Positive genetic testing resulted in utilization of genetically targeted primary disease prevention at short-term follow-up. Facilitated cascade testing is a straightforward, low-cost, easily implemented strategy with significant potential to promote early detection for affected ARRs and reduce cancer mortality and should be evaluated in larger scale clinical trials.