Development and Real-World Evaluation of a Statewide Mainstream Model of Germline Genetic Testing for BRCA1/2 and Mismatch Repair Gene Variants (Lynch Syndrome)

Purpose: To develop and evaluate an evidence-based mainstream germline genetic testing model to support cancer treatment including the BRCA1/BRCA2 and mismatch repair (MMR) genes across South Australia.

Methods: Participatory action research (PAR) and implementation science principles were used to guide the development of the statewide mainstream pathway. To support the implementation of the mainstream pathway, genetic testing packages for clinicians and consumer support materials have been developed, and an education program has been delivered to clinicians. This quality improvement study used an independent sample t-test to compare the average number of monthly tests completed via mainstream and traditional pathways during two nonconsecutive 6-month periods. Acceptability among patients and clinicians and clinician knowledge, confidence, and experience measures were assessed.

Results: The total number of BRCA1/2 tests did not increase from pre- to post-pathway implementation. However, there was a significant increase in both the number of tests ordered through the mainstream pathway (pre: mean 3.5, SD 2.07; post: mean 7, SD 2.53) and the proportion of total tests ordered via mainstreaming (pre: mean 14%, SD 9.25%; post: mean 25.0%, SD 5.48%). There were no changes in MMR gene testing patterns, with no mainstream tests ordered. Among clinicians (n = 20) who responded to the post-implementation survey, positive levels of acceptability were reported.

Conclusion: This study showed that the implementation of a statewide mainstream genetic testing pathway in a public health system improved the uptake of mainstream testing for BRCA1/2. Further understanding of the barriers to uptake across settings is needed to support effective utilization.