A genomic test for colorectal cancer risk: is this acceptable and feasible in primary care?

Introduction: Genomic tests can predict risk and tailor screening recommendations for colorectal cancer (CRC). Primary care could be suitable for their widespread implementation. Objective: We aimed to assess the feasibility and acceptability of administering a CRC genomic test in primary care. Methods: Participants aged 45-74 years recruited from 4 Australian general practices were offered a genomic CRC risk test. Participants received brief verbal information about the test comprising 45 CRC-associated single-nucleotide polymorphisms, before choosing whether to undertake the test. Personalized risks were given to testers. Uptake and knowledge of the genomic test, cancer-specific anxiety (Cancer Worry Scale), psychosocial impact (Multidimensional Impact of Cancer Risk Assessment [MICRA] score), and impact on CRC screening behaviour within 6 months were measured. Results: In 150 participants, test uptake was high (126, 84%), with 125 (83%) having good knowledge of the genomic test. Moderate risk participants were impacted more by the test (MICRA mean: 15.9) than average risk participants (mean: 9.5, difference in means: 6.4, 95% confidence interval (CI): 1.5, 11.2, p = 0.01), but all scores were low. Average risk participants' cancer-specific anxiety decreased (mean differences from baseline: 1 month -0.5, 95% CI: -1.0, -0.1, p = 0.03; 6 months -0.6, 95% CI: -1.0, -0.2, p = 0.01). We found limited evidence for genomic testers being more likely to complete the risk-appropriate CRC screening than non-testers (41 vs. 17%, odds ratio = 3.4, 95% CI: 0.6, 34.8, p = 0.19), but some mediators of screening behaviour were altered in genomic testers. Conclusions: Genomic testing for CRC risk in primary care is acceptable and likely feasible. Further development of the risk assessment intervention could strengthen the impact on screening behaviour.