The efficacy of genetic counselling for familial colorectal cancer. A randomised clinical trial.

Genetic counselling (GC) for familial colorectal cancer (fCRC) has been previously shown to improve outcomes such as emotional distress and screening adherence. This is the first randomised clinical trial to evaluate the efficacy of GC for fCRC. We included individuals affected or at-risk for fCRC (Lynch syndrome, APC-associated polyposis, other risk-associated pathogenic variants and clinically defined fCRC). Participants were randomised to (1) standard care or (2) standard care and genetic counselling. Measures include empowerment, anxiety, depression, knowledge, emotional distress, perceived social support, risk perception. Eighty-two individuals participated in the study. The average age was 44.81 years old, with 52.4% women. There was a significant effect in the counselling group (42/82) on post-intervention empowerment scores compared to the control group (40/82) (p = 0.004, d = 0.71), and similarly for depression (p = 0.025, d = 0.40), anxiety (p = 0.036, d = 0.35) and knowledge (p = 0.016, d = 0.25). Exploratory analysis show that several sociodemographic, affective and cognitive variables are moderating the improvement in empowerment following genetic counselling. Our data show significant improvements for both primary endpoint (empowerment) and secondary endpoints (knowledge, depression, anxiety, emotional distress). Genetic counselling is an effective intervention for fCRC both when the diagnosis is part of a syndrome or clinically defined, and both for affected or at-risk individuals.