Will knowledge of gene-based colorectal cancer disease risk influence quality of life and screening behavior? Findings from a population-based study.

BACKGROUND: Several gene variants conveying a modestly increased risk for disease have been described for colorectal cancer. Patient acceptance of gene variant testing in clinical practice is not known. We evaluated the potential impact of hypothetical colorectal-cancer-associated gene variant testing on quality of life, health habits and cancer screening behavior.
METHODS: First-degree relatives of colorectal cancer patients and controls from the Seattle Colorectal Cancer Familial Registry were invited to participate in a web-based survey regarding testing for gene variants associated with colorectal cancer risk.
RESULTS: 310 relatives and 170 controls completed the questionnaire. Quality of life for the hypothetical carrier state was modestly and nonsignificantly lower than current health after adjustment for sociodemographic and health factors. In the positive test scenario, 30% of respondents expressed willingness to change their diet, 25% to increase exercise, and 43% to start colorectal cancer screening. The proportions willing to modify these habits did not differ between groups.
CONCLUSIONS: Testing for gene variants associated with colorectal cancer risk may not influence quality of life, but may impact health habits and screening adherence. Changing behaviors as a result of testing may help to reduce cancer incidence and mortality, particularly among those at higher risk for colorectal cancer.