Health Behaviors and Cancer Diagnosis Among Individuals with Pathogenic Variants Associated with Hereditary Breast and Ovarian Cancer or Lynch Syndrome

Background: /Objectives: Individuals carrying hereditary breast and ovarian cancer (HBOC) and Lynch Syndrome (LS)-associated pathogenic variants have increased risk for cancers. The study examined the association between cancer diagnosis and health behaviors i.e., smoking, alcohol consumption, level of physical activity, and body mass index (BMI) among individuals with pathogenic variants associated with HBOC or LS. Methods: We used baseline and 18-month follow-up data from carriers of HBOC-or LS- associated variants from the Swiss CASCADE cohort. Generalized linear models with random effects were applied. Results: More than half (58%) of participants had at least one cancer diagnosis. Analyses of 856 observations from 518 individuals (HBOC:410, LS:108) showed that, after controlling for potential confounders, the proportion of current smokers was not significantly different between individuals diagnosed with cancer and never-diagnosed individuals (ß=4.5, p=0.18). Similarly, alcohol intake was not associated with cancer diagnosis (adjusted: ß= -0.2, p=0.51), although it was positively associated with time since genetic testing (ß=0.09, p< 0.01). Levels of physical activity were lower among individuals with cancer compared to never-diagnosed individuals (adjusted: ß= -0.5, p=0.002). There was no difference in BMI between individuals with cancer and individuals never diagnosed with cancer. Conclusions: Findings showed a decrease in levels of physical activity among carriers of HBOC- or LS-associated variants with a cancer diagnosis compared to never-diagnosed individuals, but no differences in smoking, alcohol consumption, or BMI. It is possible that near-term health behavior adjustments among individuals with HBOC- or LS-associated variants are associated with genetic testing results.