Lynch syndrome (LS) mutation carriers may reduce their cancer risk by adhering to lifestyle recommendations for cancer prevention. This study tested the effect of providing LS mutation carriers with World Cancer Research Fund-the Netherlands (WCRF-NL) health promotion materials on awareness and knowledge of and adherence to these recommendations. In this randomized controlled trial (n = 226), the intervention group (n = 114) received WCRF-NL health promotion materials. All LS mutation carriers were asked to fill out questionnaires at 2 weeks before (baseline, T0) and at 2 weeks (T1) and 6 months (T2) after the intervention. Linear mixed models were performed on awareness (0-7) and knowledge (0-7) of the recommendations, and on the secondary outcomes, that is adherence, distress, cancer worry, and risk perception. Compared with the control group, the intervention group became significantly more aware (overall mean difference = 1.24; 95%CI = 0.82-1.67) and obtained significantly improved knowledge of the recommendations (overall mean difference = 1.65; 95%CI = 1.27-2.03). Differences were significantly larger for T1 (P interaction = .003 and ≤.001, respectively) but remained significant for T2. No effect on secondary outcomes was found. In conclusion, provision of WCRF-NL health promotion materials increases awareness and knowledge of lifestyle recommendations for cancer prevention among LS mutation carriers without causing additional distress, but does not affect adherence. This may subsequently promote adherence to lifestyle recommendations, leading to potential health benefits. The aim of this randomized controlled study was to test the effect of providing LS mutation carriers with WCRF-NL health promotion materials on awareness and knowledge of the WCRF/AICR cancer prevention recommendations.In addition, we tested the effect of providing these WCRF-NL health promotion materials on adherence to these recommendations and on levels of distress, cancer worry and cancer risk perception.
| METHODSThe medical ethical research committees of the Radboud university medical center and Maastricht University Medical Centre granted permission to perform this study.
| Participants and study proceduresLS mutation carriers were eligible for participation in this study if mutation status was confirmed by DNA testing and carriers were informed about the LS carriership at Radboud or Maastricht University Medical Center within the last 6 years, and were aged between 18 and 65 years at the time of inclusion in the study between April and September 2015. LS mutations carriers were excluded if they had insufficient command of the Dutch language to fill out Dutch questionnaires or if they were currently participating in the GeoLynch study, a prospective cohort study among LS mutation carriers, 18 to prevent interference between both studies.After informed consent was obtained, eligible participants were randomized into an intervention or control group (Figure 1). To minimize the risk of interference between family members, randomizati...