Background: There is concern that cancer screening may result in apparent perception of health security and thereby reduce people's incentives for changes towards a favorable lifestyle. The present large-scale population based trial investigates long-term effects of colorectal cancer screening on lifestyle changes.

Methods: The present study evaluated changes in lifestyle after 11-years of follow-up among men and women (aged 50-55 years) randomized to a flexible sigmoidoscopy screening for colorectal cancer or to a no-screening control group in the Norwegian Colorectal Cancer Screening Prevention trial (NORCCAP). The lifestyle factors (including body weight, smoking status, physical exercise and consumption of selected dietary items) were assessed by a questionnaire at inclusion and after three and 11 years, respectively. We tested differences in lifestyle changes over the 11-year follow-up period in single factors and total score (0-4 points, higher score translates to more healthy lifestyle) between individuals randomized to screening and control groups, and between screening participants with positive and negative screening results by logistic regression and ANCOVA analysis, adjusting for covariates including baseline lifestyle differences.

Results: A total of 3,043 (44%) individuals randomized to screening and 2,819 (40%) randomized to the control group completed the questionnaires both at inclusion and after 11 years. We found a small, less favorable change in lifestyle in the screening group (total lifestyle score 1.43 at inclusion; 1.58 after 11 years) compared to the control group (total lifestyle score 1.49 at inclusion; 1.67 after 11 years); adjusted difference -0.05 (95% CI -0.09 to -0.01; p=0.029). 11-year change in total lifestyle score was less favorable in screening participants with positive compared to those with negative screening result (adjusted difference -0.16 (95% CI -0.25 to -0.08; p<0.001)).

Conclusions: Invitation to colorectal cancer screening has no large long-term adverse effect on lifestyle. However, the present study suggests that patients with positive screening results may be inclined to a less favorable lifestyle compared to those who tested negative at screening.

Citation Format: Paula Berstad, Magnus Løberg, Inger Kristin Larsen, Mette Kalager, Øyvind Holme, Michael Bretthauer, Geir Hoff. Colorectal cancer screening and long-term lifestyle changes: A randomized controlled trial. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr C04.

©2013 American Association for Cancer Research.
2013