Post-study aspirin intake and factors motivating participation in a colorectal cancer chemoprevention trial.

We conducted an exploratory, cross-sectional study examining motivators for study participation and post-study aspirin intake in a chemoprevention trial. The parent clinical trial aimed to determine the optimal aspirin dose for colorectal cancer chemoprevention using prostaglandin E-2 as a mucosal biomarker. This trial was randomized and double-blinded in 60 subjects with prior sporadic colorectal adenoma(s) and evaluated three aspirin doses or placebo taken once daily for 4 weeks. A cross-section of 55 evaluable participants who completed the chemoprevention trial were mailed a 16-item, self-administered questionnaire evaluating subject demographics, motivational factors, and health-related behaviors within the framework of Pender's Health Promotion Model (HPM). Forty-three (78%) of 55 participants returned the questionnaire. The most important motivators for study participation were altruistic, i.e., a desire to help future generations at risk of colorectal cancer and personal factors including a desire to reduce one's own risk. Nineteen (44%) of 43 respondents reported that they chose to take daily aspirin post-study without knowledge of study results. At a mean follow-up of 17.3 months, 18 of these 19 subjects continued to take aspirin regularly. Regular use of vitamin supplements pre-study was found to correlate with post-study aspirin use (Mann-Whitney U test, U = 154.0; P = 0.04). We demonstrate, for the first time, that participation in a chemoprevention study can influence the decision to continue the study drug, if available, to reduce perceived cancer risk. Continued post-study aspirin intake indicates an impact of study participation on a health-related behavior and underscores the importance of patient education to guide such decision-making.