Patient participation and compliance in cancer chemoprevention trials: issues and concerns.

Cancer chemoprevention trials have unique characteristics that make the tasks of participant recruitment, enrollment, and long-term adherence to the study protocol and intervention regimen especially difficult. Barriers to patient accrual, long-term participation, and optimal adherence are inherent in clinical trial design and organization, and are frequently associated with the attitudes and behavioral dynamics of physicians and the participants themselves. Attracting racially and ethnically diverse populations to trial participation adds additional problems and considerations. Careful planning early in the design phase of a chemoprevention clinical trial must take into account these numerous issues. Clinical investigators should seek expert advice from a number of health care disciplines to better design chemoprevention protocols that minimize logistic complexity, maximize participant eligibility, simplify data collection, and take into account the complex behavioral dynamics of the clinical trial process.