Validation of a model predicting enrollment status in a chemoprevention trial for breast cancer.

We evaluated the performance of a regression model in predicting enrollment status in a chemoprevention trial for breast cancer using a population independent of that from which the model was derived. In years 1 and 2 of recruitment, questionnaires were completed by eligible participants following attendance at informational meetings about the Breast Cancer Prevention Trial. The variables in the original model, based on women recruited in year 1, included not being able to take estrogen replacement therapy (ERT), concern about the side effects of tamoxifen, the possibility of getting a placebo, the out-of-pocket expenses associated with the trial, and disagreement with the statement "significant others would be reassured if the respondent was taking tamoxifen.

Factors related to enrollment in the breast cancer prevention trial at a comprehensive cancer center during the first year of recruitment.

Background: Using an a priori theoretic model of behavior change, factors predicting enrollment in a randomized chemoprevention trial during the first year of recruitment were assessed prospectively.

Methods: Eligible participants were asked to complete a 90-item semistructured questionnaire after attendance at an informational meeting. Components of the Health Belief Model (including perceived susceptibility, perceived severity, perceived benefits and barriers, cues to action, and health motivation), health status, preventive health behaviors, and social influence were assessed in relation to enrollment.