THE CAROTENE AND RETINOL EFFICACY TRIAL (CARET) TO PREVENT LUNG-CANCER IN HIGH-RISK POPULATIONS - PILOT-STUDY WITH ASBESTOS-EXPOSED WORKERS

Pilot studies are an essential component for major chemoprevention tri als. Prior to initiating the multicenter Carotene and Retinol Efficacy Trial to assess the effectiveness of beta-carotene and retinol for pr eventing lung cancer, we conducted pilot studies in Seattle between 19 85 and 1988 in two high risk populations: current and former heavy smo kers and asbestos-exposed workers. The Asbestos Workers Pilot Study fo r the Carotene and Retinol Efficacy Trial demonstrated that recruitmen t of asbestos-exposed participants with relevant risk factors was feas ible from identified sources. We documented negligible toxicity and hi gh adherence with the protocol, schedule, and intervention. Results fr om the pilot led to extension of the placebo run-in period, changes in the eligibility criteria, improvements in recruitment strategies and scheduling, elimination of stratification by risk factors in randomiza tion, modifications of study vitamin dosage and of side effects monito ring, and refinement of trial design parameters for Carotene and Retin ol Efficacy Trial. The Smokers Pilot is reported in the accompanying a rticle (G. E. Goodman et al., Cancer Epidemiol., Biomarkers & Prev., 2 : 389-396, 1993).