This chemoprevention trial tests the efficacy of retinol and beta- carotene in preventing lung cancer in two related high-risk populations: (a) heavy smokers recruited from insurance-based sources, and (b) current and former workers with heavy occupational asbestos exposure recruited from workers' compensation and employment-based sources. The double-blind two-arm randomized protocol compares placebos with a daily combination of 30 mg beta- carotene plus 25,000 IU retinol. We will recruit eligible asbestos-exposed subjects from the San Francisco/Oakland area. We will participate in implementing a cost-effective, well-integrated, multi-clinic strategy, with the Seattle-based coordinating center for project management and data analysis. During the first 3 years of the new grant period (1988-91) we will recruit and enroll 800 subjects randomized according to the multi center protocol. We will provide all necessary data to evaluate accrual, coordination, and costs in geographically-dispersed clinic sites to generate best estimates of the remaining needs for the full-scale enrollment and follow-up. Current assumptions and projections indicate that the full-scale Efficacy Trial will be capable of detecting significant reductions in lung cancer incidence in the high-risk groups combined, and in either subgroup alone, with 13,000 smokers and 4000 asbestos-exposed subjects.
Cartmel, B; Dziura, J; Cullen, M R et al. (2005) Changes in cholesterol and triglyceride concentrations in the Vanguard population of the Carotene and Retinol Efficacy Trial (CARET). Eur J Clin Nutr 59:1173-80 |
Barnhart, S; Keogh, J; Cullen, M R et al. (1997) The CARET asbestos-exposed cohort: baseline characteristics and comparison to other asbestos-exposed cohorts. Am J Ind Med 32:573-81 |
Brodkin, C A; McCullough, J; Stover, B et al. (1997) Lobe of origin and histologic type of lung cancer associated with asbestos exposure in the Carotene and Retinol Efficacy Trial (CARET). Am J Ind Med 32:582-91 |
Omenn, G S; Goodman, G E; Thornquist, M D et al. (1996) Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med 334:1150-5 |