CARET, the beta-carotene and retinol efficacy trial to prevent lung cancer in high-risk populations.

BACKGROUND

CARET is a multi-center collaboration, with participants recruited in Seattle, Portland, San Francisco, Irvine, Baltimore and New Haven.

METHODS

CARET is a two-armed double-blind randomized chemoprevention trial to test the hypothesis that oral administration of beta-carotene 30 mg/day plus retinyl palmitate 25,000 IU/day will decrease the incidence of lung cancer in high-risk populations: heavy smokers and asbestos-exposed workers who have smoked. The agents combine anti-oxidant and nuclear tumor suppressor mechanisms. Fastidious monitoring for possible side effects is facilitated by inclusion of a Vanguard population (continued from pilot studies).

RESULTS

As of 31 July 1991, 8129 participants had been randomized into the Trial, of the 18,000 needed. Efficacy results are expected in 1998.

CONCLUSIONS

The Trial demonstrates the movement of environmental epidemiology into interventionist research to prevent adverse health effects.