The beta-carotene and retinol efficacy trial (CARET) for chemoprevention of lung cancer in high risk populations: smokers and asbestos-exposed workers.
CARET is a multicenter, two-armed, double-masked randomized chemoprevention trial in Seattle, Portland, San Francisco, Baltimore, Connecticut, and Irvine, to test whether oral administration of beta-carotene (30 mg/day) plus retinyl palmitate (25,000 IU/day) can decrease the incidence of lung cancer in high risk populations, namely, heavy smokers and asbestos-exposed workers. The intervention combines the antioxidant action of beta-carotene and the tumor suppressor mechanism of vitamin A. As of April 30, 1993, CARET had randomized 1,845 participants in the 1985-1988 pilot phase plus 13,260 "efficacy" participants since 1989; of these, 4,000 are asbestos-exposed males and 11,105 are smokers and former smokers (44% female). Accrual is complete everywhere except Irvine, which was the last center added (1991), and the safety profile of the regimen to date has been excellent. With 14,420 smokers, 4,010 asbestos-exposed participants, and 114,100 person-years through February 1998, we expect CARET to be capable of detecting a 23% reduction in lung cancer incidence in the two populations combined and 27, 49, 32, and 35% reductions in the smokers, female smokers, male smokers, and asbestos-exposed subgroups, respectively. CARET is highly complementary to the alpha-tocopherol-beta-carotene study in Finland and the Harvard Physicians Health Study (beta-carotene alone) in the National Cancer Institute portfolio of major cancer chemoprevention trials.
Omenn
G S
GS
Fred Hutchinson Cancer Research Center, University of Washington School of Public Health, Seattle 98195.
Goodman
G
G
Thornquist
M
M
Grizzle
J
J
Rosenstock
L
L
Barnhart
S
S
Balmes
J
J
Cherniack
M G
MG
Cullen
M R
MR
Glass
A
A
D000368:Aged; D016588:Anticarcinogenic Agents / Q000627:therapeutic use*; D001194:Asbestos / Q000009:adverse effects*; D002338:Carotenoids / Q000009:adverse effects / Q000627:therapeutic use*; D004224:Diterpenes; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D010865:Pilot Projects; D000084562:Retinyl Esters; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D014481:United States; D014801:Vitamin A / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D019207:beta Carotene
D016588:Anticarcinogenic Agents; D004224:Diterpenes; D000084562:Retinyl Esters; D019207:beta Carotene; D014801:Vitamin A; D001194:Asbestos; C014794:retinol palmitate; D002338:Carotenoids