Strategies for recruitment to a population-based lung cancer prevention trial: the CARET experience with heavy smokers. Beta-Carotene and Retinol Efficacy Trial.
The Beta-Carotene and Retinol Efficacy Trial tested the effect of the combination of beta-carotene (30 mg) and retinyl palmitate (25,000 units) daily on the incidence of lung cancer in high-risk individuals. In study centers located in Seattle, WA; Portland, OR; and Irvine, CA, we recruited current and recent ex-cigarette smokers, aged 50-69 years. Our primary method of recruitment was by mailing study information and eligibility questionnaires to age-selected health insurance subscribers. A total of 1,216,549 subscriber households were contacted, which resulted in 16,449 enrollments and 12,184 randomizations. Other methods of recruitment yielded 1421 enrollments and 1002 randomizations. Seventy-four % of those participants who enrolled in the 3-month placebo run-in were randomized. The major reasons for nonrandomization once subjects were enrolled were: becoming ineligible (13%), concern about or development of side effects attributed to the study vitamins (18%), loss of interest or being too busy (23%), and not showing up at the appointed time or not willing to come to the study center (23%). Here, we discuss the reasons for nonparticipation and for subjects leaving the trial prior to randomization and possible modifications of trial design and procedures to address these problems. This recruitment approach provided a constant flow of potentially eligible participants, screened out many ineligible and uninterested persons prior to the scheduling of a study center visit, and ensured randomization of committed participants. A major limitation of this study was that the pool of minorities that was reached was small.
Goodman
G E
GE
Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA. ggoodman@cclink.fhcrc.org
Valanis
B
B
Meyskens
F L
FL
Williams
J H
JH
Metch
B J
BJ
Thornquist
M D
MD
Omenn
G S
GS
D000368:Aged; D002140:California / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009922:Oregon / Q000453:epidemiology; D018579:Patient Selection; D010865:Pilot Projects; D011897:Random Allocation; D012907:Smoking / Q000009:adverse effects; D014801:Vitamin A / Q000627:therapeutic use; D014861:Washington / Q000453:epidemiology; D019207:beta Carotene / Q000627:therapeutic use
D019207:beta Carotene; D014801:Vitamin A