Recruitment strategies and consent rates in a national prospective colorectal cancer screening cohort: results from year 1 of the Voyage Study.

Objective: To identify the optimal incentive protocol for maximising participation while managing study costs during the Voyage trial.
Design: Prospective cohort (Voyage trial) of colorectal cancer (CRC) incidence and mortality outcomes in individuals screened with multitarget stool DNA (mt-sDNA) served as the population. A subset was randomised to receive postage stamps as a pre-consent incentive, or as a post-consent incentive after completion of the consent and questionnaire. Descriptive statistics from year 1 are reported.
Results: During year 1 of the Voyage trial, a total of 600 258 individuals with mt-sDNA orders received at Exact Sciences Laboratories were randomly selected and invited to participate. Of those, 26 429 (4.4%) opted in, 14 365 of whom (54.3%) consented. The opt-in and consent samples were similar to the target population with respect to sex but differed by geographic residence and age (p<0.001). For the embedded incentive experiment, 2333 were randomised to the pre-incentive arm, while 2342 were randomised to the post-incentive arm. Overall consent rate in the incentive trial was 56.4% (60.9% for the pre-consent incentive arm (1421/2333) vs 52.0% for the post-consent incentive arm (1217/2342), p<0.001). Cost reduction was observed for the pre-consent incentive group, and higher response rates were seen among older versus younger individuals.
Conclusions: Pre-consent incentive option was associated with a higher participation rate and lower costs and was used for the remainder of study recruitment. CRC incidence and mortality vary with age; thus, adjusting for differential participation by age and region will be important in analyses of Voyage data.
Trial Registration Number: NCT04124406.
Competing Interests: Competing interests: KJY, REC, CRK, EJK, JLSS, JAG and JEO are employees of Mayo Clinic and received funding for this study through a grant from Exact Sciences Corporation. BK and JJL are employees and shareholders of Exact Sciences. At the start of the work herein, LJFR was an employee of the Mayo Clinic, whereby she offered scientific input to Exact Sciences for research studies through a contracted services agreement between Mayo Clinic and Exact Sciences Corporation. During the writing of this manuscript, she became a full-time employee of Exact Sciences Corporation. Currently, she is an employee of Mayo Clinic only.
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