Use of online recruitment strategies in a randomized trial of cancer survivors

Background/Aims: Despite widespread Internet adoption, online advertising remains an underutilized tool to recruit participants into clinical trials. Whether online advertising is a cost-effective method to enroll participants compared to other traditional forms of recruitment is not known. Methods: Recruitment for the Survivorship Promotion In Reducing IGF-1 Trial, a community-based study of cancer survivors, was conducted from June 2015 through December 2016 via in-person community fairs, advertisements in periodicals, and direct postal mailings. In addition, Right Column banner ads were purchased from Facebook to direct participants to the Survivorship Promotion In Reducing IGF-1 Trial website. Response rates, costs of traditional and online advertisements, and demographic data were determined and compared across different online and traditional recruitment strategies. Micro-trials optimizing features of online advertisements were also explored. Results: Of the 406 respondents to our overall outreach efforts, 6% (24 of 406) were referred from online advertising. Facebook advertisements were shown over 3million times (impressions) to 124,476 people, which resulted in 4401 clicks on our advertisement. Of these, 24 people ultimately contacted study staff, 6 underwent prescreening, and 4 enrolled in the study. The cost of online advertising per enrollee was $794 when targeting a general population versus $1426 when accounting for strategies that specifically targeted African Americans or men. By contrast, community fairs, direct mail, or periodicals cost $917, $799, or $436 per enrollee, respectively. Utilization of micro-trials to assess online ads identified subtleties (e.g. use of an advertisement title) that substantially impacted viewer interest in our trial. Conclusion: Online advertisements effectively directed a relevant population to our website, which resulted in new enrollees in the Survivorship Promotion In Reducing IGF-1 Trial at a cost comparable to traditional methods. Costs were substantially greater with online recruitment when targeting under-represented populations, however. Additional research using online micro-trial tools is needed to evaluate means of more precise recruitment to improve yields in under-represented groups. Potential gains from faster recruitment speed remain to be determined.