Background: Sending faecal occult blood tests (FOBT) by mail has been proposed both as a method to increase participation and a way to reduce staff costs in colorectal cancer screening.
Methods: Two multicentre randomized controlled trials (ISRCTN10351276) were performed: one randomly assigned 3196 individuals who had previously participated in colorectal screening to receive a FOBT kit at home or a standard invitation; in the second, 4219 people aged 50-69 years who did not respond to a screening invitation were either sent a FOBT or a standard recall letter. The cost per returned kit was calculated in each arm.
Results: Participation was higher with direct FOBT mailing in both trials: relative risk 1.11 (95% CI 1.06-1.17) and 1.36 (95% CI 1.16-1.60) for previous responders and non-responders, respectively. The cost per returned kit for previous responders ranged from 4.24€ to 16.10€, and from 3.29€ to 7.36€ with FOBT mailing and standard invitation, respectively, not including staff costs; for non-responders it ranged from 17.13€ to 46.80€, and from 7.36€ to 18.30€ with FOBT mailing and standard recall, respectively.
Conclusions: The FOBT mailing strategy modestly increased participation. This method can be used on a population of previous responders to reduce personnel costs and workload. When used as a reminder to non-responders, this method increases costs.