Background: Participation rates in colorectal cancer screening in Germany are low. We therefore investigated the effectiveness of different invitation models for immunological stool blood tests (fecal immunological tests, FITs).
Methods: A randomized controlled trial in 50- to 54-year-old clients of the health insurance provider AOK Baden-Wuerttemberg. A total of 17 532 insured persons were randomized to receive: (A) an invitation letter including a FIT (n = 5850); (B) an invitation letter including an option to request a FIT (n = 5844); or (C) an invitation letter only (n = 5838; control group, routine practice). Reminder letters were sent to half the members of groups A and B, selected at random, after 4 weeks. The primary endpoint was the use of a FIT within 1 year of the date of the invitation letter. IRRID: RR2-10.2196/16413. Registration: DRKS00011858.
Results: The invitation letter with a FIT enclosed (A) increased usage from 10% to 29.7% compared with the control group (+19.7% points, p < 0.0001; men: +19.4%, women: +18.8%). The invitation letter with a FIT request option (B) increased usage from 10% to 27.7% (+17.7% points, p < 0.0001; men: +17.7%, women: +17.4%). Reminders increased usage in group A by 7.5% points and in group B by 8.5% points. Participation among women was higher than among men in all groups. The FIT positivity rate was 6.9%. A subsequent colonoscopy was reported for 64.3% of FIT-positive participants, and advanced neoplasia was found in 21.3% of these cases.
Conclusion: Letters of invitation that include a FIT and those that offer low-threshold access to a FIT achieve strong, comparable increases in the usage of FIT in the context of colorectal cancer screening.