Effect of Various Invitation Schemes on the Use of Fecal Immunochemical Tests for Colorectal Cancer Screening: Protocol for a Randomized Controlled Trial

Background Fecal occult blood testing has been offered for many years in the German health care system, but participation rates have been notoriously low. Objective The aim of this study is to evaluate the effect of various personal invitation schemes on the use of fecal immunochemical tests (FITs) in persons aged 50-54 years. Methods This study consists of a three-armed randomized controlled trial: (1) arm A: an invitation letter from a health insurance plan including a FIT test kit, (2) arm B: an invitation letter from a health insurance plan including an offer to receive a free FIT test kit by mail upon easy-to-handle request (ie, by internet, fax, or reply mail), and (3) arm C: an information letter on an existing colonoscopy offer (ie, control). Within arms A and B, a random selection of 50% of the study population will receive reminder letters, the effects of which are to be evaluated in a substudy. Results A total of 17,532 persons aged 50-54 years in a statutory health insurance plan in the southwest of Germany—AOK Baden-Wuerttemberg—were sent an initial invitation, and 5825 reminder letters were sent out. The primary end point is FIT usage within 1 year from receipt of invitation or information letter. The main secondary end points include gender-specific FIT usage within 1 year, rates of positive test results, rates of colonoscopies following a positive test result, and detection rates of advanced neoplasms. The study was launched in September 2017. Data collection and workup were completed in fall 2019. Conclusions This randomized controlled trial will provide important empirical evidence for enhancing colorectal cancer screening offers in the German health care system. Trial Registration German Clinical Trials Register (DRKS) DRKS00011858; https://bit.ly/2UBTIdt International Registered Report Identifier (IRRID) DERR1-10.2196/16413