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

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.