Implementing organized colorectal cancer screening programs in Europe-protocol for a systematic review of determinants and strategies

Background: With a high mortality of 12.6% of all cancer cases, colorectal cancer (CRC) accounts for substantial burden of disease in Europe. In the past decade, more and more countries have introduced organized colorectal cancer screening programs, making systematic screening available to entire segments of a population, typically based on routine stool tests and/or colonoscopy. While the effectiveness of organized screening in reducing CRC incidence and mortality has been confirmed, studies continuously report persistent program implementation challenges. This systematic review will synthesize the literature on organized CRC screening programs. Its aim is to understand what is currently known about the barriers and facilitators that influence the implementation of these programs and about the implementation strategies used to navigate these determinants.

Methods: A systematic review of primary studies of any research design will be conducted. CENTRAL, CINAHL, EMBASE, International Clinical Trials Registry Platform, MEDLINE, PsycINFO, and Scopus will be searched. Websites of (non-)government health care organizations and websites of organizations affiliated with authors of included studies will be screened for unpublished evaluation reports. Existing organized CRC screening programs will be contacted with a request to share program-specific grey literature. Two researchers will independently screen each publication in two rounds for eligibility. Included studies will focus on adult populations involved in the implementation of organized CRC screening programs and contain information about implementation determinants/ strategies. Publications will be assessed for their risk of bias. Data extraction will include study aim, design, location, setting, sample, methods, and measures; program characteristics; implementation stage, framework, determinants, strategies, and outcomes; and service and other outcome information. Findings will be synthesized narratively using the three stages of thematic synthesis.

Discussion: With its sole focus on the implementation of organized CRC screening programs, this review will help to fill a central knowledge gap in the literature on colorectal cancer screening. Its findings can inform the decision-making in policy and practice needed to prioritize resources for establishing new and maintaining existing programs in the future.

Systematic review registration: PROSPERO (CRD42022306580).