Addressing the immigrant screening gap: A systematic review on interventions to increase colorectal cancer screening among immigrants in the United States

Introduction Colorectal cancer (CRC) screening rates are lower among immigrants in the United States (US) than the general population. Immigrant communities face structural barriers that disincentivize engagement in CRC screening. A growing body of literature has evaluated the effects of interventions aimed at increasing CRC screening engagement among immigrants, but findings have not been systematically synthesized. We systematically evaluated quantitative studies of interventions to increase CRC screening among immigrants in the US. Methods We searched English-language peer-reviewed and grey literature on interventions to improve CRC screening rates among immigrants, published between January 1, 2000 and April 30, 2025 in seven databases: PubMed, Cochrane Library, CINAHL (EBSCO), ClinicalTrials.gov, Embase, Scopus, and Web of Science and imported into Covidence. Two reviewers independently screened records and extracted data. Risk of bias was assessed using the Cochrane Risk of Bias 2 (ROB2) tool for randomized controlled trials, and the Risk of Bias in Non-Randomized Studies of Interventions (ROBINS-I) tool for other study designs. Quantitative synthesis was restricted to studies that explicitly defined immigrants in their population. The protocol was registered in PROSPERO (CRD42023488183) and published in PLOS One. Results The primary outcome was CRC screening completion. Of 1,824 unique records screened, 45 studies were included (39 randomized trials, 6 non-randomized studies), representing over 21,000 participants. Individualized education (n=12), navigation-based interventions (n=17; including patient navigation alone and navigation plus culturally targeted materials), and non-individualized educational campaigns (n=7) were the most evaluated strategies, alongside mailed outreach with fecal tests and telephone reminders (n=4). Across trials reporting screening outcomes for both intervention and control arms (n=19), interventions increased screening by an average of 20% compared with control, with culturally tailored navigation-based approaches generally yielding the largest gains. Substantial heterogeneity in immigrant group definitions, settings, and outcome measures, coupled with limited and inconsistently collected immigration-related variables, constrained cross-population comparisons and precluded a formal meta-analysis. Conclusions Culturally and linguistically tailored patient navigation emerged as the most effective approach. Limited and inconsistently collected immigration-related information and heterogeneity across immigrant groups restricted inference but the findings still offer concrete guidance for practitioners and policymakers developing tailored programs and policies to improve CRC screening uptake among immigrant populations in the US.