The Impact of Follow-up Colonoscopy on Survival in a Fecal Immunochemical Test-Based Colorectal Cancer Screening Program: A Nationwide Study

BACKGROUND: Various colorectal cancer screening programs are thought to be responsible for the decline in colorectal cancer incidence and mortality in developed countries. However, a few recently published studies indicate that many patients do not fully complete the preplanned colorectal cancer screening. Currently, there is a lack of high-volume data examining patient compliance and its impact on the screening program results. OBJECTIVE: To assess the relationship between participation and compliance within the program and the mortality of patients who participate in the screening program. DESIGN: Large database cohort study. SETTINGS: Nationwide colorectal cancer screening program of a European Union country (Lithuania). PATIENTS: Data of patients aged 50 to 74 years who participated in the colorectal cancer screening program from January 2013 to December 2019 were extracted from a national database. MAIN OUTCOME MEASURES: Mortality data were extracted on all persons who died from 2013 through December 2020. Patients were divided into 4 groups according to their adherence to the colonoscopy screening program. RESULTS: A total of 1,521,394 patients participated in the screening program. A positive fecal immunochemical test was detected for 127,503 patients (8.3%), of whom 55,202 (43.3%) proceeded with further colonoscopy. Patients who had a negative fecal immunochemical test result had the lowest mortality rates (4.9%), and patients who had a positive fecal immunochemical test result but did not undergo follow-up colonoscopy had the worst mortality rate (8.6%; p < 0.001). The logistic regression model indicated that patients with a positive fecal immunochemical test and without a subsequent colonoscopy had a significantly increased mortality risk (OR 2.18; 95% CI, 2.12-2.24; p < 0.001). LIMITATIONS: Lack of data on timing of colonoscopy, comorbidities, lifestyle factors, or previous medical history. CONCLUSIONS: Our study indicates that noncompliers with colonoscopy, especially women, after a positive fecal immunochemical test are at a significantly increased all-cause mortality risk.