564P A large-scale real-world study for colorectal cancer screening

Colorectal cancer (CRC) is a major public health concern worldwide. CRC screening is recommended for average-risk population starting at age 45 to 50. However, the participation rate of CRC screening is often low due to lack of awareness or limited access to screening. Fecal DNA tests have shown promising performance in detecting CRC, but large-scale, prospective, population-based evidence for screening effectiveness has been lacking. A community-based CRC screening program was implemented in Wuhan, Hubei Province, China, from 2021 to 2022. Residents aged between 45 and 60 were eligible. Stool samples were self-collected and returned to the community health centers. A fecal DNA test (ColoTect®) which detected methylation status of SDC2, ADHFE1, and PPP2R5C was used, with a sensitivity of 88% for detecting CRC and a sensitivity of 46% for detecting advanced adenoma, at a specificity of 92%. Participants who tested positive were advised to receive diagnostic colonoscopy. All participants provided written informed consent. 105,537 subjects were invited, 102,348 subjects returned stool samples and 101,217 passed quality control. 4,483 (4.4%) subjects tested positive for fecal DNA test, and 3,200 (71.3%) underwent colonoscopy. Among these, 2347 (73.3%) had abnormal colonoscopy findings, of which 1,330 (56.7%) subjects received pathological diagnosis. Positive predictive values (PPVs, number of cases/number of colonoscopies) for CRC, adenomas, polyps were 1.3%, 16.3%, and 21.6%, respectively; 28.0% of all colonoscopies showed colorectal neoplasm but lack pathological diagnosis. 6.1% showed other abnormalities such as enteritis. Compared to a national CRC program implemented in Hubei Province between 2018 and 2019 using fecal immunochemical tests and CRC risk assessment questionnaires, current program showed a lower initial positive rate (4.4% vs. 17.4%), higher PPVs for CRC (1.3% vs. 0.08%) in the age-matched group, and a higher adherence rate for colonoscopy (71.3% vs. 18.2%). Preliminary prospective evidence suggested that fecal DNA tests had promising diagnostic yield in population-based CRC screening, outperforming FIT/risk assessment questionnaire-based screening strategy.