This is a multicenter, observational study designed to develop and validate a diagnostic model for colorectal cancer and advanced colorectal neoplasia among adults undergoing routine-care colonoscopy in the Chinese population.
The study will enroll adults aged 18 to 80 years who have already been scheduled or planned to undergo colonoscopy according to routine clinical care, physical examination, or screening pathways at participating medical institutions. The study will not invite, organize, require, or otherwise arrange colonoscopy for any participant. Colonoscopy, bowel preparation, anesthesia assessment, biopsy, pathology examination, and subsequent clinical management will be performed solely according to the existing clinical pathway of each participating institution.
After informed consent, participants will be invited to complete a standardized electronic questionnaire before their scheduled colonoscopy. The questionnaire will collect self-reported information on demographic characteristics, lifestyle factors, environmental exposures, personal medical history, family history of colorectal cancer, prior colonoscopy history, and gastrointestinal symptoms. The study team will also abstract colonoscopy and pathology results from medical records. No additional biological specimens will be collected for research purposes.
The primary clinical outcome is prevalent colorectal advanced neoplasia, defined as colorectal cancer, advanced colorectal adenoma, or advanced colorectal serrated lesion identified through colonoscopy and associated pathology. Statistical and machine-learning approaches will be used to develop and validate diagnostic models. Model performance will be evaluated by discrimination, calibration, and clinical net benefit in internal validation and multicenter external validation.