Colorectal Cancer Screening in Chinese Rural Communities

Prior treatment

• Previous diagnosis of colorectal cancer, history of resection of colorectal polyps (especially high-grade lesions or serrated lesions with dysplasia), or diagnosis of inflammatory bowel disease (ulcerative colitis, Crohn's disease).

Other illness

• Presence of severe comorbid conditions (e.g., severe cardiac, pulmonary, hepatic, or renal insufficiency) resulting in a life expectancy of less than 10 years, or physical condition unable to tolerate colonoscopy and bowel preparation.
• Conditions such as severe coagulopathy, recent acute myocardial infarction or stroke (e.g., within the past 3 months), or severe psychiatric illness preventing cooperation.
• Inability to understand the study content and provide informed consent due to cognitive impairment, language barriers, or other reasons.

Other

• Completion of a high-quality colonoscopy within a specified timeframe (e.g., within the past 1 year) with normal results (no polyps or only 1-2 tubular adenomas \<10mm), or completion of a high-quality sigmoidoscopy within a specified timeframe (e.g., within the past 3 years) with normal results.
• Generally excluded due to safety considerations regarding screening colonoscopy during these periods.
• Judged by the investigator to have a very high likelihood of being lost to follow-up during the study period, making completion of the screening pathway unlikely.

• Between 45 and 74 years old (inclusive).
• Permanent resident within the geographic area covered by the screening program (typically defined as residing in the area for a minimum period, e.g., 6 months or more), and possessing local household registration (hukou) or residency documentation.
• Self-reported absence of symptoms suggestive of colorectal cancer (e.g., rectal bleeding, change in bowel habits, abdominal pain, palpable abdominal mass, unexplained anemia, or unintentional weight loss).
• No prior diagnosis of colorectal cancer or precancerous lesions (e.g., high-grade intraepithelial neoplasia, serrated lesions with dysplasia).
• Not currently participating in another colorectal cancer-related clinical study that might interfere with the screening outcomes.
• Willing and able to provide written informed consent, agreeing to participate in the screening program and comply with subsequent follow-up procedures (e.g., fecal testing, colonoscopy).