This is a cross-sectional cohort study based on community population jointly developed by Northern Jiangsu People's Hospital and Shanghai Kunyuan Biological Technology Co., LTD. This study will verify the real world results of polygene methylation detection of colorectal cancer in a large prospective cohort of community population, which is expected to enroll 80,000 permanent residents in Yangzhou city. The preliminary design period of the study is 5 years. In this study, questionnaire survey and polygene methylation test of colorectal cancer were used as the primary screening method, and colonoscopy was used as the further validation examination method to screen colorectal cancer and precancerous lesions. The diagnosis and outcome of all lesions were based on colonoscopy and pathological examination. The evaluation indexes include sensitivity, specificity, detection rate of precancerous lesions and adenoma.

The study is expected to complete baseline examinations of 80,000 subjects within 1 year. Community members who sign informed consent forms will complete the Colorectal cancer Risk Factor Assessment Questionnaire, history collection, and colorectal cancer polymethylation test early screening at baseline. Subjects who tested positive for polygene methylation screening for colorectal cancer will undergo a fecal immunochemistry (FIT) test, a blood carcinoembryo antigen (CEA) test, and colonoscopy within 3 months. Telephone follow-up medical history was collected at 1, 2, 3, and 4 years after baseline, and telephone follow-up survival outcomes were studied at 5 years after baseline. During the follow-up, patients diagnosed with colorectal cancer by colonoscopy will reach the study end point, and patients treated with polyps or adenomas found during colonoscopy will also reach the study end point.

Inclusion Criteria:

• 1) Permanent resident population of Yangzhou; 2) Chronological age: 40~74 years, including critical value (refer to birth date of id card); 3) Have full capacity of conduct; 4) After enrollment, they could voluntarily cooperate to complete the Colorectal cancer Risk Factor Assessment Questionnaire and accept telephone follow-up; 5) Agree to timely feed back the information related to tumor diagnosis to the investigator during the study process; 6) Willing and able to sign informed consent.

Exclusion Criteria:

• 1) History of colorectal cancer and other malignant tumors; 2) previous colorectal resection; 3) are receiving any cancer-related treatment; 4) Those who have received major surgical treatment such as blood transfusion and transplantation within 3 months; 5) Participate in other interventional clinical investigators within 3 months; 6) Pregnant or lactating women; 7) Patients with autoimmune diseases, genetic diseases, mental diseases/disabilities and other diseases considered unsuitable for the study by the researcher; 8) Poor compliance, unable to complete the study according to the judgment of the researcher.

The subjects of this study were permanent residents in Yangzhou who met the inclusion criteria