The incidence rate and mortality of colorectal cancer are increasing year by year. Most colorectal cancer develops from colorectal adenoma and is a disease that can be prevented and controlled. Thanks to early screening, the incidence rate and mortality of colorectal cancer have declined year by year. However, due to poor compliance with colonoscopy and the lack of efficient and convenient early screening methods, it is difficult to screen for colorectal cancer in China. According to the data from Shanghai Xuhui District Center for Disease Control and Prevention, the proportion of colonoscopies in high-risk groups for colorectal cancer is less than 18%.

This project plans to use the latest colorectal cancer screening technology, namely, 5hmC detection in peripheral blood and DNA methylation detection in feces, for those who are positive in the colorectal cancer incidence risk questionnaire or fecal occult blood in Xuhui District, Shanghai. It is strongly recommended that subjects with positive screening should undergo colonoscopy, to effectively improve the rate of colonoscopy and the early diagnosis rate of colorectal cancer. At the same time, to explore the screening efficiency of the early diagnosis model of 5hmC cancer.

Inclusion Criteria:

• Age ≥ 50 years old and<75 years old;

  • The initial screening was positive (fecal occult blood or colorectal cancer risk questionnaire was positive)； ③ Receive sample collection; ④ Sign the informed consent form.

Exclusion Criteria:

① History of colorectal cancer, colorectal adenoma, and treatment;

• Enteroscopy was performed after the initial screening was positive; ③ The subject or family members could not understand the conditions and objectives of the study or refused to participate in the study.

Residents of Xuhui District, Shanghai, who are initially screened as high-risk for colorectal cancer by Shanghai Xuhui District Center for Disease Control and Prevention, and do not receive a colonoscopy. People who are willing to accept the screening program.