China Colorectal Cancer Screening Trial 1 (C-Cost1)

Colorectal cancer (CRC) is one of the most common malignancies in China. Currently, its incidence rate is increasing at a rate of 4% per year, exceeding the global annual average growth rate. Screening and early diagnosis of colorectal cancer and precancerous lesions are key measures to reduce the disease burden of colorectal cancer in China. In previous clinical studies, colorectal cancer screening in high risk population received extensive attention. However, it cannot be ignored that the majority of sporadic colorectal cancers occur in the average risk population. Therefore, there is an urgent need to develop new approach for colorectal cancer screening in the average risk population in China. Fecal Immunochemical Testing (FIT) initial screening followed by diagnostic colonoscopy is widely recommended by colorectal cancer screening guidelines worldwide. The current colorectal cancer screening approach faces challenges including limited sensitivity of initial screening technologies and insufficient population coverage in organized screening programs in China. As initial screening technologies, non-invasive blood tests which detects cfDNA methylation have been reported to have higher accuracy than FIT in detecting colorectal cancer. However, There is a lack of randomized controlled trials (RCTs) comparing the effectiveness of colonoscopy, FIT and FIT plus blood test for colorectal cancer screening. In China Colorectal Cancer Screening Trial 1 (C-Cost1), we propose to perform a multicenter, cluster randomized, parallel group trial directly comparing colonoscopy with FIT and with FIT plus blood test in the average risk population in China. The main research hypotheses are: (1) The screening protocol of FIT group (Group B) is non-inferior to the colonoscopy group (Group A) in the colorectal cancer mortality rate at 10 years; (2) The screening protocol of FIT plus blood test group (Group C) is superior to the FIT group (Group B) in the colorectal cancer mortality rate at 10 years. Either of the two hypotheses being met is acceptable.