Evaluation of the Effectiveness of Colonoscopy, Fecal Immunochemical Test and Risk-adapted Screening Strategies in Population-based Colorectal Cancer Screening: A Multicenter Randomized Controlled Trial

  Objective  To evaluate the feasibility and effectiveness of colonoscopy, fecal immunochemical test(FIT) and risk-adapted screening strategies in population-based colorectal cancer screening.

  Methods  Based on the randomized controlled trial of colorectal cancer screening(TARGET-C) which was carried out in 6 centers of 5 provinces in China from May 2018 to May 2021, the participants who met the inclusion criteria of the study were randomly assigned to one of the following screening intervention groups in a ratio of 1∶2∶2, which were colonoscopy group, FIT group and risk-adapted screening group(participants evaluated to be at high risk were recommended to undertake colonoscopy, those at low risk were recommended to undertake FIT and FIT positive people received colonoscopy). The 3 groups received different schemes of colorectal cancer screening, in which the colonoscopy group only received baseline screening, whereas the FIT group and the risk-adapted screening group received annual follow-up screening on the basis of baseline screening. The main outcome was the detection rate for advanced colorectal neoplasm(including colorectal cancer and advanced adenoma). The participation rate, detection rate for any neoplasm and resource load of colonoscopy among different screening groups were further analyzed.

  Results  A total of 19 373 participants meeting the inclusion and exclusion criteria were enrolled, including 8082 males(41.7%) and 11 291 females(58.3%), with an average age of (60.5±6.5) years. Among them, 3883 were in the colonoscopy group, 7793 in the FIT group, and 7697 in the risk-adapted screening group. After 1 or 3 rounds of screening(2 rounds of follow-up screening completed in FIT group and risk-adapted screening group), the overall participation was the highest for the FIT group(99.3%), followed by the risk-adapted screening group(89.2%) and the coloscopy group(42.3%). According to the intention-to-treat analysis, the detection rates of advanced neoplasm in the colonoscopy group was higher than that in the FIT group(2.76% vs. 2.17%, OR_{colonoscopy vs FIT}=1.30, 95% CI: 1.01-1.65, P=0.037); there were no statistically significant differences regarding the detection rates of advanced neoplasm between the colonoscopy group and the risk-adapted screening group(2.76% vs. 2.35%, OR_{colonoscopy vs risk-adapted screening}=1.19, 95% CI: 0.93-1.51, P=0.156), and between the risk-adapted screening group and the FIT group(2.35% vs. 2.17%, OR_{risk-adapted screening vs FIT}=1.09, 95% CI: 0.88-1.34, P=0.440). The number of colonoscopies needed to be performed to detect one advanced neoplasm was used as an indicator to evaluate the resource load of colonoscopy. The number was the highest for the coloscopy group(15.4), followed by the risk-adapted screening group(10.2) and the FIT group(7.8).

  Conclusions  The risk-adapted screening strategy is feasible and effective in population-based colorectal cancer screening, and could serve as an effective supplement to the traditional colonoscopy and FIT-based colorectal cancer screening strategies.