Colorectal Cancer and Advanced Adenoma after Single CT Colonography or Biennial FIT Screening in the SAVE Randomized Controlled Trial

Background A 5-year screening interval for CT colonography (CTC) and a 2-year screening interval for fecal immunochemical tests (FITs) have been recommended on the basis of the natural history of colorectal cancer (CRC). Purpose To assess whether the recommended 5-year interval for screening CTC is appropriate and whether CTC is associated with earlier diagnosis relative to biennial FIT screening. Materials and Methods This secondary analysis of the SAVE randomized controlled trial was conducted between March 2012 and March 2018; 14 981 participants aged 54-65 years were randomly assigned to groups undergoing a single CTC examination or three biennial FITs for CRC screening. After the trial period ended, all participants aged younger than 70 years were invited to undergo biennial FIT. The incidence rates of CRC and advanced adenoma (AdA) until December 31, 2021 (mean, 8.4 years of follow-up), in the 1286 participants who underwent CTC and 6027 participants who underwent at least one trial FIT were compared using Cox regression models adjusted for age, sex, and socioeconomic status. Results In the CTC arm, one interval CRC was observed during the 5 years following CTC, and no cancers were detected thereafter. Overall, nine CRC cases were diagnosed in the CTC arm and 58 in the FIT arm, with no statistically significant difference in CRC incidence rates between the two groups (adjusted hazard ratio, 0.73 [95% CI: 0.36, 1.47]; P = .38). All stage IV CRCs (n = 7) occurred in the FIT arm. By the end of follow-up, the CTC arm showed a persistently and significantly higher incidence rate of AdA compared with the FIT arm (adjusted hazard ratio, 1.46 [95% CI: 1.11, 1.92]; P = .007). Conclusion The 5-year interval for screening CTC is appropriate and might be associated with earlier diagnosis relative to FIT screening. Clinical trial registration no. NCT01651624 © RSNA, 2025 See also the editorial by Pietryga and Kim in this issue.