Five- or 10-year colonoscopy for 1-2 non-advanced adenomatous polyps (FORTE) NRG-CC005 study: A randomized phase III non-inferiority trial comparing colorectal cancer incidence in participants with 1-2 non-advanced adenomas randomized to a 5- and 10-year surveillance colonoscopy exam schedule versus a 10-year surveillance colonoscopy exam schedule.

Abstract

TPS3631 Background: Adenomatous polyps are the acknowledged precursors of colorectal cancer (CRC). Identification and removal of adenomas is the mechanism by which screening is effective in reducing CRC incidence and mortality. Patients with 1-2 non-advanced adenomas ( < 1 cm with neither villous components nor high grade dysplasia) are recommended to return at a timing ranging from 5-10 yrs. However, evidence for the benefit, optimal timing, and recommended frequency of surveillance colonoscopy is not available. A randomized, clinical trial to demonstrate the difference in results between 5- or 10-yr surveillance for participants with non-advanced adenoma can guide clinical practice. Methods: NRG-CC005/FORTE is a prospective, randomized, non-blinded, Phase III, non-inferiority clinical trial comparing CRC incidence in participants randomized to recommendation for a 5- and 10-yr vs. a 10-yr only surveillance colonoscopy exam schedule. Other pre-defined exploratory endpoints include incidence of advanced adenomas, CRC mortality, and incidence of stage III-IV CRCs. Stratification factors include age, gender, and time from qualifying colonoscopy to randomization. Participants ≥50 and < 70 yrs of age at the time of randomization with a first-time diagnosis of 1-2 non-advanced tubular adenomas from the qualifying colonoscopy within 4 yrs prior to randomization will be eligible. Participants with a clinical diagnosis of a significant genetic risk for CRC or with a family history of CRC diagnosed at ≤60 yrs in a first degree relative or in two first degree relatives diagnosed at any age are ineligible. Other ineligibility criteria include prior history of CRC or colorectal adenomas, a hyperplastic polyp measuring ≥1 cm or traditional serrated adenomas, or life expectancy < 10 yrs due to comorbid conditions. Collection of blood, stool, and tissue samples is planned. Statistics: The primary endpoint for the trial is CRC incidence. The trial is focused on CRCs diagnosed between year 5 and year 10. By incorporating a window of +/- 1 yr to allow for somewhat earlier and later procedures, as typically occurs in clinical medicine, the primary endpoint will include incident cancers identified in years 4 through 11. A crude 4- to 11-yr incidence rate of 0.387% is assumed for the 5- and 10-yr schedule arm. The study is powered at 90% to detect a non-inferiority margin difference of 0.387% at alpha 5% in CRC incidence rate between two schedules. 9,500 participants are to be enrolled. Support: U10CA180868, -180822, UG1CA189867, U24CA196067 Clinical trial information: NCT05080673.