Colonoscopy and FIT Screening Detect More Early-Stage Colorectal Cancers in SCREESCO Trial
Screening with colonoscopy or FIT in 278,280 Swedish 60-year-olds detected more stage I-II colorectal cancers than usual care, with advanced cases declining. Adverse gastrointestinal and cardiovascular events rose slightly in the first year.
Screening for colorectal cancer with either colonoscopy or fecal immunochemical testing (FIT) detects more early-stage cancers than usual care, according to new findings from the SCREESCO trial involving over 278,000 Swedish 60-year-olds. The study, published in Nature Medicine, found higher rates of stage I–II colorectal cancer in both screening arms, while advanced cancer cases decreased, particularly in the FIT group.
The randomized trial assigned 278,280 individuals aged 60 years to once-only colonoscopy, two rounds of two-stool FIT with a low cutoff of 10 μg g−1 feces, or usual care, in a ratio of 1:6 for colonoscopy versus control and 1:2 for FIT versus control. The analysis included 31,113 individuals in the colonoscopy arm, 60,267 in the FIT arm, and 186,671 controls for colonoscopy, of whom 120,521 also served as controls for the FIT arm.
After a median follow-up of 4.8 years, the incidence rate of colorectal cancer was 107.9 per 100,000 person-years in the colonoscopy arm versus 99.9 in controls (incidence rate ratio [IRR] 1.08, 95% CI 0.91–1.28), and 96.0 in the FIT arm versus 103.9 in controls (IRR 0.92, 95% CI 0.81–1.05). Rates of stage I–II colorectal cancer were higher in the colonoscopy arm (IRR 1.38, 95% CI 1.09–1.74) and in the FIT arm (IRR 1.19, 95% CI 0.99–1.43) compared with controls.
The researchers also reported that the number of cases of advanced colorectal cancer decreased in both intervention groups, with the clearest results seen among participants who underwent FIT: 0.61 percent developed colorectal cancer compared with 0.73 percent in the control group.
Rates of cardiovascular and gastrointestinal events were slightly higher in the intervention arms during the first year, when most colonoscopies were performed, and subsequently became more similar to controls. The events were unusual, and all-cause mortality was the same across all groups. The researchers noted that the increase in CRC detection implies a benefit of screening, while the increase in adverse events suggests some initial harm.
The SCREESCO study started in 2014. Participants were identified via the population register and randomized into the three groups, with those in the FIT arm receiving a follow-up colonoscopy if they had a positive test. When precursors to cancer were found during colonoscopy, patients received treatment according to current guidelines, such as polyp removal. Participants were followed via registers until 2020, and the researchers plan to follow them until 2030 to evaluate long-term mortality. The trial is registered at ClinicalTrials.gov under NCT02078804.