Study 2 Overview (Forsberg et al)
Objective: To investigate the effect of colorectal cancer screening with once-only colonoscopy or fecal immunochemical testing (FIT) on colorectal cancer mortality and incidence.
Design: Randomized controlled trial in Sweden utilizing a population registry.
Setting and participants: Patients aged 60 years at the time of entry were identified from a population-based registry from the Swedish Tax Agency.
Intervention: Individuals were assigned by an independent statistician to once-only colonoscopy, 2 rounds of FIT 2 years apart, or a control group in which no intervention was performed. Patients were assigned in a 1:6 ratio for colonoscopy vs control and a 1:2 ratio for FIT vs control.
Main outcome measures: The primary endpoint of the trial was colorectal cancer incidence and mortality.
Main results: A total of 278,280 participants were included in the study from March 1, 2014, through December 31, 2020 (31,140 in the colonoscopy group, 60,300 in the FIT group, and 186,840 in the control group). Of those in the colonoscopy group, 35% underwent colonoscopy, and 55% of those in the FIT group participated in testing. Colorectal cancer was detected in 0.16% (49) of people in the colonoscopy group and 0.2% (121) of people in the FIT test group (relative risk, 0.78; 95% CI, 0.56-1.09). The advanced adenoma detection rate was 2.05% in the colonoscopy group and 1.61% in the FIT group (relative risk, 1.27; 95% CI, 1.15-1.41). There were 2 perforations noted in the colonoscopy group and 15 major bleeding events. More right-sided adenomas were detected in the colonoscopy group.
Conclusion: The results of the current study highlight similar detection rates in the colonoscopy and FIT group. Should further follow-up show a benefit in disease-specific mortality, such screening strategies could be translated into population-based screening programs.