medwireNews: Inviting people to fecal immunochemical test screenings results in noninferior colorectal cancer (CRC) mortality compared with invitations to colonoscopy screening, with a higher participation rate, shows a COLONPREV trial analysis.
Relative to colonoscopy, “a less invasive approach, such as faecal immunochemical test, has been validated as an effective strategy for population-based, organised colorectal cancer screening, with potentially significant implications for global health-care policies,” write Antoni Castells (University of Barcelona, Spain) and colleagues in The Lancet.
Interim analysis of the COLONPREV study previously demonstrated that individuals were more likely to participate in fecal immunochemical test screening than colonoscopy, with CRC detection rates similar for the two groups.
The latest analysis focuses on the difference in CRC-related mortality at 10 years, as well as the secondary outcomes of CRC incidence, all-cause mortality major complications, and the diagnostic yield of screen-detected premalignant lesions, the authors say.
The investigators used data on 53,051 healthy participants in Spain aged 50–69 years with no personal history of CRC, adenoma, or inflammatory bowel disease, no family history of hereditary or familial CRC, and no severe comorbidities or previous colectomy.
Between 2009 and 2021, the participants were randomly assigned to receive a biennial fecal immunochemical test (n=26,719) or one-time colonoscopy (n=26,332), and participants were able to switch screening strategies depending on their preference. Invitations for the relevant procedure were sent to each participant, with reminders sent 3 and 6 months after the initial letter.
Participants undergoing fecal immunochemical testing were indicated for work-up colonoscopy if they had at least 15 µg or 20 µg of hemoglobin/g of feces in the first and subsequent screening rounds, respectively.
The participants in the fecal immunochemical test screening group were followed up for 310,521 person–years, and those in the colonoscopy group for 304,669 person–years. The two groups were almost identical in terms of their demographic characteristics, with an average age of 58.8 years, 52.8% being women, and the majority being White.
Castells and colleagues found that people invited to a fecal immunochemical test were significantly more likely to participate than those invited to undergo colonoscopy, with respective rates of 39.9% and 31.8%, and a risk ratio (RR) of 0.79 for colonoscopy versus fecal immunochemical testing.
The fecal immunochemical testing group had a numerically, but not significantly, higher, risk for CRC mortality at 10 years than the colonoscopy group (0.24 vs 0.22%). The risk difference of 0.02 percentage points was below the threshold of 0.16, and therefore the fecal immunochemical test met the criteria for noninferiority.
Those in the fecal immunochemical testing group had a similar 10-year risk for CRC to that of the colonoscopy group, with comparable rates of 1.22% and 1.13%, respectively.
Castells et al note that more than a third of CRC cases diagnosed in both the colonoscopy and fecal immunochemical test groups were detected by examinations performed for non-screening purposes, such as surveillance and clinical manifestations. They call this “an interesting finding that was made possible by the pragmatic nature of this study, which helps to clarify the true impact of screening programmes.”
The researchers detected half as many cases of colorectal polyposis among the fecal immunochemical test group than the colonoscopy group (0.1 vs 0.2%, significant odds ratio [OR]=2.5). They were also significantly less likely to identify advanced colorectal lesions (2.4 vs 3.2%, OR=1.39) and non-advanced colorectal lesions (1.5 vs 4.5%, OR=3.17).
Both groups experienced major complications, occurring in 0.3% of the participants, with events including bleeding and perforation. There was also no significant difference in the risk for all-cause mortality at 10 years (7.68 vs 7.64%).
In an editorial related to the study, Michael Bretthauer and Mette Kalager, both at the University of Oslo in Norway, say that “[a]bsolute risks are important for transparent prioritization in health care, and for individuals when assessing personal priorities for preventive services. The COLONPREV trial provides patients, caregivers, and policy makers with long-awaited evidence to decide which test to choose.”
They add: “Consensus when the studies started was that 10 years is a sufficient follow-up duration to obtain reliable estimates. However, it has been argued that longer follow-up is needed to assess the full potential of colorectal cancer screening tests.” They therefore welcome the plans of the COLONPREV investigators to continue their follow-up.
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Lancet 2025; doi:10.1016/S0140-6736(25)00145-X
Lancet 2025; doi:10.1016/S0140-6736(25)00288-0