Colonoscopy and FIT at age 60 catch colorectal cancer earlier

By Dr. Priyom Bose, Ph.D.Reviewed by Lauren HardakerFeb 24 2026

Inviting adults to colorectal cancer screening at age 60 shifts diagnoses to earlier stages without reducing short-term death rates, highlighting both the promise and trade-offs of population-based cancer detection.

Study: Colonoscopy and fecal immunochemical testing versus usual care in diagnostic colorectal cancer screening: the SCREESCO randomized controlled trial. Image credit: Jo Panuwat D/Shutterstock.com

A recent Nature Medicine study conducted a large-scale SCREESCO randomized trial to assess whether colorectal cancer (CRC) screening at age 60, delivered via primary colonoscopy or fecal immunochemical testing (FIT), provides greater benefits or harms than usual care among adults aged 60.

Variability in International CRC Screening Approaches

Many organizations, including the American College of Gastroenterology and the European Society of Gastrointestinal Endoscopy, recommend CRC screening for individuals aged 50–75 years, either by colonoscopy or FIT. While colonoscopy screening has been widely studied, few randomized trials have compared FIT to usual care. Although colonoscopy can cause serious adverse events, these remain rare, and randomized evidence on screening-related benefits and harms compared to usual care is limited.

Colonoscopy is usually offered only to people at higher risk, based on results from non-invasive tests that show more blood in the stool. In many countries, most people are screened for CRC using FIT every 2 years, especially those aged 50–75.

Notably, there is considerable international variability in the cutoff values used to define a positive FIT result, ranging from 8.5 μg hemoglobin per gram of feces to 120 μg/g. This variability reflects differences in national health policy, population risk profiles, and healthcare resources and can influence both the sensitivity and specificity of screening programs and downstream colonoscopy demand.

To guide health policy on the early detection and removal of CRC and precancerous lesions, it is essential to quantify both the benefits and risks of CRC screening.

The SCREESCO Trial Design

The SCREESCO randomized controlled trial (RCT) in Sweden was designed to directly compare different approaches to detecting CRC. In this trial, participants were randomly assigned to one of three groups: a primary colonoscopy screening group, a group receiving two rounds of two-stool FIT screening conducted 2 years apart, using a positivity threshold of 10 μg hemoglobin per gram of feces in either sample to increase sensitivity, or a control group that continued with usual care and was not invited to screening. This design allowed researchers to evaluate the effectiveness and risks of both colonoscopy and FIT screening strategies alongside the standard healthcare approach.

Biennial one-sample FIT screening has been offered in the Stockholm-Gotland region since 2015 for individuals aged 60–69 years, and since 2020 for those aged 60–74 years, with cutoffs of 40 μg/g for women and 80 μg/g for men. The nationwide rollout of this FIT-based program, applying the same criteria, began in 2021 and aims to be completed by 2026.

Using comprehensive national health registers, the SCREESCO RCT assessed the diagnostic yield, total CRC cases diagnosed, and adverse events in the screening and control groups during the diagnostic phase (2014–2020), with a median follow-up of approximately 4.8 years, on an intention-to-screen basis. The study also evaluated whether randomization produced comparable groups at baseline, whether screening increased CRC detection, particularly for early-stage (I–II) cancer, compared to usual care, and whether screening was associated with short-term adverse effects, including cardiovascular and gastrointestinal events and death from any cause.

Screening Boosts Early-Stage Cancer Detection without Affecting Overall Mortality

The SCREESCO randomized trial enrolled over 278,000 Swedish adults and randomly assigned them to colonoscopy, FIT, or no screening groups. Demographics and health history were balanced across groups, and the median follow-up time was nearly five years. Participation rates differed between groups: approximately 35 % of those invited to colonoscopy and 55 % of those invited to FIT completed at least one screening round, reflecting the intention-to-screen design.

Screening with colonoscopy or FIT shifted CRC diagnoses toward earlier stages, although the absolute number of cancers detected remained small relative to the overall population studied. The colonoscopy group had a 38 % higher rate of early-stage CRC detection compared to controls, and the FIT group had a 19 % increase. Conversely, late-stage CRCs were less common among those screened, with reductions observed in both screening arms and somewhat more pronounced in the FIT group.

Despite this stage shift, the total number of CRC cases across groups remained similar during this diagnostic-phase follow-up, indicating that screening may have advanced the timing of cancer detection within the current follow-up window rather than demonstrating a reduction in overall incidence; longer follow-up is required to determine whether screening ultimately prevents cancers or reduces mortality, and the possibility of some overdiagnosis cannot yet be excluded.

Short-term risks were present but modest. Both screening arms experienced a slight temporary rise in gastrointestinal and cardiovascular events during the first year, but these differences diminished over time. Serious screening-related complications were rare, with a 0.2 % rate of major colonoscopy-related adverse events. At the end of the follow-up period, rates of cardiovascular events were similar between groups, though the FIT arm showed a modest increase in venous thromboembolism and gastrointestinal bleeding compared to controls.

All-cause mortality was unaffected by screening, and death rates were nearly identical in all arms over the study period. The trial was not yet designed to assess colorectal cancer–specific mortality, which remains a primary endpoint planned for longer-term follow-up. Men experienced higher overall CRC incidence and more advanced cancers than women, though rates of cardiovascular events were similar, and gastrointestinal complications were somewhat less frequent among men.

Conclusions

Both colonoscopy and FIT screening detected more early-stage colorectal cancers than usual care, without increasing overall cancer incidence during the diagnostic-phase follow-up or reducing all-cause mortality. Although gastrointestinal and cardiovascular event rates were higher in the first year after screening, these differences lessened with time.

The benefit of finding more early-stage cancers must be weighed against the short-term rise in adverse events, and longer-term follow-up will be needed to determine the effect of screening on colorectal cancer mortality and overall cancer prevention.

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