Home Stool Testing Matched Colonoscopy for Preventing Colon Cancer Deaths

CATEGORY: GUT & DIGESTIVE HEALTH

An at-home stool test offered every two years was as effective as an invitation to a one-time colonoscopy at preventing deaths from colorectal cancer in a randomized trial of more than 57,000 Spanish adults aged 50 to 69. After 10 years, 0.24% of the stool-test group had died of colorectal cancer, versus 0.22% of the colonoscopy group—a difference small enough to meet the trial’s pre-set standard for “as good as.”¹ More people also completed the stool test.

Stool Kits Every Two Years Versus One Colonoscopy

Researchers invited adults at average risk of colorectal cancer—no symptoms, no personal or family history—and randomly assigned them to one of two screening offers. The first was a single colonoscopy, an exam in which a doctor inspects the entire large intestine with a thin, flexible camera while the patient is sedated. The second was a fecal immunochemical test, a small kit used at home that detects tiny traces of blood in the stool—an early warning sign of cancer—repeated every two years for up to five rounds. Anyone whose stool test came back positive was offered a colonoscopy to find the cause. Both groups were then followed for a full decade through health and death records to count colorectal cancer cases and deaths.

55 Colonoscopy Deaths Versus 60 With Stool Testing

Over the 10 years, 55 people in the colonoscopy group (0.22%) and 60 people in the stool-test group (0.24%) died of colorectal cancer. That difference cleared the strict statistical bar the researchers had set in advance for declaring the stool-test program “no worse” than colonoscopy. That bar, set before the trial began, was a gap of less than 0.16 percentage points in colorectal cancer death risk at 10 years.¹ The number of colorectal cancers diagnosed over the decade was also similar in the two groups.

39.9% Completed Stool Testing Versus 31.8% Colonoscopy

A screening test can only prevent deaths if people actually take it, and here the two approaches split: 39.9% of the stool-test group completed screening, compared with 31.8% of the colonoscopy group. A colonoscopy typically involves a day of bowel preparation, sedation, and time off work; the stool test is completed at home in minutes and mailed back. The investigators concluded the noninvasive test may be a practical alternative for organized screening programs.

Results Apply to Screening Invitations at Average Risk

This was a randomized trial—the strongest design for comparing two approaches—but it compared population-level screening invitations, and participation in both groups fell well short of public-health goals. The finding also does not pit the two tests against each other in practice: a positive stool test still leads to a colonoscopy, so the two work as partners rather than rivals. The results apply to average-risk screening, not to people with symptoms or elevated risk. And a positive stool test is not a cancer diagnosis—hemorrhoids and other benign conditions can also leave blood in the stool.

Nine Trials of 830,000 People Found No Clear Drop

A 2026 pooled analysis of nine randomized trials covering more than 830,000 people found neither stool testing nor colonoscopy invitations clearly lowered colorectal cancer deaths versus no screening over about a decade.² A larger Swedish trial of 278,000 adults found no drop in cancer diagnoses after about five years with either approach; death results are not yet reported.³ Together they suggest the comparison applies to screening invitations rather than to tests people actually complete.

Key Takeaways

• In a 10-year randomized trial of more than 57,000 adults aged 50 to 69, an at-home stool test every two years was as effective as a one-time colonoscopy invitation at preventing colorectal cancer deaths (0.24% vs. 0.22%).¹
• Participation was higher with the stool test—about 40% completed it, versus about 32% for colonoscopy.
• The two tests work together in practice: a positive stool-test result is followed up with a colonoscopy, and a positive result is not itself a diagnosis.

References

1. Castells A, Quintero E, Bujanda L, et al. Effect of invitation to colonoscopy versus faecal immunochemical test screening on colorectal cancer mortality (COLONPREV): a pragmatic, randomised, controlled, non-inferiority trial. The Lancet. 2025;405(10486):1231–1239. link
2. Kaneko M, Sakuraba A. Long-term effectiveness of endoscopic and stool-based colorectal cancer screening strategies: a systematic review and network meta-analysis. Therapeutic Advances in Gastroenterology. 2026;19:17562848261454186. link.
3. Westerberg M, Ludvigsson JF, Metcalfe C, et al. Colonoscopy and fecal immunochemical testing versus usual care in diagnostic colorectal cancer screening: the SCREESCO randomized controlled trial. Nature Medicine. 2026;32(4):1278–1285. link.