Patients who have had high-risk colorectal adenomas removed could undergo their first surveillance colonoscopy five years after the procedure, instead of the three years currently recommended by many clinical guidelines. This is the main conclusion of the study published in the New England Journal of Medicine as part of the European EPoS (European Polyp Surveillance) project.
According to the research team, this study will lead to a change in clinical guidelines with potentially major implications, as it could reduce surveillance colonoscopies by 50%, a procedure that currently represents a substantial burden on healthcare services.
The project is led by the Instituto de Investigación Sanitaria ISABIAL and the Universidad Miguel Hernández de Alicante, in collaboration with the University of Oslo and Amsterdam University Medical Center. The study included the participation of Dr. Maria Pellisé, Head of the Digestive Endoscopy Section at Clínic Barcelona, researcher in the Gastrointestinal and Pancreatic Oncology Group at IDIBAPS and member of CIBEREHD, whose work is carried out within the framework of the Clínic Barcelona Comprehensive Cancer Centre.
High-risk adenomas and colorectal cancer prevention
Colorectal cancer is one of the most common cancers worldwide. Nearly 1.9 million new cases are diagnosed each year, and many of these cancers develop from precancerous lesions known as colorectal polyps. Among the most common are adenomas, which can be detected and removed during a colonoscopy.
When these adenomas present characteristics associated with a higher risk, such as a size greater than 10 millimetres, high-grade dysplasia, a villous growth pattern or the presence of multiple lesions, patients enter surveillance programmes involving regular colonoscopies. Currently, most clinical guidelines recommend a first follow-up colonoscopy three years after adenoma removal.
However, this recommendation is mainly based on observational studies and relatively small clinical trials, highlighting the need for more robust evidence.
More than 10,000 patients from eight European countries
EPoS II is a randomised clinical trial that included 10,799 patients from eight European countries who had undergone removal of high-risk adenomas. Participants were assigned to one of two groups: one receiving a first surveillance colonoscopy at three years and the other at five years.
The aim was to determine whether extending the interval to five years was as safe as the currently recommended strategy. To do so, researchers compared the incidence of colorectal cancer between the two groups after five years of follow-up.
Five-year surveillance does not increase cancer risk
After five years of follow-up, the cumulative incidence of colorectal cancer was 0.77% among patients assigned to surveillance at five years and 0.82% among those who followed the conventional three-year strategy.
In this five-year interim analysis, researchers concluded that delaying the first surveillance colonoscopy until five years yields results comparable to the current three-year strategy in terms of the risk of developing colorectal cancer.
In addition, the distribution of tumour stages at diagnosis was similar in both groups. Overall, more than 99% of participants did not develop colorectal cancer during the five years following adenoma removal.
Nearly half as many colonoscopies
One of the most relevant findings of the study was that the five-year surveillance strategy substantially reduced the number of colonoscopies performed. During the study period, 4,434 colonoscopies were carried out in the five-year group and 8,614 in the three-year group, representing a 48.5% reduction in procedures.
According to the researchers, these findings could help update recommendations regarding surveillance intervals after the removal of high-risk adenomas while reducing the burden associated with follow-up colonoscopies for both patients and healthcare systems, without compromising clinical safety.
The EPoS project, a European initiative involving nearly 21,000 participants
EPoS is the largest European programme dedicated to studying surveillance strategies for patients with colorectal polyps and includes almost 21,000 participants from eight European countries. The EPoS I, II and III studies are ongoing and will provide further data on surveillance strategies following the removal of colorectal polyps.
Study reference:
Jover R, Bretthauer M, Cubiella J, Barry SJE, Macios A, Barnett L, Erichsen R, Kaminski MF, Adami HO, Holme Ø, Ijspeert J, Ferlitsch M, Dinis-Ribeiro M, Pellise M, Martínez-Roca A, Baile-Maxía S, de-Castro L, Bujanda L, Díez-Redondo P, Nilsen JAN, Nguyen HD, Bernklev L, Tilma J, Løve US, Jaensch C, Pilonis ND, Szura M, Bialek A, van Berkel A, Spaander MCW, Ter Borg F, van Leerdam ME, Hernán MA, Regula J, Løberg M, Dekker E, Kalager M; EPoS Study Group. Colonoscopy Intervals and Colorectal Cancer Incidence after Adenoma Removal. N Engl J Med. 2026 Sep 17;395(11):1051-1061. doi: 10.1056/NEJMoa2603816.
