Longer intervals between colonoscopies may be safe
Patients who have had high-risk polyps removed from their bowel can probably wait five years, rather than three, until their next colonoscopy without increasing their risk of colon and rectal cancer. This is shown by two new studies published in the *New England Journal of Medicine*, in which researchers from the Karolinska Institutet have participated. The findings could reduce the number of examinations and thus the burden on both patients and the healthcare system.
Every year, around 1.9 million people worldwide are diagnosed with bowel cancer. To prevent the disease, many countries have introduced screening programmes that enable more polyps to be detected and removed before cancer develops.
However, some patients are assessed as being at increased risk of developing new polyps or cancer and are therefore recommended to undergo regular follow-up colonoscopies. These examinations are resource-intensive for the healthcare system and can be perceived as burdensome for patients.
The first results from the European Polyp Surveillance (EPoS) study, a large randomised research project on follow-up after polyp removal, are now being presented. In the EPoS II study, 10,799 patients across eight European countries who had previously had high-risk adenomas – a type of polyp – removed were followed up. Participants were randomised to undergo their first follow-up colonoscopy after either three or five years.
Low risk in both groups
After five years of follow-up, the risk of colorectal cancer was very low in both groups. Among those who waited five years for their first check-up, 0.77 per cent developed cancer, compared with 0.82 per cent among those examined after three years. Nor did the researchers observe any clear differences in how far the cancer had progressed when it was detected.
At the same time, the longer follow-up interval meant that the number of colonoscopies fell sharply. During the follow-up period, nearly 4,200 fewer examinations were carried out in the group that waited five years for their first follow-up.
”More than 99 per cent of patients did not develop colorectal cancer within five years of the polyps being removed. “The results suggest that we need to reassess when these patients should be called in for their next colonoscopy,” says Hans-Olov Adami, Professor Emeritus at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet, who coordinated the Swedish part of the research project.
At the same time, the researchers are presenting results from the parallel EPoS III study, which involved 1,861 patients with so-called serrated polyps, another type of polyp that can also be a precursor to cancer. In that group, too, the risk of cancer was low. After five years, around one per cent of the participants had developed colorectal cancer and none had died from the disease.
“The low risk of cancer was observed in both patients with high-risk adenomas and those with serrated polyps. This also underlines the importance of the first colonoscopy, as the studies are based on the polyps having been detected and completely removed,” says Hans-Olov Adami.
See the study for details of funding and any conflicts of interest.
Publication
”Colonoscopy Intervals and Colorectal Cancer Incidence after Adenoma Removal”, Rodrigo Jover, Michael Bretthauer, Joaquin Cubiella, Sarah J.E. Barry, Anna Macios, Lauren Barnett, Rune Erichsen, Michal F. Kaminski, Hans-Olov Adami, Øyvind Holme, Joep IJspeert, Monika Ferlitsch, Mario Dinis-Ribeiro, Maria Pellise, Alejandro Martínez-Roca, Sandra Baile-Maxía, Luisa de-Castro, Luis Bujanda, Pilar Díez-Redondo, Jens Aksel Nordberg Nilsen, Hong Dung Nguyen, Linn Bernklev, Jørgen Tilma, Uffe Schou Løve, Claudia Jaensch, Nastazja D. Pilonis, Mirosław Szura, Andrzej Bialek, Annemarie van Berkel, Manon C.W. Spaander, Frank Ter Borg, Monique E. van Leerdam, Miguel Hernán, Jaroslaw Regula, Magnus Løberg, Evelien Dekker, Mette Kalager, NEJM, online September, 16 2026, doi: xx