People with ulcerative proctitis, a milder and more limited form of ulcerative colitis, are not at higher risk of developing rectal cancer than the general population. This is shown in a new Swedish registry study from Karolinska Institutet, published in Gastroenterology. The findings may contribute to more individualized follow-up of patients with inflammatory bowel disease.
Ulcerative colitis has long been linked to an increased risk of cancer in the colon or rectum, but the risk varies depending on how widespread the inflammation is. For people with ulcerative proctitis, where the inflammation is limited to the rectum, the link with rectal cancer has been unclear. The new study now provides clearer information.
The researchers identified nearly 16,000 people in Sweden who had been diagnosed with isolated ulcerative proctitis between 1997 and 2023. These were compared with just over 158,000 people from the general population who did not have inflammatory bowel disease. By linking several national health registries, the participants could be followed for a median of over ten years.
The results show that the incidence of rectal cancer and precancerous lesions, known as high-grade dysplasia, was very low in both groups. After ten years of follow-up, approximately 0.2 percent of both the patient group and the comparison group had developed rectal cancer. The researchers also saw no increased risk of rectal cancer in patients who later developed more widespread colitis.
“Our results are reassuring for patients with ulcerative proctitis. Despite long-term inflammation in the rectum, we see no increased risk of cancer compared to the general population,” says Åsa Hallqvist Everhov, senior physician in surgery and associate professor at the Department of Clinical Epidemiology, Institute of Medicine Solna, Karolinska Institutet, and first author of the study.
“This supports a more individualized approach to cancer surveillance in inflammatory bowel disease, where the extent of the disease plays a crucial role,” says Ola Olén, senior physician in pediatric gastroenterology and adjunct professor at the Department of Clinical Epidemiology, Institute of Medicine, Solna, Karolinska Institutet.
The study is based on prospective data from, among others, the national IBD registry SWIBREG, the Cancer Registry, and the Patient Registry. The research was funded by, among others, the Swedish Research Council, the Cancer Foundation, the Bengt Ihre Foundation, and ALF funds from Region Stockholm. Several of the researchers report research collaborations or support from pharmaceutical companies, while others have no conflicts of interest according to the study.