Patients with inflammatory bowel disease (IBD) are at an increased risk of developing colorectal cancer (CRC). In individuals with ulcerative colitis (UC) or Crohn’s disease (CD) affecting the large intestine, the risk of CRC is estimated to be twice as high as in the general population. Although the overall risk of developing complications ranges from 1.1 to 5.4% after 20 years of disease progression, which may appear relatively low, it is crucial to assess individual risk factors. These include sex, disease severity, duration, and other variables, which influence the likelihood of pathological changes and guide further patient management (1, 2). The incidence of colorectal cancer (CRC) among patients with IBD has recently declined, which can be attributed to the implementation of endoscopic surveillance programmes and the introduction of more precise endoscopic techniques. Therefore, to reduce the likelihood of these changes and provide optimal patient care, multiple factors must be considered. High disease severity and extensive inflammatory changes are associated with a greater risk of precancerous conditions in the colon. Patients with pancolitis are at an increased risk of developing lesions compared to those where inflammation is limited to the left side of the colon. Patients with rectal lesions do not exhibit a higher risk of cancer compared to the general population. It is important to emphasise that in patients with Crohn’s disease, only those with colonic lesions are at an increased risk of CRC.

Additionally, severe lesions (e.g., in patients with chronically uncontrolled inflammation) and the presence of strictures further increase the likelihood of CRC. Furthermore, untreated dysplastic changes can elevate the risk of CRC by up to ninefold. Precancerous lesions are more frequently observed in men and individuals diagnosed at a younger age. Also, it is important to emphasise that a detailed family history plays a crucial role in risk stratification. Patients with a positive family history of CRC, particularly in first-degree relatives under 50 years of age, have an increased likelihood of developing cancerous lesions.

A significant risk factor for patients is primary sclerosing cholangitis (PSC), especially in those with UC. The incidence of CRC in patients with PSC is estimated at 3.3 cases per 1,000 patients per year (95% CI: 1.9-5.6), with cancerous lesions occurring more frequently on the right side of the colon (3).

Liver transplantation does not appear to prevent the development of lesions, although data on this subject remain limited. The presence of pseudopolyps has been a topic of controversy. Initially, it was believed that they might be linked to an increased incidence of colon cancer and a higher risk of colectomy. However, retrospective studies, including those by de Jong et al., have shown no such association (4).

Given the increased risk of dysplasia in patients with IBD, specific oncological surveillance guidelines have been established to help reduce the incidence of CRC and related mortality. According to the European Crohn’s and Colitis Organisation (ECCO) guidelines, screening colonoscopy should be performed in all patients within 8 years after the onset of IBD (i.e., the first symptoms) (1). The only exception to this rule is patients with lesions limited to the rectum. These patients should undergo routine endoscopic screening, consistent with the recommendations for the general population. However, due to the often progressive nature of the disease, the situation can be dynamic, and progression of changes should be anticipated. Consequently, patients who initially exhibited changes limited to the rectum might, after a few years, develop lesions extending to the left side of the colon, as observed during follow-up examinations like sigmoidoscopy. Such patients require oncological surveillance according to the previously mentioned protocol (5).