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TOPLINE:

Patients with inflammatory bowel disease (IBD), especially those who had been diagnosed before 20 years of age, and with primary sclerosing cholangitis (PSC) had an elevated risk for colorectal cancer (CRC).

METHODOLOGY:

• Researchers conducted a cohort study to analyse the effect of IBD with and without PSC on the risk for CRC.
• They enrolled patients with IBD diagnosed between January 1969 and December 2014 from the Swedish National Patient Register, including those who underwent colectomy.
• Patients were classified as those having PSC on the basis of the diagnosis of cholangitis. A total of 85,813 patients with IBD alone and 3066 with IBD and concomitant PSC were included.
• Each patient with IBD was matched with five control individuals from the general population without IBD (n = 432,037).
• Information on the diagnosis of CRC and cause of death was obtained using register data. Synchronous cancer was defined as two or more CRCs occurring within or less than 180 days.

TAKEAWAY:

• Patients with IBD and concomitant PSC and those without PSC had an increased risk for CRC (incidence rate [IR], 269 and 95 cases per 100,000 person-years, respectively) compared with matched control individuals (IR, 58 cases per 100,000 person-years; P < .001). Those with unclassified IBD and PSC had the highest risk for CRC (IR ratio [IRR], 7.38; 95% CI, 5.56-9.63).
• Compared with control individuals, patients diagnosed with IBD before the age of 20 years, with or without PSC, demonstrated a significantly elevated risk for CRC (IRR, 74.97 and 18.75, respectively; P < .001).
• CRC was more likely to be in the proximal colon among patients with IBD and PSC than among those with IBD without PSC and control individuals, with 37.5% vs 27% and 22.4% of CRC being located in the caecum and ascending colon.
• Synchronous cancers were found in 4.7% of patients with IBD and PSC and 4.4% of those with IBD without PSC vs 1.9% of control individuals (P < .001). Those with IBD and PSC had the highest mortality (adjusted hazard ratio, 2.56; P < .001).

IN PRACTICE:

"In PSC+ [IBD with a concomitant PSC diagnosis], primary CRC is more often located in the proximal colon. This must be considered when counselling patients with IBD regarding type of resection for cancer and choice of restorative surgery," the authors of the study wrote.

SOURCE:

This study was led by Maie Abdalla, MD, PhD, Department of Surgery and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden. It was published online on July 22, 2025, in Clinical Gastroenterology and Hepatology.

LIMITATIONS:

The register included only hospital discharge diagnoses before 2001, potentially missing outpatients with milder disease. Variables such as diet, smoking, family history of CRC, colitis severity, tumour stage, and others could not be accounted for. PSC lacks a specific International Classification of Diseases code; therefore, researchers had to combine a cholangitis code with an IBD diagnosis to identify cases.

DISCLOSURES:

This study was supported by the Medical Research Council of Southeast Sweden and by grants from the Swedish state under the agreement between the Swedish government and the county councils, the ALF agreement, Sweden. One author reported being an employee of AstraZeneca and having shares in the same. The author also reported receiving prior research funding and honoraria for lectures and consultancy from various pharmaceutical companies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.