IBD with primary sclerosing cholangitis linked to increased risk of CRC

Patients with inflammatory bowel disease (IBD) face an increased risk of colorectal cancer (CRC), and this association is especially pronounced for those who have primary sclerosing cholangitis (PSC), according to a study.

Researchers used data from the Swedish National Patient Register and identified 88,879 patients with IBD. These patients were matched to 432,037 controls from the general population.

In the IBD cohort, 3,066 had PSC. Those who did vs did not have PSC were more likely to be younger at IBD diagnosis (median 28.9 vs 37.5 years; p<0.001), have Crohn’s disease (odds ratio, 0.34, 95 percent confidence interval [CI], 0.30–0.38), and to have undergone colectomy (hazard ratio [HR], 1.11, 95 percent CI, 1.00–1.24; p=0.046).

Compared with controls, the IBD cohort overall had an 83-percent increased risk of CRC (HR, 1.83, 95 percent CI, 1.72–1.96; p<0.001). The incidence rate of CRC was 269 per 100,000 among IBD patients with PSC, 95 per 100,000 among IBD patients without PSC, and 58 per 100,000 among controls. Median follow-up time until cancer diagnosis was 19.2, 13.9, and 14.9 years, respectively.

PSC patients whose IBD was diagnosed within age 20 years had a markedly elevated risk of CRC compared with controls (incidence rate ratio, 74.97, 95 percent CI, 44.7–126.1; p<0.001). Furthermore, IBD patients with PSC had 9–16 times higher risk of cancer in cecum/ascending, transverse, and descending colon relative to sporadic CRC among controls.

Synchronous cancer was seen in 4.7 percent of IBD patients with PSC, 4.4 percent of IBD patients without PSC, and 1.9 percent of controls (p<0.001).

The associations reported in this study should be considered when monitoring and counselling patients with IBD.