Childhood IBD Tied to Higher Cancer Risk Later

By David Douglas

April 09, 2020

NEW YORK (Reuters Health) - Children with inflammatory bowel disease (IBD), and in particular Crohn's disease (CD), are at an elevated risk of developing cancer in adulthood, according to researchers in Canada.

As Dr. Wael El-Matary of the University of Manitoba, in Winnipeg, told Reuters Health by email, "Our study showed children diagnosed with IBD have a twofold increase in the chance of developing cancer over many years, but cancer is still an uncommon event."

In a paper in Gastroenterology, Dr. El-Matary and colleagues note that the established association between IBD and gastrointestinal cancers may be due to intestinal inflammation. Extra-intestinal cancers such as lymphoma and leukemia may be related to impaired immune surveillance.

"However," they add, "this risk has not been well described in a population-based setting in children with IBD."

Using the University of Manitoba IBD Epidemiology Database, the researchers identified 947 patients with IBD contracted before the age of 18 years. Of these, 576 had CD and the remaining 371 had ulcerative colitis (UC). The median age at IBD diagnosis was 14 years.

Cancers diagnosed in cases and in 9,272 controls between 1984 and 2018 were determined through linkage to the Manitoba cancer registry. Data on outpatient medication use, including azathioprine and anti-tumor necrosis factor (TNF) agents, was also obtained.

The researchers stress that the information gathered is particularly representative of the population of Manitoba. All residents have access to comprehensive universal health insurance, and with no premium to pay non-participation is minimal.

Overall cancer rates in the IBD patients were 114 per 100,000 person years compared to 57 per 100,000 person years in controls.

There were 17 cases of cancer after an IBD diagnosis compared to 75 in controls (hazard ratio, 2.0), a significant difference. In the IBD group the median age at diagnosis was 37 years and cancers reported included colorectal, nonmelanoma skin cancer and lymphoma.

The cancer risk was significantly higher in those with CD compared with controls (HR, 2.47), but only numerically higher in those with UC (HR, 1.24).

Gastroenterologist Dr. Michael J. Bartel of Fox Chase Cancer Center, in Philadelphia, told Reuters Health the study provides "additional evidence that IBD, in this case CD more than UC, is associated with cancers later in life, both colon cancers as well as other cancers like lymphoma."

Dr. Bartel, who was not involved in the study, added, "More interestingly, thiopurines (odds ratio, 0.43) and anti-TNF agents (OR, 0.56) were not significantly associated with the cancer development."

SOURCE: Gastroenterology, online March 29, 2020.