MONTREAL — The risk for gastrointestinal cancer in Crohn's disease appears to be higher among patients who continue to have inflammatory disease and lower among those treated with steroids, the immunosuppressive agent azathioprine, or surgery.
The findings in an 11-year retrospective analysis “suggest controlling the inflammation, or the disease activity, can reduce or eliminate any risk of GI-related cancer,” Elizabeth Strevel, M.D., of the University of Toronto, said in an interview.
The investigation, which she presented as a poster at the World Congress on Gastroenterology, used databases to review the cases of 1,351 Crohn's disease patients hospitalized at the city's teaching centers. Of those patients, 65 had one or more malignancies, 37 of which originated in the gastrointestinal tract.
Patients who had a surgical intervention were at a decreased risk of malignancy of all types (odds ratio [OR] 0.4), as were patients who were given azathioprine (OR 0.4). A similar association was found for the use of steroids (OR 0.5).
“When we looked at all malignancies, indicators of increased inflammation, such as fistula, increased the risk of cancer,” said Dr. Strevel, noting an odds ratio of 1.7. “That became more prevalent when we did a subgroup analysis, just in the GI cancer group. It indicated that what we found in the whole group was probably just an effect of the GI cancers. Also, we found that the effect of the immunosuppressive agent azathioprine became more strongly protective in the subgroup, indicating that the effect is mostly on GI cancers,” Dr. Strevel said.
“While malignancy isn't overly present in Crohn's disease, it is obviously a complication with a lot of morbidity and mortality,” she explained.
“Given the numbers, it would be hard to do a randomized controlled trial. But a prospective cohort study following these people in a database, seeing what happens and assessing, will provide more accurate information,” she added.