Inflammatory bowel disease (IBD) is commonly treated with immunomodulators such as azathioprine and 6-mercaptopurine.
Studies examining lymphoma risk in IBD patients treated with these medications have been underpowered and have yielded conflicting conclusions.
D Lewis and colleagues conducted a meta-analysis to provide a more precise estimate of the relative risk of lymphoma among IBD patients treated with azathioprine or 6-mercaptopurine.
Studies were included if they were written in English language and in full article.
The researchers included cohort studies specifically designed to evaluate cancer as an adverse outcome of treatment with azathioprine or 6-mercaptopurine.
|The combined data of 6 studies showed a pooled relative risk of 4|
The team calculated pooled standardized incidence ratios to estimate the relative risk of lymphoma associated with therapy.
The team assessed heterogeneity using Poisson regression.
A sensitivity analyses examined the influence of individual studies on risk estimate and heterogeneity statistics.
The researchers identified 6 studies that met the inclusion criteria.
When the data were combined across all studies, the team found that the pooled relative risk was 4.
The sensitivity analysis showed that exclusion of any study had a relatively small effect on the pooled relative risk estimate.
However, the team noted that excluding either the study with the highest or lowest relative risk eliminated the statistically significant heterogeneity.
Dr Lewis' team concludes, “Our data suggest an approximate 4-fold increased risk of lymphoma in IBD patients treated with azathioprine and 6-mercaptopurine.”
“The increased risk of lymphoma could be a result of the medications, the severity of the underlying disease, or a combination of both.”