Investigators from New Zealand and England assessed whether there is an increased risk of malignancy after treatment with azathioprine for inflammatory bowel disease (IBD).
Previous studies have found that there was an increased risk of malignancy after azathioprine therapy in renal transplant and rheumatoid arthritis patients.
Aziathioprine was given to 626 of 2204 patients (855 with Crohn's disease and 1349 with ulcerative colitis), for a mean duration of 27 months.
The mean follow up from diagnosis was 13.7 years and the mean follow up form the start of azathioprine treatment was 6.9 years.
|4.5% of patients both treated and not treated with azathioprine developed cancer.
| Alimentary Pharmacology & Therapeutics |
Some 31 cancers were observed in 30 patients treated with azathioprine (4.5%) and 77 cancers were observed in 70 patients not treated with azathioprine (4.5%).
Logistic regression analysis showed that treatment with azathioprine did not significantly affect the risk of development of cancer.
Eight patients had lymphoma; 3 had been given azathioprine.
For patients with ulcerative colitis, the number of colorectal cancers (including high-grade dysplasia) in patients given azathioprine was 8 of 355 (2.2%), compared with 28 of 994 (2.8%) for patients not given azathioprine.
The team found that the cumulative risk of colorectal cancer or dysplasia after 10, 20, 30, and 40 years of ulcerative colitis was 0.4%, 1.3%, 9%, and 15.5%, respectively.
Professor A. G. Fraser, of the University of Auckland, New Zealand, concluded on behalf of fellow authors, "There was no increased risk of cancer diagnosis following azathioprine treatment."