A team from Philadelphia, Pennsylvania, USA, examined the risk of Hodgkin's and non-Hodgkin's lymphoma among patients with inflammatory bowel disease (IBD).
The authors performed a retrospective cohort study using the General Practice Research Database.
IBD patients were matched to randomly selected controls on age, sex, and primary care practice.
Lymphoma rates were also compared with published age- and sex-specific rates.
| Azathioprine and 6-MP did not appear to increase lymphoma risk.
| Gastroenterology |
The study included 6605 patients with Crohn's disease, 10,391 with ulcerative colitis, and 60,506 controls. The subjects were followed for an average of 3.7, 3.9, and 4.4 years, respectively.
The incidence of lymphoma was not increased in patients with IBD (relative risk = 1.20).
In subgroup analyses, an increased risk was not observed among patients with Crohn's disease (relative risk = 1.39) or ulcerative colitis (relative risk = 1.11).
Compared with IBD patients not treated with azathioprine or 6-MP, the relative risk of lymphoma among the 1465 IBD patients treated with these medications (average, 106 mg/day for 2.0 years) was 1.27.
Author James D. Lewis, of the University of Pennsylvania School of Medicine, concluded on behalf of his colleagues, "Patients with IBD do not have an increased risk of lymphoma as compared with the general population.
"Although we cannot completely rule out a modest increased risk of lymphoma with azathioprine or 6-MP therapy, an increased risk was not observed in this cohort."