P349. Risk of lymphoma in patients with inflammatory bowel disease: A Korean single-center study
S.‑K. Park1, B.D. Ye1, S.‑K. Yang1, D.‑H. Yang1, K.W. Jung1, K.J. Kim1, J.‑S. Byeon1, S.‑J. Myung1, J.‑H. Kim1
1University of Ulsan College of Medicine, Asan Medical Center, Gastroenterology, Seoul, South Korea
Background: Previous studies on the risk of lymphoma in Western inflammatory bowel disease (IBD) patients have shown conflicting results. Moreover, the incidence and risk factors of lymphoma in Asian IBD patients remain unclear. Therefore, we investigated the incidence, clinical characteristics, and risk factors of lymphoma in a Korean IBD patient population.
Methods: IBD patients who were also diagnosed with lymphoma were identified from an IBD database of the Asan medical center in Korea. The standardized incidence ratio (SIR) of lymphoma was calculated using data from the Korea Central Cancer Registry (KCCR) of the National Cancer Center. In addition, the clinical characteristics of the IBD patients with lymphoma were abstracted. Finally, risk factors for lymphoma were determined by comparing cases with a matched IBD control group.
Results: A total of 2767 patient who were diagnosed with IBD between July 1997 and September 2010 and followed for more than one year were reviewed. Six cases of lymphoma were identified during follow-up after diagnosis of lymphoma. The median age at diagnosis of lymphoma was 42.5 years (range, 33–50 years) and median duration of IBD at diagnosis of lymphoma was 98 months (range, 2–216 months). Four patients had underlying ulcerative colitis and two had Crohn's disease. Subtypes of lymphoma were non-Hodgkin's lymphoma in five patients and Hodgkin's lymphoma in one patient. Three of six patients (50%) had history of taking azathioprine. However, anti-TNF-alpha agents were not given in any patients. The SIR for lymphoma was 5.28 (95% confidence interval 1.93–11.50). Drug exposure including 5‑aminosalicylic acids, corticosteroids, azathioprine, and anti-TNF-alpha agents was not associated with risk of lymphoma in a case–control study.
Conclusions: In our Korean IBD patient cohort, risk of lymphoma appears to be higher compared with the general population. Drug exposure did not show any association with risk of lymphoma. Further larger scaled studies are required to elucidate the incidence and risk factors of lymphoma in Asian IBD patients.