Hematologic malignancies in the Japanese patients with inflammatory bowel disease

Abstract

Although attention has been focused for over 20 years on the possible increased risk for hematologic malignancies (HM) in patients with inflammatory bowel diseases (IBD) receiving immune-modulators or anti-TNF-alpha antibodies, the association is still controversial. To understand the actual conditions of HM in the Japanese patients with IBD, the research committee for IBD supported by the Ministry of Health, Welfare and Labor of Japan (IBD-MHWL) conducted a multi-center retrospective study. Questionnaires for the development of HM in IBD patients were sent to the 70 facilities participating with IBD-MHWL in the first survey, followed by the second survey using a more detailed questionnaire, sent to the 27 members with HM patients. Out of a total of 36,939 IBD patients in 70 facilities, 28 cases of HM related with IBD [12 of 10,500 UC patients (0.11 %), 16 of 6,310 CD patients (0.25 %)] were analyzed. The numbers of UC patients who developed HM were 2 (0.15 %) from the group receiving and 10 (0.13 %) from the group non-receiving thiopurine, without significant differences. The numbers of CD patients who developed HM were 4 (0.39 %) from the group receiving and 12 (0.21 %) from the group non-receiving thiopurine, without significant differences. The odds ratios of developing HM by thiopurine were 1.37 (95 % CI 0.30-6.24) in UC patients and 1.86 (95 % CI 0.60-5.78) in CD patients. Our results suggested that thiopurine therapy may not be a risk factor for HM in Japanese patients with IBD. Further accumulation of cases and prospective studies are necessary to conclude this important issue.