Is there an increased risk of lymphoma and malignancies under anti-TNF therapy in IBD?

Tumour necrosis factor alpha (TNF-alpha) inhibitors ensure valuable treatment advantages for patients with inflammatory bowel diseases (IBD) by offering a more targeted anti-inflammatory therapy. In contrast, there is concern that it might increase the risk of long-term complications including infections and the risk for malignancies and non-Hodgkin's lymphoma (NHL). Although the results from hospital- and population-based studies are conflictive, the results of a meta-analysis suggest that patients receiving purine analogues for the treatment of IBD have a lymphoma risk 4-fold higher than expected. Analyses of lymphoma risk in patients receiving biologic agents directed against tumor necrosis factor-alpha are confounded by concomitant use of immunosuppressive agents in most of these patients. Nevertheless, in a recent meta-analysis, a 3-fold increased risk of NHL was found in patients with previous immunomodulator exposure, while scattered case reports point to the potentially increased risk of a rare form of NHL (Hepatosplenic T-cell lymphoma) with the use of azathioprine-anti-TNF combination. The absolute rate of these events remains, however, low and should be weighed against the substantial benefits associated with treatment. In contrast, data obtained from observational studies and registries did not show an increased risk for solid tumours or lymphoma in patients with anti-TNF exposure. The aim of this review is to summarize the available evidence on the association between malignancy and anti-TNF treatment in IBD.