Lymphoma in Patients with Inflammatory Bowel Disease: A Multicentre Collaborative Study Between GETAID and LYSA.

Background: Inflammatory bowel disease [IBD] is associated with an increased risk of developing lymphoma. Although recent data have clarified the epidemiology of lymphoma in IBD patients, the clinical and pathological characteristics of lymphoma in IBD remain poorly known.

Methods: Patients with IBD and lymphoma were retrospectively identified in the framework of a national collaborative study including the Groupe d'Étude Thérapeutique des Affections Inflammatoires du Tube Digestif [GETAID] and the Lymphoma Study Association [LYSA]. We characterized clinical and prognostic features for the three most frequent lymphoma subtypes occurring in IBD. We performed a multicentre case-control study. Controls [lymphoma de novo] were matched [5:1] to cases on gender, age at diagnosis, lymphoma subtype, year of diagnosis, and IPI/FLIPI indexes. Overall survival and progression-free survival were compared between cases and controls.

Results: In total, 133 IBD patients with lymphoma were included [males = 62.4%, median age at lymphoma diagnosis = 49 years in males; 42 years in females]. Most had Crohn's disease [73.7%] and were exposed to thiopurines [59.4%]. The most frequent lymphoma subtypes were diffuse large B cell lymphoma [DLBCL, 45.1%], Hodgkin lymphoma [HL, 18.8%], and follicular lymphoma [FL, 10.5%]. When matched with 365 controls, prognosis was improved in IBD patients with DLBCL compared to controls [p = 0.0064, hazard ratio = 0.36] or similar [HL and FL].

Conclusions: Lymphomas occurring in IBD patients do not seem to have a worse outcome than in patients without IBD. Due to the rarity of this situation, such patients should be managed in expert centres.