Diminishing prognostic role of preexisting diabetes mellitus for patients with diffuse large B-cell lymphoma in the rituximab era.

Rituximab reforms the treatment of diffuse large B-cell lymphoma (DLBCL) and the prognostic significance of baseline patient features should be reevaluated. Few population-based studies have investigated the association of diabetes mellitus (DM) and outcomes of lymphoma; however, the results remain inconclusive. From January 1, 2000 to December 31, 2009, a total of 468 consecutive newly diagnosed DLBCL patients receiving first-line chemotherapy with cyclophosphamide, vincristine, doxorubicin, and prednisolone (CHOP) or rituximab plus CHOP (R-CHOP) were enrolled. Pre-existing DM was defined according to medical history, use of antidiabetic medications, or any record of an abnormal hemoglobin A1c test. Progression-free survival (PFS) and overall survival (OS) were estimated and compared using the Kaplan-Meier method with a log-rank test. CHOP was administered in 194 patients, and 274 patients received R-CHOP. DM was identified in 16.2 % (76/468) of patients. Diabetic patients were older and more performance restricted, compared to the non-DM patients in both the CHOP and R-CHOP groups. In the CHOP group, 5-year PFS and OS were inferior in DM patients (PFS, 32.4 vs. 50.0 % (P = 0.039); OS, 38.2 vs. 62.5 % (P = 0.002)). However, outcomes were similar for both DM and non-DM patients in the context of R-CHOP treatment (PFS, 69.0 vs. 57.3 % (P = 0.179); OS, 76.2 vs. 69.8 % (P = 0.586)). The response rate of chemotherapy in DM patients was also improved to a level similar to non-DM patients with rituximab use. In conclusion, the prognostic significance of preexisting DM in DLBCL patients is changing in the rituximab era. The potentially additional benefit of rituximab in DM patients merits further investigation.