Addition of Rituximab to CHOP Regimen Improves Clinical Outcome in Non-Germinal Center Type Diffuse Large B-Cell Lymphoma.

Background: In recent years, diffuse large B-cell lymphoma (DLBCL) has been classified into the germinal center B-cell (GC) type, the activated B-cell (ABC) type, and the type 3 using global gene expression profiling or immunohistochemical staining. It has been reported that the GC type DLBCL showed significantly longer survival than the non-GC (ABC and the type 3) type DLBCL treated with CHOP or CHOP like regimen not using rituximab.

Methods: We analyzed retrospectively the prognosis between the GC and non-GC types of DLBCL treated with R-CHOP regimen. All 50 patients with DLBCL, diagnosed between July 2003 and July 2005 were included in this study. The pathology was reviewed by hematopathologist and confirmed to be de novo DLBCL according to the WHO classification. Patients with primary CNS- and post-transplant lymphomas were excluded. GC type or non-GC type DLBCL was determined by immunohistochemistry such as the expression patterns of CD10, BCL-6, and IRF-4 (MUM1). All patients were initially treated with six cycles of R-CHOP regimen consisting of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone. If we evaluated partial response after six cycles of R-CHOP, the patients have added radiation therapy.

Results: The patients consisted of 30 GC type and 20 non-GC type DLBCL with a median age of 61.0 yr (range 31–83 yr). The median follow up of surviving patients was 24 months. CR rate between GC and non-GC types were 57.0% vs. 75.0%, p=0.186, and overall response rate were 87.0% vs. 90.0%, p=0.929, respectively. The median of progression free survival was 17.3 months vs. 19.6 months, p=0.80. There is no statistical significance difference between two groups.

Conclusion: These results suggest that addition of rituximab to CHOP regimen improves clinical outcome of non-GC type DLBCL as well as GC type DLBCL.