Prognostic impact of immunohistochemically defined germinal center B-cell and nongerminal center B-cell subtypes of diffuse large B-cell lymphoma in rituximab era.

Abstract

e18517 Background: Diffuse large B-cell lymphoma (DLBCL) can be molecularly subtyped as either germinal center B-cell (GCB) or non-GCB. The role of rituximab(R) in these two groups remains unclear. Methods: We studied 204 patients with de novo DLBCL (107 treated with CHOP; 97 treated with R-CHOP); patients being stratified into GCB and non-GCB on the basis of BCL-6, CD10 and MUM1 protein expression. The relationships between clinical characteristics, survival data and immunophenotype were studied. Results: The median follow-up was 51months for CHOP group and 56 months for R-CHOP group. The 5-year overall survival (OS) in the CHOP and R-CHOP group was 50.4% and 66.6% (p=0.031), respectively. GCB patients had a better 5-year OS than non-GCB patients whether treated with CHOP (65.0% vs. 40.9%; p=0.011). In contrast, there’s no difference in the 5-year OS for the GCB and non-GCB with R-CHOP (76.5% vs. 61.3%; p=0.141). In non-GCB subtype, additional rituximab improved survival than CHOP (61.3% vs. 40.9%; p=0.0303). Conclusions: These results indicated that addition of rituximab to standard chemotherapy eliminate the prognostic value of immunohistochemically defined GCB and non-GCB phenotypes in DLBCL by improving the prognostic value of non-GCB subtype of DLBCL