Outcome in different molecular subtypes of diffuse large B-cell lymphoma: Indian experience.

Abstract

e18518 Background: DLBCL has emerged as a heterogeneous disease and gene expression profiling has divided it into distinct molecular subtypes of Germinal center B-Cell (GCB) and Non-GCB- cell origin. These subtypes are reported to vary in the treatment responses and outcome. Methods: We analysed 97 consecutive patients of DLBCL who had satisfactory paraffin block of baseline biopsy. After reviewing diagnosis of DLBCL, sequential immunohistochemical staining with CD10, bcl6 and MUM1 was performed in all the cases. Using these markers the cases were sub-classified into GCB and non-GCB types as per Hans’ algorithm. Baseline presentation, stage, international prognostic score and treatment outcome were recorded. Survival was assessed by Kaplan-Meier survival curves and results were compared using log-rank test. Results: Thirty-three (34%) patients were classified in GCB group while 64(66%) patients in non-GCB group. Median age in both the groups was 50 years. High IPI score2-5 (GCB-34%, non GCB-72%;p 0.005) and stage 3,4 (GCB-39%,nonGCB-61%;p 0.04) were higher in non-GCB group. All the patients were treated with 6-8 cycles of CHOP based regimen and involved field radiotherapy wherever required. Complete remission rate (GCB-52%, nonGCB-27%; p0.02) was higher in GCB group. Three year overall survival, 75% and 63 %( p0.04), and event free survival was 63% and 43 %( p0.02) in GCB and non GCB subtypes, respectively. There was no difference in between two groups for performance status, LDH level and age. Conclusions: In our study, GCB-DLBCL patients had better response rate, EFS and OS in comparison to non GCB subtype. There were higher number of patients with advanced stage and high IPI score in non-GCB subtype which might have contributed to the poorer outcome.