Background: Diffuse large B cell lymphoma is classified into two molecular prognostic subgroups: germinal center B cell like (GCB) and activated B cell like (ABC), based on cell of origin (COO). The Hans algorithm based on immunohistochemistry (IHC) analysis helps classifying DLBCL into GCB and non-GCB subtypes in clinical practice. The non-GCB subtype has been correlated with inferior overall survival in the pre-rituximab era. The use of chemoimmunotherapy has shown variable results.
Aims: We compared retrospectively the outcomes of DLBCL patients treated with R-CHOP in our center according to the COO.
Methods: We retrospectively reviewed patients diagnosed with DLBCL and treated with R-CHOP from January 2010 to December 2020. Only patients with the COO obtained according to the Hans alborithm were include in the analysis. Demographic, prognostic and therapeutic data were collected. Overall survival (OS) and progression free survival (PFS) were estimated by the Kaplan-Meier method and compared by the log rank test. The COX model was used for the multivariate analysis.
Results: A total of 140 patients with DLBCL treated with R-CHOP were analysed. Sixty-one had their COO identified by IHC. Median age was 58 years. 72% were male. 43 (70%) had advanced stage. According to Hans algorithm, 19 (31%) GCB origin, 42 (68%) were non-GCB. The median OS and PFS time were not reached for the total population. The OS wasn’t reached for the GCB and was estimated at 42 months for the non-GCB (p=0.039).The median progression free survival time was 24 months for non-GCB and not reached for GCB (p=0.049).When adjusted for other prognostic scores (IPI, R-IPI, NCCN-IPI, CNS-IPI) the GCB sub-type was significantly associated with longer OS HR=3,7 (95% CI, 1,03 -13,3) and PFS, HR=3,7 (95% CI, 1,13 - 12,1).
Summary/Conclusion: In our local DLBCL population treated with immunochemotherapy the COO according to the Hans algorithm, despite the small number, was suprinsingly found to be a significant independent prognostic factor. This should be confirmed in future prospective studies in our region.