Dose-Adjusted EPOCH-R in Aggressive B-Cell Lymphomas: Efficacy, Molecular Prognostic Factors, and Real-World Outcomes from a Multicenter Turkish Cohort-A Turkish Oncology Group (TOG) Study.

Background and Objectives: Comprehensive real-world data on dose-adjusted EPOCH-R (DA-EPOCH-R) incorporating molecular prognostic stratification remain limited. We evaluated the long-term efficacy, safety, and prognostic determinants of DA-EPOCH-R in a multicenter Turkish cohort. Materials and Methods: This retrospective study included 140 patients with aggressive B-cell lymphoma (diffuse large B-cell lymphoma [DLBCL], n = 81; primary mediastinal B-cell lymphoma [PMBL], n = 39; other, n = 20) treated with DA-EPOCH-R at five academic centers (2015-2020). Molecular profiling included immunohistochemistry (MYC, BCL-2, BCL-6) and fluorescence in situ hybridization (FISH). Survival was estimated by Kaplan-Meier analysis with Cox regression for prognostic factors. Results: At a median follow-up of 50.1 months, 5-year overall survival (OS) and event-free survival (EFS) rates were 71.3% and 66.3%, respectively (complete response rate: 68.6%). Molecular subtypes included double-expressor (DEL; n = 39), triple-expressor (TEL; n = 21), double-hit (DHL; n = 17), and triple-hit lymphoma (THL; n = 11). Five-year OS by IPI risk group ranged from 88.6% (low) to 49.4% (high) (p = 0.005). DEL status did not confer inferior OS (p = 0.738), whereas DHL and THL had markedly poor outcomes (p < 0.001). In multivariate analysis, IPI ≥ 3 (HR 2.54; p = 0.007) and MYC FISH rearrangement (HR 3.62; p < 0.001) independently predicted inferior OS. Grade 3-4 neutropenia occurred in 57.1%, with no grade 3-4 cardiotoxicity. Conclusions: DA-EPOCH-R provides favorable long-term outcomes in aggressive B-cell lymphomas. DEL status did not confer a survival disadvantage, an association that is hypothesis-generating and requires confirmation, as the present design cannot establish a causal mechanism. FISH-defined DHL/THL remain associated with dismal outcomes, warranting novel therapeutic strategies.