Treatment intensification does not improve outcomes beyond rituximab-based therapy in primary mediastinal B-cell lymphoma: a multicenter retrospective analysis.

A relevant proportion of the predominantly young patients with primary mediastinal B-cell-lymphoma (PMBCL) cannot be cured with current therapies and treatment recommendations vary. The optimal first-line regimen, particularly regarding etoposide intensification, remains debated. We retrospectively analyzed 128 patients diagnosed with PMBCL and treated heterogeneously at three different German institutions between 1992 and 2020. The analysis focused on the effects of rituximab use, etoposide incorporation, consolidative radiotherapy, and dose-density of R-CHOP (14 vs. 21) on clinical outcome. Rituximab significantly improved survival in multivariate analysis, with favorable 3-year-overall survival (OS) rates of 92% for both R-CHOP and R-CHOEP. Neither etoposide addition nor consolidative radiotherapy affected OS. In the rituximab era, the benefit of treatment intensification appears less pronounced than previously reported.