How I treat primary mediastinal B-cell lymphoma

Abstract

The World Health Organization now recognizes primary mediastinal B-cell lymphoma (PMBCL) as a unique clinical and biologic entity. PMBCL is distinct from other B-cell non-Hodgkin lymphoma subtypes and has features that overlap with classical Hodgkin lymphoma, including a peak incidence in the adolescent and young adult population, mediastinal presentation of disease, and molecular alterations in JAK2 and programmed death ligands. Because PMBCL is rare, there are few prospective clinical trials to guide therapy, resulting in no single standard of care. Given the long life expectancy of survivors of PMBCL, treatment approaches must balance maximizing cure while minimizing long-term toxicity. In this article, I review my approach to the treatment of PMBCL, incorporating data from adult and pediatric studies, as well as recent advances in our understanding of the molecular basis of PMBCL.

Figure 1.

Immunophenotype and common molecular alterations among thymic B-cell–derived lymphomas.

Figure 2.

Proposed treatment algorithm for management of PMBCL. ⁺Observation alone without RT after therapies other than DA-EPOCH-R has not been studied in prospective trials to date. The ongoing IELSG-37 trial seeks to determine whether RT can safely be omitted in these patients. *RT alone or combined modality with auto-SCT are both reasonable approaches in this scenario and have not been compared in clinical trials. PD, progressive disease; SD, stable disease.