Primary mediastinal B-cell lymphoma: evolution and prospects for first-line therapy. Literature review

Primary mediastinal B-cell lymphoma is an aggressive non-Hodgkin’s lymphoma that occupies a borderline position between diffuse large B-cell lymphoma and classical Hodgkin’s lymphoma. Due to the rare occurrence and the small number of prospective clinical studies, uniform standards for the treatment of primary mediastinal B-cell lymphoma have not been defined. The outcome in refractory or recurrent course remains extremely unfavorable, so the choice of the optimal first-line therapy regimen is especially relevant. The first-line therapy is represented by two main regimens: R-CHOP and DA-EPOCH-R, which have proven their effectiveness in retrospective studies. Given the aggressive course of lymphoma, more intensive approaches to therapy remain the most preferred. R-CHOP induction therapy is followed by consolidation with radiotherapy or alternative regimens (R-ICE). The DA-EPOCH-R mode does not require mediastinal consolidation irradiation. After the end of drug treatment, in order to differentiate the residual tumor tissue from fibrous and inflammatory changes in the mediastinum and determine the indications for subsequent radiation therapy, PET-CT is performed, which, however, has a high percentage of false positive results. Initiated clinical trials will provide rationale for consolidation radiotherapy after rituximab-containing regimens with a complete metabolic response, will determine the feasibility of using PET-CT as a differential diagnostic method, the advantage of the DA-EPOCH or R-CHOP regimen, as well as the need for the use of immunoconjugates, inhibitors of immune control points in combination with standard therapy in order to improve long-term results of treatment.