[Eight-year experience in treating aggressive mediastinal large B-cell lymphomas].

Aim: To make a differential diagnosis of diffuse large B-cell lymphoma (DLBCL) with primary involvement of the mediastinal lymph nodes (LN) and primary mediastinal large B-cell lymphoma (PMLBCL); to evaluate the efficiency of a modified NHL-BFM-90 (M-NHL-BFM-90) program in the treatment of the above nosological entities.

Subjects And Methods: The investigation enrolled 60 patients with large B-cell lymphoma (LBCL) with primary involvement of mediastinal LN who had been treated at the Hematology Research Center, Ministry of Health of Russia, in 2004 to 2012. The diagnosis of PMLBCL and DLBCL with primary involvement of mediastinal LN was based on histological findings, the phenotype of tumor cells, and molecular evidence. Treatment was performed according to the M-NHL-BFM-90 program. Three pregnant women received predelivery polychemotherapy (PCT) according to the VACOP-B protocol and continued to have a DexaBEAM chemotherapy regimen 3-4 weeks postpartum. In case of a residual mass, all the patients underwent consolidation radiotherapy to the mediastinal area in a total focal dose of 36 Gy.

Results: The diagnosis of PMLBCL was established in 39 patients: 10 men and 29 women whose ages were 18 to 60 years (median age 30 years); DLBCL with primary involvement of mediastinal LN was verified in 21 patients: 8 men and 13 women whose age was 21 to 70 years (median age 30 years). After m-NHL-BFM-90 treatment protocol, 5-year overall survival rates in the patients with DLBCL with primary involvement of mediastinal LN and in those with PMLBCL were 95+/-5 and 86+/-6% and 5-year event-free survival rates were 95+/-5 and 78+/-7%, respectively. All the pregnant women diagnosed with PMLBCL who had received the VACOP-B --> delivery--> Dexa-BEAM PCT regimen during pregnancy achieved remission. The follow-up periods were 30, 36, and 42 weeks.

Conclusion: The patients with new-onset LBCL and primary involvement of mediastinal LN are a heterogeneous group that includes patients having two different diagnoses: PMLBCL and DLBCL. The efficiency of high-dose PCT is different in the patients with DLBCL with primary involvement of mediastinal LN and in those with PMLBCL (in spite of their similar clinical features, similar epidemiological characteristics, and the presence of the same unfavorable prognostic factors at onset).