Primary mediastinal large B-cell lymphoma: frontline treatment with an alternating chemotherapy regimen based on high-dose methotrexate. A single institution experience

Background and Aims: In this retrospective analysis, we report our experience with the high-dose methotrexate-based chemotherapy B-ALL protocol of the German ALL study group followed by consolidative mediastinal radiotherapy in patients with adult primary mediastinal large B-cell lymphoma (PMLBCL) as a single-center trial. Setting and Design: Nineteen patients with newly diagnosed/untreated PMLBCL who were treated between June 1999 and May 2013 were included. Patients received a high-dose methotrexate protocol consisting of six cycles. Materials and Methods: Patients received thrice block A [day 1: methotrexate 1,500 mg/m 2 for 24 h; days 1-5: ifosfamide 800 mg/m 2 ; days 4-5: VM-26 100 mg/m 2 and ara-C 2x150 mg/m 2 (bid); days 1-5: dexamethasone 10 mg/m 2 p.o.] and thrice block B [day 1: vincristine 2 mg i.v., MTX as in block A; days 1-5: cyclophosphamide 200 mg/m 2 ; days 4-5: adriamycin 25 mg/m 2 ; days 1-5: dexamethasone 10 mg/m 2 p.o.] applied alternatively every 3 weeks. Results: After chemotherapy five patients achieved CR, nine patients CRu and four patients PR. The restaging procedures after consolidation radiotherapy showed an overall response rate of 95% (9 CR and 9 CRu). With a median follow-up of 56 months, progression free survival and overall survival at 60 months were 88%. The most common grade 3/4 hematological toxicities were leukocytopenia and neutropenia (100%), thrombocytopenia (95%), and anemia (63%). Conclusion: Our data suggest that the current high-dose methotrexate-based chemotherapy protocol followed by consolidation mediastinal radiotherapy in patients with adult PMLBCL is feasible, effective, and moderately tolerated.