Mantle cell lymphoma: diagnostic criteria, clinical aspects and therapeutic problems.

In 1992, after a history of more than two decades a subgroup within the diffuse low-grade B cell lymphomas designated centrocytic lymphoma, lymphocytic lymphoma of intermediate differentiation or mantle zone lymphoma gained general acceptance, now referred to as mantle cell lymphoma. Similarities between these entities were emphasized by identification of rearrangement and overexpression of CCND1 (bcl1/PRAD1) gene in the majority of cases. Unlike in all other non-Hodgkin's lymphomas sex distribution demonstrates a striking preponderance of males over females with a ratio of 3:1. Initial parameters in all published series are advanced disease with generalized lymphadenopathy in 90%, bone marrow infiltration in 60-75%, splenomegaly in 55%, hepatomegaly in 35%, gastrointestinal involvement in about 25% and peripheral blood lymphocytosis in 20-30% of patients. In generalized disease, clinical course is characterized by continuous progression with a median survival probability of 3-4 years within most series. Overall response rates of 56-88% with complete remissions in the range of 9-58% are attainable but relapse occurs predominantly within 20 months. At present there is no evidence that any conventional regimen is curative. Prospective multicenter studies are mandatory to overcome this therapeutic dilemma. Patients suitable for some form of maintenance or consolidation therapy should initially be treated intensively by anthracycline-containing regimens. Whether maintenance with interferon or intermittent chemotherapy including new agents, like purine analogues or (un)conjugated monoclonal antibodies are able to influence overall survival is a matter of (ongoing) investigations. Further experimental approaches arise from antisense oligonucleotides or ribozymes blocking the overexpression of bcl-1 especially in this lymphoma entity. At present high-dose myeloablative consolidation radiochemotherapy followed by stem cell rescue in first remission seems to be the most attractive option in younger patients.