Short-term, intensive chemotherapy regimen is equally effective in Burkitt lymphoma (BL) and in the novel WHO 2008 entity “B-cell lymphoma intermediate between DLBCL and BL".

The diagnosis of Burkitt Lymphoma (BL) relies on precise histologic, immunophenotypic, cytogenetic and molecular features. The 2008 revision of the WHO Classification of Lymphoid Tissue Tumors defined a new provisional entity termed “B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL” (hereafter intermediate) to define cases of high-grade, mature B-cell NHL only partially fulfilling the criteria for BL (i.e. higher morphological heterogeneity, variable BCL2 expression, non-homogeneous Ki-67 staining, other immunophenotypical aberrations). The optimal treatment of very aggressive B-NHL is still undefined. Standard chemotherapy regimens (i.e. CHOP) are clearly inadequate to face these high kinetic lymphomas. Better results were obtained also in adults with the use of short-term, pediatric-inspired, intensive chemotherapy regimens, and recently with the addition of Rituximab. However, informations about the treatment of intermediate NHL are lacking. Thirty-eight patients (29 males, aged 17-77 years, median 34) with very aggressive, advanced B-NHL were homogeneously treated from 1988 to March 2011 at our Institution with a short-term intensive protocol alternating fractionated cyclophosphamide, vincristine and adryamicine (cycle A) with high-dose methotrexate and cytarabine (cycle B) plus intrathecal prophylaxis. Rituximab was added since 2002 in 26 patients. After revision according to the WHO 2008 criteria, 22 cases were confirmed as BL and 16 were reclassified as intermediate lymphoma. Clinical presentation was similar in both groups. The large majority of patients had advanced disease (Ann Arbor III-IV 34/38, 89.5%) and very high kinetic (Ki-67≥90% 27/36, 75%). A leukemic phase was present in 5/22 BL (22.7%) and in 6/16 intermediate lymphomas (37.5%). Of the 36 evaluable patients, 33 (91.7%) achieved the complete remission, 2 did not respond or had progressive disease (5.5%). We observed 2 toxic deaths (5.5%). Relapses occurred in 3/18 BL (16.7%) and 3/15 intermediate cases (20%). After a median follow-up of 74 months (range 6-267), the Event-Free Survival rate is 69.4%, without any significant difference between BL and intermediate lymphomas. The addition of Rituximab did not significantly influence the outcome. Our data suggest that intensive, pediatric-inspired, short-term regimen is a valuable option for treating very aggressive B-NHL and determines comparable results in BL and in intermediate lymphomas