Immuno-chemotherapy containing rituximab is associated with improved survival in primary CNS B cell lymphoma.

Background. Primary central nervous system lymphoma (PCNSL) is a rare and biologically distinct subset of non-Hodgkin lymphoma. Due to its low incidence, optimal treatment strategies remain uncertain and are currently based upon outcomes from retrospective series and small phase-II studies. In addition to improving survival outcomes in systemic B cell lymphomas, rituximab penetrates the CSF after intravenous administration and also reduces CNS relapse in high-risk systemic DLBCL. However its role in PCNSL remains uncertain. We report the results of a retrospective study examining the impact of rituximab, methotrexate, cytarabine and radiotherapy in patients managed with curative intent at four university teaching hospitals between 1996-2011. Methods. A retrospective study of consecutive cases of PCNSL treated at the participating institutions was performed in accordance with institutional ethical guidelines. Patients were included if they were HIV negative and had a first presentation of biopsy-proven primary CNS lymphoma or intravascular large B cell lymphoma according to WHO 2008 criteria. Patients were excluded if they were HIV positive or not treated with curative intent. Survival correlates were assessed by Cox regression using SPSS. Results. Of 164 patients, 30 were treated with palliative intent; 134 patients met the criteria for the study. The median age was 65 years (range 21-81), 49% male. At diagnosis, 31% had an ECOG performance status (PS) >1 and 43% an elevated serum lactate dehydrogenase (LD). Deep lesions, multiple lesions and cytology positive CSF involvement were found in 63%, 52% and 14% respectively. There was no difference in base-line characteristics between rituximab recipients and non-recipients. Histological diagnosis was DLBCL (122), T cell lymphoma (4), low-grade B cell lymphoma (1), indeterminate (3) and intravascular large B cell lymphoma (4).Chemotherapy regimens included single agent high-dose methotrexate (HD-MTX, >=2g/m2; n=83), comb