Prognostic Factors of the Primary Central Nervous System Lymphoma: Clinical Experience from a Tertiary Care Center in the Middle East.

 Primary central nervous system lymphoma (PCNSL) is a rare extra nodal non-Hodgkin's lymphoma. The optimal treatment for PCNSL is still unclear. In this study, we present our experience with management of PCNSL in a tertiary care center in Iran.  In this retrospective study, 58 patients with tissue diagnosis of PCNSL were studied. All patients were treated with chemotherapy including intravenous high-dose methotrexate, rituximab and temozolomide and radiotherapy by the same oncologist. Statistical analysis was performed using SPSS.  The mean overall survival (OS) in this study was 37.4 ± 13.6 months and the mean progression free survival (PFS) was 35.1 ± 9.8 months. The mean time to progression was 15.2 ± 8.79 months among 8 patients who experienced progression in this series. Finding of a positive CSF cytology was not linked with disease progression, while HIV infection and multifocal involvement at initial presentation were strongly linked to a lower PFS. The single most important factor affecting the OS was the histopathologic type of the PCNSL; two of the three patients who died from their disease in this series had non-B cell PCNSL, whereas only one patient with DLBCL died because of brainstem involvement.  The results of this study show a lower rate of HIV-infection in patients with PCNSL as compared to the series from the western countries. Non-B cell histopathology and HIV-infection were found to be associated with the dismal prognosis.