ObjectiveTo explore the clinical characteristics and the relationship between rational therapy and prognosis in primary central nervous system lymphoma (PCNSL).MethodsClinical data of 23 patients pathologically confirmed as PCNSL and treated in our hospital from January 2005 to December 2007 were collected and analyzed retrospectively.SPSS 13.0 statistical analysis software was used to analyze the correlation between therapy,clinical characteristics and prognosis.Among the 23 patient,10 were male and 13 were female,with a median age of 50 (2-75) years old.Eighteen patients were undertaken lumbar puncture,and tumor cells in cerebral spinal fluid (CSF) was found in 4 patients.Tumorectomy was performed in 8 patient,while 15 patients biopsy.Among them,4 accepted whole brain irradiation,6 accepted associated chemotherapy based on a high-dose of methotrexate (MTX)and 13 accepted radiotherapy combined with chemotherapy.Results Kaplan-Meier analysis showed that in this serial patients,the median survival time was 45.0 months and the 3-year survival rate was 56.5％.Log-Rank test revealed that the whole survival time and the non-progression survival time of radiotherapy combined with chemotherapy (43.8 and 30.0 months,respectively) and high-dose MTX chemotherapy ( 39.7 and 29.7 months,respectively )were much longer than those of radiotherapy alone (25.7 and 19.8 months,respectively,all P ＜ 0.05 ).Log-Rank test showed no significant difference between high-dose MTX chemotherapy alone and radiotherapy combined with chemotherapy (P ＞0.05 ),but the whole survival time was much shorter in high-dose MTX chemotherapy ( P ＜ 0.05 ).ConclusionsThe detection of tumor cells in CSF can confirm the diagnosis,but pathological biopsy is the gold standard.The efficacy of associated chemotherapy based on a high-dose of MTX combined with radiotherapy is much better than radiotherapy or chemotherapy alone.