Results of primary central nervous system lymphoma treated by radiation and chemotherapy: retrospective analysis of twelve institutions in the Tokai District of Japan, 1995-1999.

Purpose: We analyzed the therapeutic results and prognostic factors of 46 primary central nervous system lymphoma (PCNSL) patients who were treated at twelve institutions in the Tokai district of Japan between 1995 and 1999. We compared the results with those of a Japanese nationwide survey performed in the past.
Materials and Methods: We sent each institution a questionnaire about the state of patients' disease, pathological type, method and doses of radiotherapy, regimen and intensity of chemotherapy, and patients' prognoses. The range of patients' ages was 33 to 93 years (median, 61 years). Thirty-one were men and 15 were women. The most prevalent histology was diffuse large B cell type (33 patients). We used the Kaplan-Meier method to calculate the survival rate and Cox's proportional hazards model to analyze the prognostic factors.
Results: The five-year cumulative survival rate was 25%, and the median survival time was 22.7 months. The five-year disease-free survival rate was 23%. In monovariate analysis, patients who were both younger than 60 years old and had a WHO performance status (PS) score equal to or less than 2 showed a better survival rate. Furthermore, the patients receiving systemic chemotherapy showed a significantly better local control rate. In addition, patients who received systemic chemotherapy achieved a higher complete remission rate than those not receiving it. However, no factors that significantly influenced survival rate were identified in multivariate analysis.
Conclusion: We demonstrated that the therapeutic outcome of PCNSL patients has recently improved. In particular, patients with good PS showed better local control than those with poor PS. However, we could not identify any significant prognostic factors in PCNSL patients.