Treatment of Primary Central Nervous System Lymphoma with High-dose Methotrexate and Radiotherapy in HIV-negative Patients.

Background: We assessed the outcome of high-dose methotrexate (HD-MTX) chemotherapy with or without radiotherapy (RT) in primary central nervous system lymphoma (PCNSL) patients.

Methods: Fifty-one HIV-negative patients with an average age of 50.3 years were treated with chemotherapy regimen included 2500 mg/m(2) MTX with Leucovorin rescue and 1.4 mg/m(2) vincristine (day two), which was administered every other week for 6 weeks. Only the patients who were younger than 60 years received RT. All patients received two cycles of 3000 mg/m(2) cytarabine at the end of the treatment for two successive days.

Results: Diffuse large B-cell lymphoma was the most common histologic subtype (90.2%), and twenty-six (51.0%)patients had multiple brain lesions. The median survival of patients who were younger than 60 years was 37 months. For patients who were older than 60 years, the median survival was 20 months. The median survival of men and women were 30 and 34 months, respectively. There was no significant difference in survival of patients in terms of age and sex. Overall, sixteen patients (31%) out of fifty-one patients died, five of them were older than 60 years and eleven were younger than 60 years. Twenty-five (49%) of all patients experienced relapse, and 10 (40%) of them died after rechemotherapy.

Conclusions: The base of our chemotherapy regimen was HD-MTX as the regular doses of MTX cannot penetrate the blood brain barrier (BBB). Our results indicated that the combination of HD-MTX with RT may not influence the outcome of PCNSL; thus, RT cannot be the first line therapy.