Background: This prospective multicentric phase II study aimed to confirm the results of the C5R protocol of high-dose methotrexate (MTX)-based chemotherapy (CT) for immunocompetent primary central nervous system lymphoma.
Patients and methods: A total of 99 patients received age-adapted CT (C5R protocol) followed by radiotherapy. Patients younger than 61 years (group 1, n = 45) received the full C5R with MTX, doxorubicin, vincristine, cyclophosphamide, and cytarabine. Patients aged 61-70 years (group 2, n = 36) received reduced doses. Patients older than 70 years (group 3, n = 18) received four courses of MTX, cyclophosphamide, and etoposide.
Results: Median age was 63 years and 51% of patients had performance status of more than one. Seventeen patients died of toxicity during CT. Complete response was achieved in 56%, 53%, and 28% of patients in groups 1, 2, and 3, respectively. With a median follow-up of 83 months, the 5-year progression-free survival was 31%, 28%, and 11% and the 5-year overall survival 42%, 31%, and 17% for groups 1, 2, and 3, respectively. Leukoencephalopathy occurred in 32% of assessable patients, in both group 1 and groups 2-3.
Conclusion: The C5R protocol was feasible in the multicentric setting with favorable long-term survival in patients younger than 60 years. Despite dose adaptation, results in older patients were disappointing.