Primary central nervous system lymphoma treated with high-dose methotrexate, high-dose busulfan/thiotepa, autologous stem-cell transplantation and response-adapted whole-brain radiotherapy: results of the multicenter Ostdeutsche Studiengruppe Hamato-Onkologie OSHO-53 phase II study.

BACKGROUND We investigated the efficacy and safety of tandem high-dose methotrexate (HD-MTX) induction followed by high-dose busulfan/thiotepa (HD-BuTT) with autologous peripheral blood stem-cell transplantation (aPBSCT) and response-adapted whole-brain radiation therapy (WBRT) in patients with newly diagnosed primary central nervous system lymphoma. PATIENTS AND METHODS Twenty-three patients were treated with HD-MTX on days 1 and 10. In case of at least a partial remission (PR), HD-BuTT followed by aPBSCT was given. Patients without response to induction or without complete remission (CR) after HD-BuTT received WBRT. RESULTS Sixteen patients received HD-MTX and HD-BuTT achieving a CR/PR rate of 69%/13%. CR/PR rates for all patients (n = 23) were 70%/13%. There were three deaths during therapy. With longer follow-up three neurotoxic deaths occurred in irradiated patients (n = 9), while no persistent neurotoxicity was seen after HD-BuTT without subsequent WBRT. At a median follow-up of 15 months (range 1-69) median event-free survival (EFS) and overall survival (OS) for all patients were 17 and 20 months (Kaplan-Meier), after HD-BuTT 27 months and "not reached", respectively. Estimated 2-year EFS and OS were 45% and 48% for all patients versus 56% and 61% for the HD-BuTT group, respectively. CONCLUSION MTX induction followed by HD-BuTT is an effective and very short time-on-treatment regimen. Median survival for patients treated with high-dose chemotherapy is not reached yet. The induction regimen needs optimisation. In this study WBRT was associated with a high incidence of severe neurotoxicity.