Treatment of Primary Central Nervous System Lymphoma: Standard Treatments According to the Japanese 2019 Guideline and Novel Treatments

Abstract

Management of primary central nervous system lymphoma (PCNSL) includes induction and consolidation therapies in newly diagnosed patients, as well as second-line therapy in relapsed or refractory patients. The current standard-of-care induction therapy involves methotrexate (MTX)-based multi-agent immunochemotherapy with rituximab, methotrexate, procarbazine, and vincristine. Deferral or dose reduction of radiation therapy is considered in consolidation therapy, especially in elderly patients who carry a high risk of radiation-induced delayed neurotoxicity. Since elderly patients comprise the main population of PCNSL, minimally toxic treatments that are effective and feasible for them are strongly needed. For second-line therapy, rechallenge using MTX-based chemotherapy (in patients with a prior durable response to MTX-based chemotherapy) or radiation therapy is considered. Bruton's tyrosine kinase inhibitor tirabrutinib (for relapsed and refractory PCNSL) and high-dose chemotherapy with autologous stem cell transplantation support using thiotepa and busulfan (BuTT) were approved by the Japanese Ministry of Health and Welfare in March 2020 and has recently become available for clinical practice. While these novel treatments seem promising, the optimal use of these treatments along with the standard-of-care therapy of PCNSL should be defined and investigated in clinical trials.