Abstract
Recent clinical studies for defining a standard treatment of primary central nervous system lymphomas (PCNSL) have demonstrated that high-dose methotrexate (MTX) -based chemotherapy that precedes whole brain irradiation is most effective for achieving longer survival rates for the patients. But the high-dose MTX chemotherapy not infrequently induces delayed neurotoxicity, which produces progressive dementia, particularly in elderly patients older than 60 years old. Furthermore, there are some MTX-resistant tumors and patients with severe renal disfunction in whom high-dose MTX cannot be employed. To reduce severe neurotoxicity, PCNSL patients were treated by chemotherapy alone with radiotherapy deferred as long as possible, but the prognostic outcome was worse than that of the combination therapy of high-dose MTX and radiation. In the future, determination of the optimum dose of MTX, selection of additional effective chemotherapeutic agents and possible reduction of radiation dose should all be solved in order to establish a standard treatment for PCNSL.
