Primary central nervous system lymphoma.

Primary central nervous system lymphoma (PCNSL) comprises approximately 5 % of all primary brain tumors. During the past two decades the incidence of PCNSL has increased, and as a result clinical research to determine the optimal treatment for PCNSL patients also has increased. Diagnosis is based on histopathologic findings traditionally established by biopsy only. More recent data raise controversy and challenges this biopsy-only paradigm, showing a potential advantage for surgical resection with progression-free survival (PFS) and overall survival (OS). Using high-dose intravenous (IV) methotrexate-based chemotherapy alone or as part of a regimen can lead to disease cure. The role of whole brain radiotherapy (WBRT) remains controversial and more frequently is omitted to avoid potential delayed neurocognitive effects, especially in patients older than age 60 years. Newer data from Memorial Sloan Kettering Cancer Center (MSKCC) using five cycles of Rituximab, Methotrexate, Vincristine, and Procarbazine (R-MVP) followed by low-dose WBRT (2,340 cgy), and then two cycles of Ara-C had excellent disease control with low neuro-toxicity and is now the basis of an ongoing RTOG (Radiation Treatment Oncology Group) trial comparing early versus delayed WBRT. Other chemotherapeutics and novel treatments, such as autologous stem cell transplantation, are being studied for potential use in PCNSL. Unlike many other primary brain tumors seen in adults, PCNSL is potentially curable; therefore, balancing treatment decisions with long-term neurocognitive effects and toxicities is crucial.