Haema 2017; 8(1): 64-73
by Chrisavgi Lalagianni
Department of Hematology and Bone Marrow Transplantation, Papanikolaou General Hospital, Thessaloniki, Greece
Abstract
PCNSL is a rare aggressive non-Hodgkin lymphoma, usually of large B-cell histology, restricted to the nervous system. Its prognosis is worse than that of systemic lymphomas. The diagnosis should be confirmed by stereotactic biopsy or vitrectomy where appropriate, as concurrent ocular and/or leptomeningeal involvement is common. To date, there is no standard approach to PCNSL treatment. Methotrexate in high doses is the single most effective chemotherapeutic agent and methotrexate-based regimens are used for induction, often in combination with other agents, such as cytarabine, etoposide, nitrosureas and temozolomide. Rituximab was used in induction or intrathecally, because of low CNS penetration. Its addition to HD-MTX appears to improve CR rates as well as progression-free survival. The tumor is radiosensitive and combined modality treatment with HD-MTX based chemotherapy plus whole brain radiotherapy (WBRT) prolongs disease free survival. This benefit has to be weighed against the increased risk of severe neurotoxicity in long-term survivors. Currently most protocols try to omit WBRT by using dose intensive consolidation. Autologous haemopoietic cell transplantation has been used under this concept and also in relapsed patients. Ongoing randomized trials are testing the role of WBRT, Rituximab and transplantation in the treatment of PCNSL. Primary extranodal lymphomas (en-NHL) arise from tissue other than lymph nodes or spleen. The gastrointestinal tract is frequently involved. The most common location is the stomach, where half of the enNHL are DLBCL, either de novo or transformed MALT. Other sites of DLBCL extranodal lymphomas (except CNS) include bone, testis and breast. Signs and symptoms depend on the localization and the stage is usually limited (IE, IIE). Treatment is generally that of DLBCL, but loco-regional irradiation plays a greater role than in nodal NHL.