The Diagnosis and Treatment of Primary CNS Lymphoma

Primary central nervous system lymphoma is a diffuse large B-celllymphoma with exclusive manifestation in the central nervous system (CNS), leptomeninges, and eyes. Its incidence is 0.5 per 100 000 persons per year.Currently, no evidence-based standard of care exists.

This review is based on pertinent publications (2000-2017) retrieved by aselective search in PubMed.

The clinical and neuroradiological presentation of primary CNS lymphoma isoften nonspecific, and histopathological confirmation is obligatory. The disease, if left un- treated, leads to death within weeks or months. If the patient's general condition permits, treatment should consist of a high-dose chemotherapy based on methotrexate (HD- MTX) combined with rituximab and other cytostatic drugs that penetrate the blood-brain barrier. Long-term survival can be achieved in patients under age 70 by adding non- myeloablative consolidation chemotherapy or high-dose chemotherapy with autologous stem cell transplantation (HD-AST) to the induction therapy. Clinical trials comparing the efficacy and toxicity of these two treatment strategies are currently underway. Con- solidation whole-brain radiotherapy is associated with the risk of severe neurotoxicity and should be reserved for patients who do not qualify for systemic treatment. Some 30% of patients are refractory to primary treatment, and at least 50% relapse. In patients who are still in good general condition, relapse can be managed with HD-AST. Re- exposure to conventional HD-MTX-based polychemotherapy is another option, if the initial response was durable. The 5-year survival rate of all treated patients is 31%,according to registry data.

Current recommendations for the treatment of primary CNS lymphomaare based on only a small number of prospective clinical trials. Patients with this disease should be treated by interdisciplinary teams in experienced centers, andpreferably as part of a controlled trial.