Primary Central Nervous System Lymphoma: A Literature Review, Diagnosis, Treatment, and Prognosis

BACKGROUND. Primary lymphoma of the CNS (PLCNS) is one of the rare extranodal lymphoid tumors, which, in the vast majority of cases, is represented by diffuse large B-cell lymphoma (DLBCL). Tumor location, poor performance status with frequent neurological deficits as well as elderly age of the majority of patients restrict the opportunities for both diagnosis and treatment of this disease. AIM. To study the clinical manifestations and chemotherapy options for patients with newly diagnosed PLCNS. MATERIALS & METHODS. This study was based on the clinical data from 29 PLCNS patients treated at the Drug Chemotherapy and Hematology Department of the NN Blokhin National Medical Cancer Research Center from 2020 to 2025. The median age was 57 years (range 34–71 years), 35 % of patients were over 60 years of age, there were 16 (55 %) men. On presentation, more than a half of patients (n = 18; 62 %) had poor performance status (ECOG > 2). By immunohistochemical analysis, DLBCL was diagnosed in all patients: in 22 cases stereotactic biopsy was performed to verify the diagnosis, whereas in 7 cases open surgery was needed. An absolute majority of patients (n = 26; 90 %) received high-dose methotrexate (3–3.5 g/m2) as part of various combined regimens: R-MVT in 19 (66 %), R-MVР in 2 (7 %), R2-MV in 4 (14 %), and R-МAra-C in 1 (3 %) cases. Those 14 (48 %) patients who achieved antitumor effect after 2–4 cycles underwent consolidation in the form of external beam radiation therapy (n = 6; 21 %) or high-dose chemotherapy (n = 8; 28 %) with autologous hematopoietic stem cell transplantation (auto-HSCT). Maintenance therapy with temozolomide or lenalidomide was administered to 10 (35 %) patients. RESULTS. With the median follow-up of 13 months, the 2-year progression-free survival (PFS) was 34.5 % (median 9 months), and the 2-year overall survival (OS) was 54.3 % (median 35 months). The most important prognostic factor was achievement of complete remission (CR): the median PFS in patients with CR was 17 months vs. 2 months in patients without it, the median OS was 35 months and 5 months, respectively. Consolidation therapy, regardless of the method used (radiation therapy or auto-HSCT), also considerably improved the rates of long-term survival: the 2-year PFS was 55.1 % vs. 9.7 % without consolidation, the 2-year OS was 79.5 % and 30.5 %, respectively. CONCLUSION. PLCNS is characterized by a highly aggressive course. Administration of methotrexate-based regimens combined with alkylating or immunomodulatory agents followed by consolidation therapy is associated with improved rates of long-term survival. The results of first-line therapy present a key factor in determining the outcome of the disease, since the available treatment options for relapsed/refractory tumors of this kind are extremely limited and hardly effective.