The Outcomes of Diffuse Large B-cell Lymphoma Patients with Synchronous and Early Central Nervous System Involvement: A Single-Center Experience.

Background: Diffuse large B cell lymphoma (DLBCL) is the most commonly diagnosed subtype of non-Hodgkin's lymphoma (NHL). R-CHOP has significantly improved clinical outcomes in patients with DLBCL, however, its indication in the prevention of CNS relapse and recurrence is still inconsistent. Moreover, prophylactic methotrexate and/or cytarabine have been used prophylactically for DLBCL patients is at high risk of CNS relapse and to treat CNS DLBCL, however, their efficacy remains unclear.

Methods: The aim of our retrospective study was to determine the incidence of CNS in-volvement in patients with DLBCL and to describe its risk factors and survival outcomes.

Results: A total of 406 patients with DLBCL were identified, and 17 (4.2%) of DLBCL patients had CNS involvement i.e. 9 (2.2 %) at diagnosis and 8 (~2%) at relapse. The patients were younger, had advanced stage, high CNS-IPI, and had extra nodal involvement. Seven out of the 17 patients who survived received chemotherapy and a prophylactic methotrexate. Considering the CNS-IPI, of the 146 patients with high CNS-IPI at presentation, 18 received the prophylactic HDMTX and 3 (16.7%) of them had CNS relapse. Two (1.6%) out of 128 who did not receive the prophylactic HDMTX had CNS relapse. On the other hand, of the 223 patients with intermediate CNS-IPI, 25 received the prophylactic HDMTX and 2 (8%) of them had CNS relapse and in 198 patients who did not receive the prophylactic HDMTX, 2 (1.01%) had CNS relapse. The 5-year progression-free survival and overall survival rates for the entire cohort were 73% and 84%, respectively. The median OS for those who had CNS involvement was 17 months and the 2-year OS was 40%.

Conclusion: CNS involvement in DLBCL has a poor prognosis, thus, aggressive CNS-directed therapy should be considered, especially in young patients.