Central Nervous System Involvement in Patients with Diffuse Large B Cell Lymphoma: Analysis of the Risk Factors and Prognosis from a Single-Center Retrospective Cohort Study.

PURPOSE: The aim of this study was to identify the risk factors for central nervous system (CNS) involvement in systemic diffuse large B-cell lymphoma (DLBCL) patients and to explore prognostic for DLBCL patients with CNS involvement (relapse or progression).

PATIENTS AND METHODS: This was a retrospective cohort study in our hospital. Data were collected from all DLBCL patients diagnosed in our institutes from January 2013 to June 2018. Clinical information was collected from medical records.

RESULTS: The participants included 138 patients with DLBCL. Among them, 38 patients were diagnosed as CNS lymphoma, including 15 patients exhibited CNS involvement while DLBCL was pathologically confirmed, and 23 patients developed CNS lymphoma during or after initial chemotherapy. The median disease-free interval to CNS involvement was 13 months. Multivariate analysis identified elevated serum lactate dehydrogenase (LDH) level [hazard ratio (HR)=4.035; 95% confidence interval (95% CI): 1.147-14.195] was an independent predictor of CNS involvement. The median progression-free survival (PFS) and overall survival (OS) time of DLBCL patients with CNS involved were 12.5 months and 22 months, respectively. Multivariate prognostic analysis showed that eastern cooperative oncology group (ECOG) score>2(P=0.018; HR=7.333; 95% CI: 1.424-42.002), elevated serum LDH level (P=0.046; HR=6.510; 95% CI: 1.035-40.949), deep lesion (P=0.005; HR=10.957; 95% CI: 2.050-58.569), and CNS with systemic involvement (P=0.023; HR=2.730; 95% CI: 1.151-6.479) were independent poor prognostic factors for the patients. The cases with lymphocyte absolute count >0.75×109 /L (HR=0.047; 95% CI: 0.003-0.732) had better prognosis. The OS of DLBCL patients with secondary CNS lymphoma was inferior to DLBCL patients without CNS involvement. There was no significant difference between the patients with CNS and extra-CNS involvement. There was no significant difference between the patients with CNS involvement and stage III-IV DLBCL cases without CNS lymphoma.

CONCLUSION: In conclusion, elevated serum LDH was independent high-risk factor for secondary CNS lymphoma. For DLBCL patients with CNS involvement, ECOG score>2, elevated serum LDH level, deep lesion, lymphocyte absolute count ≤0.75×109 /L and CNS with systemic involvement retained a significant association with outcome.