Primary Central Nervous System Lymphoma of T Cell Origin: A Descriptive Analysis of 45 Cases from the International PCNSL Collaborative Group.

To describe the demographic and tumor related characteristics and outcomes for patients with primary T-cell central nervous system lymphoma (TPCNSL). A retrospective series of patients with TPCNSL was compiled from twelve cancer centers and seven countries. This study involved 35 male and 10 female patients with a median age of 60 years (range 3–84). Twenty (44%) had Eastern Cooperative Oncology Group performance status (PS) of 0 or 1. Twenty six (58%) had involvement of a cerebral hemisphere and sixteen (36%) had lesions of deeper sites in the brain. Two patients had primary spinal cord lesions and one had meningeal disease only. Serum lactate dehydrogenase (LDH) was elevated in 7 of the 22 cases (32%) and cerebrospinal fluid (CSF) protein was elevated above normal in 19 of the 24 cases (79%) with available data. The median disease specific survival (DSS) for all patients was 25 months (95% confidence interval (CI) 11–38 months). The two and five-year DSS were 51 % (CI 35–66 %) and 17 % (CI 6–34 %) respectively. Univariate and multivariate analyses were conducted for the following factors: age (≤ 60 vs. > 60 years), PS (0 or 1 vs. 2, 3 or 4), involvement of deep structures of the central nervous system (no vs. yes), and methotrexate (MTX) use in the primary treatment (yes vs. no). Only PS and MTX use were significantly associated with better outcome with hazard ratios (HR) of 0.2 (CI 0.1–0.4) and 0.4 (CI 0.2–0.8) respectively. This is the largest series ever assembled of TPCNSL. The presentation and outcome appear similar to that of PCNSL of B cell origin. PS 0 or 1 and administration of MTX are associated with better survival. TPCNSL does not appear to require a different therapeutic management approach than B-cell PCNSL.