International study on low-grade primary central nervous system lymphoma

Objective: The aim of this study was to characterize the clinical presentation, course, and outcome of low-grade primary central nervous system lymphoma. Methods: Cases were assessed in a retrospective series collected from 18 cancer centers in 5 countries. Results: Forty patients (18 men, 22 women; median age, 60 years [range, 19-78]) were identified. Involvement of a cerebral hemisphere or deeper brain structures was seen in 37 patients, only leptomeningeal involvement in 2 patients, and spinal cord disease in 1 patient. Chemotherapy/radiotherapy was conducted in 15 patients, radiotherapy alone in 12, chemotherapy alone in 10, and tumor resection alone in 2, whereas 1 patient received no treatment. The median progression-free, disease-specific, and overall survival were 61.5 (range, 0-204), 130 (range, 1-204), and 79 (range, 1-204) months, respectively. Only age 60 years or older was associated with shorter progression-free (p = 0.009), disease-specific (p = 0.015), and overall survival (p = 0.001) in multivariate analysis. Interpretation: Low-grade primary central nervous system lymphoma differs from the high-grade subtype in its pathological, clinical, and radiological features. It has a better long-term outcome than primary central nervous system lymphoma in general with age 60 years or older adversely affecting survival.