Immunodeficiency-associated primary CNS lymphomas: an International Primary CNS Lymphoma Collaborative Group study

ABSTRACT: Immunodeficiency-associated primary central nervous system lymphoma (ID-PCNSL) represents a clinicopathologically distinct PCNSL subtype, for which large studies and prognostic models are lacking. To address this gap, the International PCNSL Collaborative Group conducted a retrospective multicenter study, integrating clinical, radiological, and pathological data from 308 ID-PCNSL cases, diagnosed at 23 participating sites in 7 countries. Preexisting immunodeficiency included administration of immunosuppressants for transplantation (41.2%) or autoimmunity (36.7%) and HIV infection (21.7%). All tumors were diffuse large B-cell lymphomas, with Epstein-Barr virus (EBV) detected in 79.2%. Immune reconstitution together with rituximab and methotrexate-based chemotherapy was associated with the highest response rates and prolonged progression-free survival, irrespective of immunodeficiency subtype and EBV status. Survival outcomes were highly variable, with a 54-month median overall survival. Multivariable Cox regression identified age (per year increment; hazard ratio [HR], 1.05 (95% confidence interval [CI], 1.02-1.07); P< .001), Karnofsky performance status (KPS) 60 years, KPS