A prognostic scoring system for immunodeficiency-associated primary cns lymphomas: an international multi-center study

Abstract BACKGROUND Immunodeficiency-associated (ID-) primary CNS lymphomas (PCNSL) were introduced as a distinct entity in the 2021 World Health Organization classification of brain tumors. Given their rarity, larger clinical studies and prognostic models to guide management are lacking. METHODS PCNSL, newly diagnosed between 2004-2023 at six centers in the USA and in Germany, were retrospectively analyzed for concurrent immunodeficiency. Clinical, radiological, and pathological data were collected and assessed for prognostic significance using univariate and multivariate analyses. RESULTS Among 1112 patients with newly diagnosed PCNSL, 93 (8.4%) were identified as ID-PCNSL. Median age at diagnosis was 57 years and most tumors (66%) stained positive for Epstein-Barr virus (EBV). In addition to immune reconstitution, tumor-directed treatments were administered in 91/93 patients. These included chemotherapy (87%), radiation (25%), and autologous stem cell transplantation (14%). Outcome varied with a median overall survival (OS) of 46 months (range: 1-206 months). Age ≥ 60 years, Karnofsky performance status (KPS) < 70, EBV positivity, and non-rituximab or -methotrexate-based chemotherapy were associated with shorter OS on multivariate analysis adjusting for clinical and demographic factors. A prognostic scoring system was designed based on the sum of treatment-unrelated (age, KPS, EBV) unfavorable factors. The resulting score was highly prognostic and stratified ID-PCNSL into four subgroups: median OS was not reached, 90, 26, and 1 months (p < 0.0001) in cases with zero, one, two, or three unfavorable factors, respectively. Prognostic value was retained when limiting analysis to patients (n = 53), who had received HD-MTX and rituximab combination chemotherapy, with median OS of 98, 90, 46 and 4 months (p < 0.0001). CONCLUSIONS EBV was associated with inferior outcome in ID-PNCSL, which may reflect peculiar genetic alterations. An easily-applicable prognostic score based on three variables (age, KPS, EBV) allowed ID-PCNSL stratification into four risk groups. Prospective validation and therapeutic relevance warrant further investigation.