A Novel Prognostic Score for Disease Progression and Mortality in Patients With Newly Diagnosed Primary Large B‐Cell Lymphoma of Immune‐Privileged Sites

Primary large B-cell lymphoma of immune-privileged sites (IP-LBCL), a recently defined entity in WHO-HAEM5, includes primary diffuse large B-cell lymphoma (DLBCL) occurring in immune-privileged areas like the central nervous system (PCNS-LBCL), vitreoretinal system (PVR-LBCL), and testis (PT-LBCL) in immunocompetent patients. This study aimed to identify prognostic factors and create a predictive model for IP-LBCL. We analyzed 213 newly diagnosed IP-LBCL patients from April 2006 to April 2023. A nomogram and prognostic index, IPLBCL-PI, were developed based on elevated LDH, ECOG ≥ 2, and PCNS-LBCL subtype as independent risk factors for poorer PFS. IPLBCL-PI categorized patients into four risk groups: low, low-intermediate, intermediate-high, and high. The model effectively predicted both PFS and OS in the training cohort and was validated in two external centers. Subgroup analyses showed that IPLBCL-PI outperformed the Nottingham/Barcelona (NB) and Memorial Sloan Kettering Cancer Center (MSKCC) models in PCNS-LBCL and was comparable to the International Prognostic Index (IPI) in PT-LBCL. IPLBCL-PI is the first prognostic model for IP-LBCL, offering risk stratification and aiding clinical decision-making for this rare entity.