Risk Stratification in Pediatric Non-Hodgkin Lymphoma Using Maximum Tumor Dissemination and Metabolic Tumor Burden on Baseline 18 F-FDG PET/CT.

Abstract

Pediatric non-Hodgkin lymphoma (NHL) is the third most common childhood malignancy, but reliable prognostication remains challenging. This study aimed to evaluate the prognostic value of baseline 18 F-FDG PET/CT parameters reflecting disease spread, the largest interlesion distance (Dmax), and total metabolic tumor volume (TMTV), in pediatric patients with NHL. We retrospectively enrolled 98 pediatric patients with NHL (74 males, 24 females; median age, 10.4 y; range, 0.3-17.9 y) who underwent FDG PET/CT for staging between January 2008 and November 2024. TMTVs were defined using a 41% maximum standardized uptake value threshold. Distances between all lesion pairs were calculated to determine Dmax. Prognostic significance of FDG PET/CT parameters and clinical factors for survival outcomes was evaluated using univariate analysis. Based on surrogate TMTV (sTMTV) and sDmax, patients were stratified into no (n = 61), 1-risk (n = 17), and 2-risk factor groups (n = 20). In the univariate analysis, advanced stage (≥IV), bone marrow involvement, elevated serum lactate dehydrogenase (LDH) level (>500 IU/L), sTMTV, sDmax, and the PET-based risk group were significant prognostic factors for event-free survival ( P < 0.05). For overall survival, significant factors included LDH level, sTMTV, sDmax, and the PET-based risk group ( P < 0.05). The PET-based risk stratification was also reflected in survival outcomes. sTMTV and sDmax derived from FDG PET/CT are significant prognostic biomarkers in pediatric NHL. Their combination enables effective stratification of pediatric patients with NHL into distinct risk groups and may inform future risk-adapted management strategies, potentially improving survival in this population.