Post-Transplant Lymphoproliferative Disorder Onset in Liver Transplant: UNOS-STAR Database Analysis.

INTRODUCTION: Post-transplant lymphoproliferative disorder (PTLD) presents with diverse clinical features, etiologies, and outcomes. While pathological classifications exist, clinical categorization remains relatively undefined. This study aimed to clinically classify PTLD based on onset after liver transplant (LT) using the Standard Transplant Analysis and Research database. METHODS: Out of 111,845 liver transplant recipients, 1442 PTLD cases were identified between 1997 and 2023. Adults (≥18) and pediatric patients were analyzed separately. Cumulative incidence was assessed by patient characteristics, and Epstein-Barr virus (EBV)-related PTLD was defined as EBV-seronegative recipients with seropositive donors. RESULTS: Pediatric PTLD incidence was higher and occurred earlier, especially in children under 5 y. Over half developed PTLD within 2 y post-LT across both monomorphic and polymorphic types. EBV-related PTLD was more frequent within 2 y post-LT (51.5%) versus after 2 y (39.1%, P = 0.066) and had better prognosis (P = 0.041). In adults, PTLD was more common in males >60 y and in patients with autoimmune liver disease, though patients with autoimmune had better survival (P < 0.001). Late-onset PTLD was more frequent in those with autoimmune liver disease. Prognosis was best in autoimmune liver disease and worst in older males (P < 0.001). CONCLUSIONS: By comparing PTLD based on early and late onset in children and adults, we reveal distinct clinical entities with unique pathophysiological behaviors. The inclusion of disease onset into the clinical classification of PTLD may enable personalized treatment strategies for high-risk patients.