Treatment of Monomorphic Posttransplant Lymphoproliferative Disorder in Pediatric Solid Organ Transplant: A Multicenter Review.

Posttransplant lymphoproliferative disorder (PTLD) is the most common posttransplant malignancy in children. We reviewed data from 3 Canadian pediatric centers to determine patient characteristics, treatment approaches, and outcomes for children with monomorphic PTLD. There were 55 eligible children diagnosed between January 2001 to December 2021. Forty-eight patients (87.2%) had B-cell PTLD: Burkitt lymphoma (n = 25; 45.4%) and diffuse large B-cell lymphoma (n = 23; 41.2%), the remainder had natural killer (NK)/T-cell lymphoma (n = 5; 9.1%), Hodgkin lymphoma (n = 1;1.8%), or other (n = 1;1.8%). Thirty-nine (82.1%) patients with B-cell PTLD were treated with rituximab and chemotherapy with or without a reduction in immunosuppression (reduced immune suppression). The chemotherapy used was primarily one of 2 regimens: Mature Lymphoma B-96 protocol in 22 patients (56.4%) and low-dose cyclophosphamide with prednisone in 14 patients (35%). Most patients with T/NK-cell lymphoma were treated with reduced immune suppression + chemotherapy (n = 4; 80%). For all patients with monomorphic PTLD, the projected 3-year event-free survival/3-year overall survival was 62% and 77%, respectively. Of the patients, 100% with T/NK-cell PTLD 100% progressed or relapsed and, subsequently, died of disease. For patients with B-cell PTLD, there was no significant difference in outcome between the two main chemotherapy regimens employed.