Abstract P076

ATAXIA TELANGIECTASIA ASSOCIATED PEDIATRIC HODGKIN LYMPHOMA: HIGH RESPONSE RATES BUT SUBSTANTIAL NON RELAPSE MORTALITY

Background: Ataxia-telangiectasia (AT) is a rare inherited disorder characterized by immunodeficiency, defective DNA damage response, chromosomal instability, and marked radiosensitivity, predisposing affected children to lymphoma while increasing treatment-related toxicity. Evidence guiding optimal management of Hodgkin lymphoma (HL) in children with AT remains limited.

Methods: We retrospectively reviewed children with AT diagnosed with HL at Children’s Cancer Hospital Egypt between July 2007 and July 2024. Data included clinical presentation, disease characteristics, frontline treatment, dose modifications, number of cycles, interim response, and survival.

Results: Fourteen patients were identified; median age at diagnosis was 9 years (range, 6-17), and 11/14 were male. Advanced presentation was frequent, with stage IV disease in 7/14 (50.0%) and B symptoms in 6/14 (42.9%). Risk stratification showed 7/14 high-risk, 5/14 intermediate-risk, and 2/14 low-risk disease. Histology was predominantly classical HL, with mixed cellularity in 8/14 (57.1%) and nodular sclerosis in 5/14 (35.7%); 1 case showed features intermediate between diffuse large B-cell lymphoma and classical HL. Frontline treatment was heterogeneous and toxicity-adapted: 4/14 patients received AVPC with 50% dose reduction, 3/14 AVPC with 25% reduction, 1/14 full-dose AVPC, and 4/14 ABVD. One additional patient received 2 cycles of dose-reduced ABVD without doxorubicin, then shifted to dose-reduced COPDAC. The patient with intermediate features received rituximab alone because of very poor general condition. Eleven patients achieved complete metabolic response after 2 cycles, 1 had progressive disease, and 2 died before response evaluation. Despite the high early response rate, all patients ultimately died, predominantly from non-relapse causes, mainly chest infection, respiratory failure, and septic shock. Median survival was 6 months.

Conclusion: AT-associated pediatric HL appears highly chemosensitive, but outcomes are dominated by extreme non-relapse mortality, mainly related to infectious, pulmonary, and treatment-related complications. These findings underscore the need for AT-adapted strategies that preserve efficacy while minimizing toxicity, with intensive prophylaxis, pulmonary support, and immune optimization.