RADT-75. RADIATION-INDUCED BRAIN TUMORS IN PEDIATRIC AND YOUNG ADULT CANCER PATIENTS: A 23-YEAR SINGLE-CENTER EXPERIENCE

Abstract INTRODUCTION Radiation-induced brain tumors (RIBTs) represent a significant long-term complication in survivors of pediatric and young adult malignancies treated with cranial irradiation. Although uncommon, these secondary tumors contribute substantially to late morbidity and mortality. This study presents a single-center experience with RIBTs diagnosed over a two-decade period. METHODS We conducted a retrospective review at King Faisal Specialist Hospital & Research Centre (KFSH-RC), Riyadh, Saudi Arabia, identifying all patients diagnosed with RIBTs between 2002 and 2025. Patient data were obtained from electronic medical records and clinical notes. Collected variables included demographics, primary tumor type, latency period, and characteristics of the secondary brain tumors. RESULTS A total of 24 patients with RIBTs were identified, comprising 15 males (62.5%) and 9 females (37.5%). The mean age at primary tumor diagnosis was 12.6 years. The mean latency from radiation therapy to secondary tumor diagnosis was 14.1 years, with a mean age of 27.2 years at RIBT presentation. The secondary tumors included radiation-induced meningiomas (n = 14), gliomas (n = 5), and sarcomas (n = 5). Among patients with meningiomas, the mean age at primary diagnosis was 12.1 years, with a mean latency of 15.5 years and a mean age of 27.2 years at RIBT diagnosis. Glioma patients had a mean primary diagnosis age of 14.8 years, latency of 14.7 years, and RIBT presentation age of 26.8 years. Sarcoma patients exhibited a mean primary diagnosis age of 11.5 years, latency of 8.3 years, and RIBT presentation age of 27.5 years. The most common primary malignancy was medulloblastoma (n = 10), followed by leukemias and other CNS and head and neck tumors. CONCLUSION Radiation-induced meningiomas were the predominant secondary tumors in this cohort, displaying longer latency periods compared to gliomas and sarcomas. These findings underscore the importance of long-term surveillance in survivors of cranial irradiation to enable early detection and optimal management of RIBTs.