NCMP-27. CHARACTERISTICS OF RADIATION-INDUCED BRAIN TUMORS AFTER CRANIAL IRRADIATION

Abstract

Abstract INTRODUCTION The use of radiation therapy (RT) improves the outcome of cancer patients, while additionally increasing the risk of radiation-induced neoplasms in cancer survivors. The most common radiation-induced brain tumors (RIBT) are gliomas (RIG), meningiomas (RIM), and sarcomas (RIS). To investigate the characteristics of RIBT, we reviewed our case series and all relevant cases from the literature review. METHODS From our case series and literature review, we identified 920 RIBT patients who received cranial irradiation. We analyzed the age at irradiation for primary disease. The latency period from irradiation to the development of each RIBT and the median overall survival (OS) of RIBT were analyzed with Kaplan–Meier method. RESULTS Among RIBT patients, 23.2 % were irradiated less than 5 years, and 41.6% were irradiated in the first decade. The median age (interquartile range) at cranial irradiation were 9 (4.35 - 16) years in RIM patients, 9 (5 - 23) years in RIG patients, and 27 (13.7 - 40) years in RIS patients. The latency periods from irradiation to the development of RIM was significantly longer than RIG and RIS (RIM: 21 years, RIG: 9 years, RIS: 10 years; p < 0.0001). The median OS was significantly longer in patients with RIM than in those with RIG and RIS (RIM: not reached, RIG: 11 months, RIS 11 months; p < 0.0001). CONCLUSIONS RIG and RIS had a poor prognosis, while RIM had a relatively better prognosis. Because RIBTs develop more than a decade after cranial irradiation, long-term follow-up is crucial.