P14.89 What happens after 15 years? A clinical picture of a cohort of survivors of CNS tumors treated with whole-brain irradiation in a National Cancer Center

Abstract BACKGROUND Radiotherapy (RT) is standard curative treatment for many tumours, specially brain tumours. However, RT causes damage to normal brain tissue due to genetic instability, impairment of synaptic plasticity and increased oxidative stress and inflammation. With improved treatment, patient survival also increased in years, making long-term effect of RT more evident. Late toxicities of RT are well described for pediatric survivors but there is scant literature on late toxicities in adult survivors and, in general, the adult brain is considered less susceptible to radiation damage. MATERIAL AND METHODS Retrospective analysis of adult patients treated with whole-brain RT with more than 15 years of follow-up. Clinical charts were reviewed to collect clinical, demographic and outcome data. RESULTS From 18 patients found (mean age at diagnosis of 27 years, 13 male/ 5 female), 5 were diagnosed with medulloblastoma, 5 CNS lymphoma, 5 with germinoma, 3 with ependymoma and 1 with teratocarcinoma. Most common presentations were headache (61,1%), seizure (16,7%) and dizziness (16,7%). 5 patients (27,8%) had hydrocephalus at diagnosis. All patients received whole-brain RT (mean 40Gys, varying between 21 to 60Gys), alongside with complete surgical resection in 11 patients (61,1%) and chemotherapy in 10 patients (55,6%). Mean follow-up time was 23,6 years and only 1 patient died due to lymphoma recurrence 16,7 years after the initial diagnosis. During follow-up, all patients had late RT induced changes, leukoencephalopathy in 16 patients (88,9%; mean 8,6 years after RT), ischemic stroke in 9 patients (50,0%; mean 16,0 years after RT), cerebral microbleeds in 14 patients (77,8%; mean 15,4 years after RT), cognitive decline in 12 patients (66,7%; mean 15,8 years after RT), radio-induced meningioma in 3 patients (16,7%; mean 18,1 years after RT) and epilepsy in 2 patients (11,1%; mean 10,5 years after RT). Also 1 patient had neurosensorial loss 14,2 years after RT and another one had subarachnoid haemorrhage due to ruptured aneurysm 19 years after RT. CONCLUSION Our results show that late RT induced effects are progressive and irreversible in the adult survivors, in a very similar manner as has been reported in the pediatric survivors. The impact on quality of live is increasing as patients survive longer. RT is still an important tool in neuro-oncology, but its role in curing brain tumors needs further study.