ESTRO 2021 Abstract Book

S870

ESTRO 2021

patients who were treated with SRS to meningioma(s) between 2014-2018. Results

Thirty patients (10 males; 20 females) were identified. The median age at commencement of SRS was 52.68 years. Twenty-eight patients had one lesion treated, two patients had two lesions treated. Fifty percent of patients had SRS for lesions that recurred post-surgical resection. Fourteen patients had histologically proven grade 1 meningioma, two patients had a diagnosis of grade 2 and one patient had a diagnosis of grade 3. Thirteen patients were radiologically diagnosed. Six patients had prior radiotherapy to the brain. The most commonly used dose was 25 Gray/5 fractions (n=9). Twenty patients were treated with SRS alone; ten patients with hybrid rapid arc radiotherapy technique. Median follow up was 1.7years. Of the 25 patients on whom follow up imaging and clinical follow up data is available, 21 have stable lesions. In four patients, disease progression was noted on follow up imaging at 1.6, 3.5, 0.4 and 1.8 years after SRS. Conclusion Our analysis showed that SRS is an effective treatment option in patients with meningiomas and should be considered as primary treatment for unresectable meningiomas and in cases of meningiomas that require radiotherapy where surgery is contraindicated. Po-1045 Wholebrain Vs Radiosurgery/Fractionated Stereotactic Radiationtherapy: Experience In Our Center. A. Alayón Afonso 1 , M. Montero Feijoo 1 , J. Olivera Vegas 1 , J. Ayerbe García 2 , I. Azinovic Gamo 1 , S. Gomez Tejedor 3 , L. Guzmán Gómez 1 , J. Luna Tirado 1 , C. Díaz Silvera 1 , J. Vara Santos 1 , A. Nieto Riveiro 1 , A. Martínez Felipe 4 , M. Perez Cobo 1 , W. Vásquez Rivas 1 1 hospital Universitario Fundación Jiménez Díaz, Servicio De Oncología Radioterápica, Madrid, Spain; 2 hospital Universitario Fundación Jiménez Díaz, Servicio de Neurocirugía, Madrid, Spain; 3 Hospital Universitario Fundación Jiménez Díaz, Servicio de Radiofísica, Madrid, Spain; 4 Hospital Universitario Fundación Jiménez Díaz, Servicio de radiofísica, Madrid, Spain Purpose or Objective To analyse the increase in hypofractionated craneal radiation treatments to the detriment of wholebrain radiotherapy and to compare toxicities between both treatments. Materials and Methods 180 patients with malignant lesions that underwent a radiation treatment were analyzed between 2016 and 2018. Two types of linear accelerators (LINAC) were used, Synergy Beam modulator and Agility. The fixation systems used were Fraxion and Leksell for radiosurgery (SRS) and standard thermoplastic mask for Wholebrain radiotherapy (WBRT). A dose of 30 Gy was given in WBRT, between 18 to 24Gy in single fraction in SRS and an equivalent biological dose in 3 to 5 fractions in fractionated stereotactic radiotherapy (FSR). Results Of the 180 patients in this study, 51,7% of them were treated with WBRT, 39,4% with SRS and 8.9% with FSR. In 2016 the most common treatment was WBRT (51.9%) followed by SRS (46.8%). In 2017 most of the patients were treated with SRS or FSR (adding up to 72.2%) whereas only 27.8% were treated with WBRT. In 2018 WBRT was the predominant treatment with a 70.2% of the planifications performed while SRS and FSR added up to a 29.8%. Since 2018, SRS and FSR began to be used as standard technique when possible. In case that the previous techniques could not be performed and WBRT had to be used, an integrated boost was added in lessions greater than 1 cm instead of WBRT alone. Toxicity was uncommon in all treatments but it was more frequent in patients undergoing WBRT (83% of all neurological deficits were diagnosed in this group). The only symptom that had the same proportion in WBRT and SRS was headache (50%).