Abstract Book

ESTRO 37

S367

Radioterápica de la Universidad de Murcia, Madrid, Spain 4 Instituto Neurológico de Colombia, Epidemiology, Medellín, Colombia 5 Imoncology, Neurosurgery, Madrid, Spain 6 Imoncology, Radiation Physics, Madrid, Spain 7 Gustave Roussy Cancer Campus, Radiation Oncology, Villejuif, France 8 University Hospital Virgen del Rocio, Methodology Unit, Seville, Spain 9 University Hospital Virgen del Rocio, Department of Radiation Oncology, Seville, Spain Purpose or Objective The treatment of glomus jugulare tumors (GJT) remains controversial due to its high morbidity. Historically, these tumors have primarily been managed surgically. The purpose of this retrospective review was to assess the tumor and clinical control rates as well as long term toxicity of GJT treated with radiosurgery. Material and Methods Between 1993 and 2014, 30 patients with GJT (31 tumors) were managed with radiosurgery. Twenty-one patients were female and the median age was 59 years. The median volume of GJTs was 56 cc, ranging between 0.4 to 462.4 cc. All patients had symptoms before radiosurgery. The most common CN involvement was the VIII CN in 68% (N = 21) of patients. Forty percent (N = 12) had hearing loss and tinnitus while 33% (N = 10) had deafness. Twenty-eight patients (93%) were treated with radiosurgery at either 12 Gy (N=2) or 14 Gy (N=26), and two patients (7%) with stereotactic radiosurgery up to 24Gy and 27.5Gy, respectively. A 6 MV linear accelerator with a high-precision mechanical fastening (SRS 200, University of Florida, Gainesville, FL) was used for 29 cases (94%). Sixteen patients (52%) underwent prior surgery according to remitted reports from neurosurgeons with 12 and 4 partial and complete resections, respectively. Additionally, six (38%) out of the 16 operated patients underwent preoperative transarterial embolization and reoperation was performed in five patients (31%) because of tumor recurrence. Two patients (7%) had received prior conventional fractionated radiotherapy five (56Gy) and eight (50Gy) years, respectively, before radiosurgery. Results The mean follow-up was 4.6 years (range, 1.5–12 years); during this period, overall symptom control was achieved in 96.8% of patients, as 48.4% (n = 15) improved, 48.4% (n = 15) was unchanged and only 3.2% (n = 1) worsened. The overall tumor control by magnetic resonance imaging was 96.7%, of which in 67.7% (n = 21) the lesion remained stable and 29% (n = 9) showed size reduction without in any case showing a disappearance of the tumor. Only one lesion recurred (3.2%), for which a second radiosurgical treatment performed two years later was ineffective, resulting in death three years after the initial treatment. Toxicity was experienced in 12.9% (N = 4) of patients and all cases were grade 1, with a median time of onset of toxicity of 4.9 months, ranging between 1.2 and 6.6 months, although improvement was achieved without complications. There was no late toxicity in any patient. Univariate analysis showed a statistically significant association between patients having one cranial nerve (CN) involvement before radiosurgery and a higher risk of lack of improvement of symptoms (OR: 5.24,95% CI 1.06- 25.97,P = 0.043). Conclusion Radiosurgery is an effective and safe treatment modality for GJT. Patients having one CN involvement before radiosurgery show a higher risk of lack of improvement of symptoms.

ongoing. After a median follow-up time of 7 months, no grade >2 late neurological toxicity was recorded. Conclusion The SIB-VMAT technique was found to be feasible and safe at the recommended doses of 45Gy to PTV2 and 77.5Gy (biological effective dose –BED- of 157.6 Gy, alpha/beta 3) to PTV1 in the postoperative treatment of patients with glioblastoma. PO-0717 Phase II study of hypofractionated stereotactic RT in recurrent HGG: preliminary results G.A. Carta 1 1 Istituto Clinico Humanitas, Radiotherapy and Radiosurgery, Rozzano Milan, Italy Purpose or Objective Retrospective studies investigated the use of salvage re- irradiation for malignant glioma recurrence/progression with encouraging results. Based on this background, we designed a phase II study to evaluate efficacy and safety of re-irradiation for patients with recurrent HGGs. Primary endpoints were Progression free survival (PFS) and overall survival (OS) rate, secondary endpoint incidence of severe toxicity. Material and Methods Patients aged ≥18 years, with Karnosky performance status (KPS) ≥70, histopathologically confirmed grade II-IV glioma, estimated survival ≥ 3 months, single brain lesion and an interval time from previous radiotherapy ≥ 6 months were included. The gross tumor volume (GTV) corresponded to the abnormality on the post contrast- enhancing T1-weighted images and Methionine CT-PET, clinical target volume (CTV) as GTV plus 2 mm of margins and planning target volume (PTV) as the CTV plus 1 -mm. The total dose and fractionation schedule were determined with the aim to obtain a BED10 ≥ 60 Gy and BED2 ≤ 180 Gy. Patients outcome was evaluated using MRI 1 months after RT and every 3 months thereafter, according to RANO criteria. Results Among patients treated in our institution for recurrent glioma this is a preliminary evaluation of the first 82 patients treated. Forty-five were male and 37 female with a median age of 50 years (range 23-82 years); 12 had a KPS 70-80 and 70 KPS 90-100. Twenty-six patients underwent radiation therapy alone, 8 surgery plus RT, 32 surgery plus concomitant and adjuvant chemoradioterapy, and 16 RT plus concurrent and/or adjuvant chemotherapy. The median follow-up time was 35 months (range 5-141 months). The median, 1, 2 years PFS from recurrence were 13 months, 54.4% and 21.8% , respectively. The median, 1, 2 years overall survival (OS) from recurrence were 16 months and 73.5%, and 31%, respectively. No severe toxicity or neurological deterioration were recorded. A more favorable trend was recorded for younger patients, underwent gross total resection, and with grade II-III glioma at diagnoses compared to grade IV. Conclusion According to our results, HSRT could be considered a safe and feasible approach for recurrent high grade glioma. Multidisciplinary evaluation is mandatory to assess the best treatment in these poor prognosis patients. PO-0718 Radiosurgery for glomus jugulare tumors: a long-term follow-up of 30 patients K. SALLABANDA 1 , H. Barrientos 2 , D.A. Isernia Romero 3 , C. Vargas 4 , J.A. Gutierrez Diaz 5 , C. Peraza 6 , E. Rivin del Campo 7 , J.M. Praena-Fernandez 8 , J.L. López-Guerra 9 1 GRUPO IMO, Radiosurgery/ Cyberknife, Madrid, Spain 2 Instituto Neurológico de Colombia, Neurosurgery, Medellín, Colombia 3 Imoncology Fundación, Máster Internacional en Aplicaciones Tecnológicas Avanzadas en Oncología