ESTRO 2022 - Abstract Book

S961

Abstract book

ESTRO 2022

Median follow-up after radiosurgery was 9 months (3-12 months). Pain relief was achieved for the three patients: one after 2 weeks; other after 5 months and the last one after 1 week. The second one got his pain cycle worse 3 weeks after SRS and required intrahospital treatment to pain control, only one patient presents hypoesthesia on the face after 4.5months. Conclusion Stereotactic radiosurgery in a LINAC is feasible technique and Exactrac-Dynamic System® can provide a safety treatment delivery. SRS is a well-established, efficient and safety option for the treatment of TN, associated with a low risk of facial paresthesia and high probability of pain relief.

PO-1131 hypofractionated and intesified radiotherapy in glioblastoma multiforme

Í. Nieto Regueira 1 , V. Ochagavia Galilea 2 , V. Muñoz Garzón 3 , A. Naranjo 2 , P. Sosa Fajardo 1

1 Hospital Meixoeiro. CHUVI, Radiation Oncology, Vigo, Spain; 2 Hospital Meixoeiro, Radiation Oncology, Vigo, Spain; 3 Hospital Meixoeiro, CHUVI, Radiation Oncology, Vigo, Spain Purpose or Objective Glioblastoma Multiforme (GM) is the most frecuent primary malignant tumor in the central nervous system. It still has a poor prognosis. Only 30 % of the patients survive more than one year , and 5% of them, more than five years. Surgery is the first step in treatment, with complete resection if possible. Radiotherapy is the first adjuvant treatment option. Conventional treatment is 60 Gy total dose, 2 Gy per day. The association of adjuvnat RT and concurrent Temozolomide improves overall survival, in comparation with RT alone: 14.6 mounths vs 12.1 mounths. Surgical reintervention and reirradiation increase global survival from 6 to 10 months. Bevacizumab (BCB), alone or in association with Lomustine or Irinotecan, has an important anti-edema effect. It is indicated in recidivant Glioblastoma. To analized the tolerance and overall survival in patients with Glioblastoma Multiforme treated with hypofractionates and intensified radiotherapy, in a phase II prospective trial, is our purpose Materials and Methods Between january 2016 and may, 2020 we have treated 89 GM patients, 60 men (67%) a 29 women (33%) with Intensity Modulated Radiation Therapy (IMRT) . Median age was 60.1 (31-83 years old). 54 patients were treated wit total/subtotal surgical resection (60%). 35 patients werw only biopsied (45%) All of them received IMRT, in 20-25 fractions, (24.5 median fractions) in a dose escalated phase II trial, from a total dose of 66 Gy, to 76 Gy in biopsied patients. (EQD2 80 Gy), as follows: PTV1 : 50 Gy in 2 Gy per fraction. PTV2 , as a concurrent boost receiving 66-76 Gy (median 68 Gy) 2.2 – 3 Gy per fraction. 75 patients received concurrent Temozolomide 75 mg/m ² , 69 patients of them received at least three adjuvant Temozolomide cycles (Stupp protocol) Organs at risk were delimited: Braim stem, chiasm and optical nerves, motor cortex, pyramidal path, pituitary and cerebrum. After treatment, follow-up were done every 3 mounth with MRI . After clinical and/or radiological progression, patients with good performance status underwent: - Chemotherapy 28 patients (58%) : 12 patients CPT-11-BCB; 8 patients BCB alone; 2 patients Lomustine. - Re RT: 14 - Surgical reintervention: 7 Results Hypofractionated and intensified radiotherapy was well tolerated. 95 % of the patients finished the treatment All the breaks during radiation treatment were produced by the disease. During the follow-up, MRIs were performed every 3 months. Compatible changes due to treatment /radionecrosis, unable to rule out progression, were observed in 45% of patientes who underwent surgery, 74 % of biopsied patients, and the 85% of reirradiated patients. Overall Survival (OS) measured, starting on the first day of RT, in months: -Mediam global survival was 19 months (3-60 months) - In the group of patients who underwent surgery OS: 25 months (3-60 months) -In the group of biopsied patients OS was 12 months (2-28 months) - In the reirradiated group OS was 39 months. Seven patients underwent sugical reintervention. OS: 19 months (3-60 months) 5 of them glioblastoma were observed in pathological study, in the other two, necrosis and post radiation changes were informed. In this group OS is 54 months (p>0.2) Conclusion Hypofractionated and intensified radiotherapy improves OS in patients with Glioblastoma Multiforme, compared to conventional treatment (Stupp ). This treatment double the survival in the biopsied group and triples in reirradiated and reinterventioned groups B. Vázquez Barreiro 1 , F. López Campos 2 , M.L. Vázquez de la Torre González 1 , M. Caeiro Muñoz 3 , V. Ochagavía Galilea 3 , I. Nieto Regueira 1 , M.A. Naranjo Sánchez 1 , M. Gonzalez Rodríguez 1 , E. Azevedo González 4 , J. Vázquez Rodríguez 5 , A. González Pose 5 , V. Muñoz Garzón 1 1 Hospital Meixoeiro (CHUVI), Radiation Oncology, Vigo, Spain; 2 Hospital Universitario Ramón y Cajal, Radiation Oncology, Madrid, Spain; 3 Hosptital Meixoeiro (CHUVI), Radiation Oncology, Vigo, Spain; 4 Hospital Álvaro Cunqueiro (CHUVI), Neurosurgery, Vigo, Spain; 5 Hospital Meixoeiro (CHUVI), Medical Physics, Vigo, Spain Purpose or Objective To assess long-term local control of VS after SRS. Secondary outcomes were toxicity and hearing preservation as well as its association with clinical or SRS treatment factors. PO-1132 Clinical outcomes after radiosurgery in vestibular schwannomas