ESTRO 36 Abstract Book

S609 ESTRO 36 _______________________________________________________________________________________________

2 Complesso Ospedaliero San Giovanni Addolorata, Fisica Sanitaria, Roma, Italy 3 Complesso Ospedaliero San Giovanni Addolorata, Oncologia Medica, Roma, Italy Purpose or Objective New technologies, as IMRT, VMAT and Helical Tomotherapy (HT) is one of the most emerging aspect of radiation therapy, especially regarding brain tumors management; glioblastoma (GBM), for its radio-resistance and high rate of local recurrence, is a challenging field of application of new technologies. In this retrospective study we evaluated the impact of altered fractionation, administered with HT, associated with temozolomide (TMZ) in the treatment of GBM. Material and Methods From 2010 to 2014, 23 patients with primary diagnosis of GBM were treated at our Institution. Median age was 57 (range 26-75) and all patients had histologically proven diagnosis of GBM; 15 patients (65%) had a radiological proven residual disease after surgery. Bio-molecular markers profiling was not routinely analyzed; molecular genetic profile, using FISH test, was assessed in 11 (48%) of the 23 patients; evaluation of MGMT promoter was performed in 10 patients: 7 presented an unmethylated profile, and 3 a methylated status. In 6 patients mutations of IDH1 were tested and only in 2 patients they are present. Considering extent of the disease and its location, patients were treated with two different radiation therapy schedules. In 16 patients (70%) two different volumes were identified: PTV1, encompassing surgical bed and/or residual disease (GTV1) with a margin of 0.5 cm, treated with a total dose of 59.8 Gy in 23 fractions of 2.6 Gy, and PTV2, obtained expanding the PTV1 of 1 cm all around, treated with a total dose of 46 Gy in 23 fractions of 2 Gy (Simultaneous Integrated Boost SIB technique). In the remaining 7 patients (30%) it was possible treated a single volume (PTV1) with a total dose of 59.8 Gy in 23 fractions of 2.6 Gy. According to the EORTC regimen, concomitant daily TMZ dose of 75 mg/mg was administered for the entire period of radiation therapy followed by adjuvant schedule at a dose of 150- 200 mg/mq daily for 5 consecutive days every 4 weeks. Results All patients completed the combined therapy without grade ≥3 acute toxicity. Complete blood count every 2 weeks, and contrast-enhancement brain MR every 3 months were performed during follow up. At the time of the present study, 12 patients (52%) were died, 2 patients (9%) had disease progression, two patients (9%) had a radiological evidence of stable disease (SD) and 7 (30%) were free from disease. The average follow-up was 12 months (range 2-46) and median overall survival (OS) was 12 months with a progression free survival (PFS) average time of 7.6 months. Conclusion Our results, in terms of OS and PFS, are similar to the literature ones; but it is remarkable that about 65% of patients had a subtotal resection and therefore a poor prognosis and poor expected outcome as well documented in large previous studies. Altered fractionation that we used achieved similar results of standard schedule of treatment of 60 Gy in 30 fractions, without increasing acute and late toxicity, and reducing total time of about 25%.

1 Tokyo Metropolitan Cancer and Infectious diseases Center Komagome Hospital, Radiation Oncology, Tokyo, Japan 2 Saitama Medical University International Medical Center, Radiation Oncology, Hidaka, Japan 3 Kobe Minimally Invasive Cancer Center, Radiation Oncology, Kobe, Japan 4 Mie University Hospital, Radiation Oncology, Tsu, Japan Purpose or Objective Spine Stereotactic Body Radiotherapy (Spine SBRT) is rapidly being accepted in the clinic especially in North America without high quality evidence. In Japan, this treatment, however, has not been accepted widely. Since several toxicities such as 10% to 39% of vertebral compression fractures (VCF), high-grade toxicity of esophagus and radiation myelopathy have been reported, we decide to perform a small multi-center feasibility trial to validate the safety and feasibility of Spine SBRT to In this prospective multi-center single arm trial, patients from 3 centers in Japan were allocated to receive Spine SBRT to their one or two continuous vertebral bone metastases. Patients were eligible if ECOG performance status 0, 1 or 2, group 1 or 2 in Recursive Partitioning Analysis (RPA) Index, stable in Spinal Instability Neoplastic Score, grade I or II in Bilsky grade and aged 20 to 75 years. Rate of treatment related grade 3 or worse toxicities during 6 months after treatment was the primary endpoint and toxicities were evaluated with Common Terminology Criteria for Adverse Events version 4.0 by intent-to-treat until patients’ death or at least 6 months. Severity of pain was scored 0 to 10 on the Brief Pain Inventory (BPI) before and after treatment. Amounts of opioid analgesic intakes were also recorded before and after treatment. Pain response was evaluated according to Inter national consensus on palliative radiotherapy endpoints. This study is registered with University hospital Medical Information Network, number UMIN000013428. Results Between March 2014 to October 2015, 20 patients are assigned to this trial with median follow up of 330 days. The locations of bone metastases were follows; cervical vertebra 2 patients (10%), thoracic vertebra 7 patients (35%), lumber vertebra 10 patients (50%), sacrum vertebra 1 patients (5%). Patient’s reported pain scores before treatment were follows; Median over all survival time from treatment was 330 days (ranged 35-736). Twelve patients were group 1 and eight patients were group 2 in RPA index. No treatment related grade 3 or worse toxicity was observed entire the trial (0%). Rate of grade 1 or 2 toxicities were follows; grade 1 esophagitis 15%, grade 1 dermatitis 10%, grade 1 mucositis 5%, grade 1 pain flair 5% and grade 1 dizziness 5%. Pain response rate 1 month after treatment and 6 months after treatment was as follows, respectively: Complete Response (CR) 15% and 12%, Partial Response (PR) 5% and 0%, Indeterminate Response (IR) 65% and 82%, and Pain progression (PP) 15% and 5% (Figure). Grade 2 VCF was observed in 1 patient (5%) entire this trial. Conclusion No grade 3 or worse toxicities were observed. This study validated the safety and feasibility of Spine SBRT. EP-1115 Linac vs viewray in brain metastases: a dosimetric comparison of hypofractionated IMRT and VMAT F. Cellini 1 , M. Ferro 1 , E. Placidi 2 , S. Chiesa 3 , B. Diletto 1 , M. Massaccesi 1 , C. Votta 4 , C. Masciocchi 5 , V. Frascino 1 , G.C. Mattiucci 6 , L. Azario 7 , V. Valentini 6 , M. Balducci 6 1 Fondazione Policlinico A. Gemelli, Gemelli ART - Radiation Oncology, Rome, Italy accept it in our clinic. Material and Methods

EP-1114 A prospective multicenter feasibility trial of Spine Stereotactic Body Radiation Therapy T. Hiroshi 1 , T. Furuya 1 , K. Nihei 1 , Y. Kumazaki 2 , K. Miyaura 2 , H. Mayahara 3 , H. Nishimura 3 , M. Nakayama 3 , Y. Nomto 4 , N. Shikama 2 , K. Karasawa 1