ESTRO 38 Abstract book

S668 ESTRO 38

Guy's Hospital, Cancer Center, London, United Kingdom ; 3 university hospital southampton, Department of Radiology, Southampton, United Kingdom ; 4 university hospital southampton, Wessex Neurosurgery Center, Southampton, United Kingdom Purpose or Objective Recursive partitioning analysis is one of the important factor that determine patients' prognosis and choice of our treatment.The aim of this study is to emphasize the role of stereotactic radiosurgery(SRS)/radiotherapy (SRT) in patients with brain metastasis RPA class II. Material and Methods Hundred and twenty-four patients treated for brain metastasis at University hospital Southampton between November 2016 and June 2018. Eighty-eight (71%) patients were treated with SRS, 36 (29%) patients treated with SRT, choice of SRS/SRT was chosen depending on tumour size and dose to normal brain tissue or proximity to normal risk structures e.g. brain stem. Median dose for SRS patients was 18Gy single fraction (range: 12-21Gy), and for SRT 21Gy in 3-5 fractions (range: 21-25Gy). All patients treated on linear accelerator ELKTA® with Agility™MLC and Exactrac™system. Dose prescription ranged between 60% and 72% isodose line. ™. OAS calculated from the date if treatment till date of last follow-up. Results Median age at referral was 65 year, with 50% of the patients aged between 56 and 71 year. Fourteen patients were between 76 and 80 year. Sixty-seven female (54%) and 57 (46%) male. Fifty patient (40%) had lung cancer diagnosis, 19 patients (15%) diagnosed with melanoma the rest were between, Breast 14 patients (11%), renal cell 12 patients (10%), colorectal 8 patients (6%) others 21 patients(18%). Main toxicity profile was brain oedema and need for steroid longer than our defined protocol of 8 days, one patient had brain stem necrosis following single fraction 15Gy for 2.5cm lesion, improved on steroids for 8 weeks without evidence of recurrence. Survival analysis was done for 81 patients only,10 patients didn’t have follow up data, the rest of patients were enrolled at a later time and did not have a minimum follow-up of 6 months at the time of the last data cutoff. Median overall survival for the whole group was 15 months (95% CI 10.05 -19.94), progression free survival 12months (95% CI 8.88- 15.11). Majority of our patients 65% classified as Class II disease OAS for this group was 11months (95%CI 8.17-13.8) and PFS was 10months (95% CI 8.07 -11.7). Conclusion SRS/SRT is effective in patients with brain metastasis Class II RPA longer follow-up is still needed. EP-1207 Fractionated stereotactic radiation therapy for resected brain metastases: a preliminary report A. Di Marzo 1 , F. Trippa 1 , P. Anselmo 1 , F. Arcidiacono 1 , S. Terenzi 1 , L. Draghini 1 , M. Italiani 1 , M. Casale 1 , M. Muti 1 , S. Fabiani 1 , E. Maranzano 1 1 "S. Maria" Hospital Terni, Radiotherapy Oncology Centre, Terni, Italy Purpose or Objective Cavity stereotactic radiosurgery (SRS) or fractionated stereotactic radiation therapy (FSRT) are emerging treatment options after surgical resection of brain metastases (BM). Recent randomized trials, aimed to clarifying the adverse effects of postoperative whole- brain radiation therapy (WBRT) for BM have confirmed the association of neuro-cognitive and quality of life decline with WBRT. The recent phase 3 NCCTG study comparing SRS and WBRT for resected BM showed comparable overall survival and superior preservation of cognitive function after SRS, supporting the rationale for limiting WBRT to only patients where it is clinically essential. We present a preliminary report of our experience on surgical cavity FSRT.

EP-1205 A new alpha particle treatment for recurrent or aggressive head and neck squamous cell carcinoma A. Popovitzer 1 1 Rabin Med. Ctr. Beilinson Campus, Department of Radiation Oncology, Petah-Tikva, Israel Purpose or Objective The first clinical trial in humans with skin and oral cavity squamous cell carcinoma was performed in order to evaluate the effect of a unique intra-tumoral alpha radiation based tumor ablation treatment termed Diffusing Alpha emitters Radiation Therapy (DaRT). DaRT relies on alpha particles and thus, effective against hypoxic tumors. DaRT seeds can be produced with various intensities, sizes, and shapes and enable custom designed seeds. In our prior animal studies, we demonstrated the effectiveness of the treatment in mice for many tumors. In this first Human study, we evaluated its role for Skin and Oral Cavity Squamous cell Carcinoma. Material and Methods Materials/Methods: A Radium-224 loaded sources (DaRT seeds) were inserted into solid tumors and released by recoil short-lived alpha-emitting atoms (Rn-220, Po-216. Pb-212, Bi-212, Po-212, Tl-208). These atoms disperse in the tumor and spray it with highly destructive alpha radiation. The decay products diffuse in the tumor mass to a distance of at least 5 mm. Thus, a sizable fraction of the tumor is irradiated by alpha particles, and because of their short half-life, only small amounts of the isotopes disperse in the body. Results Results: A feasibility and safety clinical study is ongoing and currently, 18 patients were treated. All patients were radiation resistant recurrent histopathological confirmed skin or head and neck SCC, and tumor size ≤ 5 centimeters in the longest diameter, were enrolled. Treatment was delivered based on a CT-simulation pre-treatment plan. The Ra-224 Alpha DaRT Seeds were inserted under local anesthesia using a specially designed Alpha DaRT Applicator. The seeds (1 cm long and 0.7 mm in diameter) each carrying a dose of 2 µCi were placed 6 millimeters from each other. CT was used to check the position of the radioactive seeds. Two to four weeks after implantation the seeds were removed, and six weeks after treatment CT was performed to assess the effect of treatment. Blood tests and urinalysis were performed during the treatment. The Age of the patients ranged between 70 to 94 (median 81) .Eleven patients had recurrent oral cavity SCC and seven diagnosed with aggressive skin SCC. All were treated within radiation failure fields(Radiation dosage >60 Gy). With a median follow up of 5 months, All tumors responded to the treatment; 13 tumors had a complete response, five tumors showed a partial response. No major toxicity was noted. The areas around the treated tumors were not necrotic and no radionecrosis developed Conclusion Conclusion: In this feasibility and safety human study we demonstrated that alpha particles based DaRT exhibit enhanced radiobiological potential. The treatment was effective against radio-resistant SCC tumors without major toxicity.

Electronic Poster: Clinical track: CNS

EP-1206 SRS/SRT for patients with brain Metastasis RPA Class II disease: Results from Single institution M. El-Haddad 1 , O. ALSalihi 2 , L. Eley 1 , E. Johnson 1 , M. Chandrasekaran 1 , K. Nyathi 1 , H. Trieu 1 , S. Kumar 1 , C. Birch 1 , F. Sheikh 3 , H. Joy 3 , P. Grundy 4 , J. Ching 1 , J. Duffill 1 , S. Geoff 1 1 university hospital southampton, Clinical Oncology, Southampton, United Kingdom ; 2 St Thomas' Hospital