ESTRO 38 Abstract book

S882 ESTRO 38

dominant areas of progression (n=6). No grade 3 or greater toxicity was reported. Conclusion Although heterogeneous patients populations, SABR to non-spine bone metastases showed high local control rate with acceptable toxicity. Appropriate treatment indication and unified response evaluation are important for the future clinical trials and wide application of SABR to non-spine bone metastases in the clinic.

EP-1637 Validation of a predictive model for survival in elderly patients treated with radiotherapy H. Park 1 1 Dankook University Hospital, Radiation Oncology, Cheonan, Korea Republic of Purpose or Objective Elderly patients are more likely to have poor performance status and comorbidities. There is a reluctance to extensively investigate and treat elderly patients. Patient selection based on prognosis is necessary to provide appropriate treatment. This study was conducted to validate a predictive model for survival of elderly patients treated with palliative radiotherapy. Material and Methods From February 2015 to February 2018, a total 41 patients aged 80 and older underwent palliative radiotherapy. Prognosis in Palliative care study predictor (PiPS), Palliative prognostic index (PPI) and Delirium-Palliative prognostic score (D-PaP) were used for prediction of survival. The Clinical prediction of survival (CPS) was excluded from the D-PaP score. The median biologically effective dose (BED) was 39 Gy 10 (range, 28-75 Gy 10 ) with dose-per-fraction of 2.5-7.0 Gy. Results Among 41 patients, 1 patient didn’t receive the scheduled treatment. During the median follow-up duration of 1.8 months (range, 0.2-27.5 months), 20 patients referred to hospice care center and 6 patients died. The 1- and 6- months overall survival (OS) rates were 97.0% and 87.3%, respectively. The 1- and 6-months OS of patients who were predicted to live more than a month according to PiPS were 100% and 90.7%, respectively. Patients with PPI and D-PaP without CPS less than 4 points, the 1- and 6-months OS were 100% and 93.8% each. The 1- and 6-month OS were 80.0% and 0% in the patients with D-PaP without CPS 4 points or more (p<0.001). D-PaP without CPS score showed significant correlation with survival (p=0.033). Conclusion The prognostic prediction models can be used to predict prognosis in elderly patients who need palliative radiotherapy. These models can be used to guide clinical decisions, including patient selection, total dose and schedule of radiotherapy. Further studies are needed to develop a more appropriate prediction models for elderly patients. EP-1638 Radiotherapy and Immunotherapies in elderly: a systematic literature review L. Belgioia 1 , I. Desideri 2 , A. Errico 3 , C. Franzese 4 , A. Daidone 5 , L. Marino 6 , M. Fiore 7 , P. Borghetti 8 , D. Greto 2 , A. Fiorentino 9 1 AIROGiovani Italian Association of Radiation Oncology- Young Members Working Group., Department of Health Science DISSAL, Genoa, Italy ; 2 AIROGiovani Italian Association of Radiation Oncology-Young Members Working Group., Department of Biomedical- Experimental and Clinical Sciences “Mario Serio”- Section of Radiation Oncology, Florence, Italy ; 3 AIROGiovani Italian Association of Radiation Oncology- Young Members Working Group., Mons. R. Dimiccoli Hospital- Radiation Oncology, Barletta, Italy ; 4 AIROGiovani Italian Association of Radiation Oncology- Young Members Working Group., Department of Radiotherapy and Radiosurgery, Rozzano, Italy ; 5 AIROGiovani Italian Association of Radiation Oncology- Young Members Working Group., Radiation Oncology, Mazara del Vallo, Italy ; 6 AIROGiovani Italian Association of Radiation Oncology-Young Members Working Group., Rem- Radiation Oncology, Catania, Italy ; 7 AIROGiovani Italian Association of Radiation Oncology-Young Members Working Group., Campus Bio-Medico University- Radiation Oncology, Rome, Italy ; 8 AIROGiovani Italian

Electronic Poster: Clinical track: Elderly

EP-1636 Linac-based radiosurgery in elderly patients: mono-institutional experience on 110 brain metastases F. Gregucci 1 , A. Fiorentino 1 , S. Corradini 2 , V. Figlia 1 , R. Mazzola 1 , F. Ricchetti 1 , R. Ruggeri 1 , F. Alongi 1,3 1 Hospital Sacro Cuore Don Calabria- Cancer Care Center, Radiation Oncology, Negrar, Italy ; 2 LMU University Hospital, Radiation Oncology, Munich, Germany ; 3 University of Brescia, Radiation Oncology, Brescia, Italy Purpose or Objective To analyze the feasibility and clinical results of linac- based stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (SFRT) with Flattening Filter Free (FFF) volumetric modulated arc therapy (VMAT) in elderly patients affected by Brain Metastases (BMs) with the idea of improving patients' compliance at treatment Patients selected for the present analysis were > 65 years old with a life expectancy of > 3 months, good performance status, a controlled or synchronous primary tumor, a number of BMs <10 with a diameter <3 cm. All patients were treated with FFF Linac-based SRS/SFRT. The prescribed total dose (15–30Gy/1–5 fractions) was based on BMs size, proximity to organs at risk and intent of treatment. Acute and late toxicity was assessed according to CTCAE v4.0. A retrospective analysis of patients, BMs, treatment characteristics and outcomes included toxicity, local control (LC), overall survival (OS) and intracranial progression free survival (iPFS), were performed. MedCalc v18.2 was utilized for statistical analysis. Results From April 2014 to December 2017, 40 elderly patients with 110 BMs were treated by FFF-VMAT Linac-based SRS/SFRT. Median age was 70 years (range 65-83). The median number of BMs was 2 (range 1-10). The median PTV was 1 cc (0.1-42) and the median diameter of BMs was 1 cm (0.6-3). In case of multiple BMs, the median cumulative PTV was 10.3 cc (range 0.9-65.9 cc). Median biologically effective dose (BED) calculated with an alfa/beta value of 12 Gy was 47.2 Gy, with 87% of BMs receiving an efficacy dose ≥ 40 Gy. The median beam on time was 2 min (range 1,5-4) for lone lesion , while for multiple BMs, the treatment time was 11 min (range 9-15). With a median follow-up time of 28 months (range 6-50), median and 1-year OS were 9 months and 39%, respectively; median iPFS was 6 months. No difference in terms of outcomes were observed between patients under or over the age of 70 years (p=0.2 and p=0.18). At the time of the analysis, LC was reported in 109/110 BMs (99.1%): 12 BMs had a complete response; 51 a partial response; 46 a stable disease. One BM (0.9%) progressed after 2 months. The analysis of LC profile stratified by clinical and treatment variables has shown that BM volume (<1cc) and higher SRS/SFRT dose (≥ 40 Gy) correlated to positive treatment local response (p=0.01; p=0.0017). No adverse events more than grade 2 were observed. Conclusion The present findings highlight the feasibility, safety and effectiveness of FFF Linac-based SRS/SFRT in elderly patients with BMs. and their quality of life. Material and Methods