ESTRO 2020 Abstract book

S611 ESTRO 2020

Dimensional criteria (>5cm) and tight margins to normal adjacent structures are declared as major limiting factors for dose prescription in 77% and 95% of the centers, respectively. A 5-fractions schedule with a total dose of 30-35 Gy (Table) is delivered by the majority of the centers (72%), for both LAPC and borderline resectable patients. The optimal prescription isodose level is chosen between 85-95% in the 80% of the centers, with a heterogeneity contained between 110-120% of the prescribed dose. An individual Internal Target Volume is generated in the 77% of the centers. Clinical Intensity Modulated Arc Therapy (IMAT) is planned in 85% of the centers, employing a multifunctional LINAC in the most of the cases. Daily Image-Guided Radiotherapy (IGRT) is performed before each fraction by all centers.

PO-1064 Pancreatic cancer SBRT: reaching consensus in a national survey by AIRO Gastrointestinal Group L. Gasparini 1 , F.C. Di Guglielmo 1 , C. Di Carlo 2 , C. Rosa 1 , C. Bonfiglio 1 , S. Marcucci 1 , N. Adorante 1 , P. Franco 3 , M. Lupattelli 4 , M. Nuzzo 1 , D. Genovesi 1 , L. Caravatta 1 1 SS. Annunziata Hospital- “G. D’Annunzio” University, Department of Radiation Oncology-, Chieti, Italy ; 2 Civil Hospital, Department of Radiation Oncology, Ancona, Italy ; 3 City of Health and Science, Department of Radiation Oncology, Turin, Italy ; 4 S. Maria Misericordia, Radiation Oncology Unit, Perugia, Italy Purpose or Objective Currently, stereotactic body radiation therapy (SBRT) is intensively investigated in pancreatic cancer treatment, thanks the advantages of a short overall treatment time, minimal interruption of systemic therapy and high ablative doses to the tumor. However, a great variability among different centers can be observed about indications, volume definition, doses and technical equipment. Then, the study group of gastrointestinal malignancies of Italian Association of Radiation and clinical Oncology (AIRO) proposed a national survey aiming to investigate current clinical practice of pancreatic SBRT focusing on planning strategies, motion management, accuracy and delivery. Material and Methods In October 2018, a survey composed of 6 sections with 54 questions was administered to all Centers performing pancreatic SBRT. Results were analyzed and the percentage agreement in excess of 60% of respondents was reported. Results Twenty-two Institutes joined the study. SBRT is mainly performed in the setting of unresectable locally advanced pancreatic cancer (LAPC) (100%). Computer Tomography (CT) simulation is performed in 95% of the centers (4D CT simulation in 63%), and iodinated contrast medium is administered in 72%. Customized immobilization devices (Vac-lok, Thermoplastic mask) are adopted in 89%, and organ motion control methods are used in the 63% of the cases (Figure). In 20/22 centers (90.1%) co-registration with diagnostic CT (72%), Magnetic Resonance Imaging (MRI, 61%), and/or 18F-Positron Emission Tomography (PET, 57%) is carried out for target volumes delineation. Clinical Target Volume (CTV) is defined as Gross Tumor Volume (GTV) with 2-5 cm margins by 60% of the centers.

Conclusion This survey illustrates the current status of treatment strategies for pancreatic SBRT in Italy. The agreement among centers about indications, organ motion management, multimodal imaging for volume delineation and daily IGRT suggests that a high quality treatment is performed in the majority of the Italian institutes. A consensus decision making between all members could be conducted to standardize SBRT approach in this scenario. PO-1065 Adjuvant chemoradiation (CRT) for gastric cancer: toxicity profile and outcome in Albanian patients F. Kraja 1 , E. Karaulli 1 , I. Akshija 2 , E. Rapushi 1 , B. Doci 1 , E. Tola 1 , E. Cuedari 1 , S. Ademi 1 , E. Hafizi 1 , O. Spahiu 1 , A. Hoti 3 1 University Hospital Centre "Mother Teresa"- Tirana- Albania, Oncology, Tirana, Albania ; 2 University Hospital