ESTRO 2021 Abstract Book

S309

ESTRO 2021

Conclusion The adoption of Kernel density approach is feasible, automatic, and might represent a robust tool for the identification/adoption of a probabilistic definition of the CTV.

OC-0414 Stereotactic body radiotherapy: neoadjuvant strategy of chemoradiation in pancreatic adenocarcinoma M.C. Rubio Rodríguez 1 , X. Chen-Zhao 2 , M. López 1 , E. Sánchez-Suagar 1 , O. Hernando 1 , E. Vicente 3 , Y. Quijano 3 , H. Durán 3 , S. Prados 4 , S. Tabernero 5 , A. Cubillo 6 , R. Alvarez 7 , I. Vázquez 8 , M.L. Orgáz 9 , D. Zucca 10 , J. García Ruiz-Zorrila 11 , A. Montero 1 , R. Ciérvide 1 , J. Valero 1 , M. García-Aranda 1 , B. Alvarez 12 , R. Alonso 1 , M. Núñez 1 , M.A. de la Casa 10 , P. Fernández-Letón 10 1 Hospital Universitario HM Sanchinarro. HM Hospitales, Radiation Oncology, Madrid, Spain; 2 Hospital Universitario HM Puerta del Sur. HM Hospitales , Radiation Oncology, Madrid, Spain; 3 Hospital Universitario HM Sanchinarro. HM Hospitales, General and Gastrointestinal Surgery, Madrid, Spain; 4 Hospital Universitario HM Sanchinarro. HM Hospitales , Gastroenterology, Madrid, Spain; 5 Hospital Universitario HM Sanchinarro. HM Hospitales, Gastroenterology, Madrid, Spain; 6 Hospital Universitario HM Sanchinarro. HM Hospitales , Medical Oncology, Madrid, Spain; 7 Hospital Universitario HM Sanchinarro. HM Hospitales, Medical Oncology, Madrid, Spain; 8 Universidad CEU San Pablo, Oncology, Madrid, Spain; 9 Univesidad CEU San Pablo, Oncology, Madrid, Spain; 10 Hospital Universitario HM Sanchinarro. HM Hospitales, Medical Physics, Madrid, Spain; 11 Hospital Universitario HM Sanchinarro. HM Hospitales , Medical Physics, Madrid, Spain; 12 Hospital Universitario HM Sanchinarro. HM Hospitales , Radiation Oncology, Madrid, Spain Purpose or Objective Induction multiagent chemotherapy and intensification of radiation dose with SBRT has been studied as a neoadjuvant (NA) strategy for pancreatic adenocarcinoma (PA), in order to improve curative resection rates, pathological response, local control and survival . Materials and Methods Patients with non-metastatic PA underwent SBRT as part of a NA strategy in a prospective observational study. CT-scan, 18-FDG-PET-CT, and endoscopic ultrasound(EU) were performed at diagnosis, before SBRT and surgery. Previous to SBRT, 2 intrapancreatic internal-fiducials were located guided-by EU in all patients. SBRT was delivered in 5 to 10 fractions, sequentially 3-4 weeks after induction chemotherapy. Surgery was performed at least 6 weeks after SBRT, in resectable patients, after restaging.