ESTRO 37 Abstract book

S777

ESTRO 37

However, Intra-abdominal oesophageal wall thickness was greater than that of the thoracic oesophagus. EP-1428 Early outcomes following neoadjuvant therapy for borderline resectable pancreatic cancer R. Goody 1 , M. Arunsingh 1 , L. Murray 1 , R. Adair 2 , R. Albazaz 3 , A. Anthoney 4 , C. Beckett 5 , A. Cairns 6 , F. Collinson 4 , A. Guthrie 3 , A. Kenyon 7 , C. Macutkiewicz 2 , L. Sanni 6 , M. Sheridan 3 , A. Smith 2 , P. Trainor 7 , G. Radhakrishna 8 1 Leeds Teaching Hospitals NHS Trust, Clinical Oncology, Leeds, United Kingdom 2 Leeds Teaching Hospitals NHS Trust, Pancreatico-biliary Unit, Leeds, United Kingdom 3 Leeds Teaching Hospitals NHS Trust, Radiology, Leeds, United Kingdom 4 Leeds Teaching Hospitals NHS Trust, Medical Oncology, Leeds, United Kingdom 5 Bradford Teaching Hospitals NHS Foundation Trust, Gastroenterology, Bradford, United Kingdom 6 Leeds Teaching Hospitals NHS Trust, Pathology, Leeds, United Kingdom 7 Leeds Teaching Hospitals NHS Trust, Hepatobiliary and Upper Gastrointestinal Clinical Nurse Specialist Team, Leeds, United Kingdom 8 The Christie NHS Foundation Trust, Clinical Oncology, Manchester, United Kingdom Purpose or Objective Incomplete resection of pancreatic adenocarcinoma is associated with poorer outcomes, even following adjuvant chemotherapy (CT). There is no randomised data to guide use of neoadjuvant therapy (NAT), but a number of meta-analyses support its role in increasing complete resection (R0) rates. Early outcomes were reviewed following introduction of a NAT pathway for borderline resectable pancreatic adenocarcinoma within a Regional Specialist Pancreatic Unit. Material and Methods Records of all patients with borderline resectable pancreatic cancer referred for NAT between 07/2015 and 09/2017 were reviewed. Cases of technically or medically inoperable disease were excluded. Treatment consisted of CT with sequential concurrent chemoradiotherapy (CRT). For CRT, a contrast enhanced 4D planning scan was acquired. A dose of 50.4-54 Gray in 28-30 fractions with concurrent capecitabine was delivered using a multi-field 3D conformal technique and online cone beam CT image guidance. Multi-disciplinary review of all patients who completed NAT identified potential candidates for resection. The Kaplan-Meier method was used to determine overall survival (OS), with differences assessed using the log rank test. Results Thirty-two patients with borderline resectable pancreatic cancer were referred, with median age 64 years. Tumour location was head:body:tail of pancreas in 24:7:1 patients. Thirty-one had confirmed or suspicious histology. On updated pre-NAT imaging, two patients had progressive disease (PD) and were excluded from further analysis. In addition, 4 patients who had not yet completed NAT at the time of analysis were excluded. Median follow-up was 14.6 months (mo). Of the remaining 26 patients, 24 completed CT and 2 enrolled directly in a national clinical trial of stereotactic ablative radiotherapy (SABR). In total 3 patients received SABR within a clinical trial, seventeen other patients commenced CRT. There was one probable treatment related death, likely related to capecitabine gastrointestinal toxicity and sepsis. Seven patients (27%) had successful resections with 100% R0. There was one pathological complete response. No early post-operative deaths occurred, and median post-operative length of stay was 15 days. For the whole cohort median OS was

15.9 mo, with 13.5 mo for unresected pts, and not yet reached for resected pts (p=0.099). Conclusion This is a safe and feasible treatment regimen, response rates were as expected. R0 resection rate and early survival rates are encouraging. Development of a dose- escalated VMAT technique or margin-intensive SABR may further optimize the radiotherapy component of NAT. EP-1429 Stereotactic body radiation therapy as neoadjuvant/radical treatment for pancreatic adenocarcinoma X. Chen Zhao 1 , E. Sanchez Saugar 1 , M. Lopez Gonzalez 1 , O. Hernando Requejo 1 , A. Montero Luis 1 , J. Garcia Ruiz- Zorrilla 2 , M. De la Casa de Julian 2 , M. Garcia-Aranda Pez 1 , R. Ciervide Jurio 1 , J. Valero Albarran 1 , J. Palma Delgado 1 , R. Alonso Gutierrez 1 , J. Perez Moreno 2 , L. Alonso Iracheta 2 , D. Zucca Aparicio 2 , P. Garcia de Acilu 2 , J. Marti Asenjo 2 , P. Fernandez Leton 2 , C. Rubio Rodriguez 1 1 University Hospitals HM Sanchinarro - Puerta del Sur, Radiation Oncology, Madrid, Spain 2 University Hospitals HM Sanchinarro - Puerta del Sur, Medical Physics, Madrid, Spain Purpose or Objective Pancreatic adenocarcinoma (PA) remains one of the most lethal malignancies. Surgery is the only curative treatment. Chemotherapy (CH), radiotherapy or both are now been studied as neoadjuvant approaches. We are going to review feasibility and single centre experience with stereotactic body radiation therapy (SBRT) and a gating technique as a neoadjuvant or radical treatment in PA. Material and Methods Since February 2014, 23 patients (p) with a median age of 67.6 years (range 43-86) with histologically proven adenocarcinoma of the pancreas were enrolled on this protocol. Five p (21.3 %) were treated with a radical intent and 18 p (78.7 %) as a part of a neoadjuvant treatment. For all patients treated with neoadjuvant intent, CH had given before SBRT. Neoadjuvant CH schedule: 14 p received gemcitabine nab-paclitaxel, 3 p FOLFIRINOX and 1 patient with unknown CH schedule. Prior to radiation, at least 2 gold fiducials markers were located into the tumour guided by gastro-endoscopic ultrasound. All the SBRT treatments included intravenous and oral contrast CT or PET-CT for GTV delineation. Intensity-modulated radiation therapy (IMRT) and daily image-guided radiation therapy (IGRT) with intrafraction control of tumour motion with a Novalis Exactrac Adaptive Gating System were performed in all patients. Total dose: 50 Gy in 5 fractions were prescribed in 20 p (87%), 1 p was treated with 35 Gy in 5 fractions, 1 p was treated with 40Gy in 10 fractions and 1 p was treated with 50Gy in 10 fractions. Results With a median follow-up (FU) of 8.8 months (range 1 - 36 months), 7 p (30.4%) are alive without tumour, 4 p (17.4%) are alive with distance metastases and 12 p (52.2%) have died; median overall survival (OS) was 13.2 months (range 4.5 – 42.1 months) and the actuarial 12 and 24 months OS was 64.3% and 22% respectively. Twenty p (86.9%) remain locally controlled and median time to local progression was 12.7 (range 6.6 – 42 months). For any kind of progression disease, the actuarial progression-free survival at 12 and 24 months were 62.5% and 35.7% respectively. Fourteen patients (78%) underwent surgery. Tumour-free margins were achieved in all cases. Pancreatic SBRT was well tolerated in our cohort of patients. No grade 3 or higher toxicity was observed. Two p (8.7%) developed grade 2 epigastric pain and/or grade 2 asthenia.