Abstract Book

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(0-2). We had no cases of pulmonary or cardiologic toxicity > G2-G3. Sixteen (24.24%) patients had disphagia G2. Ten patients (15.15 %) did not receive a complete CROSS regimen. Fifteen patients (22.7 %) did not undergo surgery due to progressive disease (9 pts), unfitness (3 pts) and death occurring during neoadjuvant treatment (3: 2 myocardial infarction and 1 aortic dissection). Fifty- one patients (82.2 %) underwent oesophagectomy. Two experienced radiologists and nuclear medicine physicians specialized in gastro-oesophageal cancer reviewed both pre- and post neoadjuvant treatment CT images and PET/CT images, respectively. The sensitivity of CT and PET/CT were 94% and 95% respectively versus final histology. Partial or complete response was observed in more than 90% of the cases (radiological/metabolic) and was confirmed after surgical intervention (67% partial or complete and 27% stable response). Tumor down-staging was recorded in 67% of patients and nodal down-staging in 50%. Complete pathological response was recorded in 15 cases (22.7 %). Median follow-up was 21.9 months. Conclusion VMAT was applied in the context of neoadjuvant chemoradiotherapy for the treatment of medium and distal oesophageal carcinoma with satisfactory results in terms of tolerance and toxicity. EP-1427 A comparative study of the normal oesophageal wall thickness based on 3DCT, 4DCT and CBCT S.C.H.&.I. Chaoyue Hu 1 , S.C.H.&.I. Jianbin Li 1 , S.C.H.&.I. Jinzhi Wang 1 , S.C.H.&.I. Qian Shao 1 , S.C.H.&.I. Wei Wang 1 , S.C.H.&.I. Yanluan Guo 1 , S.C.H.&.I. MIn Xu 1 , S.C.H.&.I. Wenwu li 1 , S.C.H.&.I. Yong Huang 1 1 Shandong cancer hospital affiliated to Shandong Universi ty, Department of Radiology- Shandong Cancer Hospital & Institute, Jinan, China Purpose or Objective The purpose of this study was to compare the normal oesophageal wall thickness based on three-dimensional computed tomography (3DCT), four-dimensional CT (4DCT) and cone beam CT (CBCT) to provide a reference for the delineation of oesophageal tumours. Material and Methods Contrast-enhanced 3DCT, 4DCT and CBCT scans were acquired from 33 patients with lung cancer or metastatic lung cancer. The outer oesophageal wall was manually contoured on each 3DCT, 4DCT MIP ( the maximum intensity projection of 4DCT), 4DCT 50 (the end expiration phase of 4DCT) and the CBCT data sets. The average thoracic and intra- abdominal oesophageal wall thicknesses were measured (defined as R 3DCT , R 50 , R MIP , and R CBCT ). Results For the thoracic and the intra-abdominal segments, there were no significant differences between R 3DCT and R 50 , but there were significant differences between R 3DCT and R MIP , and R 3DCT and R CBCT (p=0.000–0.013). For the lower and intra-abdominal oesophagus, there were no significant differences between R CBCT and R MIP (p=0.170, p=0.130). However, for the upper and middle oesophagus, R CBCT were larger than R MIP (p=0.014, p=0.006). There were no significant difference between upper and middle segments on 3DCT, 4DCT (4DCT 50 and 4DCT MIP ) and CBCT images. Intra- abdominal oesophageal wall thickness was greater than that of the thoracic oesophagus. There were no differences between the upper and lower, and middle and lower oesophagus (p=0.053, p=0.377) on CBCT images. Conclusion Oesophageal wall thickness of the same segment differed according to imaging modality. Uniform criterion to

delineate the gross target volume could not be adopted. The thickness of the upper and middle segments on the same CT image differed no remarkably. 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