42 Chapter 4 The main objective of this study was therefore to evaluate which clinical and treatment-related factors are associated with cardiac and/or lung toxicity in oesophageal cancer patients after definitive CRT. The secondary objective was to determine whether these toxicities are associated with OS. Methods and materials The study population of this retrospective cohort study consisted of 216 oesophageal cancer patients who had been referred to the department of radiation oncology in Osaka for definitive CRT from January 2007 to December 2013. All patients had histologically confirmed carcinoma of the oesophagus and were staged using CT scans of the neck, chest and abdomen and endoscopic evaluation. When local treatment was considered, endoscopic ultrasound was performed. Based on these findings, patients were restaged according to the 7th edition of the AJCC cancer staging manual [17]. Target volume delineation was performed on a 3D planning CT scan. The clinical target volume (CTV) consisted of the primary tumour and suspicious lymph nodes with a 2-3 cm margin in cranio-caudal direction along the oesophagus and 5-10 mm margin in the transversal plane. An additional margin of 5-10 mm was taken from CTV to PTV in all directions. For T2 and T3 tumours and in the case of positive lymph nodes, an area of elective nodal irradiation was delineated depending on the location of the tumour. For all these patients, the mediastinum was treated to a total dose of 40 Gy. For upper and middle thoracic tumours, the supraclavicular region was included in the elective nodal area as well. For the middle and distal tumours, the truncal region was included in the target volume and in some cases, elective nodal irradiation was omitted based on poor clinical condition or very poor prognostic factors. For each patient, the whole heart (WH) and its substructures, including the right and left atria (RA and LA, resp.) and right and left ventricles (RV and LV, resp.) were contoured using an automatic delineation tool based on the atlas by Feng et al[18]. Since the pericardium cannot be identified on CT images, we used a surrogate pericardium (PC), by creating a 3D structure with the WH contour as inner border and the WH + 5 mm as outer border. The lungs were delineated and considered as one organ. Treatment was given on a daily basis, using 10 MV photons in 1.8 to 2.0 Gy daily fractions to a total dose of 50.4 to 66.0 Gy (median dose: 60 Gy). All patients were
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