Carcinological oesophageal resection surgery is one of the so-called major digestive surgeries, i.e. involving a high perioperative risk (morbidity and mortality) in patients who are malnourished or at high risk of malnutrition. Nutritional therapy for these patients is an important part of overall perioperative management. Lewis-Santy oesophageal surgery requires a thoracic approach (thoracotomy or thoracoscopy) and an abdominal approach (laparotomy or laparoscopy). Resumption of oral feeding is contraindicated in the immediate postoperative period. The use of a feeding jejunostomy is not systematic. The methods used to manage artificial nutritional support vary between centres, but the foreseeable duration of fasting and/or intake of less than 50% of nutritional requirements is always greater than 5 days. At present, total energy requirements are calculated using formulae that take into account the patient's inflammatory state (stable, unstable or stabilised patient), theoretical ideal weight and previous nutritional status, in order to come as close as possible to actual energy expenditure, and are the subject of perioperative nutrition protocols specific to each centre. Indirect calorimetry makes it possible to reliably measure energy expenditure during the perioperative period. The OESOCAL study continues this line of reasoning. It assumes that energy expenditure may vary according to the surgical approach, and that indirect calorimetry can be used to optimise nutritional support in order to avoid over- or under-nutrition, which may be responsible for an increase in infectious complications.