Inclusion Criteria:  Operable patients who are planned to undergo or who recently underwent neoadjuvant chemoradiotherapy according to CROSS followed by surgical resection for histologically proven oesophageal squamous cell carcinoma or adenocarcinoma of the oesophagus or oesophago-gastric junction Age ≥18 Written, voluntary, informed consent.  Exclusion Criteria:  Non-FDG-avid tumour at baseline PET-CT scan Initial treatment with endoscopic resection Patients who underwent of who are planned to undergo definitive chemoradiotherapy Language difficulty, dementia or altered mental status prohibiting the understanding and giving of informed consent.