Oesophageal cancer. Gross specimen of an oesophagus showing large tumour growth and extensive ulceration. Malignant tumours of the oesophagus carry a poor prognosis, despite advances in diagnostic techniques. An oesophageal tumour may reveal itself only when it has grown sufficiently to cause dysphagia, the inability to swallow. At this stage the tumour may have invaded the underlying mediastinum (the middle section of the chest cavity excluding the lungs), and removal is no longer possible. Causes include excessive alcohol consumption and heavy smoking.