2 The condition, current treatments and procedure
2.1 Gastrointestinal stromal tumours are a type of soft tissue sarcoma formed from abnormal cells in the tissues of the gastrointestinal tract. Gastrointestinal stromal tumours are most common in the stomach and small intestine but they can develop anywhere along the length of the gastrointestinal tract.
2.2 The grade of gastrointestinal stromal tumour is based on the mitotic rate. There are 2 grades: G1 (low grade – the cancer cells have a low mitotic rate, they are growing slowly and less likely to spread) and G2 (high grade – the cancer cells have a high mitotic rate, they are growing faster and more likely to spread).
2.3 The choice of treatment for gastrointestinal stromal tumours depends on several factors, including the location, size and mitotic rate of the tumour, whether the tumour is metastatic, recurrent or refractory, and the person's overall health. The standard treatments include surgery (open, laparoscopic, robotic or endoscopic surgery), targeted therapy using drugs or other substances, watchful waiting and supportive care.
2.4 This procedure uses a full thickness resection device, which allows endoscopic resection with a single step, clip and cut technique. For example, 1 device comprises a modified snare to remove the tumour and deeper layers of the stomach wall, and a clasp device that closes the full thickness of the stomach wall.
2.5 The device is attached to the end of an endoscope and advanced through the mouth and the oesophagus to the stomach. Gradual dilation may be needed to help the device pass through the upper and lower oesophageal sphincters. The tumour is grasped at its centre and slowly pulled into the cap of the device completely. A clip is released, closing the site of a potential defect in the stomach wall. A snare simultaneously encloses the tumour and cuts it away, then it is retrieved for histological analysis.
2.6 After the tumour is removed, the endoscope is reinserted and the surgical site is examined for signs of haemorrhage and to check that the clip has closed the stomach wall. The procedure is usually done with the patient under sedation, but sometimes general anaesthesia is needed.