Endoscopic Submucosal Dissection (ESD)

The wall of the digestive tract is built in layers. The innermost lining, the mucosa, is where most gut cancers begin, and beneath it lies the submucosa, a looser layer above the muscle. When a cancer is caught early and is still limited to these upper layers, the risk that it has spread to lymph nodes is low, and removing the lesion completely can be enough treatment. ESD is the endoscopic technique designed for this. The specialist marks the edge of the lesion, injects a fluid cushion into the submucosa to lift it away from the muscle, cuts around it and then dissects carefully underneath, removing it in one piece, known as en bloc. Unlike simpler snare techniques such as endoscopic mucosal resection, which may remove large lesions in several fragments, ESD gives the pathologist an intact specimen with clear edges to assess. The stomach, oesophagus or colon is kept, so eating and bowel function are preserved.

ESD is recommended for early neoplasia, meaning cancers or high-grade precancerous changes that appear confined to the lining with no sign of deeper invasion or spread. Typical examples are early gastric cancers, early squamous cancers of the oesophagus, early neoplasia arising in Barrett's oesophagus, and large flat colorectal polyps or early rectal cancers in which a focus of cancer is suspected and removal in one piece matters. Selection relies on high-definition and magnifying endoscopy with special light filters, biopsies and, in some cases, endoscopic ultrasound or a CT scan to look for spread. ESD is not suitable when a tumour has clearly grown into the muscle layer, when lymph nodes are involved or when a lesion is too large or deep to remove safely. In those situations surgery, sometimes with chemotherapy or radiotherapy, is the standard path, and the endoscopy and surgical teams decide together.

ESD is carried out in an endoscopy suite or operating theatre under deep sedation or general anaesthesia, with carbon dioxide rather than air used to expand the gut because it is absorbed quickly and reduces bloating. The specialist first marks a margin around the lesion with small dots of electrical current, then injects a lifting solution beneath it. A fine electrosurgical knife passed through the endoscope cuts the lining around the marks and then works under the lesion through the submucosa, while a clear cap on the scope tip holds the tissue open. Vessels are sealed as they are met, and the injection is topped up as needed. Once free, the lesion is retrieved, pinned flat and sent to the laboratory. The base is checked, visible vessels are treated, and the defect may be closed with clips. Depending on size and location, the procedure commonly takes about 1 to 3 hours.

Good candidates have an early lesion that the endoscopy team judges removable in one piece, and are fit enough for sedation or anaesthesia; age alone is rarely a barrier, and ESD can be a gentler choice than surgery for older people or those with other illnesses. Before deciding, the team reviews your endoscopy images, biopsy slides or reports and any scans, and often repeats a detailed endoscopy to map the lesion. Blood tests include clotting. Blood thinners and antiplatelet medicines need careful planning with your doctors because they raise the bleeding risk, and some cannot be stopped safely without a bridging plan. For lesions in the oesophagus or stomach you fast beforehand; for colorectal lesions you take a full bowel preparation, as for colonoscopy. International patients usually begin by sending images, pathology and scan reports, so suitability can be assessed before travel.

After ESD you are observed in hospital, typically for 1 to 3 nights. Drinking is usually allowed the next day, followed by a soft or light diet for a few days, and acid-suppressing medicine is given after stomach and oesophageal procedures to help the wound heal. Mild pain or bloating is common and settles quickly. The team watches for signs of delayed bleeding, such as vomiting blood or passing black or bloody stools, and for pain or fever that could suggest a perforation. Because delayed bleeding mostly appears within the first one to two weeks, staying about 7 to 10 days near the hospital is sensible before a long flight, and avoiding heavy lifting and alcohol during that time helps. A follow-up endoscopy is usually planned a few months later to check the scar, and it can often be arranged at home with the full report.

ESD is a well-established procedure in experienced hands, but it carries more risk than a routine endoscopy. Bleeding during the procedure is common and is controlled through the scope; delayed bleeding occurs in a minority of patients and is usually treated with another endoscopy. Perforation, a hole through the gut wall, is uncommon and is often closed with clips at once, although some cases need antibiotics, a longer stay or, rarely, surgery. After removal of a large part of the circumference of the oesophagus or stomach outlet, scarring can narrow the passage and may need stretching. The pathology report is central: it states whether the margins are clear and whether the depth and features of the tumour carry a low risk of spread. If so, ESD is usually curative and surveillance follows; if the risk is higher, the team may recommend surgery to remove lymph nodes.