Endoscopic submucosal dissection (ESD) is an advanced therapeutic endoscopy that allows the resection (removal) of tumours in the colon or anus without the need for open surgery. It uses a thin and flexible tubular instrument called a colonoscope.
The colonoscope is inserted through the anus and a solution is injected submucosally (beneath the mucous membrane) to elevate the area affected by the tumour. The tumour is then removed and a tissue sample can be obtained for further laboratory diagnosis. Endoscopic submucosal dissection needs to be performed by experienced endoscopists due to its complexity and technical difficulty.