Endoscopic submucosal dissection (ESD) is a minimally invasive endoscopic procedure used to remove abnormal growths or lesions in the gastrointestinal tract, such as early-stage cancers or large polyps. During ESD, an endoscope equipped with specialized tools is inserted through the mouth (for lesions in the esophagus or stomach) or anus (for lesions in the colon or rectum). The endoscope is used to lift the abnormal tissue away from the underlying layers of the gastrointestinal wall, and then precise incisions are made to dissect and remove the lesion. ESD allows for en bloc resection (removal in one piece) of larger lesions, which can be more difficult to remove with traditional endoscopic techniques like polypectomy. ESD is an effective and minimally invasive treatment option for selected patients with early gastrointestinal cancers or precancerous lesions.