During the ESD, you will be given sedation by an anesthesia team. The doctor will insert a long, thin tube called an endoscope through your mouth and down your esophagus or up through your anus if the growth is in your colon. The growth will be identified using special dyes or imaging techniques, and the borders will be marked so that the doctor can easily see it. A liquid will be injected into the tissue beneath the growth to make it easier to remove and lift it away from the deeper muscle layer of the wall. Then, the doctor will use a highly precise cutting knife to remove the growth as well as a small amount of surrounding tissue.