Centers of Excellence
It is a known fact that sporadic colon cancer develops in polyp areas, which are precancerous lesions.
There are 3 types of colon polyps:
- Pedunculated polyps, which have a stalk and project from the colon surface.
- Sessile polyps, which project from the colon surface, but do not have a visible stalk.
- Flat polyps, which do not project or project very slightly from the colon surface.
The procedure to remove flat polyps must be performed by a gastroenterology or invasive endoscopy specialist for two main reasons:
- Removal of these polyps, particularly when they are located in the right part of the colon that has thinner walls, may cause complications, such as colon wall perforation, resulting in peritonitis.
- If the procedure is not performed properly, the residual precancerous tissue may develop into cancer in the future.
For the flat polyps to be removed, they must first be detected. Detecting them is not an easy task because often these polyps are not visible with conventional endoscopes.
To detect them, high-definition endoscopes must be used, in combination with specialized techniques, such as chromoendoscopy and narrow band imaging. As soon as the polyps are detected, they are inspected with the magnification endoscopy technique, and the severity of the dysplasia is determined.
The removal of this type of polyps is a procedure requiring specialization. First the polyps are sprayed with a stain, to define their boundaries, which are often not clearly visible with simple endoscopy.
After that, solutions are injected beneath the polyps, so that the mucosa is separated from the submucosa, thus minimizing the possibility of colon perforation during resection. After the polyp is elevated, it is removed using a special snare.
Large polyps are removed by piecemeal resection or by use of a new method called submucosal dissection. The removed tissue is pinned on a cork board and sent for biopsy.