Dr Ana Wilson is a specialist in endoscopic procedures used to examine and treat problems in the large bowel. Her skills include performing therapeutic colonoscopy to remove polyps from the colon, a procedure known as polypectomy.
Polypectomy can usually be performed at the same time during a diagnostic colonoscopy, achieving two procedures in one. This is good for insurers and even better for patients. No-one wants to have an extra colonoscopy if they can avoid it.
What are colonic polyps?
Colonic polyps, also known as colorectal polyps, colon polyps or bowel polyps, are small growths in the lining of the large intestine. In most cases they do not cause symptoms and as many as one in five people may have them without ever knowing it. They are usually discovered during unrelated bowel investigations.
Polyps may be no more than a small raised bulge in the bowel lining, or they may be pedunculated, which means that the polyp looks like a small bulb on a thin stalk that is attached to the bowel wall.
Do colonic polyps mean you have bowel cancer?
Not necessarily. Most small polyps are not cancerous, but some have the potential to turn cancerous as they develop. Some types of polyp, such as adenomatous polyps and serrated polyps begin as benign growths but turn cancerous, whereas other types of polyps, such as hyperplastic polyps do not have cancerous potential. As a rule, the larger the polyp, the more likely it is to be cancerous.
Once you have had one polyp, you are more likely to develop others over time, any of which could become cancerous if they are left alone or are undetected.
Why are polyps removed?
Polyps are often removed as a precaution, to take them away before they get the chance to become cancerous. Removing polyps significantly reduces your risk of developing bowel cancer, the second biggest cancer killer in the UK.
Once you have had polyps identified and removed, you will need to undergo regular colonoscopy surveillance at time intervals dictated by the size and number of polyps in case they return.
How are colonic polyps removed?
Polyps are usually removed during an initial colonoscopy performed to detect polyps. In some patients, a second procedure may be required for the polypectomy if the circumstances were not optimal during the diagnostic endoscopy, or if there are so many polyps they cannot be removed safely in one go.
Polyps on a stalk are removed using a snare – a thin wire is looped around the polyp and pulled tight, like a cheese wire, to cut the polyp off. This is done with or without an electric current to cauterise the polyp base to prevent bleeding.
Polypectomy is not painful, and is generally safe. There are recognised small risks of polypectomy including bleeding and perforation of the bowel- the incidence of these rare events is greater with larger polyps.
Removing larger polyps using endoscopic mucosal resection
Large, flat polyps cannot be removed as easily as small pedunculated polyps, as it can be hard to get around or under the polyp with the snare. For this reason, they are usually removed using a technique called endoscopic mucosal resection (EMR). This technique can still be done during a colonoscopy.
If you have an endoscopic mucosal resection, a small amount of saline is injected under the polyp to lift it away from the bowel wall. It can then be snared with a wire in the standard way with a reduced risk of bowel perforation.
EMR takes between 10 minutes and an hour, depending on the size and location of the polyp.
Analysing colonic polyps after removal
Once removed, polyps are normally sent to the laboratory to be examined for signs of cancerous changes. If cancer is detected, you may need further investigations, to ensure that all of the cancer has been removed. You may need additional treatment such as surgery, radiotherapy or chemotherapy, to give you the best possible chance of cure.