What are colon polyps?
Polyps are benign tumors that involve the lining of the intestines (noncancerous tumors or neoplasms). They can be found in various locations in the digestive tract but are more common in the colon. Its diameter varies from 4 mm to several centimeters. They look like small bumps that grow on the lining of the intestine and protrude through the lumen (cavity of the intestines). Sometimes they grow on a “stem” and look like mushrooms. Some polyps can also be flat. Many patients have multiple polyps scattered in different parts of the colon.
Some polyps may contain small carcinogenic areas, although the vast majority do not have this complication.
It is proven that colon cancer begins as a polyp. However, only 1 in 20 polyps becomes cancer, but since it cannot be determined which one it will be, they must all be removed through a polypectomy.
Polyps are very common in adults, whose chances of getting polyps increase with age. Between 30% and 50% of adults over the age of 50 develop polyps.
It is not known exactly what causes polyps, but it has been mentioned as risk factors: a diet high in fat and red meat and low in fiber; smoking and obesity. There is definitely a genetic factor.
The greatest risk factor for developing polyps is being older than 50 years. A family history of colon polyps or colon cancer increases the risk of developing polyps. Also, patients with a personal history of polyps or colon cancer are at risk of developing new ones. There are even some rare polyps or cancer syndromes that run in families and increase the risk that polyps will develop at younger ages.
There are two common types: hyperplastic polyp and adenoma. The hyperplastic polyp does not present a cancer risk and is therefore not as significant. On the other hand, adenoma is believed to be the precursor (origin) of most colon cancers, although most adenomas never develop into malignant tumors.
Histology (observing tissue under a microscope) is the best way to differentiate between hyperplastic and adenomatous polyps. While it is impossible to know which adenomatous polyps will develop into malignant tumors, the largest polyps are the most likely to develop into these tumors, and some of the largest (larger than 2 cm) may already contain small areas of cancer.
Because the doctor cannot be sure of the tissue type because of the appearance of the polyp, doctors generally recommend removing all polyps that are found during colonoscopy.
Most polyps have no symptoms. The largest ones cause blood in the stool, but even these are usually asymptomatic. Therefore, the best way to detect polyps is to examine people who have no symptoms.
Because colonoscopy is the most accurate way to detect polyps, many experts now recommend this study as a screening method to remove polyps that are found or suspected to exist during the same procedure.
Most polyps that are found during the colonoscopy and are completely removed during the procedure. There are various removal techniques; cut them with a wire, with forceps for biopsy and/or burn the base of the polyps with an electric current. This is called Polypectomy (resection of polyps).
Because the lining of the intestines is insensitive to cuts or burns, resection of polyps does not cause discomfort. The resected polyps are then examined under a microscope to determine the type of tissue and to detect any type of cancer.
If a large or foreign-looking polyp is removed
or left for possible surgery, the endoscopist may mark the site by injecting small amounts of Chinese ink into the wall of the intestine. This is called an “endoscopic tattoo.”
Polyps removal (or polypectomy) during colonoscopy is a routine outpatient procedure. Possible, but rare, complications include bleeding from the polypectomy site and perforation (a hole or tear) of the colon. Bleeding from the polypectomy site can be immediate or take several days, persistent bleeding can almost always be stopped with treatment during colonoscopy. Perforations that require surgery for repair, rarerly occur.
Your doctor will decide when to repeat your colonoscopy. The interval will depend on factors such as the number and size of the polyps removed, their tissue type, and the quality of colon cleansing.
The quality of the cleaning will affect the doctor’s ability to see the surface of the colon. If the polyps were small, and the colon was well seeing and checked during your colonoscopy, your doctor will generally recommend repeating the study within three to five years.
If the follow-up colonoscopy did not show polyps, you probably won’t need another procedure in the next five years. However, if the polyps were large and flat, your doctor may recommend repeating the colonoscopy in a few months to make sure that the polyps were all removed. The doctor will discuss the available options with you.
Sources: Dr. Pablo Navarro and “American Society for Gastrointestinal Endoscopy” www.UpToDate.com
Ejemplo de polipectomía