The three types of colon polyps you need to know

Most people are aware that gastroenterologists remove polyps during colonoscopies because they “can turn into cancer”. But this is an oversimplification because there are different polyps, and some have no potential to turn into cancer, and the follow-up interval between colonoscopies may therefore be longer, 10 years as opposed to 5 or 3 years. The three polyp types you need to know are adenomas, hyperplastic polyps and flat polyps.

Why do only few people know what polyp they had?

Many, if not most gastroenterologists, send patients a letter with “biopsy” results (but rarely the official pathology report, see below) and recommend a follow-up interval for a repeat colonoscopy. However, patients just assume that they do not need to know the details, just that they had “polyps”. This can lead to unnecessary colonoscopies because that biopsy letter is never available when they see their next primary care physician or gastroenterologist, either because the patient moved, changed health plans, or their doctor is no longer available. Dr. Gottlieb and staff always try to procure the biopsy report from your last colonoscopy if needed.

The adenomatous polyp (adenoma) requires follow-up

An adenoma is a gland-like growth that develops on the surface of the lining of the colon (mucosa). An adenoma is not cancerous simply because it has not (yet) acquired the ability to spread, the hallmark of cancer. When adenomas turn into cancer, which happens after many years of growth, they are called adenocarcinomas. The adenomatous polyp is the kind everybody talks about or means when the discussion is about colon cancer prevention:

Remove the adenoma – prevent the carcinoma

Polyps that are bigger than 10 mm (1 cm, 3/8 inch) or have special features under the microscope (villous appearance) are called ‘advanced adenomas’. Advanced adenomas have a higher risk of turning into cancer (adenocarcinoma) earlier. If removed during colonoscopy, a 3-year follow up is typically recommended, not because they recur at the same location (they don’t, if completely removed), but because there is a concern that the colon is more prone to have or develop new polyps that could become cancerous.

A hyperplastic colon polyp does not require follow-up

Hyperplastic polyps are very common (50 – 80% of normal individuals) and are cause by delayed shedding of the cells that make up the surface lining. They have no (or virtually no) cancer potential. They are typically encountered in the rectum or sigmoid colon (closer to the anus) and are typically less than 5 mm in size. They are typically removed if there is concern that they may in fact be adenomas. If during your colonoscopy only hyperplastic polyps are found, follow-up may be in 10 years; unless you are at higher risk for colon cancer because of family history, prior personal history of adenomas, or other factors (inflammatory bowel disease, for example).

Flat polyps – can be hard to find but are important

These 2 images of flat conventional adenomas emphasize the importance of high-quality bowel preparation and a detailed examination that will allow detection of flat lesions. The examiner should look for subtle changes in color, shape, and texture of the colon surface, as well as interruption of the normal background vascular pattern. Source: (Doug Rex)

So-called “sessile serrated polyps” and “flat conventional adenomas” are of great concern to gastroenterologists. They don’t stand out like other polyps because they are flat, often hide behind folds, have a smooth surface, indistinct borders, and may be covered by mucus. Sessile serrated polyps also tend to occur more on the right side of the colon. These are all factors that make them harder to detect, and harder to remove completely. Most gastroenterologist take extra care to evaluate the right side of the colon and you can improve the chances of detection by paying meticulous attention to the bowel prep. Sessile serrated polyps are followed up like ordinary adenomatous polyps because they generally have the same cancer risk.

Polypoid lesions you do not need to know

A variety of lesion under the lining of the colon can give a polypoid appearance and there are also inflammatory polyps, so called hamartomas and juvenile polyps. Your gastroenterologist will discuss the implication of these findings with you. Appointments for colonoscopy with Dr. Klaus Gottlieb can be made in Templeton, CA, or San Luis Obispo, CA.

Understanding Your Colon Pathology Report

Should you have access to the official pathology report from your colonoscopy (the report for doctors with technical language) and you want to make sense of it, this is the go-to resource:  Understanding Your Pathology Report: Colon Polyps (Sessile or Traditional Serrated Adenomas)




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