Should you really be getting colonoscopies more often than the United States elects a new president? Frequent colonoscopies may be lifesaving for some, but you ought to know whether that someone is you before you take a doctor’s word that you need a repeat procedure.

Colonoscopy is a great medical advance, no doubt. Physicians can not only detect abnormal growths called polyps that are red flags for colon cancer, they can remove them on the spot. No polyp found? Great. You won’t be due for another colonoscopy for another 10 years if you have no family history of colorectal cancer or polyps or other conditions that increase the risk of colorectal cancer, such as inflammatory bowel disease. But if a polyp is found and removed, your doctor could be calling you back in for a repeat colonoscopy in as few as three years. You may even be asked to have a third colonoscopy before the 10-year mark. If you are questioning whether these repeat colonoscopies are always necessary, you’re onto something. A new study from Norway shows that requiring a repeat colonoscopy before the 10-year mark in everyone whose initial colonoscopy detects a polyp doesn’t make sense. And, beyond taking into account those study results, there are things you can do yourself to limit the number of colonoscopies you need.


Most colon cancers start out as small growths (polyps) in the lining of the colon that go through subtle changes over the course of several years. Most colon polyps are adenomas, and the vast majority—about 90%—are completely harmless. But because it’s usually not possible to tell which adenomas will become cancerous, doctors pluck out any that they find during a colonoscopy.

If no polyps are found during colonoscopy or when one or two small polyps (less than one centimeter in length) are found and removed, your risk of colorectal cancer is considered low, according to medical organizations, such as the American College of Gastroenterology, that set care standards. Another colonoscopy could be recommended in 10 years if no polyp is found or if a removed polyp is not an adenoma. If the polyp is an adenoma, you might be asked to redo a colonoscopy in five years’ time.

When more than three small polyps, a medium-sized polyp (one centimeter) made of suspicious cells, or a large polyp (larger than one centimeter) is found, you are considered at high risk, and the next colonoscopy could be scheduled in as little as three years. However, the Norwegian study concluded that some repeat colonoscopies for low-risk polyps could be done less frequently than they are now. Here’s why: After following nearly 41,000 patients for up to 19 years, the researchers found that the risk of dying of colon cancer was lower in patients who had one or two low-risk polyps, including small adenomas, removed than in the general population. Why monitor folks at low-risk more closely than the rest of the population then? On the other hand, patients who had high-risk polyps removed were still at an increased risk for dying of colon cancer compared with the general population, and so frequent monitoring for them is smart.


Until colorectal cancer screening guidelines are updated based on information from studies such as the Norwegian one, most American gastroenterologists will continue to tell patients who’ve had one or two small polyps removed to get another colonoscopy in five to 10 years, depending on the type of polyp that was removed and other factors such as family history of colorectal cancer, age, weight and other medical issues that might increase risk of colorectal cancer (such as inflammatory bowel disease, as mentioned).

In the meantime, you can optimize your colonoscopic screening exam to help ensure that it gets done right the first time by following these tips from Gottumukkala S. Raju, MD, a professor in the department of gastroenterology, hepatology and nutrition at The University of Texas MD Anderson Cancer Center in Houston…

Prepare for the colonoscopy the right way. If your colon is not clean and clear enough, detection of polyps during colonoscopy may be a challenge, and the test might have to be repeated, cautioned Dr. Raju. His advice is to follow to the letter the preparation instructions that you get from your doctor and not try to cut corners. Be warned that cramps and intense diarrhea can be consequences of the prep, and it is important to endure them and not skip steps because, if you don’t completely follow through with the prep, you set yourself up for an unsuccessful colonoscopy and will be told to repeat the whole process.

Ask about the split-dose preparation, which cleans the colon more thoroughly than other preps. It involves taking half the dose of the prep the evening before the colonoscopy and the remaining half six hours before the procedure. The first dose washes the colon and the second dose rinses the colon clean.

Especially do not be shy about asking your doctor what to expect during bowel prep and colonoscopy and to explain the prep instructions until you are fully satisfied that you understand them and can accurately follow them.

Get all the details about polyp removal. After a colonoscopy, it is important to find out not only if polyps were found and removed, but how many, what size and what type they were. Ask the doctor whether this puts you in a low-, moderate- or high-risk category. This knowledge is key to help you understand why the doctor is telling you to come back in three, five, eight or 10 years for another colonoscopy and whether the recommended interval is reasonable. For example, if you are at low risk but are told to return for a colonoscopy in three years—or are at high risk but told to wait another eight years before retesting—question why.

Dr. Raju also advises that you make sure a doctor performing the colonoscopy doesn’t cut corners by not informing you about whether the procedure was incomplete. Sometimes colonoscopies can be incomplete—by no fault of the specialist performing the procedure. A kink or blockage in the large intestine might obstruct the doctor’s ability to get a complete view of the area. Another cause that sabotages a complete colonoscopy is that stool or bile is sticking to the colon despite the bowel prep (which is why it is so important to do the bowel prep right to best ensure that this doesn’t happen).

In the case that a colonoscopy is incomplete, you may want to have a repeat colonoscopy just to be sure that no polyps were missed. Most doctors would tell you if the procedure was incomplete and give you the option of a redo. To be absolutely sure that your colonoscopy was complete if the doctor does not offer this information, ask. You have a right to know and to decide the next steps.