Did you have a screening colonoscopy less than 10 years ago, with perfectly normal results? Or are you over the age of 75? If either applies, you should think twice if your doctor recommends repeating the test now. Reason: A shocking percentage of colonoscopies are done on people who don’t need them—and for whom the expense, discomfort and risks are wholly unnecessary—according to a recent study.

To understand the new research, you first need some facts about colorectal cancer…


Colonoscopies are not inherently bad, of course. To the contrary, they are the undisputed gold standard of colon cancer detection and are proven to reduce the risk for death from colorectal cancer. They also prevent cancers from developing. That’s because most colon cancers start out as small polyps (growths) that, over the course of 10 years or so, slowly grow and go through changes that turn them into cancer. Colonoscopy gives doctors a chance to spot and remove potentially dangerous polyps, often before they turn cancerous.

Starting screening at age 50 is important because typically there are no warning signs that can be seen without a colonoscopy. But given how slowly the disease progresses, the current guidelines from the US Preventive Services Task Force recommend that subsequent routine screening colonoscopies be done only once every 10 years for patients who are not at increased risk for colon cancer. For a person who is at increased risk—for instance, due to a family history of the disease or a previous colonoscopy that revealed something worrisome—earlier and more frequent screening is appropriate.

Colon cancer’s slow-growing nature is also the reason why the guidelines recommend that doctors stop routine colonoscopy screening once a person reaches age 76 and halt all colonoscopy testing after age 85. By that time, frankly, a person is far more likely to die from something else before colon cancer could turn fatal. This shifts the pendulum, so that the benefits of colonoscopy no longer outweigh its potential harms, such as colon perforation, bleeding and/or temporary fecal incontinence from the procedure…and cardiopulmonary problems from the sedation. Though these complications are not common, they are more likely to occur and harder to treat in older people.

Official guidelines aren’t infallible, of course. Recommendations can and do change as new information emerges. For now, though, the guidelines represent the consensus of opinion from top experts in the field—which is why it’s worrisome that they are so often being ignored.


For the new study, researchers scoured Medicare records for people over age 70 and older from all of Texas and from other areas around the US, trying to determine how many colonoscopies were being done inappropriately. Because they didn’t have access to complete medical records, they couldn’t say for sure that certain colonoscopies were inappropriate, so they used the term “potentially inappropriate.” For instance, colonoscopies deemed potentially inappropriate included screening colonoscopies done less than 10 years after previous colonoscopies that had been completely normal…and screening colonoscopies done on people older than 75.

If the records showed that the patient had had a barium enema or abdominal CT in the preceding three months, the researchers assumed that the patient was having the colonoscopy to diagnose a medical problem rather than to screen for cancer. In a case like that, the colonoscopy was not deemed potentially inappropriate. Similarly, when there was a previous diagnosis of anemia, gastrointestinal bleeding, abdominal pain or some other potentially colon-related problem, the colonoscopy was considered to be diagnostic rather than routine screening and thus was not considered potentially inappropriate.

After reviewing nearly 120,000 records, researchers saw some startling patterns emerge…

  • Roughly 23% of the colonoscopies were potentially inappropriate.
  • In people between the ages of 76 and 85, a troubling 39% of colonoscopies were potentially inappropriate.
  • The physicians who were most likely to perform inappropriate colonscopies were gastroenterologists (as opposed to some other type of specialist)…had graduated from medical school before 1990…and were working in “high-volume” practices (those that performed more than 175 colonoscopies per year).


The lesson here is that, before you (or a loved one) agree to a screening colonoscopy, ask your physician why it’s being recommended. Then click here to see whether the reason given is in compliance with the current guidelines.

If your doctor’s recommendation differs from the guidelines, he or she may have a good reason. For instance, if you come a family with great longevity and can fully expect to live into your 90s or even to 100, your doctor may think that it’s in your best interest to get a routine colonoscopy in your 80s if you are in good health, particularly if you never had a screening colonoscopy before.

However, if there seems to be no valid reason for another colonoscopy and no reason to classify you as being at increased risk, ask your doctor whether a less invasive screening test, such a fecal occult blood test, will suffice. If he still insists on the colonoscopy, you may want to seek a second opinion…or simply say no. It’s your colon, it’s your money, it’s your decision.