I was surprised recently to learn that lots of colonoscopies in the US are not performed by gastroenterologists—physicians who, of course, specialize in the diagnosis and treatment of digestive conditions.

Primary-care doctors and general surgeons also are doing these vitally important screenings that can detect and save a patient from cancer.

Do they do as good a job?

Well, a new study compares how good the colonoscopies are when done by these three types of doctors—and, trust me, the results may influence the type of doctor you choose to perform your next colonoscopy.


In the study, when researchers examined medical data for men and women ages 70 to 89, they found that in comparison to people who did not have colonoscopies…

  • People who had colonoscopies done by gastroenterologists ended up having a 65% lower risk of dying from colorectal cancer.
  • People who had colonoscopies done by primary-care physicians had a 57% lower risk of dying from colorectal cancer.
  • People who had colonoscopies done by surgeons had a 45% lower risk of dying from colorectal cancer.

In other words, a colonoscopy performed by any of these types of doctor reduces the risk for colorectal cancer death—but this study suggests that when it’s performed by a gasteroenterologist, specifically, the risk for colorectal cancer death is lowest of all.

Now, is it possible that patients who were at highest risk for cancer, perhaps because of existing illness or family history, tended to choose to go to surgeons for their colonoscopies, and perhaps that’s why their survival rates were the lowest? That is a possibility, the researchers noted—although using that logic, you’d think that the healthiest patients would have chosen primary-care doctors for their procedures and that therefore primary-care docs’ results would have been the best…but that wasn’t true.

The study was a retrospective analysis of medical data, so researchers didn’t have any information about the patients’ preexisting health. And (unfortunately) they did not analyze how each type of doctor fared in terms of complication rates.

One limitation of the study is that researchers weren’t able to assess why the patients were having colonoscopies in the first place. So it’s possible that patients who had symptoms that were suggestive of colon cancer were sent to surgeons, and that could have affected the results.

Until more research is done, what we know so far is that gastroenterologists’ patients did best in avoiding death from the main disease that colonoscopies are supposed to find.


To learn more about why gastroenterologists may have come out on top, I talked with study coauthor Nancy Baxter, MD, PhD, who cited three potential reasons…

  • More initial training. To become a board-certified gastroenterologist, a doctor must complete a two- to three-year fellowship that includes specific education and training on GI procedures such as colonoscopy.
  • Higher volume. Gastroenterologists tend to perform more colonoscopies than other physicians (one recent study estimates that they perform roughly two-thirds of colonoscopies). The more experience doctors have, the more skilled they tend to become at both performing the procedure and spotting cancerous or precancerous tissues.
  • Continuing medical education. To remain board-certified, gastroenterologists must continue their education and training to remain up-to-date on the latest developments in their field.


This study suggests that, when you are going to have a colonoscopy, your odds of not becoming a victim of colon cancer are highest when choosing a gastroenterologist. So you can start by looking for a board-certified gastroenterologist in your area at the Web site of the American College of Gastroenterology.

But is a gastroenterologist always going to be a better choice? Not necessarily, said Dr. Baxter. Remember, this study looks at overall odds in a large group of patients. There are probably many primary-care doctors and surgeons who perform the procedure just as well as gastroenterologists or sometimes better, said Dr. Baxter. It’s just that it might take a little work to find them.

The key to a successful colonoscopy is finding a physician with a good track record at detecting adenomas (the most common precancerous polyps). Whichever type of physician you consult, Dr. Baxter suggests asking, “What is your adenoma detection rate?” Current guidelines from the American Gastroenterological Association suggest that for patients older than age 50, doctors should have at least a 15% adenoma-detection rate in females and at least a 25% detection rate in males. Make sure that the physician you choose meets your high standards—because when it comes to your health, you should accept nothing less.