Both real and virtual colonoscopies work. Which does Dr. Walt recommend?

Reuters News is reporting that doctors who perform colonoscopies should not be worried that they may lose business to so-called virtual colonoscopies, despite reports that both approaches work equally well at detecting colon cancer.

My Take?

When I turned 50, I knew it was time for colon cancer screening. Given the choice of the “gold standard,” colonoscopy, and screening with a CT scan, I chose the later.

Why? CT colonograpy was, for me, dramatically less expensive ($600 compared to $3500), required no sedation, and had a bit easier of a bowel prep.

My risks? If a polyp had been found, I would have needed colonoscopy – although my radiologist had a gastroenterologist on stand-by, so that I would NOT have to repeat the bowel prep at another time.

And, at that time, we didn’t know if CT colonograpy was as good as colonoscopy. Now, however, we have a better idea.

Details of a study showing both techniques work equally well were published in the New England Journal of Medicine this last Wednesday. Partial results had been presented at medical meetings.

Dr. Daniel Johnson of the Mayo Clinic in Scottsdale, Arizona and colleagues did both virtual colonoscopies and standard colonoscopies on 2,500 volunteers. They found that the virtual technique, which uses an X-ray computed tomography or CT scanner, detected 90 percent of precancerous polyps 10 millimeters or larger.

Regular colonoscopies are done by gastroenterologists using a flexible lit tube passed through the bowel. A device on the end can remove polyps for testing right away.

But with a virtual colonoscopy, also known as CT colonography or CTC, there is no sedation, so patients can quickly go back to their normal activities, the cost is significantly lower than a colonoscopy, and there is less risk of the bowel being punctured.

Both require drinking strong laxatives, a major complaint among patients. And if lesions are spotted during a virtual colonoscopy, the patient will require a standard procedure to remove them.

Virtual colonoscopies can also be briefly uncomfortable because they require briefly inflating the bowel (insufflation) with carbon dioxide while the patient lies on a scanner. However, insufflation CO2 is much less uncomfortable that insufflation with room air, as the bowel absorbs CO2 much mor quickly.

“Both techniques are going to miss some lesions, both polyps and cancers,” Johnson told Reuters Health in a telephone interview. “In our study, there was a patient with a 35 millimeter mass that was missed in colonoscopy but found in CT colonography. None of these tests are perfect.”

Colorectal cancer kills 52,000 people in the United States each year, according to the American Cancer Society. Most Americans are advised to begin getting regular colonoscopies at age 50. 

Why? It’s one of the best colon cancer preventions we have. Virtually ALL colon cancers start in polyps in the colon. When found and snipped off and removed, the cancer is prevented.

Also, polyps with early colon cancer can be easily removed preventing the cancer from spreading or growing into a more dangerous stage.

However, only about half of the 70 million Americans at risk for colon cancer are getting screened now, and the choice of CTC may encourage more people to be tested, experts say.

Gastroenterologists “are nervous that a lot of business will be taken away from them,” Dr. Johnson told Reuters.

But the availability of a noninvasive method “has actually increased our colonoscopy volume,” said Dr. Brooks Cash of the American Gastroenterology Association and a gastroenterologist at the National Naval Medical Center in Bethesda, Maryland, where both techniques are used.

That means more people need a follow-up colonoscopy to remove any polyps that could grow into tumors.

Cash estimated that colonoscopies typically account for 50 to 60 percent of a gastroenterologist’s income.

“It appears to be a very reasonable, very accurate test for colon cancer screening,” he said in a telephone interview. “It will get them (patients) into the store, if you will. Then they can use either test.”

Johnson said CTC uses half the radiation of a standard CT scan.

So, which do I recommend?

Actually, neither. I give my patients a chart with the risks, benefits, and costs of each. And, then armed with good information, they are able to make the choice that is best for them.

And, in the case of my wife, Barb – she chose colonoscopy. Why? Her dad had colon cancer prevented with a polyp removal at colonoscopy. And, we found a gastroenterologist who performs colonoscopy for the same fee as CTC.

Barb, whose test was normal, will not need a follow-up test for 10 years. I, on the other hand, will need either a follow-up CTC or colonoscopy five years after my original test.  

 

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