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The Realities of
Virtual Colonoscopies

by Andrew Elias

When my wife insisted that I get my first colonoscopy I made an appointment to make her happy. As it turned out it might have saved my life.

Colorectal cancer is the leading cause of cancer-related deaths in the united States, with approximately 150,000 cases of colon cancer diagnosed each year. Approximately 60,000 patients die of the disease yearly. But colon cancer can be prevented if polyps are discovered and removed early because tumors take years to develop. Unfortunately too many people remain largely unscreened due, in part, to poor public awareness and foolish avoidance of current screening techniques. The American Cancer Society recommends that everyone should be screened at age 50 and then every three to five years.

Virtual colonoscopy is a new technique that uses a CT scanner and computer virtual reality software to look inside the colon without having to insert a long tube into the colon or without having to fill the colon with liquid barium, as with a conventional colonoscopy.

I spoke with Dr. Randolph Knific, an interventional radiologist with Radiology Regional Center about the importance of having a colonoscopy done and new ‘virtual’ procedure.

You’re an Interven-tional Radiologist?

Randolph Knific, MD: Actually that’s my subspecialty. But for virtual colonoscopy, or CT colonoscopy, you don’t need to be one. It means I have additional training.

What is an interventional radiologist?

In radiology, a lot of what we do is diagnostic radiology, whereby we are looking at data, images, information from patients to try and figure out what is going on, to address the problem or disease or just to screen for illnesses, which is the case with the CT colonoscopy. In interventional radiology it’s doing something to the patient, hence the term interventional. Usually it’s some type of catheter or probe with a minimally invasive surgical type of procedure. It’s a form of surgical procedure where they are donepercutananeously (through the skin) through small incisions rather than an open type of surgery like a surgeon will do in an operating room.

You use the terms virtual colonoscopy and CT colonoscopy. Are they the same or different?

The terminology is still evolving. What you’ll most likely see on the internet or in publications is virtual colonoscopy. ‘Colonoscopy’ being the procedure that we’re so familiar with, where a doctor puts a fiberoptic tube into the GI tract to look at it. And ‘virtual’ was coined because the procedure that we do resembles the fiberoptic procedure, but uses computers to get there. There’s really nothing virtual about the procedure. The CT procedure is a real procedure, so some people say it’s not really virtual anything. It’s CT colonoscopy or CT colonography.

Why is it so important to be have a colonoscpy done, virtual or conventional?

Obviously our angle with all of this is battling colon cancer or colorectal cancer—the third most commonly diagnosed cancer in the United States and also the second most deadly cancer. Iit’s a real problem. There’s approximately 60,000 deaths per year in the United States from colon cancer so it’s significant and we need to do more to battle it. That’s the bad news. The good news is the way cancer grows in our bodies tends to be slow compared to some other diseases. In colon cancer, almost all of them start as a polyp and the polyp slowly grows over time and eventually transforms into a malignancy and that’s when it becomes a bad actor.

The reason there’s good news is that that slow growth period gives us a chance to get to the polyp and remove it before it becomes a cancer. Not all polyps are cancerous or pre-cancerous, but some are and we really can’t tell which are until we remove them. So the approach for most of us is when we find polyps we want to remove them. If we can get people screened for colon cancer we can hopefully catch it at the polyp stage, remove it and then prevent that person from having to suffer from cancer.

Who are the candidates for virtual colonoscopy as opposed to conventional colonoscopies?

That’s a good question. Let me first emphasize that our main concern is that people get screened whether they pick the virtual kind or the conventional kind. Right now only 30% of people that should be screened are getting screened, so we just want more people to get screened.

After I had four polyps removed they told me if I hadn’t gone I wouldn’t have lasted too many more years and that I should tell everyone I know to go and get screened.

We’re still working on the exact recommendations of the timing of when to do it, but pretty much beginning at age 50 people should have a colonoscopy or a virtual colonoscopy every ten years.

I think a lot of the problem is people being afraid of the nightmare stories of getting prepared for the colonoscopy. That is not a nice 18 hours.

That’s right, and these recommendations are changing. Anyone who has risk factors such as family history perhaps should have it done more often. For instance, high-risk people with polyps may need a procedure every two years. But normally, if you get one at age 50 and its normal then you can wait five to ten years to get another one because of the fact that these things grow so slowly.

What‘s the difference between the two procedures and what exactly goes on when you get the virtual colonoscopy?

You have to start with a clean colon and that’s one of the challenges of any of these procedures. We can’t see anything if the colon contains stool or ingested material so you still have to go through the cleansing part that I think you were referring to when you said the eighteen hours before was miserable. We need people to undergo this preparation when they take material to help clean out the colon the day before.
For the virtual colonoscopy the patient goes through a radiology office or department for a CAT scan. This is a CAT scan-based procedure and we insert a small chip into the patient to introduce air to inflate the colon, so something does go in but not very far—just enough to introduce some air. When the colon is filled with air then the CAT scan does the rest. There’s no needles, there’s nothing else the person has to do except hold still and hold their breath.

So there’s no pain—maybe some discomfort?

Except the filling of the colon can cause cramping in some people, but it’s short-lived, it goes pretty fast. Then we typically flip the patient over and scan them again.

Is the preparation the same for both types of procedures?

Very similar. One difference is we also give some coating material to the person so when they come for our procedure, if we’re trying to sort out a problem area or not, if it has the coating material that we gave them then we know it’s just something they ate.

There’s no anesthesia when you do the virtual procedure so that’s a bit safer?

Correct. That’s significant because some people cannot tolerate the anesthesia. If their health is fragile or they have emphysema or a heart condition the anesthesia can be risky, so that’s completely eliminated.

There’s also no known risk from the virtual procedure. The risks from having a regular colonoscopy are low—serious complications are probably about 2%—but as far as we know there are no risks from the virtual colonoscopy.

What are the risks of a conventional procedure?

From a fiberoptic or regular colonoscopy perforation is the main risk. The average colon is about five or six feet long and they have to push this tube all the way around and through and sometimes it can cause a small tear in the colon.

Is the accuracy the same?

I’ll be honest, I’m not convinced, but one study that received a lot of popularity came out in the New England Journal of Medicine, and said that the virtual colonoscopy was slightly better. Then several months after that, an article came out in JAMA, the Journal of the American Medical Association, that the virtual colonoscopy was not as good as the regular colonoscopy. Most people involved with this think that the JAMA article had some flaws in it, and we think the first article that showed it’s better is probably more accurate. It’s fair to say that it’s still being looked at, but most likely they’re very close.

So as far as advantages and disadvantages, they’re about the same so the only real difference is the anesthesia?

The accuracy is going to be very close. We think. The virtual colonoscopy is less invasive because there’s no known risk, you can’t suffer a perforation or the rare death that you can get from regular colonoscopy. In the studies, most patients tolerated the virtual procedure better. There’s no sedation, if that’s a factor for a person. And it is faster. Once you get on the scanner it’s over within about 15 minutes or so and there’s no recovery time. You just get up and walk away.

When did they first start doing virtual colonoscopies?

I know people have been tinkering with it for more than 10 years. It has become more used in the last few years because of the improvement in the technology. It turns out to do it right, and this is one of the reasons we didn’t like that second article I mentioned, you need a CAT scanner that is very powerful and can do a lot of thin slices very fast. In our practice we have the first 16 slice scanner in Lee County and that allows us to get these very thin, high-resolution slices that help us do a good job. Now that those scanners are commercially available, people are able to offer this service pretty much everywhere.

Are there disadvantages?

The biggest disadvantage of the virtual colonoscopy is that it’s not covered by most insurance companies, so it may be an out of pocket exam. In our practice we recognize that so we’re trying to do it at a deeply discounted rate. Another disadvantage is that the point of all this is to find the polyps and remove them so they won’t cause the colon cancer. With the virtual colonoscopy, we might be able to find them just as well, but we can’t take them out.

So you would have to have a regular colonoscopy to take them out?

That’s correct. But for most people, when we find they have no polyps or that they are tiny ones that just need to be watched, then they don’t need a regular colonoscopy. If we do find something then we need to go on to a traditional colonoscopy to have them removed.

There’s a significant portion of the time when the regular colonoscopy can’t get all the way around—they get 70% or 80% or 90% of the way around—but once they start they want to check the whole colon so then they might send the patient for a virtual colonoscopy the same or next day to look at the other 10% or 20%.

Is it becoming more popular to get the virtual colonoscopies?

We think that we are able to examine some people who would not have had their colon examined otherwise and that, I think, is going to be the real benefit of having this technology. We know that most people who should get checked don’t and if at least some of them come in and get checked with this then we’re way ahead and are going to save some lives.

Women are a lot more likely to go to a doctor than men and yet it seems with a colonoscopy women are just as reluctant to go as men. It’s all about avoiding that preparation. They have to find a better way to make the prep less scary.

That’s the worst part. I can tell you that right now there are people looking to figure out a way to take something by mouth that coats everything you swallow. We have one now that I mentioned we use, but it doesn’t work well enough to avoid the cleaning out preparation. So we’re searching for something that people can drink that will be able to distinguish what’s in their GI tract from something that was swallowed, but that’s way down the line…years or maybe never.

So the main thing you want our readers to know is that they should definitely be checked, whether it’s a traditional or virtual colonoscopy.

Correct. If someone picks this article up and decides all right, I’m willing to give it a try, we might change someone’s life—save someone’s life. •

from the September-October 2004 issue

"If someone picks this
article up and decides,
'Alright, I'm willing to give it a try',
we might save someone's life."