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IBD and Colorectal Cancer: Keeping a Close Watch

Posted Aug 24 2008 1:49pm
ANNOUNCER: People with inflammatory bowel disease have an increased risk of developing colorectal cancer, compared to the general population. But doctors caution: the risk must be kept in perspective.

DAVID T. RUBIN, MD: Well, this remains a rare complication of this disease. But the studies that have estimated the lifelong prevalence of this condition or the risk overall is about 3.6 percent or 3.5 percent or three people out of a hundred, in their lifetime, might develop this condition.

We can break it down further, if we actually ask what's the likelihood over time, because time is a significant variable. Two percent after eight years of inflammation, eight percent after twenty years of disease and eighteen percent after thirty years of disease.

ANNOUNCER: All patients with ulcerative colitis face this increased risk. So do some people with Chron's disease.

THOMAS A. ULLMAN, MD: It wasn't appreciated until the 1980s that patients with Crohn's disease were at an increased risk as well. This is because patients with Crohn's disease don't necessarily have disease in the colon. It turns out that probably patients with Crohn's disease are at an equivalent risk for developing colon cancer as patients with ulcerative colitis provided that they have a similar duration of disease and a similar extent of colon involved.

ANNOUNCER: Within the population of people with IBD, there are other risk factors.

DAVID T. RUBIN, MD: The risks of cancer in inflammatory bowel disease include more extensive disease -- in other words, more of the bowel being involved -- longer duration of disease, people who have a family history of colon cancer independent of a family history of inflammatory bowel disease are at increased risk for cancer with their IBD, and a condition which causes inflammation of the bile ducts in the liver called primary sclerosing cholangitis appears to be an independent risk factor for cancer in inflammatory bowel disease. More recently, researchers have suggested that the degree of inflammation is an independent risk factor for cancer.

ANNOUNCER: Colonoscopies and biopsies of tissue samples taken from the colon are the main techniques used in surveillance for colon cancer, or for pre-cancerous conditions.

DAVID T. RUBIN, MD: The sequence of events that lead to cancer in inflammatory bowel disease are not the same as cancer in people who don't have inflammatory bowel disease. What we believe to occur is that inflammation leads to a precancerous state called dysplasia.

Dysplasia is not necessarily visible to the colonoscopist, and so the way we look for this is by doing random surveillance biopsies throughout the bowel and then have a pathologist carefully analyze those for dysplasia.

ANNOUNCER: When the pathologist returns a report of dysplasia, many doctors recommend having the colon removed, regardless of how early or advanced are the cellular changes.

STEVEN H. ITZKOWITZ, MD: If an expert pathologist tells you it's high-grade dysplasia, there's a very strong likelihood that there may already be cancer in the colon at that time or in the near future. The likelihood may be anywhere from 45 to 65 percent, in several studies. So, if high-grade dysplasia is found, most physicians would recommend that the colon should come out because of the high risk of either a coincidental colon cancer at that time or a subsequent colon cancer.

With low-grade dysplasia, there's a little bit more controversy, because the rate of simultaneous colon cancer or subsequent colon cancer tends to be a little bit lower, but, nonetheless, because of our failings, our inability to see all cancers before they become problematic, many doctors will recommend, even with low-grade dysplasia, that you consider removing the colon.

ANNOUNCER: When dealing with low-grade dysplasia, or when inflammation makes it difficult to determine whether dysplasia is present, some doctors may recommend heightened surveillance, in lieu of immediate surgery.

STEVEN H. ITZKOWITZ, MD: The alternatives, if you find low-grade dysplasia and either the physician or the patient doesn't want an operation, would be just very close monitoring, meaning bringing the patient back for another surveillance colonoscopy. I like to say within three to six months. If you're very nervous, there's nothing wrong with bringing them back in a month or two months, depending upon your level of anxiety. But you don't want to wait much more than about six months, because, if that low-grade dysplasia is confirmed, or, God forbid, if there's high-grade dysplasia or worse, you want to be able to act on that quickly.

ANNOUNCER: While people with IBD face higher risk of colorectal cancer, drugs that they routinely take may help reduce that risk.

THOMAS A. ULLMAN, MD: Chemoprevention is the use usually of a medication -- that's the chemo part -- to prevent the development, in this case, of colon cancer. So when we talk about chemoprevention for colorectal cancer in ulcerative colitis, we're talking about medications used for the prevention of dysplasia and cancer.

ANNOUNCER: One drug -- ursodeoxycholic acid, also known as ursodiol -- has shown some promise in helping protect against colon cancer and dysplasia in people with IBD and primary sclerosing cholangitis of the liver. Drugs used for IBD alone may have a similar effect.

DAVID T. RUBIN, MD: The other major therapy that we've been interested in and it seems to have chemopreventive properties is the 5-aminosalicylic acid therapies, which many of our patients will know as their mesalamine drugs, such as Asacol, Pentasa, Colazal and Dipentum. The classic drug, over many years now, has been Azulfidine. Any one of those drugs may have some additional chemopreventive properties.

ANNOUNCER: Doctors say any possible chemopreventive effect is likely to take place early on in the process of cellular change.

THOMAS A. ULLMAN, MD: The drugs that we have so far that we use as chemopreventive agents, it's not clear where in the colitis-to-dysplasia-to-cancer pathway that they work. Certainly, preliminary evidence suggests that it's in the earlier phases prior to the development of dysplasia and that once you've hit dysplasia, the horse is already out of the barn.

ANNOUNCER: Another development in cancer prevention for people with IBD is an improvement in techniques to examine the colon.

STEVEN H. ITZKOWITZ, MD: I think there are some new developments that are coming down the pike. First of all, at the time of your surveillance colonoscopy, the doctor can now use what we call a dye spray, where they can inject sort of a blue dye that will highlight areas that might not have been so visible to the naked eye and target biopsies to those areas, so we have a better chance of picking up dysplasia, if it's there. So that's a very promising technique.

ANNOUNCER: In the future, continued surveillance may become more common following the discovery of dysplasia, especially if chemoprevention proves effective. But now, doctors say dysplasia is a call to action.

THOMAS A. ULLMAN, MD: If high-grade dysplasia is identified, walk -- you don't have to run -- but walk over to a surgeon's office. Do yourself a favor and have your surgery. You may, in fact, have a cancer already. And while it would be nice to save the colon, it's far more important to save one's life.

For patients with low-grade dysplasia, I would recommend the same. You can probably walk a little bit slower, but you should certainly meet a surgeon. You should certain discuss with your gastroenterologist just how much you might be at risk for having, at that moment, a cancer already or developing a cancer in the future.

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