Preventing Colon Cancer

Colon cancer prevention has been in the news quite a bit since summer,  2000.  The death of Katie Couric's husband in his early forties led to a lot of media attention concerning the 60,000 people who die annually of colon cancer in the United States.  Since most colon cancers evolve from normal tissue, to polyp, to colon cancer over a five or ten-year period, it would seem reasonably easy to prevent most colon cancers.  Yet, there is often reluctance to go through procedures involving the colon when one has no symptoms and no risk factors.

Several articles appeared in the last year suggesting that many polyps start high up in the colon, beyond the reach of the flexible sigmoidoscope (without any polyps lower down in the colon).  This would enable patients screened with the short exam, to allow significant polyps to go unidentified. These polyps could potentially turn into colon cancers, in spite of 'proper screening' according to 'current recommendations'.

 Some studies have shown the benefit of cards identifying microscopic blood in the stool. Finding microscopic blood in the stool might lead to colonoscopy, and this might identify a polyp high in the colon. However, the false negative rate is very high, as most polyps do not bleed, and those that do bleed tend to bleed intermittently.  In fact, most of the time when the cards come back 'positive', it is due to hemorrhoidal bleeding or a small cut near the anus called a fissure.  Sometimes it is due to blood in rare meat, or due to aspirin-induced irritation in the stomach.  So most positive cards actually are falsely positive!

The bottom line is that we are getting much more aggressive these days.   We are starting to perform colonoscopies every five years starting around age fifty, or earlier if there is a family history of colon polyps or colon cancers.  This pertains equally for men and women.

Some have asked about new non-invasive techniques for colon cancer screening.  A virtual colonoscopy has recently been developed.  This 3D MRI is constructed as a holographic image.  It looks like you are taking a ride through the colon in a little spaceship!  The problem is that the patient needs a great 'cleanout'. One needs a clean colon even more than with a colonoscopy! During a colonoscopy, I can move the residue, suction it out, or see the area around the residue.  With the virtual MRI, any residue could be confused with a growth, especially a flat growth. 

In most cases, the hardest part of the colonoscopy is the preparation, not the procedure itself.  I can knock people out with Demerol and Valium, and in most cases, I can make patients comfortable. The virtual colonoscopy will pick up about 90% of cancers when done under ideal circumstances.  But it misses 10% of cancers!!  It misses a third of 1-cm. polyps, which may be only months away from turning into cancers. It often identifies abnormalities that turn out to be pieces of stool. In some studies, virtual colonoscopy has been even less accurate. It is important to remember that virtual colonoscopy needs an even more adequate preparation than the colonoscopy. The prep is the hardest part of the procedure.  Therefore, the procedure may be a long way off, and depending on the price, it might not be feasible.  Since 30 or 40 percent of patients may have false positive findings, virtual colonoscopy may lead to a lot of unnecessary angst and expense.

Another interesting non-invasive possibility involves looking for malignant DNA in the stool.  By identifying 'bad DNA' in the stool, one can be sure that a colonoscopy is necessary to look for and remove a 'bad lesion'.  This DNA search is somewhat inaccurate, and it is years away, but it does show promise.

Lastly, I am asked about the pill, which is coming out to replace the colon prep.  Many hate the taste of the colon prep, but please note it is far better than the gallon of fluid, the Colyte approach.  The pill will be out around January 2001.  Visicol is the name, and it will require taking 40 pills over a two-day period. After a 12-hour fast, 3 pills are taken every fifteen minutes for a total of twenty pills and 8 glasses of water.  The next morning,   the same 20 pill drill must be repeated.  So the pill is really 40 pills and 16 glasses of water after a 12 hour clear liquid diet.

So for now, and for the near future, realize that the preparation is the tough part of the colonoscopy. There are ways to make it a little more palatable (see colonoscopy preparation in office documents).

If the colon is clean and all is normal, it is usually sufficient to repeat the colonoscopy every five years.

  If necessary, I can almost totally knock patients out with Demerol and Valium.   With an excellent clean out, (I CANNOT EMPHASIZE THIS ENOUGH), the procedure may be surprisingly painless, and may only take five minutes.  Dr. Yaffe.