Colorectal cancer is the second most common serious cancer in the developed world, but it is also one of the most preventable. Most colorectal cancers develop from benign (noncancerous) polyps in the colon or rectum, which can be identified and removed during a colonoscopy screening. Many people who have had colorectal polyps take nonsteroidal anti-inflammatory drugs (NSAIDS), including aspirin, to reduce the risk of recurrent colorectal polyps. But since NSAIDs are associated with stomach ulcers, researchers are investigating whether celecoxib (Celebrex)—a special kind of prescription NSAID designed to lower the risk of gastrointestinal complications—can help prevent colorectal polyps and cancer.

Two new studies in the August 31, 2006 New England Journal of Medicine investigated the effects of celecoxib in people who had colorectal polyps removed. The researchers found that celecoxib was associated with a reduced risk of recurrent polyps, but one of the studies suggested that the medication may be associated with serious cardiovascular problems.

About the Study

The participants in both studies had precancerous colorectal polyps removed during colonoscopies before the study began. In the first study, the researchers randomly assigned 1,561 participants to take 400 milligrams of celecoxib or a placebo pill once daily. In the second study, the researchers randomly assigned 2,035 participants to receive 200 milligrams of celecoxib, 400 milligrams of celecoxib, or a placebo pill twice daily. All participants had colonoscopies one and three years after the studies began to determine whether they had new or recurrent colorectal polyps. The researchers closely watched the participants to determine if any adverse events occurred.

In the first study, the participants taking celecoxib were 36% less likely than those taking the placebo to have a colorectal polyp detected within three years. In the second study, the participants taking 200 milligrams of celecoxib twice daily were 57% less likely than those taking the placebo to have a polyp detected within three years, while those taking 400 milligrams of celecoxib twice daily were 66% less likely.

Also in the second study, a safety committee found that celecoxib was associated with a two- to three-fold increased risk of serious cardiovascular events (death from cardiovascular causes, heart attack , stroke , or heart failure). Because of this, researchers had participants stop taking the study medications in both trials before they could finish them.

Both studies were limited because the end point was the detection of colorectal polyps—not the development of colorectal cancer. However, it would be ethically problematic to follow study participants until they developed cancer when simply removing the precancerous polyps would effectively prevent the cancer from ever occurring.

How Does This Affect You?

These studies suggest that celecoxib may help prevent the formation of precancerous colorectal polyps in people who have already had polyps removed. Celecoxib may be even more effective than aspirin, which has been shown to reduce the recurrence of colorectal polyps by approximately 20%, compared with the 36-66% reductions seen in these studies.

But the increased risk of serious cardiovascular events found in the second study is concerning. It is not clear that the benefits of taking celecoxib to reduce the possibly of recurrent polyps outweighs its risks for most patients. For now, doctors and patients need to decide who should take celecoxib on a case-by-case basis. The medication, for example, may be most appropriate for patients at extremely high risk of recurrent polyps (eg, strong family history or personal history of colorectal cancer) who cannot tolerate other more conventional forms of NSAIDs. If you fall into this category, you may wish to discuss the possibility of taking celecoxib with your doctor.