THURSDAY, Oct. 26, 2006 (HealthDay News) -- Increased use of colonoscopy and other screening seems to have resulted in a drop in colon cancer rates in the United States, new research shows.
Another study finds that colonoscopy results are typically valid for at least 5 years -- allaying fears that shorter testing intervals might be needed.
And a third study suggests the end of colonoscopy altogether. Instead, a tiny video capsule could help doctors scan the bowel for irregularities.
All three studies were expected to be presented at this week's annual meeting of the American College of Gastroenterology, in Las Vegas.
"I think that they all are reporting very encouraging information," said Dr. Durado Brooks, director of colorectal cancer at the American Cancer Society.
Colorectal malignancies are the second leading cancer killer in the United States. Unlike many cancers, however, this disease is largely preventable through detection of precancerous polyps.
"You could argue that no one should get colon cancer at all," said Dr. Jerald Wishner, director of the colorectal cancer program and colorectal surgery at Northern Westchester Hospital in Mt. Kisco, N.Y. "We're not just trying to find early cancers. We're trying to prevent cancer from ever developing with early screening," he said
The American College of Gastroenterology currently recommends that average-risk individuals start screening at age 50. The preferred method is a colonoscopy once every 10 years. Other methods are available but have to be performed more frequently.
The first study, by a team from the University of California, Irvine, found that increased screening for colorectal cancer may have spurred a corresponding U.S. decline in the incidence of the disease from 1988 to 2002. Looking at information from a nationwide database, the researchers included screening methods such as colonoscopy, sigmoidoscopy (an examination of the lower bowel) and fecal occult blood testing.
According to the researchers, the incidence of colon cancer has decreased from 42.8 per 100,000 in 1988-90 to 38.6 per 100,000 in 2000-02, the study found.
Between 1997 and 2002, there was an 80 percent increased use of colonoscopy by Americans, the California team noted.
"I don't know that they've proved cause-and-effect, but what we have is clearly a high-level association," Brooks said. "I think that most people in the field are comfortable and confident that screening is making a difference."
The second study, led by researchers at Indiana University, found that the results of a colonoscopy appear to be valid for at least five years.
"There are a lot of physicians, gastroenterologists and primary care physicians who are uncomfortable with the 10-year screening interval that's recommended," Brooks said. "This study helps to reinforce the fact that if a good colonoscopy is done, then there's a very low likelihood that that person is going to develop colorectal cancer at least within the next five years and probably significantly further out. There's a fair body of evidence that a 10-year screening interval is reasonable."
And with a view to the future, a third study reported that colon-capsule endoscopy -- a procedure in which patients swallow a small video capsule that travels through the colon looking for problems -- could one day be the new standard of screening.
As described by a team from Mount Sinai School of Medicine in New York City, the capsule was more effective in detecting precancerous polyps than virtual colonoscopy but less effective than traditional colonoscopy, the study found.
One problem with the device is that the patient's colon still has to be cleansed beforehand. "This is the unpleasant part of a colonoscopy, so you have lost some of the potential benefit," Brooks said, adding that it is, nevertheless, "intriguing and holds some promise."
The study's lead author stated that he had financial ties to the device's manufacturer, Given Imaging Ltd.
More information
Learn more about colorectal cancer at the U.S. Centers for Disease Control and Prevention.
