Colonoscopy May Cut Advanced Cancer Risk by 70%
A colonoscopy examines the inside of the large intestine with a camera-tipped tube. The test enables the physician to remove any precancerous growths -- adenomatous polyps -- which sometimes develop into cancer. Colorectal tumors are a major cause of death from cancer in the United States, with about 137,000 new cases and 52,000 deaths every year, according to the U.S. Centers for Disease Control and Prevention.
For the study, published in the March 5 issue of the Annals of Internal Medicine, the authors reviewed health records of more than 1,000 average-risk adults between the ages of 55 and 85 who were members in four health management organizations (HMOs).
The researchers identified 474 people with late-stage colon cancer and then looked back 10 years to see if they had been screened for the disease with colonoscopy or sigmoidoscopy. They compared them to 538 "control" patients and used additional information from state or local tumor registries to see whether there was an association between having had a colonoscopy or sigmoidoscopy and developing cancer.
Dr. David Bernstein, a gastroenterologist at North Shore University Hospital in Manhasset, N.Y., said the study had a critical design flaw. "Making assumptions that any cancers that were found would have been seen 10 years prior doesn't make sense," he said. "It doesn't prove that these cancers didn't occur two years ago."
A key part of effective colon screening is getting the tests at the recommended interval, experts say. To better understand what might be effective in prodding people to get screening, another study published this month in the same journal found that people who were mailed a letter, a pamphlet and a fecal occult blood test kit completed recommended screening twice as often and for less cost than those who were not reminded or got automated and other reminders by nurse coaches.
Doubeni recommends something far more simple: doing the fecal occult blood test every year right around the time of your birthday.
Learn more about colon cancer from the U.S. National Library of Medicine .