Colonoscopy saves lives, according to a study that provides the first direct evidence that the procedure keeps people from dying of colon cancer, reducing that risk by half.
The research, reported yesterday in the New England Journal of Medicine, found that removing precancerous polyps spotted during a colonoscopy, a standard procedure today, dramatically cuts the chance of dying from the disease. The study followed 2,602 patients who had the suspicious growths removed during the test over a median of 15.8 years.
“It is a strong study that reiterates what many of us in the field had suspected,” said Scott Kopetz, a colon cancer specialist at the University of Texas MD Anderson Cancer Center in Houston, who was not involved with the study. “It is one of the first that gives us an estimate on the amount that the death rate has been reduced.”
Colonoscopy, in which a tube with a camera is slid up the rectum so a doctor can visualize the colon, is one of colon cancer screening several tests recommended by the American Cancer Society and other groups. Polyps found can be removed during the procedure. Many people avoid colonoscopy because it requires an unpleasant preparation to clean out the bowel.
The finding could help doctors convince more people to come in for colon cancer screening, Kopetz said.
“It can be very difficult” to get patients to do it, said Kopetz, in a telephone interview. “There is the embarrassment barrier, there is the, ‘I don’t want anyone sticking a probe in my rectum’ barrier. There are a lot of social taboos around it.” Even family members of his patients with colon cancer sometimes won’t get tested, he said.
Worth the Effort
The new result “is very helpful in continuing to make the argument” that colonoscopies are worth the effort, he said.
While the latest research doesn’t prove colonoscopies save lives in the general population, it supports colon cancer screening guidelines, said Ann Zauber, a biostatistician at Memorial Sloan-Kettering Cancer Center in New York and the report’s lead author, in a telephone interview.
“We are really reducing colon cancer deaths remarkably,” said Zauber. “It is a very strong effect long term.”
The American Cancer Society recommends that men and women get a colonoscopy or another colon cancer screening test such as fecal occult blood test starting at age 50, according to its website. Colonoscopy should be done every ten years, it recommends.
In the study, sponsored by the National Cancer Institute, the 2,602 patients who got precancerous adenomas removed were 62 on average when they started the study between 1980 and 1990, in an era where colonoscopy was not generally used as a screening exam in the healthy population. The patients were then followed for as long as 23 years.
Through the end of 2003, 1,246 of the patients who had adenomas removed had died. Only 12 of those deaths were from colon cancer, far lower than the 25.4 colon cancer deaths that would have been expected in otherwise similar patients in the general population, according to the study results.
Death rates from colon cancer were very low in a second group of 773 patients who were found to have harmless colon polyps during their colonoscopy. Only 1 of those patients died from colon cancer during the follow-up period.
The finding suggests that an initial screening could be used to separate patients into high risk and low risk groups, said Michael Bretthauer, a gastroenterologist who co-wrote an editorial accompanying the study. High risk patients, those with precancerous polyps, benefited from getting repeated colonoscopies afterwards, he said.
When no precancerous polyps are found in a patient “you can just forget about them, send them home,” said Bretthauer, at Oslo University Hospital Rikshospitalet in Norway, in a telephone interview. “They are at very low risk.”
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