Yet some experts are saying the expensive test has been oversold as the must-have gold standard when, in fact, studies suggest that it doesn't reduce colon cancer deaths any better than a much cheaper screening test called a sigmoidoscopy; that one uses a shorter scope to examine a smaller portion of the colon.
I asked two experts from Harvard Medical School -- Dr. John Saltzman, director of endoscopy at Brigham and Women's Hospital, and Dr. John Abramson, lecturer in health care policy -- to explain their conflicting views on the following question:
Is colonosopy the best way to screen for colon cancer?
Multiple tests are available to screen for colon cancer, which kills some 50,000 people each year. Both colonoscopy and sigmoidoscopy have advantages and disadvantages, but experts agree that doing either of these tests is preferred to no testing at all.
Although sigmoidoscopy has been around a long time, its use as a screening test for colon cancer has largely been replaced by colonoscopy for a number of reasons. While sigmoidoscopy is cheaper and relatively quick, it has several significant disadvantages. It does not use sedation and can be an uncomfortable examination; what's more, it only examines the bottom third of the colon, missing about half of the significant precancerous polyps and cancers.
Gastroenterologists say it's analogous to performing mammography on one breast -- certainly better than nothing, but clearly not optimal. And patients who have a polyp detected on sigmoidoscopy typically need to have a full colonoscopy to remove this polyp and look for additional polyps.
Colonoscopy is the only test that can examine both the entire colon and remove any detected polyps in one examination. Despite the proven value of screening tests such as colonoscopy, many people elect not to undergo any screening at all.
This is the tragedy that is responsible for most of the deaths due to colon cancer. I believe we should educate people about the value of preventive medicine and discuss the most appropriate option for colon cancer screening.
As recently reported in the New England Journal of Medicine, a screening colonoscopy is one of the few preventive services to save the health care system money. I believe colonoscopy is the best medicine for both the patient and our society when it comes to prevention of colon cancer.
Dr. John Saltzman is the director of endoscopy at the Brigham and Women's Hospital and an associate professor of medicine at Harvard Medical School. He currently serves as the American College of Gastroenterology's "Governor of Massachusetts".
As with most new medical technology, the benefits of colonoscopy may seem obvious but still need to be proven in well-performed scientific studies. Yes, colonoscopy visualizes more of the colon. And yes, colonoscopy allows for removal of a greater number of precancerous lesions. But no, these apparent benefits have not been shown to translate into a reduction in the incidence and mortality from cancer that is beyond the reach of a flexible sigmoidoscope.
It is true that routine colonoscopy only needs to be performed every 10 years compared with every five years for flexible sigmoidoscopy. But the increased frequency of flexible sigmoidoscopy must be weighed against its benefits: far less harsh preparation (unlike colonoscopy, it does not require laxatives to clear the entire colon); its lower cost (just one-tenth that of a colonscopy); and its lower risks since, unlike colonoscopy, it doesn't require anesthesia and isn't associated with a rare but real possibility: perforation of the colon.
In this time of acute budget shortfalls, the controversy about colonoscopy and flexible sigmoidoscopy serves as a symbol of the American health system's ills: a more expensive and potentially more dangerous procedure is considered higher quality health care -- despite the lack of scientific evidence.
Doctors need to communicate to patients that they rely on the best available science; otherwise, attempts to curtail wasteful spending will be perceived as withholding beneficial care, i.e. rationing. While Americans tolerate skyrocketing health care costs that crowd out investments in education and other vital civic needs, we won't tolerate anything that looks like medical rationing.
I believe it's the responsibility of physicians to explain to patients that adherence to truly evidence-based health care will protect them from exposure to potential harm and will protect our nation from financial Armageddon.
Dr. John Abramson is a lecturer in health care policy at Harvard Medical School and the author of "Overdosed America: The Broken Promise of American Medicine." He serves as a consultant to Wells Fargo Health Solutions.
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