Surveillance colonoscopies are performed to monitor patients after they have had either a pre-cancerous or cancerous colorectal polyp removed.
Surveillance colonoscopy is done more frequently than screening colonoscopy, which is used for early detection of colorectal cancer.
The findings could affect the estimated 20 percent to 30 percent of Americans age 50 and older who will have a polyp removed as a result of colon cancer screening, a population of some 12 to 18 million people.
"We believe colonoscopy can be a life-saving procedure, but it shouldn't be done more often than necessary," says Pauline Mysliwiec (MISH-LEE-VEE-ITZ), lead author of the study and an assistant professor of gastroenterology at UC Davis School of Medicine and Medical Center. "When it's used inappropriately, it strains health care resources and puts patients at unnecessary risk."
Expert groups have issued guidelines regarding the frequency of surveillance colonoscopy. None of the guidelines calls for surveillance after removal of a hyperplastic polyp, a benign growth not believed to become cancerous. The guidelines do recommend surveillance colonoscopy, typically every three to five years, following removal of polyps known as adenomas, which can develop into cancer.
In their new study, Mysliwiec and her colleagues at the National Cancer Institute surveyed a nationally representative sample of gastroenterologists and general surgeons, the specialties that perform most colonoscopies, in 1999 and 2000.
They found that 24 percent of the gastroenterologists and 54 percent of the general surgeons surveyed recommended surveillance colonoscopy for a small, hyperplastic polyp. For patients with a small, low-risk adenoma, many of the physicians studied recommended surveillance every three years, or even more often.
"Some surveillance colonoscopy seems to be inappropriately performed and in excess of evidence-based guidelines, particularly for hyperplastic polyps and low-risk lesions," the authors conclude.
"Overuse of colonoscopy taxes the health care system and may compromise the quality of care," the authors add. "Long waiting times of several months are already occurring in some parts of the country and could mean reduced access for symptomatic patients and those with limited means."
As public education increases the demand for and use of colorectal screening in the United States, proper allocation of colonoscopy resources becomes more critical, Mysliwiec notes.
"We hope our findings will cause closer examination of current practices and promote more effective resource utilization and patient care," she says. In the meantime, she recommends that patients talk with their doctors about the appropriate surveillance schedule for them.
"We have the opportunity to improve patient care and avoid over-burdening the health care system," she says. "Implementation of clinical guidelines regarding the use of post-polypectomy surveillance colonoscopy can help to ensure this."
The cost of a colonoscopy in the United States ranges from about $1,500 to $1,700, according to recent reports in the medical literature.
Screening colonoscopy was not looked at in the study. The American Cancer Society recommends a screening colonoscopy every 10 years for average-risk men and women age 50 and older, as one of several early detection strategies. (See attached ACS guidelines).
"Screening for colorectal cancer is vitally important," Mysliwiec emphasizes. "Since early detection makes a critical difference, it is even more important that we do what we can to promote the optimal use of colonoscopy resources."
An estimated 147,000 Americans will be diagnosed with colorectal cancer this year, according to the American Cancer Society. Nearly 57,000 will die from the disease.
UC Davis Cancer Center is the only National Cancer Institute-designated cancer center between San Francisco and Portland, Ore., and is ranked by U.S. News & World Report as one of the nation's top 50 cancer treatment centers.
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AMERICAN CANCER SOCIETY GUIDELINES FOR THE EARLY DETECTION OF COLORECTAL CANCER
Beginning at age 50, both men and women should follow one of these five testing schedules:
*For FOBT, the take-home multiple sample method should be used.
**The combination of FOBT and flexible sigmoidoscopy is preferred over either of these two tests alone.
All positive tests should be followed up with colonoscopy.
People should begin colorectal cancer screening earlier and/or undergo screening more often if they have any of the following colorectal cancer risk factors.
Journal
Annals of Internal Medicine