Many MDs perform unnecessary "surveillance" colonoscopies

Many medical physicians perform more “surveillance” colonoscopies than expert groups deem necessary, according to results of a National Cancer Institute-funded study published in the Aug. 17 issue of Annals of Internal Medicine.

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, 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.

SOURCES: “Are Physicians Doing Too Much Colonoscopy? A National Survey of Colorectal Surveillance after Polypectomy,” by Pauline A. Mysliwiec, Martin L. Brown, Carrie N. Klabunde, and David F. Ransohoff, Annals of Internal Medicine, Aug. 17, 2004.