Doctors may be recommending too many follow-up colonoscopies for patients who have had colon polyps removed, according to recent research led by UC Davis gastroenterologist Pauline Mysliwiec.

The researchers found that 24 percent of gastroenterologists and 54 percent of general surgeons recommend surveillance colonoscopy for small, hyperplastic polyps. For patients with single small, low-risk adenomas, many of the physicians recommend surveillance every three years, or even more often.

Evidence-based guidelines, in contrast, call for no extra surveillance after removal of a hyperplastic polyp, a benign growth not believed to become cancerous. And while the guidelines do recommend surveillance colonoscopy following removal of adenomas, which can develop into cancer, at most the exams are recommended only every three to five years.

"We believe colonoscopy can be a life-saving procedure, but it shouldn't be done more often than necessary," Mysliwiec says. "When it's used inappropriately, it strains health care resources and puts patients at unnecessary risk."

The findings affect the estimated 20 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. The National Cancer Institute-funded study appears in the Aug. 17 issue of Annals of Internal Medicine.