High-definition scopes accurately assess polyps
Sending resected polyps from a patient's colonoscopy to a pathologist for examination may not be necessary for experienced gastroenterologists, according to a large study published in Gastrointestinal Endoscopy (2014; doi:10.1016/j.gie.2014.09.019).
The 522-patient study, conducted by physician researchers at the Jacksonville campus of Mayo Clinic in Florida, found that physicians correctly evaluated whether a polyp was precancerous or benign using high-definition optical lenses during a colonoscopy. Their assessment was 96% or 97% accurate, depending on which of two generations of scopes was used, compared with a standard pathological evaluation of the polyps.
The researchers concluded that the pathological polyp examination now required by national practice guidelines may not be necessary, which is an advance they say could result in substantial cost savings for the patient and the health care system, as well as more rapid information and recommendations for follow-up for the patient.
"A colonoscopy is a fairly expensive procedure, and a large portion of the cost is the pathological analysis of polyps that are removed to check whether they are precancerous or benign, which is a check that determines when a patient needs another colonoscopy," said the study's senior investigator and gastroenterologist, Michael Wallace, MD, MPH, of Mayo.
"We discovered that gastroenterologists using high-definition optical scopes can provide excellent care and diagnoses of polyps without the added step of a pathological examination," Wallace said.
The research team examined use of the Exera II 180 colonoscope and the Exera III 190 colonoscope to assess 927 polyps. Both are high-definition scopes, and the earlier generation (180) is in wide use.
An optical diagnosis, sometimes referred to as a virtual biopsy was sufficient, in the hands of the experienced physicians, to determine that benign (hyperplastic) polyps were indeed benign, and that potentially precancerous (adenoma) polyps were the ones at risk for cancer development.
Investigators also found that physicians in the study had an extremely high adenoma detection rate using the scopes. The rate was 50% for the 180 model and 52% for the 190.
"A high adenoma detection rate is considered a good measure of a quality colonoscopy. Studies have shown that a rate of 33%—meaning that of 100 people who undergo a colonoscopy, adenomas are found in 33%—is excellent," said Wallace. "Current national benchmarks recommend an adenoma detection rate of at least 20%. We found substantially more adenomas."
"The more adenoma polyps that are detected, the lower the risk is of getting colon cancer. So this study shows that it is possible to use an optical scope to perform a highly accurate colonoscopy and bypass the pathology laboratory, reducing cost," he said. "Another advantage is that we can tell the patient immediately after the procedure what we found and when the next examination should be done, as opposed to waiting one to two days for a pathology result."
This Mayo study is now being used by the American Society for Gastrointestinal Endoscopy in its review of current colonoscopy guidelines for assessing whether or when pathological examination of polyps is necessary, he said.