A sensitive new probe system now being developed can tell clinicians with a high degree of accuracy if a colon polyp is benign, eliminating the need for removal and biopsy. The probe is a tiny imaging tool that can be attached to an endoscope. If a clinician finds a suspicious polyp during colonoscopy, he can magnify it 1,000 times for a closer look. (A small amount of fluorescent contrast is used to illuminate the area.) The magnification is so great that the clinician can see a single red blood cell moving through a blood vessel. By noting cell color and size, the appearance of cell nuclei, and cell arrangement in tissue, he can determine whether the polyp is benign or malignant.

In a test, the probe system was used to examine 37 polyps in 25 patients. All of the polyps were then removed and biopsied. The probe system was 89% accurate in identifying polyps that were either precancerous or benign, and 98% accurate in identifying polyps that were benign. Researchers believe they can achieve near 100% accuracy with more testing. They presented their findings at the Digestive Disease Week, a scientific meeting of gastrointestinal specialists and researchers in San Diego, Calif.