Optical Biopsy System Distinguishing between Hyperplastic and Adenomatous Polyps in the Colon during Colonoscopy

Patients and Methods

This prospective study was conducted at the Second Internal Clinic, Thomayer's Teaching Hospital, Prague, Czech Republic. Patients who were referred for endoscopy and provided informed consent were enrolled in the study between October 2007 and April 2008. A total of 53 patients were enrolled and all underwent colonoscopic examination and completed the study. Out of these, 33 were male and 20 were female with ages ranging from 30-82 years with a mean age of 62 years. Inclusion criteria were average risk for colon cancer and ability to provide consent. The exclusion criteria were poor general physical condition, use of anticoagulants which would preclude removal of polyps during colonoscopy and acute comorbidity.

• Download figure
• Open in new tab
• Download powerpoint

Figure 1.

Polyps distribution.

The polyps ranged in size from 5 mm to 30 mm, mostly being 5-9 mm, and were distributed throughout the large intestine. Most of the polyps were found in the region of the sigmoid colon (Figure 1).

The patients were given a pancolonoscopic examination using first an optical biopsy of the polyp followed by a physical biopsy and removal of the polyp. The optical biopsies were first visualized on the screen of a WavSTAT® Optical Biopsy System (SpectraScience, Inc., San Diego, CA, USA) as either green (non-suspect) or red (suspect) then noted on the patient's chart so they could later be correlated to the histology reports. In all cases, the physical biopsies were performed at the same point on the polyp as the optical biopsies using the same optical forceps.

The colonoscopic examination was conducted using a CFQ-180 colonoscope manufactured by Olympus Corporation, Tokyo, Japan. The WavSTAT® Optical Biopsy System used for the optical biopsies uses laser induced autofluroescence to obtain an objective, in vivo analysis of polyps of the large intestine. The principle behind this method is a low-intensity/non-damaging laser light which is directed from the console through an optical fiber mounted in modified biopsy forceps. These biopsy probes are directed through the working channel of the colonoscope and brought into direct contact with the actual polyp. Upon contact with the optical fiber and foot pedal activation, the tissue absorbs laser light resulting in the excitation of the tissue being examined. The resulting autofluorescent signal is sent back and analyzed by a proprietary algorithm in the system console. Within seconds a green “non-suspect” or red “suspect” result is displayed on the console's screen. An advantage of this system is that a physical biopsy sample can be taken using the same forceps from the exact place where the optical biopsy is performed (9).

All colonoscopies were performed by a single endoscopist with 15 years of experience. The patients were seen in the endoscopy clinic after undergoing standard colonic preparation to ensure the lumen of the colon was completely clean and that the surface of the polyp was free of residual stool and debris. Any residue on the mucosa of the polyp was removed using pressurized water through a spray catheter to ensure the mucosa of the polyp did not bleed. All the patients were sedated using Midazolam 2.5 mg intravenously.