New data from a multi-centric international registry study show that cellular-level imaging with Mauna Kea Technologies' Cellvizio®, the world's smallest microscope, appears to significantly improve a physician's ability to diagnose or rule out early forms of bile duct cancer during a standard endoscopic diagnostic exam.
Lead investigator Yang K. Chen, MD, FACP, FASGE, AGAF announced preliminary results of the study during an oral presentation (Abstract #788c) at Digestive Disease Week 2010, which took place in New Orleans from May 1-5. The study also showed that investigators have standardized and validated the criteria (the "Miami Classification") by which they can interpret images captured by Cellvizio, the probe-based confocal laser endomicroscopy (pCLE) system, to identify or rule out potential malignancy in the bile and pancreatic ducts.
"By using the Cellvizio mini-probe, we can visualize the cells and vessels lining the bile ducts and pancreatic ducts – thus providing key cellular-level information we need to differentiate malignant and pre-malignant tissue in these difficult-to-reach areas," said Dr. Chen, who is Director of the Digestive Health Center and Gastrointestinal Endoscopy Services, University of Colorado Hospital in Aurora, Colorado and Professor of Medicine, Division of Gastroenterology and Hepatology, University of Colorado Denver. "After nearly four decades of using conventional biopsy methods to diagnosis bile duct pathology, our ability to detect cancer is still less than 50% sensitivity. Using probe-based confocal endomicroscopy earlier in the diagnostic algorithm may help to overcome this quandary by allowing us to identify and treat patients with pancreaticobiliary disease more quickly and effectively."
Physicians enrolled more than 100 subjects in the ongoing longitudinal registry. As of February 2010, 52 of the patients qualified for inclusion in this preliminary analysis. Of the 52 patients, 39 (75%) had confirmed malignancy (25 cholangiocarcinomas and 14 other kinds of pancreatobiliary cancers).
Investigators used the Cellvizio system and Mauna Kea Technologies' CholangioFlex probe, which magnifies tissue up to 400 times its actual size, to gather 132 pCLE videos from the 52 subjects during standard Endoscopic Retrograde Cholangiopancreatography (ERCP) imaging procedures. These videos were then randomized, blindly assessed and scored using the standardized Miami Classification for image interpretation.
When investigators combined three criteria (especially epithelial structures, thick white bands, and dark clumps) in their image analysis, sensitivity reached 87% with a positive predictive value (proportion of patients with a positive test who are correctly diagnosed) of 83%. The best combination of Miami Classification image interpretation criteria for predicting malignancy will be determined at the end of the study.
Most studies on conventional bile duct biopsy techniques report an average follow up period of one year; this means that some patients with a negative biopsy may in fact have cancer that remained undetected because they did not reach one year of follow up. In this study a follow-up period of one year was required in all patients to confirm negative findings, and this portion of the study continues.
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