A study of cholangioscopy guided biopsy (Spybite®) combined with pancreaticobiliary Fluorescence in situ hybridization(PB FISH) for the diagnosis of malignant biliary stricture
Abstract:
A study of cholangioscopy guided biopsy (Spybite®) combined with pancreaticobiliary Fluorescence in situ hybridization (PB FISH) for the diagnosis of malignant biliary stricture Jeerawat Maytapa, MD1, Phonthep Angsuwatcharakon, MD1, Roongruedee Chaiteerakij, MD, PhD1 1 Division of Gastroenterology, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand Background & Aims: Endoscopic retrograde cholangiopancreatography (ERCP) is commonly used diagnostic procedure for diagnosis of malignant biliary stricture. ERCP provides tissue samples for brush cytology and endoscopic intraductal biopsies for histopathology. However, distinguishing malignant biliary stricture from benign biliary stricture is challenging due to low sensitivity of brush cytology and intraductal biopsy. This study aimed to assess sensitivity and specificity of PB FISH combined with Spybite® for diagnosis of malignant biliary strictures. Method: Patients who were evaluated for malignant biliary strictures and underwent ERCP were enrolled. Bile duct tissue were obtained from the biliary stricture sites using SpyGlassTM Direct Visualization System for direct target biopsy. The tissue was then examined histologically and by PB FISH. The PB FISH assay used a mixture of fluorescence-labeled probes to chromosomes 1q21 (gold), 7p12 (green), 8q24 (aqua), and 9p21 (red) to identify chromosome number alterations. Cytologic specimens were also obtained during ERCP using a cytology brush before Spybite® biopsy. The biliary brushing samples were tested for routine cytology and PB FISH. Sensitivities and specificities of Spybite® FISH, Spybite® pathology, FISH brushing and cytology brushing were compared. Result: Of the 30 patients enrolled, 27 were diagnosed with malignancy. The most common cancer was cholangiocarcinoma (n=15, 55.6%), followed by pancreatic cancer and IPNB (n=3, 11.1%). The sensitivities of cytology brushing and FISH brushing for detection of malignancy were 33.33% and 75%, respectively. The sensitivities of Spybite® FISH and Spybite® biopsy were 96.3% and 62.9%. The specificities of Spybite® FISH and Spybite® biopsy were 33.3% and 100%. Conclusion: PB FISH is more sensitive for detection of malignant biliary strictures in Spybite® specimen than Spybite biopsy alone. PB FISH combined with Spybite® may improve the clinical management of patients who are being evaluated for malignant biliary stricture.