Discussion
LSS, cancer, Bile duct cancer, biliary duct pre-cancer
CANCER, BILE DUCT STRICTURES, PANCREATIC CYST, BILE DUCT CANCER
Bile duct cancer is considered to be an incurable cancer that can rapidly become lethal, unless it can be detected early enough to be fully resected. Unfortunately, in most cases, it is detected at the advanced stages, which are inoperable at the time of diagnosis. Moreover, despite recent improvements in cross-sectional imaging and endoscopic technologies, differentiation of benign and malignant bile duct strictures remains a diagnostic challenge. Cross-sectional imaging lacks sensitivity to cellular structure and biochemical properties of the bile duct wall. While a combination of ERCP-based brush cytology and trans-papillary endobiliary forceps biopsy, which is often considered the gold standard, has a very high specificity of 97% to 100%, it offers sensitivity of only 47% to 86%Here, we report an endoscopic optical light scattering technique for clinical evaluation of the malignant potential of the bile duct. This technique employs an ultraminiature spatial gating fiber optic probe compatible with clinical cholangioscopes and ERCP catheters. The spectra are acquired automatically when the probe is in close proximity and at approximately a right angle to the bile duct wall. Therefore, a visual examination of the bile duct wall with a cholangioscope is useful but not required. The technique allows investigation of the internal cellular composition of the bile duct epithelium with LSS, and phenotypic properties of the underlying connective tissue hemoglobin concentration and hemoglobin oxygen saturation with diffuse reflectance spectroscopy. In the in vivo double-blind prospective pilot study described here involving 29 patients undergoing routine ERCP procedures, the technique detected biliary duct pre-cancer and early cancer with a 97% accuracy, with a 95% confidence interval (CI) of 83-100%. This diagnostic accuracy was achieved by employing the LSS information alone. The study was performed in a perspective way and employed the predetermined diagnostic cutoff for the LSS diagnostic parameter Δ, established previously in pancreatic cyst studies