Influence of stricture dilation and repeat brushing on the cancer detection rate of brush cytology in the evaluation of malignant biliary obstruction

Background: The sensitivity for cancer detection of brush cytology at ERCP is relatively low. Manipulation of the stricture and repeated tissue sampling may increase the yield. This study compared the cancer detection rate of brush cytology before and after biliary stricture dilation. Methods: In patients with a biliary stricture at ERCP of suspected malignant origin, the stricture was sampled with a cytology brush and then dilated with either a graduated dilating catheter or a dilating balloon (4-8 mm). Brushing was then repeated in all patients. Specimens were interpreted as normal, atypical (benign), highly atypical (suspicious for cancer), and malignant. Final diagnoses were based on cytology plus surgery, EUS, percutaneous biopsy, autopsy, or clinical follow-up. Results: A total of 139 patients with suspected malignant obstructive jaundice underwent 143 ERCPs (116 ultimately found to have malignant obstruction, and 27 benign disease). Dilation was performed with a catheter in 68 cases, balloon in 73, and both in 2. Brush cytology had a sensitivity of 34.5% (40/116) before dilation and 31% (36/116) after dilation (p = NS). However, sensitivity with predilation and postdilation brushing specimens combined was 44% (51/116), which was higher than that for either the predilation or postdilation brush cytology (p = 0.001). Cancer detection rates were 34.7% (17/49) after dilation with the catheter and 27.7% (18/65) after balloon dilation (p = NS). Conclusions: Stricture dilation does not improve the sensitivity of brush cytology for the detection of cancer, which remains relatively low. However, repeat brushing increases the diagnostic yield and should be performed when sampling biliary strictures with a cytology brush at ERCP.