Malignant biliary stricture at the hilum of the liver is most commonly caused by cholangiocarcinoma, local extension from gallbladder and hepatocellular carcinoma, and metastatic cancer. Endoscopic biliary brushing is the most common method used for sampling in patients with malignant biliary strictures (MBSs); however, its sensitivity is relatively low. There is still no consensus on endoscopy-based biliary brushing, although brushing 10 times in 1 specimen is routinely performed. A multicenter, prospective, randomized controlled study was performed on 443 patients who enrolled for intention-to-treat analysis. They were divided into three groups of 147, 148, and 148 patients in the 10-times, 20-times, and 30-time groups, respectively to compare the sensitivity of brush cytology for 10, 20, or 30 brushing times of a pass in 1 specimen in patients with MBSs.

Among the 3 groups were similar in baseline characteristics. The sensitivity of brush cytology was 38%, 47%, and 57% in the 10-times, 20-times, and 30-times groups, respectively, and the 30-times group showed significantly higher sensitivity than the 10-times group (P = 0.001). The multivariate analysis revealed that stricture length and the number of brushing passes were significant factors for the detection of biliary malignancy. No significant differences were observed in procedure-related complications among the 3 groups. Brushing 30 times could increase the diagnostic sensitivity without increasing complications and seems to be preferred for the endoscopic sampling and diagnosis of MBSs.

Source: Wang et al., Am J Gastroenterol. 2022 May 1;117(5):733-739.