Factors affecting the diagnostic yield of endoscopic transpapillary forceps biopsy in patients with malignant biliary strictures

Background and Aim Transpapillary biliary forceps biopsy (TBFB) is a common method to obtain histological evidence for the differential diagnosis of biliary stricture. This study aimed to evaluate the factors associated with a positive cancer diagnosis from TBFB and the number of tissue samples required to increase the diagnostic yield in patients with malignant biliary strictures. Methods A total of 376 patients who underwent TBFB for investigation of biliary stricture were included. Factors affecting the diagnostic yield of TBFB were determined using univariate analysis and multivariate logistic regression analyses. Results Bile duct cancer (odds ratio [OR] = 3.50, P = 0.002), intraductal growing type (OR = 9.01, P = 0.001), and number of tissue samples (n vs 5 <= n < 10, OR = 4.13, P = 0.01; n vs n >= 10, OR = 12.25, P n vs n >= 10, OR = 2.97, P = 0.046) were significant factors associated with positive results for malignancy. In patients with periductal infiltrating-type bile duct cancer, the number of tissue samples was a significant factor for diagnostic sensitivity (54.3% in the n < 5 group, 83.3% in the 5 <= n n >= 10 group) (P < 0.001). Conclusions Bile duct cancer, intraductal growing type, and five or more tissue samples were significant predictors of positive TBFB results in patients with malignant biliary stricture. Increasing the number of tissue samples by five or more led to higher sensitivity in bile duct cancer patients with the periductal infiltrating type.