Endoscopic sphincterotomy and endoscopic biliary stenting do not affect the sensitivity of transpapillary forceps biopsy for the diagnosis of bile duct adenocarcinoma

[Background] The pathological evaluation of tissues with cholangitis is considered difficult, which can often occur after endoscopic sphincterotomy (EST) and endoscopic biliary stenting (EBS). This study aimed to evaluate the influence of a history of EST and EBS on the sensitivity of transpapillary forceps bile duct biopsy (TB) for bile duct adenocarcinoma.[Methods] This retrospective study included consecutive cases of bile duct adenocarcinoma in which TB was performed before July 2020 until the number exceeded that required to support statistical and noninferiority analyses of the sensitivity of TB between patients with and without each variable. The incidence of postprocedural adverse events related to each factor was also investigated.[Results] Overall, 280 samples were required in each group, and 437 subjects (792 samples) were included. The sensitivity of TB was 63.6% for the subjects and 59.6% for the biopsy samples. For the biopsy samples, the sensitivity did not differ significantly between samples from patients with and without a history of EST (59.1% vs. 58.9%, P =0.952) and EBS (62.1% vs. 55.4%, P =0.065). The sensitivity was significantly higher for samples from patients with jaundice (67.9% vs. 57.0%, P =0.008). There were significantly fewer procedure-related adverse events in patients with a history of EST (10.8% vs. 19.0%, P =0.017) and EBS (12.0% vs. 21.7%, P =0.005).[Conclusions] A history of EST or EBS did not influence sensitivity of TB but significantly decreased the incidence of adverse events. To safely and reliably perform TB to diagnose bile duct adenocarcinoma, planning, including for EST and EBS, is necessary.