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Poor prognosis of pancreaticobiliary malignancies is attributed to intrinsic biological aggressiveness and the lack of reliable methods for early diagnosis. This study aimed to evaluate the feasibility and availability of pancreatic juice- and bile-derived cell-free DNA (cfDNA) for diagnosing pancreaticobiliary strictures. From October 2020 to February 2022, pancreatic juice or bile was obtained from 50 patients with pancreaticobiliary strictures during endoscopic retrograde cholangiopancreatography. cfDNAs extracted from the samples were analyzed using next-generation sequencing and a cancer gene panel. The obtained cfDNAs, genetic data and clinical information were analyzed for diagnosis. cfDNA concentrations in pancreatic juice were higher in the intraductal papillary mucinous neoplasm group than in the other groups, whereas those in bile were similar in all groups. In pancreatic juice, the sensitivity, specificity and positive and negative predictive values of cfDNA analyses were 33%, 100%, 100% and 71.4%, respectively, whereas those of cytological analyses were 0%, 100%, 0% and 62.5%, respectively. In bile, those of cell-free DNA analyses were 53%, 75%, 89.5% and 28.6%, respectively, whereas those of cytological analyses were 19%, 100%, 100% and 16%, respectively. In conclusion, pancreatic juice- and bile-derived cfDNA is a novel liquid biopsy tool that can diagnose pancreaticobiliary strictures.

Declaration of conflict of interest: NaoyaSakamoto is an Editorial Board member of JGH and a co-author of this article. To minimize bias, they were excluded from all editorial decision making related to the acceptance of this article for publication. Ethical approval: This study (registration number: UMIN000040173) was conducted in compliance with the ethical guidelines of the Declaration of Helsinki and the ethical guidelines for medical and health research

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Background One of the major complications of gastric endoscopic submucosal dissection (ESD) is delayed bleeding. The treatment of exposed vessels after completed dissection should be effective to avoid delayed bleeding. However, it’s sometimes difficult to detect the detection of exposed blood vessels on ulcers induced by ESD. A recent study reported that red dichromatic imaging (RDI) was useful for detecting exposed vessels. In this study, we aimed to measure the visibility of exposed vessels and the quantitative color difference between the exposed vessels and surrounding tissue on ulcers, as observed using RDI after completed dissection. Methods Sixty-four vessels (14 patients) in gastric ESD-induced ulcers were evaluated using both white light imaging (WLI) and RDI. The Commission Internationale de l’Eclairage 1976 (L*a*b*) color space was used to measure the color difference. The color difference was evaluated by comparing the color values of regions of interest for the point of an exposed vessel and three points surrounding an exposed vessel. The visibility of exposed vessels was evaluated using a visibility scoring system. The primary endpoint was color differences (ΔE) between the exposed vessels and surrounding tissue in each modality. Results The average ΔE values (± SEM) for WLI and RDI were 24.85 (± 1.19) and 31.83(± 1.31), respectively. The ΔE value for RDI was significantly higher than that for WLI (p < 0.01). The visibility score was improved in 54.7% (35/64) of cases. Conclusions The color differences between the exposed vessels and surrounding tissue on gastric ESD-induced ulcers were higher with RDI than with WLI, and RDI improved the visibility of exposed vessels.