# Utility of a novel sheath designed for mapping biopsy for preoperative malignant hilar biliary obstruction

## TL;DR

A new endoscopic sheath improves biopsy success and sample quality for diagnosing biliary tract cancer before surgery.

## Contribution

A novel endoscopic sheath (Endosheather) is introduced to enhance mapping biopsy for biliary tract cancer.

## Key findings

- The Endosheather group had a significantly higher technical success rate (92%) compared to conventional methods (59%).
- The Endosheather group produced better-quality specimens with both biliary epithelium and stromal tissue (77% vs. 47%).

## Abstract

Mapping biopsy (MB) aids in diagnosing superficial mucosal spread of biliary tract cancer. However, conventional MB is technically challenging, which can reduce the diagnostic yield. This study aimed to assess the usefulness of MB using the newly developed Endosheather (ES) (Piolax, Tokyo, Japan).

We retrospectively analyzed data from patients who had biliary tract cancer with hilar biliary obstruction and underwent MB. Outcome measures included the overall technical success rate, quality of specimens, impact of MB results on the treatment strategy, and adverse events (AEs), which were compared between the conventional (Conv) group and the ES group.

A total of 91 patients were included. The overall technical success rate was significantly higher in the ES group (92%, 43/47) than in the Conv group (59%, 26/44) (
P
< 0.05). The rate of samples containing both biliary epithelium and stromal tissue was significantly higher in the ES group than in the Conv group (77% [67/87] vs. 47% [32/68];
P
< 0.05). MB results affected the treatment strategy in one patient (2.3%) in the Conv group and five patients (11%) in the ES group (
P
= 0.11). There was no significant difference between the two groups in terms of AEs.

MB using ES significantly improved technical success and specimen quality, providing valuable information for preoperative assessment of patients with biliary tract cancer.