# A Retrospective Study on Biliary Cooling During Thermal Ablation of Central Liver Tumors in Taiwan

## TL;DR

This study shows that cooling the bile duct with cold saline during liver tumor ablation prevents injury and allows safe tumor removal.

## Contribution

Demonstrates the effectiveness of biliary cooling via ENBD to prevent thermal injury during central liver tumor ablation.

## Key findings

- Cold saline perfusion via ENBD prevents biliary thermal injury during RFA and MWA.
- Complete tumor eradication was achieved in all 9 patients with no biliary injury.
- One case of acute cholangitis occurred but resolved with antibiotics.

## Abstract

This retrospective study evaluates the clinical outcomes of endoscopic nasobiliary drainage (ENBD)-assisted biliary cooling during thermal ablation of central liver tumors. The findings indicate that cold saline perfusion via ENBD can effectively prevent biliary thermal injury during both radiofrequency ablation (RFA) and microwave ablation (MWA), enabling complete tumor eradication with minimal complications. This study also outlines practical endoscopic considerations and safety strategies to facilitate the integration of biliary cooling into interventional oncology protocols.

Background: Thermal ablation of centrally located liver tumors carries an increased risk of bile duct injury due to their proximity to the biliary tree. We aim to evaluate whether biliary cooling using a nasobiliary tube can effectively mitigate bile duct injury during the ablation process. Methods: We retrospectively analyzed the data of 322 patients who underwent thermal ablation at Dalin Tzu Chi Hospital from July 2020 to June 2023 and identified those who received prophylactic biliary cooling during thermal ablation for central liver tumors. Data including demographics, tumor characteristics, procedural details, and clinical outcomes were analyzed. Results: Among the 322 patients who underwent thermal ablation, 9 with central liver tumors received prophylactic biliary cooling. The median distance between the tumor and the central bile duct was 1 mm (range: 0–4 mm), the temperature of the cold normal saline was 4 °C, and the mean volume of normal saline infused was 150 mL (range: 100–200 mL). Complete ablation was achieved in all patients in a single session without any biliary injury. One patient developed acute cholangitis after ENBD placement, which resolved with antibiotic therapy. Conclusions: Biliary cooling with 4 °C cold saline through a nasobiliary tube can improve the safety and effectiveness of thermal ablation for central liver tumors.