Objective Hepatocellular carcinoma adjacent to the main bile duct has been considered a contraindication to thermal ablation. This study aimed to evaluate the safety and efficacy of low-power, long-duration microwave ablation combined with a modified nasobiliary cooling technique for treating hepatocellular carcinoma adjacent to the main bile duct.

Methods The clinical data of 13 patients with hepatocellular carcinoma adjacent to the main bile duct underwent percutaneous microwave ablation assisted by a modified nasobiliary cooling technique for bile duct protection, who were admitted to The Second Affiliated Hospital of Guangxi Medical University during the period from January 2020 to July 2024, were retrospectively analyzed. Outcomes were analyzed alongside literature reports and clinical practice experience.

Results Complete ablation was achieved in all 13 patients. One patient developed intraoperative hypertension and one experienced postoperative acute pancreatitis. The local recurrence rate was 7.7%, and the long-term biliary injury rate was 7.7%.

Conclusions  Low-power, long-duration microwave ablation combined with a modified nasobiliary cooling technique is a safe and effective treatment for hepatocellular carcinoma adjacent to the main bile duct, thereby expanding the indications for microwave ablation in hepatocellular carcinoma.