Radiofrequency Ablation Using a Balloon Catheter for Hepatocellular Carcinoma Adjacent to the Gastrointestinal Tract: Experimental and Clinical Study

Abstract

Purpose: Radiofrequency ablation (RFA) is a safe and effective technique for hepatocellular carcinoma and it has minimal morbidity and mortality. One of the most important major complications of RFA is perforation of the gastrointestinal tract, which occurs when the tumor is adjacent to the digestive tract. In particular, the risk is much higher in patients with lesions located within 1 cm from the liver surface in proximity to the digestive tract. In such cases, an artificial ascites technique has been employed. However, the separation of adjacent digestive organ from the liver is insufficient in this method. Therefore, in this study, to overcome this problem, we devised a novel RFA technique using a double-balloon catheter. In the first step, an animal experiment was performed to evaluate the safety and feasibility of the balloon RFA method. In the second step, the human pilot trial was carried out to evaluate the safety, feasibility and effectiveness of this method. Materials and Methods: We produced an 8 Fr silicone catheter equipped with 2 balloons of 2.5 cm diameter. In experiments using pigs, we first inserted this balloon catheter percutaneously into the peritoneal space between the liver and gastrointestinal tracts, filled it with cooled water, and performed RFA for in normal liver 1 cm from the liver surface. Then, heat damage to the excised liver and gastrointestinal tract was evaluated macroscopically andmicroscopically. In a human pilot study, balloon catheter RFA was performed in 4 patients with HCC (1.5 ± 0.7 cm) abutting the gastrointestinal tract. Results: In pigs, we performed each 6 RFA sessions with or without balloon catheter. It was technically easy to place the balloon catheter between liver and gastrointestinal tracts to separate them. Heat damage reached the liver surface in all lesions. In the groupwith balloon catheter, no heat damage of the gastrointestinal tracts was observed (0%, 0/6). In contrast, in the group without balloon catheter, heat damage was observed in 5/6 (83.3%): stomach (2/6), small intestine (2/6), and omentum (1/6). The coolant temperature in the balloon was significantly increased after RFA, suggesting that the heat generated by RFA was absorbed by the coolant. In the human pilot study, balloon catheter RFA was easily performed in all patients without associated complications. CT confirmed complete ablation with an appreciable safety margin in all patients, without recurrence for 20.3 ± 4.5 months. Conclusions: RFA with our balloon catheter is safe and effective for the treatment of HCC abutting the gastrointestinal tract, suggesting an expanded indication of these lesions for RFA.