Adaptive radiofrequency ablation using an Octopus multipurpose electrode for small hepatocellular carcinoma adjacent
Jeong Min Lee1,2, Jae Hyun Kim1, Gyeong Deok Jo1
1Department of Radiology, Seoul National University Hospital, Seoul, Korea.
Purpose:
This study aimed to assess the feasibility, safety, and preliminary oncologic outcomes of an adaptive radiofrequency ablation (RFA) strategy using the Octopus multipurpose (Octopus MP) electrode for small hepatocellular carcinoma (HCC) in anatomically challenging locations. Materials and.
Methods:
This prospective, single-center cohort study enrolled 76 patients with 83 small HCCs (≤3 cm) in at-risk locations, including tumors adjacent to heat-sensitive organs, central bile ducts, or major vessels and tumors in capsule-adjacent or subphrenic locations. The Octopus MP electrode incorporates integrated temperature monitoring and a central 19-gauge multipurpose needle for fluid instillation and real-time temperature sensing. An anatomy-driven protocol allocated tumors to combined percutaneous ethanol injection plus RFA (PEI-RFA) or temperature-monitored RFA (TM-RFA). The primary endpoint was the thermal injury rate, and secondary endpoints included technical success, technique efficacy, and local tumor progression (LTP).
Results:
The per-protocol analysis included 45 patients with 51 tumors in the PEI-RFA arm and 31 patients with 32 tumors in the TM-RFA arm. Technical success and 1-month technique efficacy were 100% in both arms. No major complications occurred. Thermal injury was observed in three of 45 patients (6.7%) in the PEI-RFA arm and two of 31 patients (6.5%) in the TM-RFA arm; all events were minor and self-limited. Late clinically insignificant biliary strictures occurred in four of 45 patients (8.9%) in the PEI-RFA arm and one of 31 patients (3.2%) in the TM-RFA arm. Patient-based cumulative LTP rates at 12, 24, and 36 months were 4.44%, 7.13%, and 10.95%, respectively, in the PEI-RFA arm and 3.23%, 3.23%, and 7.41%, respectively, in the TM-RFA arm.
Conclusion:
An anatomy-driven adaptive strategy using the Octopus MP electrode, which integrates established adjunctive ablation techniques within a single device, was feasible for small HCCs near critical structures and was associated with favorable safety and mid-term local control.
