Robot-Assisted Ablation of Liver Hepatocellular Carcinoma and Colorectal Metastases: A Systematic Review

Introduction: Robot-assisted liver tumor ablation has emerged as a new minimally invasive therapeutic strategy for hepatocellular carcinoma, as well as colorectal metastases with higher accuracy, in a smaller time span and with a lower radiation dose than in the manual approach. Several ablation methods count, mostly used are radiofrequency ablation, microwave ablation and cryoablation. Materials and methods: The specialty literature was surveyed in order to retrieve manuscripts reporting “robot-assisted”, “liver tumor”, “ablation”. The search strategy was applied in three different databases, Scopus, Web of Science and Embase. Fifteen original articles were selected and seven were excluded from the study, in order to compare results of robotic ablation for liver tumors both on patient series or on experimental models. Results: Out of a total of fifteen articles included in the study, six articles focused on the clinical aspect of robotic liver tumor aspect, providing patients description and characteristics on a total of 172 subjects. There were nine studies, which focused on the technical assessment of the robot during ablation on experimental model. The indications for percutaneous ablation usually include malignant tumors, hepatocellular carcinoma (55 tumors) or colorectal liver metastases (92 tumors) for lesions smaller than 3 cm in diameter, which cannot benefit from liver resection. The most commonly reported type of ablation was microwave technique (43%), followed by radiofrequency (40%). Only one article evaluated laser ablation effects and another one reported irreversible electroporation. The number of needles used for ablation according to the tumor volume varied from 1 in 50% of cases to 5 and the number of needle readjustments reached 1 to 14. The type of robot used was different in the fifteen studies. Conclusions: Development of more versatile robots and intuitive software that will reduce the total time of the procedures is highly expected, thus transforming imaging guided robotic ablation into the golden standard procedure for inoperable primary hepatic tumors or liver metastases.