Ablative strategies for recurrent hepatocellular carcinoma

Non-Thermal Liver Ablation: Existing and New Technology

Cancer has and continues to be a complex health crisis plaguing millions around the world. Alcohol ablation was one of the initial methods used for the treatment of liver lesions. It was surpassed by thermal ablation which has played a big role in the therapeutic arsenal for primary and metastatic liver tumors. However, thermal ablation has several shortcomings and limitations that prompted the development of alternative technologies including electroporation and histotripsy. Percutaneous alcohol injection in the liver lesion leads to dehydration and coagulative necrosis. This technology is limited to the lesion with relative sparing of the surrounding tissue, making it safe to use adjacent to sensitive structures. Electroporation utilizes short high-voltage pulses to permeabilize the cell membrane and can result in cell death dependent on the threshold reached. It can effectively target the tumor margins and has lower damage rates to surrounding structures due to the short pulse duration. Histotripsy is a novel technology, and although the first human trial was just completed, its results are encouraging, given the sharp demarcation of the targeted tissue, lack of thermal damage, and potential for immunomodulation of the tumor microenvironment. Herein, we discuss these techniques, their uses, and overall clinical benefit.

Radiofrequency ablation combined with toripalimab for recurrent hepatocellular carcinoma: A prospective controlled trial

OBJECTIVE

The effectiveness and security of radiofrequency ablation (RFA) in combination with toripalimab (anti-PD-1) for the treatment of recurrent hepatocellular carcinoma (HCC) was studied in this article.

METHODS

Total of 40 patients were enrolled in the study between September 2019 and November 2021. Data follow-up ends in April 2022. The study's main focus is on recurrence free survival (RFS), while the secondary objectives was safety. Chi-square tests, Kaplan-Meier, and Cox proportional hazards models were utilized to analyze the data.

RESULTS

The median follow-up period was 21.40 months, and the median RFS was 15.40 months in the group that received combination therapy, which was statistically significantly different (HR: 0.44, p = 0.04) compared with the RFA group (8.2 months). RFS rates (RFSr) at 6, 12 and 18 months in the combination therapy groups and RFA groups were 80% vs 65%, 62.7% vs 35% and 48.7% vs 18.8%, respectively. Between the two groups, significant difference of RFSr was found at 18 months (p = 0.04). No statistical differences were observed between the two groups in terms of safeness (p > 0.05). The subgroup analysis indicated that the combination of RFA and anti-PD-1 led to better RFS than RFA alone. Moreover, patients benefited more from combination therapy in the groups younger than 60 years (HR: 0.26, p = 0.018), male (HR: 0.32, p = 0.028) and Child-Pugh grade A (HR: 0.38, p = 0.032).

CONCLUSIONS

Combining RFA with anti-PD-1 showed improved RFS and was deemed safe for patients with recurrent HCC who had previously undergone RFA treatment alone.

In Vivo Thermal Ablation of Deep Intrahepatic Targets Using a Super-Convergent MRgHIFU Applicator and a Pseudo-Tumor Model

BACKGROUND

HIFU ablation of liver malignancies is particularly challenging due to respiratory motion, high tissue perfusion and the presence of the rib cage. Based on our previous development of a super-convergent phased-array transducer, we aimed to further investigate, in vivo, its applicability to deep intrahepatic targets.

METHODS

In a series of six pigs, a pseudo-tumor model was used as target, visible both on intra-operatory MRI and post-mortem gross pathology. The transcostal MRgHIFU ablation was prescribed coplanar with the pseudo-tumor, either axial or sagittal, but deliberately shifted 7 to 18 mm to the side. No specific means of protection of the ribs were implemented. Post-treatment MRI follow-up was performed at D7, followed by animal necropsy and gross pathology of the liver.

RESULTS

The pseudo-tumor was clearly identified on T1w MR imaging and subsequently allowed the MRgHIFU planning. The peak temperature at the focal point ranged from 58-87 °C. Gross pathology confirmed the presence of the pseudo-tumor and the well-delineated MRgHIFU ablation at the expected locations.

CONCLUSIONS

The specific design of the transducer enabled a reliable workflow. It demonstrated a good safety profile for in vivo transcostal MRgHIFU ablation of deep-liver targets, graded as challenging for standard surgery.