Evaluation of the Heat Sink Effect After Transarterial Embolization When Performed in Combination with Thermal Ablation of the Liver in a Rabbit Model

Intratumoral perfusion may affect microwave ablation area of hepatocellular carcinoma

OBJECTIVES

We aimed to evaluate the effect of intratumoral perfusion on microwave ablation (MWA) area in hepatocellular carcinoma (HCC).

METHODS

Patients who underwent curative MWA for HCC between October 2013 and May 2015 were enrolled. Three days before MWA, contrast-enhanced ultrasound (CEUS) was performed to illustrate the perfusion characteristics of the target lesion. Using the Sonoliver quantification software, time-intensity curves of dynamic CEUS were obtained, and quantitative parameters were extracted. Two microwave antennae were inserted into the center of the tumor and MWA was performed with a continuous power output of 50 W for 5 min. A second CEUS was performed to measure the size of the ablated region. Thereafter, an additional MWA procedure was performed until complete ablation with a 5-10-mm safety margin was achieved.

RESULTS

A total of 38 patients who underwent curative MWA for 39 HCC nodules were enrolled. The mean age was 57 years (34-80 years), and the median maximum diameter of the HCC was 3.4 cm (interquartile range, 2-6.8 cm). Time-intensity curves were obtained and the area under the curve (AUC) was selected as a parameter for intratumoral perfusion. The AUC was inversely and linearly correlated with the size of the MWA area, including long- and short-axis diameters and ablation volume. A 1,000-dB·s change in the AUC produced an average change of 1.17 ± 0.44 mm, 0.725 ± 0.355 mm, and 2.4995 ± 0.6575 cm³ in the long- and short-axis diameters and ablation volume, respectively.

CONCLUSIONS

The intratumoral perfusion of HCC was inversely correlated with MWA area size.

Radiofrequency ablation versus liver resection and liver transplantation for small combined hepatocellular-cholangiocarcinoma stratified by tumor size

PURPOSE

Although radiofrequency ablation (RFA) has been proven to provide a good survival benefit for small hepatocellular carcinoma (HCC), there is limited information about RFA for combined hepatocellular-cholangiocarcinoma (cHCC-CC). The purpose of this study was to explore the clinicopathological features of cHCC-CC and the curative effect of RFA in small cHCC-CC without distant metastases compared with liver resection (LR) and liver transplantation (LT).

METHODS

Patients with cHCC-CC, intrahepatic cholangiocarcinoma, or HCC were identified in the Surveillance, Epidemiology, and End Results database.

RESULTS

cHCC-CC had the highest rate of poor pathological grade and the lowest rate of bone metastases compared with intrahepatic cholangiocarcinoma and HCC (all P < 0.05). In patients with cHCC-CC after surgery, multivariate analysis showed that compared with RFA, LR and LT were independent protective factors for survival (all P < 0.05). But in cHCC-CC stratified by tumor size, for tumor size ≤ 3.0 cm, there was no significant difference among RFA, LR, and LT in univariate survival analysis (P = 0.285). For tumor size 3.0-5.0 cm, multivariate analysis showed that RFA for cHCC-CC yielded worse survival outcomes in comparison with that of LR (hazard ratio [HR]: 7.51, 95% confidence interval [CI]: 2.09-26.94, P = 0.002) and LT (HR: 4.48, 95% CI: 1.20-16.64, P = 0.025).

CONCLUSIONS

In patients with cHCC-CC without distant metastases, for tumor size ≤ 3.0 cm, there was no significant survival difference among RFA, LR, and LT. However, for tumor size 3.0-5.0 cm, RFA may provide a worse survival benefit than LT and LR.

Optical Fiber Distributed Sensing Network for Thermal Mapping in Radiofrequency Ablation Neighboring a Blood Vessel

Radiofrequency ablation (RFA) is a minimally invasive form of thermotherapy with great potential in cancer care, having the capability of selectively ablating tumoral masses with a surface area of several cm². When performing RFA in the proximity of a blood vessel, the heating profile changes due to heat dissipation, perfusion, and impedance changes. In this work, we provide an experimental framework for the real-time evaluation of 2D thermal maps in RFA neighboring a blood vessel; the experimental setup is based on simultaneous scanning of multiple fibers in a distributed sensing network, achieving a spatial resolution of 2.5 × 4 mm² in situ. We also demonstrate an increase of ablating potential when injecting an agarose gel in the tissue. Experimental results show that the heat-sink effect contributes to a reduction of the ablated region around 30-60% on average; however, the use of agarose significantly mitigates this effect, enlarging the ablated area by a significant amount, and ablating an even larger surface (+15%) in the absence of blood vessels.

Ruptured Hepatocellular Carcinoma: What Do Interventional Radiologists Need to Know?

Rupture of HCC (rHCC) is a life-threatening complication of hepatocellular carcinoma (HCC), and rHCC may lead to a high rate of peritoneal dissemination and affect survival negatively. Treatment for rHCC mainly includes emergency surgery, interventional therapies, and palliative treatment. However, the management of rHCC should be carefully evaluated. For patients with severe bleeding, who are not tolerant to open surgery, quick hemostatic methods such as rupture tissue ablation and TAE/TACE can be performed. We described clinical presentation, prognosis, complication, interventional management, and current evidence of rHCC from the perspective of interventional radiologists. Overall, our review summarized that interventional therapies are necessary for most patients with rHCC to achieve hemostasis, even in some patients with Child–Pugh C. Moreover, TAE/TACE followed by staged hepatectomy is a beneficial treatment for rHCC according to current clinical evidence. TAE/TACE is the first choice for most patients with rHCC, and appropriate interventional treatment may provide staged surgery opportunities for those who are not tolerant to emergency surgery to reach an ideal prognosis.

Ruptured Hepatocellular Carcinoma: What Do Interventional Radiologists Need to Know?

Rupture of HCC (rHCC) is a life-threatening complication of hepatocellular carcinoma (HCC), and rHCC may lead to a high rate of peritoneal dissemination and affect survival negatively. Treatment for rHCC mainly includes emergency surgery, interventional therapies, and palliative treatment. However, the management of rHCC should be carefully evaluated. For patients with severe bleeding, who are not tolerant to open surgery, quick hemostatic methods such as rupture tissue ablation and TAE/TACE can be performed. We described clinical presentation, prognosis, complication, interventional management, and current evidence of rHCC from the perspective of interventional radiologists. Overall, our review summarized that interventional therapies are necessary for most patients with rHCC to achieve hemostasis, even in some patients with Child–Pugh C. Moreover, TAE/TACE followed by staged hepatectomy is a beneficial treatment for rHCC according to current clinical evidence. TAE/TACE is the first choice for most patients with rHCC, and appropriate interventional treatment may provide staged surgery opportunities for those who are not tolerant to emergency surgery to reach an ideal prognosis.

Long-term Outcomes of Transcatheter Arterial Chemoembolization Combined With Radiofrequency Ablation as an Initial Treatment for Early-Stage Hepatocellular Carcinoma

IMPORTANCE

The long-term outcomes of transcatheter arterial chemoembolization (TACE) combined with radiofrequency ablation (RFA) are not determined.

OBJECTIVE

To report the long-term outcomes of TACE-RFA.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study analyzed long-term follow-up data from a phase 3 randomized clinical trial of adults with early HCC conducted from October 2006 to June 2009. Participants were randomly assigned to the TACE-RFA group or the RFA group in a 1:1 ratio and followed up approximately 6 years after the trial was closed. Data analysis was performed March 2020.

EXPOSURE

In the TACE-RFA group, TACE was performed first, and RFA was done 2 weeks later.

MAIN OUTCOMES AND MEASURES

Overall survival (OS) and recurrence-free survival (RFS).

RESULTS

Of 189 patients who were included (mean [SD] age, 54.3 [12.0] years; 146 [77.2%] men), 94 and 95 patients were assigned to the TACE-RFA group and RFA group, respectively, with their baseline characteristics well matched. Three patients in each group were lost to follow-up. The 5-year and 7-year OS rates for the TACE-RFA group vs the RFA group were 52.0% and 36.4% vs 43.2% and 19.4%, respectively (hazard ratio [HR], 0.55; 95% CI, 0.39-0.78; P = .001). The 5-year and 7-year RFS rates for the TACE-RFA group vs the RFA group were 41.4% and 34.5% vs 27.4% and 18.1%, respectively (HR, 0.66; 95% CI, 0.49-0.89; P = .007). On subgroup analysis comparing patients who had tumors larger than 3 cm with those who had tumors 3 cm or smaller, the OS and RFS survival rates in the TACE-RFA group (HR, 3.20; 95% CI, 1.91-5.35, P < .001) were significantly better than those in the RFA group (HR, 2.03; 95% CI, 1.30-3.17; P = .002).

CONCLUSIONS AND RELEVANCE

In this cohort study, combined RFA and TACE was associated with better survival than RFA alone on long-term follow-up. Patients with tumors 3 cm or smaller did not benefit as well as patients with tumors larger than 3 cm from the combined treatment.

Gel Phantom Models for Radiofrequency and Microwave Ablation of the Liver

Heat-based percutaneous thermal ablation techniques have emerged as popular and effective treatments for liver cancer. As the technology continues to evolve, there is a need for optimized methods for experimentation to identify advantageous modifications and developments. Given that assessing and comparing resulting ablation zones in animal models are costly and resource-intensive, in vitro gel phantom models can serve an important role for early-stage experimentation. There exist several gel phantom recipes that have been reported in the literature. In this review, we will review the various recipes, the pros and cons to the existing models, and future potential directions.

Ablation plus Transarterial Embolic Therapy for Hepatocellular Carcinoma Larger than 3 cm: Science, Evidence, and Future Directions

Thermal ablation is widely regarded as definitive therapy for early-stage hepatocellular carcinoma, but its efficacy decreases in tumors greater than 3 cm. Extensive clinical studies have supported improved outcomes provided through combining transarterial embolic therapy with ablation in the treatment of larger tumors. This article will provide a survey of the science and data for combination therapy in both thermal and nonthermal ablation modalities, as well as describe emerging applications.