State of the ablation nation: a review of ablative therapies for cure in the treatment of hepatocellular carcinoma

Hepatocellular carcinoma: Revising the surgical approach in light of the concept of multiparametric therapeutic hierarchy

The clinical management of hepatocellular carcinoma (HCC) is strongly influenced by several prognostic factors, mainly tumor stage, patient's health, liver function and specific characteristics of each intervention. The interplay between these factors should be carefully evaluated by a multidisciplinary tumor board. To support this, the novel "multiparametric therapeutic hierarchy" (MTH) concept has been recently proposed. This review will present the main features of available surgical treatments for HCC (liver transplantation, liver resection, ablation). Strengths and weaknesses are reported in the light of clinical decision making and of treatment allocation, with a special focus on the collocation of each treatment in the MTH framework and on how MTH may be useful in supporting clinical decision. Sequential treatments and their role to allow further surgical treatments will also be analyzed.

Ablation manual for liver cancer

Because of recent advances in energy device technology, ablation has become popular worldwide. It is less invasive and provides faster postoperative recovery compared to surgery, and therefore, it has come to be applied to a wide range of organs, such as liver, lung, kidney, thyroid, and bone/soft tissue tumors. In order to properly guide the needle to the target area, imaging support is necessary, and ultrasound, which has the advantages of high resolution and real-time capability, is the most frequently used modality. In other words, ablation can be said to be a therapeutic method that makes the most of the advantages of ultrasound. This article outlines the role of ultrasound in ablation for liver cancer and its specific usage.

A retrospective study of irreversible electroporation for tumors adjacent to perihepatic important structure

Background

Irreversible electroporation has been proved as a feasible and safe method against tumor in liver. However, few studies focused on tumors adjacent to perihepatic important structure like vessels, biliary system and gall bladder. These structures limit the effectiveness of conventional treatments. The aim of this article is to analyze the clinical outcomes of patients with hepatic tumors at the special sites who received IRE treatment and provide reliable evidence for broadening the scope of IRE's clinical application.

Methods

The clinical information of patients who underwent IRE ablation for tumors adjacent to perihepatic important structure between February 2017 and December 2021 was collected and retrospectively analyzed. All patients underwent contrast-enhanced CT or MRI for further evaluation at the 1-month follow-up and every 3 months thereafter. Post-ablation complications, recurrence, progression-free survival and overall survival were evaluated to analyze the prognosis of IRE ablation adjacent to perihepatic important structure. Categorical variables are presented as numbers followed by percentages. Continuous data are presented as the mean ± deviation. The tumor size and IRE ablation size were evaluated by the maximum diameters.

Results

Thirty-two patients who underwent IRE ablation for tumor adjacent to perihepatic important structure were studied in this research. There were 39 lesions in 32 patients treated with IRE ablation. Fourteen of them (35.9%) were located adjacent to the porta hepatis, and 8 of them (20.5%) were located adjacent to the hepatocaval confluence. Subcapsular lesions accounted for 15.4% (6 of 39 lesions). The other 11 lesions were in the para gallbladder (5 of 39 lesions, 12.8%), the caudate lobe (5 of 39 lesions, 12.8%) and the colonic hepatic flexure (1 of 39 lesions, 2.6%). According to the Clavien-Dindo classification system for complications, all relative patients with cancer experienced complications below class III except one patient who developed postoperative hemorrhagic shock and improved after timely treatment. Recurrence in situ was observed in 5 of 32 (15.6%) patients. The median PFS of the patients who received IRE ablation was 384 days, and the median OS was 571 days.

Conclusion

IRE ablation is a feasible and safe treatment strategy for tumors adjacent to perihepatic important structure. With improved equipment, optimized therapeutic parameters and long-term clinical trials, IRE will play an increasingly important role in the treatment of tumors in liver.

Emprint Microwave Thermoablation System: Bridging Thermal Ablation Efficacy between Human Patients and Porcine Models through Mathematical Correlation

To investigate the in vivo ablation characteristics of a microwave ablation antenna in the livers of humans with tumors, a retrospective analysis of the ablation zones was conducted after applying Emprint microwave ablation systems for treatment. Percutaneous microwave ablations performed between January 2022 and September 2022 were included in this study. Subsequently, immediate post-ablation echography images were subjected to retrospective evaluation to state the long ablated diameter, short ablated diameter, and volume. The calculated ablation lengths and volume indices were then compared between in vivo and ex vivo results obtained from laboratory experiments conducted on porcine liver. The ex vivo data showed a good correlation between energy delivered and both increasing ablated dimensions (both p < 0.001) and volume (p < 0.001). The in vivo data showed a good correlation for dimensions (p = 0.037 and p = 0.019) and a worse correlation for volume (p = 0.142). When comparing ex vivo and in vivo data for higher energies, the ablated volumes grew much more rapidly in ex vivo cases compared to in vivo ones. Finally, a set of correlations to scale ex vivo results with in vivo ones is presented. This phenomenon was likely due to the absence of perfusion, which acts as a cooling system.

Combining energy-based focal ablation and immune checkpoint inhibitors: preclinical research and clinical trials

Energy-based focal therapy (FT) uses targeted, minimally invasive procedures to destroy tumors while preserving normal tissue and function. There is strong emerging interest in understanding how systemic immunity against the tumor can occur with cancer immunotherapy, most notably immune checkpoint inhibitors (ICI). The motivation for combining FT and ICI in cancer management relies on the synergy between the two different therapies: FT complements ICI by reducing tumor burden, increasing objective response rate, and reducing side effects of ICI; ICI supplements FT by reducing local recurrence, controlling distal metastases, and providing long-term protection. This combinatorial strategy has shown promising results in preclinical study (since 2004) and the clinical trials (since 2011). Understanding the synergy calls for understanding the physics and biology behind the two different therapies with distinctive mechanisms of action. In this review, we introduce different types of energy-based FT by covering the biophysics of tissue-energy interaction and present the immunomodulatory properties of FT. We discuss the basis of cancer immunotherapy with the emphasis on ICI. We examine the approaches researchers have been using and the results from both preclinical models and clinical trials from our exhaustive literature research. Finally, the challenges of the combinatory strategy and opportunities of future research is discussed extensively.

The Role of Ablative Techniques in the Management of Hepatocellular Carcinoma: Indications and Outcomes

The management of hepatocellular carcinoma (HCC) remains complex and will continue to rely on the multidisciplinary input of hepatologists, surgeons, radiologists, oncologists and radiotherapists. With the appropriate staging of patients and selection of suitable treatments, the outcomes for HCC are improving. Surgical treatments encompassing both liver resection and orthotopic liver transplantation (OLT) are the definitive curative-intent options. However, patient suitability, as well as organ availability, pose essential limitations. Consequently, non-surgical options, such as ablative techniques, play an increasingly important role, especially in small HCCs, where overall and disease-free survival can be comparable to surgical resection. Ablative techniques are globally recommended in recognised classification systems, showing increasingly promising results. Recent technical refinements, as well as the emerging use of robotic assistance, may expand the treatment paradigm to achieve improved oncological results. At present, in very early stage and early stage unresectable disease, percutaneous thermal ablation is considered the treatment of choice. Owing to their different features, various ablative techniques, including radiofrequency ablation, microwave ablation, cryotherapy ablation and irreversible electroporation, have been shown to confer different comparative advantages and applicability. We herein review the role of available ablative techniques in the current complex multidisciplinary management of HCC, with a main focus on the indications and outcomes, and discuss future perspectives.

Ablation for Benign Liver Tumors: Current Concepts and Limitations

Percutaneous ablation under imaging guidance is a curative treatment that can induce complete tumor necrosis with advantages of minimal invasiveness and a low risk of complications. Thermal ablation, which includes radiofrequency ablation and microwave ablation, is a representative technique that has sufficient antitumor effects in cases of hepatocellular carcinoma with ≤3 lesions measuring ≤3 cm and preserved liver function. The short- and long-term outcomes of patients are comparable with those achieved with surgical resection. Despite their nonmalignant nature, some benign liver tumors require treatment for symptoms caused by the presence of the tumor and/or continuous enlargement. Ablation may be the treatment of choice because it has lower burden on patients than surgical treatment. This review describes the recent concepts, progress, and limitations of ablation-based treatment for benign liver tumors.

Textbook Outcome of Laparoscopic Microwave Ablation for Hepatocellular Carcinoma

In the context of spreading interest in textbook outcome (TO) evaluation in different fields, we aimed to investigate an uncharted procedure, that is, laparoscopic microwave ablation (MWA) for hepatocellular carcinoma (HCC). Absence of post-MWA complications, a hospital stay of three days, no mortality nor readmission within 30 days, and complete response of the target lesion at post-MWA CT scan defined TO achievement. Patients treated between January 2014 and March 2021 were retrospectively reviewed, and of the 521 patients eligible for the study, 337 (64.7%) fulfilled all the quality indicators to achieve the TO. The absence of complications was the main limiting factor for accomplishing TO. At multivariable analysis, Child-Pugh B cirrhosis, age of more than 70 years old, three nodules, and MELD score ≥ 15 were associated with decreased probabilities of TO achievement. A score based on these factors was derived from multivariable analysis, and patients were divided into three risk groups for TO achievement. At survival analysis, overall survival (OS) was significantly (p = 0.001) higher in patients who achieved TO than those who did not. Moreover, OS evaluation in the three risk groups showed a trend coherent with TO achievement probability. The present study, having assessed the first TO for laparoscopic MWA for HCC, encourages further broader consensus on its definition and, on its basis, on the development of clinically relevant tools for managing treatment allocation.

Detection of microwave ablation coagulation areas using ultrasound Nakagami imaging based on Gaussian pyramid decomposition: A feasibility study

In this paper, we explored the feasibility of using ultrasound Nakagami-m parametric imaging based on Gaussian pyramid decomposition (GPD) to detect microwave ablation coagulation areas. Monte Carlo simulation and phantom simulation results demonstrated that a 2-layer GPD model was sufficient to achieve the same m parameter estimation accuracy, smoothness and resolution as 3-layer and 4-layer. The performances of GPD, moment-based estimator (MBE) and window-modulated compounding (WMC) algorithms were compared in terms of parameter estimation, smoothness, resolution and contrast-to-noise (CNR). Results showed that the m parameter estimation obtained by GPD algorithm was better than that of MBE and WMC algorithms except the small window size (27 × 5). When using a window size of >3 pulse lengths, GPD algorithm could achieve better smoothness and CNR than MBE and WMC algorithms, but there was a certain loss of axial resolution. The computation time of GPD algorithm was less than that of WMC algorithm, while about 2.24 times that of MBE algorithm. Experimental results of porcine liver microwave ablation ex vivo (n = 20) illustrated that the average areas under the operating characteristic curve (AUCs) of Nakagami m_GPD, m_MBE and m_WMC parametric imaging and homodyned-K (HK) α and k parametric imaging to detect coagulation areas were significantly improved by polynomial approximation (PAX). Kruskal-Wallis test showed that the accuracy of coagulation area detection obtained by PAX imaging of m_GPD parameter had no significant difference with that of m_MBE, m_WMC, HK_α and HK_k parameters. This preliminary study suggested that Nakagami imaging based on GPD algorithm may have the potential to detect microwave ablation coagulation areas.

Versatile multi-constrained planning for thermal ablation of large liver tumors

The surgical planning of large hepatic tumor ablation remains a challenging task that relies on fulfilling multiple medical constraints, especially for the ablation based on configurations of multiple electrodes. The placement of the electrodes to completely ablate the tumor as well as their insertion trajectory to their final position have to be planned to cause as little damage to healthy anatomical structures as possible to allow a fast rehabilitation. In this paper, we present a novel, versatile approach for the computer-assisted planning of multi-electrode thermal ablation of large liver tumors based on pre-operative CT data with semantic annotations. This involves both the specification of the number of required electrodes and their distribution to adequately ablate the tumor region without damaging too much healthy tissue. To determine the insertion trajectory of the electrodes to their final position, we additionally incorporate a series of medical constraints into our optimization, which allows a global analysis where obstacles such as bones are taken into account and damage to healthy tissue is mitigated. Compared with the state-of-the-art method, our method achieves compact ablation regions without relying on assumptions on a potential needle path for optimal global search and, hence, is suitable for guiding clinicians through the planning of the tumor ablation. We also demonstrate the feasibility of our approach in various experiments of clinical data and demonstrate that our approach not only allows completely ablating the tumor region but also reducing the damage of healthy tissue in comparison to the previous state-of-the-art method.

Short pulsed microwave ablation: computer modeling and ex vivo experiments

PURPOSE

To study the differences between continuous and short-pulse mode microwave ablation (MWA).

METHODS

We built a computational model for MWA including a 200 mm long and 14 G antenna from Amica-Gen and solved an electromagnetic-thermal coupled problem using COMSOL Multiphysics. We compared the coagulation zone (CZ) sizes created with pulsed and continuous modes under ex vivo and in vivo conditions. The model was used to compare long vs. short pulses, and 1000 W high-powered short pulses. Ex vivo experiments were conducted to validate the model.

RESULTS

The computational models predicted the axial diameter of the CZ with an error of 2-3% and overestimated the transverse diameter by 9-11%. For short pulses, the ex vivo computer modeling results showed a trend toward larger CZ when duty cycles decreases. In general, short pulsed mode yielded higher CZ diameters and volumes than continuous mode, but the differences were not significant (<5%), as in terms of CZ sphericity. The same trends were observed in the simulations mimicking in vivo conditions. Both CZ diameter and sphericity were similar with short and long pulses. Short 1000 W pulses produced smaller sphericity and similar CZ sizes under in vivo and ex vivo conditions.

CONCLUSIONS

The characteristics of the CZ created by continuous and pulsed MWA show no significant differences from ex vivo experiments and computer simulations. The proposed idea of enlarging coagulation zones and improving their sphericity in pulsed mode was not evident in this study.

Impact of Sarcopenia on Two-Year Mortality in Patients with HCV-Associated Hepatocellular Carcinoma After Radiofrequency Ablation

Purpose

Radiofrequency ablation (RFA) appears effective for the treatment of hepatocellular carcinoma (HCC). Evaluation of prognostic factors is imperative for patient selection and improving treatment efficacy. This study aimed to assess sarcopenia as a predictor of the outcome of RFA in patients with HCC.

Methods

This prospective study included all patients with HCC on top of HCV-related cirrhosis who underwent RFA and followed up for a minimum of two years. CT scan was used to determine the skeletal muscle index at the psoas, erector spinae, quadratus lumborum, transversus abdominis, external and internal obliques, and rectus abdominis muscles. Cross-sectional areas were calculated to obtain a lumbar skeletal muscle index (L3-SMI).

Results

A total of 97 patients were enrolled in the study. The L3-SMI was 46.2±12.1 cm²/m². Older age was the only risk factor associated with sarcopenia (p = 0.001). The overall survival at two years for the whole group was 65.2%. Sarcopenia and MELD score were independent predictors of OS at two years with HR of 7.6 (95% CI: 3.1-18.7) and 2.2 (95% CI: 1.0-4.8), respectively. Recurrence-free survival was 84.1% at two years. Recurrence was not affected by all factors, including sarcopenia.

Conclusion

Sarcopenia is a surrogate predictor of overall survival at two years in HCC patients after RFA. Sarcopenia assessment might be an additional prognostic indicator with conventional biomarkers to optimize the selection criteria for receiving RFA for early-stage HCC.

Fast calculation of 3D radiofrequency ablation zone based on a closed-form solution of heat conduction equation fitted by ex vivo measurements

Fast calculation or simulation of the ablation zone induced by radiofrequency ablation (RFA) has a critical role in hepatic RFA planning and therapy. However, it remains challenging to approximate the ablation zone in real time, especially when more than one probe is involved in one ablation session. This paper presents a novel computational technique to calculate the 3D ablation zone of one probe RFA and two-probe switching RFA. The main idea is to get an approximate solution of the temperature distribution from a simplified Pennes bioheat equation, and further fit the solution to the coagulation measurements on ex vivo porcine liver. With a closed-form solution of temperature distribution, the calculation of the ablation zone is as simple as the commonly used ellipsoidal model, but it allows a more realistic prediction of combined ablation zones with different inter-probe spacing. The new approximation technique could potentially replace the original ellipsoidal model in the intervention planning step.

Performance of the Emprint and Amica Microwave Ablation Systems in ex vivo Porcine Livers: Sphericity and Reproducibility Versus Size

PURPOSE

To investigate the performance of two microwave ablation (MWA) systems regarding ablation volume, ablation shape and variability.

MATERIALS AND METHODS

In this ex vivo study, the Emprint and Amica MWA systems were used to ablate porcine livers at 4 different settings of time and power (3 and 5 minutes at 60 and 80 Watt). In total, 48 ablations were analysed for ablation size and shape using Vitrea Advanced Visualization software after acquisition of a 7T MRI scan.

RESULTS

Emprint ablations were smaller (11,1 vs. 21,1 mL p < 0.001), more spherical (sphericity index of 0.89 vs. 0.59 p < 0.001) and showed less variability than Amica ablations. In both systems, longer ablation time and higher power resulted in significantly larger ablation volumes.

CONCLUSION

Emprint ablations were more spherical, and the results showed a lower variability than those of Amica ablations. This comes at the price of smaller ablation volumes.

The prognostic significance of long non-coding RNAs in hepatocellular carcinoma: An updated meta-analysis

BACKGROUND

Recently, many studies have demonstrated that long non-coding RNAs (lncRNAs) are abnormally expressed in hepatocellular carcinoma (HCC) and may serve as a potential molecular biomarker to evaluate the prognosis of hepatocellular carcinoma. Therefore, we accomplished a meta-analysis built on current studies to assess the prognostic value of lncRNAs in hepatocellular carcinoma.

METHODS

The PubMed database was carefully searched to collect all eligible studies until February 20, 2019. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) of the overall survival, relapse-free survival, and progression-free survival were calculated to evaluate the prognostic significance of lncRNAs expression in hepatocellular carcinoma using Stata12.0 software. Heterogeneity, sensitivity analysis, and publication bias were also evaluated.

RESULTS

The results showed that the expression level of lncRNAs was significantly correlated with clinical outcomes. Abnormally expressed lncRNAs predicted poor overall survival (HR=2.19, 95% CI: 1.99-2.42, P<0.001; I²=44.7%, P=0.005), relapse-free survival (HR=2.68, 95% CI: 1.74-4.14, P<0.001; I²=0.0%, P=0.763) and progression-free survival of hepatocellular carcinoma patients (HR=2.44, 95% CI: 1.53-3.89, P<0.001; I²=0.0%, P=0.336). Statistical significance was also noted in subgroup meta-analyses that were stratified by follow-up time, cutoff value, and quality score. Moreover, the pooled results indicated that lncRNAs expression was significantly associated with tumor size (HR=1.48, 95% CI: 1.24-1.79), tumor number (HR=1.34, 95% CI: 1.08-1.66), and tumor node metastasis stage (HR=2.10, 95% CI: 1.48-2.99), but not liver cirrhosis and tumor differentiation (P>0.05).

CONCLUSIONS

This meta-analysis indicates that lncRNAs are strongly associated with prognosis in hepatocellular carcinoma and may serve as a promising indicator for prognostic evaluation of patients with hepatocellular carcinoma. But larger clinical studies are needed to verify its feasibility.

What's New in Percutaneous Ablative Strategies for Hepatocellular Carcinoma and Colorectal Hepatic Metastases? 2020 Update

PURPOSE OF REVIEW

Ablation techniques are now well-established treatment options available for the management of primary and secondary hepatic malignancies. Currently available ablative techniques include radiofrequency ablation (RFA), microwave ablation (MWA), cryoablation, and irreversible electroporation (IRE). Along with advances in navigational devices and targeting technologies, ablation combined with other therapies may be the next therapeutic option in thermal ablation. The purpose of this review is to evaluate the current status of ablative technologies in interventional and medical oncology for management of liver malignancies.

RECENT FINDINGS

With the use of combination techniques (i.e., ablation and transarterial embolization procedures), thermal ablation is now moving toward treating tumors larger than 3 cm in size or tumors with macrovascular invasion. Ongoing trials are examining the optimum timing of combination therapies. Thermal ablation combined with hepatic resection may increase the number of patients with metastatic colorectal carcinoma to the liver who qualify for curative surgery. Combination therapies of thermal ablation and transarterial embolization allow for promising treatment responses for larger HCC. Surgery combined with thermal ablation can potentially increase the number of patients with metastatic colon cancer to the liver who qualify for curative surgery.

Comparison of hydrochloric acid infusion radiofrequency ablation with microwave ablation in an ex vivo liver model

Objectives: To compare sizes and shapes of ablation zones resulting from hydrochloric acid infusion radiofrequency ablation (HRFA) and microwave ablation (MWA), using normal saline infusion radiofrequency ablation (NSRFA) as a control, at a variety of matched power settings and ablation durations, in an ex vivo bovine liver model.Methods: A total of 90 ablation procedures were performed, using each of three modalities: NSRFA, HRFA, and MWA. For each modality, five ablation procedures were performed for each combination of power (80 W, 100 W, or 120 W) and duration (5, 10, 20, 30, 45, or 60 min). The size of ablation zones were compared using ANOVA, the Kruskal-Wallis test, or generalized linear regression.Results: For ablation durations up to 30 min, mean transverse diameter (TD) after HRFA and MWA did not differ significantly (β = 0.13, p = .20). For ablation durations greater than 30 min, mean TD was significantly larger after HRFA than after MWA (β = 1.657, p < .001). The largest TD (9.46 cm) resulted from HRFA performed with 100 W power for 60 min.Conclusions: Compared to MWA, monopolar HRFA with power settings of 80 W-120 W and durations of less than 30 min showed no significant difference. When duration of more than 30 min, HRFA created larger ablation zones than MWA.

Reduced graphene oxide, but not carbon nanotubes, slows murine melanoma after thermal ablation using LED light in B16F10 lineage cells

Photodynamic therapy is a minimally invasive health technology used to treat cancer and other non-malignant diseases, as well as inactivation of viruses, bacteria and fungi. In this work, we sought to combine the phototherapy technique using low intensity LED (660 nm) to induce ablation in melanoma tumor in mice treated with nanoparticles. In vitro and in vivo studies were conducted, and our results demonstrated that multi-walled carbon nanotubes (MWCNTs) do not destroy tumor cells in vivo, but stimulate the inflammatory process and angiogenesis. Reduced graphene oxide (rGO), has been shown to play a protective role associated with the LED ablation, inducing necrosis, stimulation of immune response by lymphoproliferation, and decreased tumor mass in vivo. We consider that LED alone can be very effective in controlling the growth of melanoma tumors and its association with rGO is potentiated.

Chemotherapeutic Nanoparticle-Based Liposomes Enhance the Efficiency of Mild Microwave Ablation in Hepatocellular Carcinoma Therapy

Hepatocellular carcinoma (HCC) is the third leading cause of death from cancer, and the 5-year overall survival (OS) rate for HCC remains unsatisfying worldwide. Microwave ablation (MWA) is a minimally invasive therapy that has made progress in treating HCC. However, HCC recurrence remains problematic. Therefore, combination therapy may offer better outcomes and enhance MWA efficiency through improved tumor control. We have developed doxorubicin-loaded liposomes (DNPs) as an efficient nanoplatform to enhance MWA of hepatocellular carcinoma even at the mild ablation condition. In this study, we demonstrated that the uptake of DNPs by HCC cells was increased 1.5-fold compared with that of free DOX. Enhanced synergism was observed in the combination of DNPs and MWA, which induced nearly 80% cell death. The combination of mild MWA and DNPs enhanced the ablation efficiency of HCC with significant inhibition of liver tumors and accounted for the longest survival rate among all groups. A much higher accumulation of the DNPs was observed in the transitional zone than in the ablation zone. No apparent systemic toxicity was observed for any of the treatments after 14 days. The present work demonstrates that DNPs combined with MWA could be a promising nanoparticle-based therapeutic approach for the treatment of hepatocellular carcinoma and shows potential for future clinical applications.

Hyperthermia and smart drug delivery systems for solid tumor therapy

Chemotherapy is a cornerstone of cancer therapy. Irrespective of the administered drug, it is crucial that adequate drug amounts reach all cancer cells. To achieve this, drugs first need to be absorbed, then enter the blood circulation, diffuse into the tumor interstitial space and finally reach the tumor cells. Next to chemoresistance, one of the most important factors for effective chemotherapy is adequate tumor drug uptake and penetration. Unfortunately, most chemotherapeutic agents do not have favorable properties. These compounds are cleared rapidly, distribute throughout all tissues in the body, with only low tumor drug uptake that is heterogeneously distributed within the tumor. Moreover, the typical microenvironment of solid cancers provides additional hurdles for drug delivery, such as heterogeneous vascular density and perfusion, high interstitial fluid pressure, and abundant stroma. The hope was that nanotechnology will solve most, if not all, of these drug delivery barriers. However, in spite of advances and decades of nanoparticle development, results are unsatisfactory. One promising recent development are nanoparticles which can be steered, and release content triggered by internal or external signals. Here we discuss these so-called smart drug delivery systems in cancer therapy with emphasis on mild hyperthermia as a trigger signal for drug delivery.

Comparisons between radiofrequency ablation and stereotactic body radiotherapy for liver malignancies: Meta-analyses and a systematic review

INTRODUCTION

Radiofrequency ablation (RFA) is a standard ablative modality for small liver malignancies. Stereotactic body radiotherapy (SBRT) has emerged although yet suffers a lack of high-level evidence. We performed meta-analyses and a systematic review to integrate the literature and help in clinical decision-making.

METHODS

Systemic searches were performed of the PubMed, Medline, and EMBASE databases to identify controlled studies comparing RFA and SBRT.

RESULTS

Eleven studies involving 2238 patients were included. Among them, eight studies were for treating early hepatocellular carcinomas (HCCs) and three for liver metastases. Including HCCs and liver metastases studies, the pooled two-year local control (LC) rate was higher in the SBRT arm (83.8%, 95% confidence interval [CI]: 77.6-88.4) than that in the RFA arm (71.8%, 95% CI: 61.5-80.2) (p = 0.024). Among studies on liver metastases, the pooled two-year LC rate was higher in the SBRT arm (83.6% vs. 60.0%, p < 0.001). No significant difference was found between arms in HCC studies (SBRT vs. RFA: 84.5 vs. 79.5% p = 0.431). Pooled analysis of overall survival (OS) in HCC studies showed an odds ratio of 1.43 (95% CI: 1.05-1.95, p = 0.023), favoring RFA. Among the two liver metastases studies with comparative survival data, no significant difference was observed.

CONCLUSION

LC was equivalent between RFA and SBRT for HCC and better for SBRT for the treatment of liver metastases. RFA was associated with better OS for HCC, but discrepancy between LC and OS requires further investigation, as they are local modalities having comparable efficacy.

Videolaparoscopic microwave ablation in patients with HCC at a European high-volume center: Results of 815 procedures

BACKGROUND

Videolaparoscopic (VL) microwave ablation (MWA) is not included in most of the international guidelines as a therapeutic option for hepatocellular carcinoma (HCC). Aim of this study was to assess the safety of VL MWA in patients with HCC for whom resection or percutaneous ablation is unsuitable.

METHODS

A retrospective analysis was performed on a prospective database of patients with HCC treated with VL MWA at our institution from 2009 to 2016. Patient demographics, operational characteristics, and complications were recorded. Statistical analysis was performed to identify safety profile, overall survival and recurrence rate.

RESULTS

A total of 815 VL MWA were performed in 674 patients with a mean age of 64 years. Patients had a mean Model for End-stage Liver Disease score of 10 (±3); 32.8% were Child B, 44.1% Barcelona Clinic Liver Cancer B-C. Perioperative mortality was 0.4%. Overall morbidity was 30.8%, with Dindo-Clavien complications ≥3 in 2%. The median length of stay was 2 days. In 43.1% VL MWA was the first-line therapy. Overall 1-, 3-, and 5-year survival rates were 81.9%, 54.9%, and 35.9%.

CONCLUSIONS

The present is the largest series of VL ablation and the bigger number of patients with HCC treated with MW reported nowadays. It confirms the safety of a minimally invasive procedure for patients with HCC when resection or percutaneous ablation is not feasible.

Cardiac tamponade after radiofrequency ablation for hepatocellular carcinoma: Case report and literature review

RATIONALE

Radiofrequency ablation (RFA) is a safe and effective local treatment modality with a low complication rate and is commonly used to treat hepatocellular carcinoma (HCC). The clinical outcome of RFA may be closely related to the location, size, and shape of index tumors, and major complications, including hemorrhage, liver abscess, infarction, visceral organ perforation, hemothorax, pneumothorax, tumoral seeding, and hepatic failure. Cardiac tamponade is a rare and serious life-threatening complication associated with RFA. To date, a review of the medical literature reported 5 cases of cardiac tamponade after RFA for HCC. Herein, we report another case of cardiac tamponade after RFA for HCC in a 56-year-old man.

PATIENT CONCERNS

He had suffered from liver cirrhosis due to alcohol abuse. He had chronic obstructive pulmonary disease. Magnetic resonance imaging showed a 3.0-cm exophytic subcapsular HCC in segment IVa of left hepatic lobe. As the patient was at high risk for surgery because of poor lung function, RFA was selected as the treatment of choice. The index tumor was located in the vicinity of the diaphragm and colon. During RFA procedure, thermal injury to the adjacent diaphragm and colon was minimized by introducing artificial ascites. Bleeding or tumoral seeding was prevented by ablating the electrode track during electrode retraction.

DIAGNOSIS

Two hours after RFA, the patient presented with dyspnea, chest discomfort, and low blood pressure (80/60 mm Hg), suggesting cardiac tamponade. Immediate follow-up contrast-enhanced computed tomography image depicted the slightly high attenuated hemopericardium. Transthoracic echocardiography (TTE) showed a moderate amount of pericardial effusion with tamponade and a large hematoma.

INTERVENTIONS

Under fluoroscopy and portable echocardiography guidance, a cardiologist immediately inserted a 7-French pigtail catheter into the pericardial space and collected more than 200 cc of bloody pericardial fluid.

OUTCOMES

After pericardiocentesis, the patient's symptoms and hemodynamic status were dramatically improved. Follow-up TTE showed scanty amount of pericardial effusion and the drainage catheter was removed. The patient was discharged.

LESSONS

When treating HCC in the left lobe (especially segments II and IVa), attention should be paid to cardiac tamponade. The early diagnosis and immediate treatment of cardiac tamponade may increase the chance of cure.

CT-guided navigated microwave ablation (MWA) of an unfavorable located breast cancer metastasis in liver segment I

For percutaneous minimally-invasive local ablation therapies of malignant lesions within the liver computed tomography (CT) fluoroscopy or ultrasound (US) can be applied for the positioning of ablation probes. However, lesions in liver segment I and in the upper part of liver segment VIII are difficult to reach with CT fluoroscopy and US guidance even for experienced interventionalists as steep and transcostal access paths may be needed. In addition, there is always the risk to lacerate crucial vessels near the liver hilus. We report on the use of a CT-based stereotactic navigation system (CAS-One, CAScination AG, Bern, Switzerland) for the precise positioning of the ablation probe to perform a percutaneous stereotactic image-guided microwave ablation of a breast cancer liver metastasis in liver segment I that was unreachable with conventional CT or US guidance. Based on the initial planning scan and image-to-patient registration a precise positioning of the probe was possible sparing vital structures like the directly adjacent vulnerable vessels. The ablation was performed without complications fully covering the metastatic lesion with the ablation zone. To this day, there was no recurring tumor 18 months after the intervention.

Association between AKT rs2494752 single nucleotide polymorphism and the risk of metastasis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common types of human tumors, which is characterized by high morbidity and mortality rates. AKT1 transcriptional activity is implicated in HCC initiation and development. In the present study, the effects of rs2494752 single nucleotide polymorphism (SNP) on AKT1 transcriptional activity in the progression of HCC cells were investigated. A case-control study was analyzed in 1,056 HCC patients and 1,080 healthy individuals using the PCR assay method. Results indicated AKT1 expression levels were up-regulated in HCC tissue compared to adjacent normal tissues. Furthermore, a higher frequency of AKT rs2494752 AG and AA genotypes were observed in HCC cases (P=0.0046). Gene polymorphism identified C and T alleles were frequency in HCC patients compared to healthy individuals. Individuals harboring AKT rs2494752 AG/AA genotype had a vital increased susceptibility to HCC in the dominant model (P=0.0028). In addition, AKT1 rs2494752 GG genotype showed an increasing of AKT1 promoter activity determined by the luciferase assay. Furthermore, it was demonstrated that AKT1 rs2494752 GG and C polymorphism was more aggressive than other AKT1 rs2494752 cancer cells. Moreover, AKT1 rs2494752 GG markedly increased rates of response to NCT chemotherapy. Additionally, results revealed that AKT1 rs2494752 GG and C increased the risk factors of HCC. In conclusion, these results indicate that AKT1 rs2494752 polymorphisms may be regarded as a candidate gene in assessing the susceptibility, metastasis and responses to chemotherapy in the progression of hepatocellular carcinoma.

Beyond the Knife: The Evolving Nonsurgical Management of Oligometastatic Colorectal Cancer

In patients with liver-limited oligometastatic disease, the goal of treatment can be curative intent. Historically, this was accomplished in patients presenting with upfront resectable disease. The availability of increasingly efficacious chemotherapy and biologic combinations with encouraging response rates led to the potential to convert unresectable disease to resectability. Beyond the backbone of surgery, we now have a portfolio of locoregional strategies to consider.From an interventional radiology perspective, the use of portal vein embolization can facilitate hypertrophy of the liver in anticipation of resection, thus converting unresectable disease to one amenable to a surgical approach with curative intent. Technological advances in liver-directed ablative therapies have afforded the possibility of eliminate radiographically evident disease with the hope for long-term disease control. Advanced radiotherapy techniques are further increasing the therapeutic options for patients with metastatic colorectal cancer. Improvements in external-beam radiotherapy over the past 2 decades include image-guided radiotherapy, intensity-modulated radiotherapy, stereotactic body radiotherapy, and proton-beam therapy. Finally, selective internal radiation therapy (SIRT) with microspheres labeled with the β-emitter ⁹⁰Y enable targeted delivery of radiation to hepatic tumors. A coordinated multidisciplinary approach is required to integrate these nonsurgical adjuncts in an evidence-based manner to optimize outcomes for patients with potentially resectable metastatic disease. In this article, we summarize recent developments in systemic therapy, radiotherapy, and interventional liver-directed therapies that have changed the treatment landscape for patients with oligometastatic colorectal cancer.