Prognostic factors for survival in patients with hepatocellular carcinoma after percutaneous microwave ablation

Using Patient-Specific 3D Modeling and Simulations to Optimize Microwave Ablation Therapy for Liver Cancer

Microwave ablation (MWA) of liver tumors presents challenges like under- and over-ablation, potentially leading to inadequate tumor destruction and damage to healthy tissue. This study aims to develop personalized three-dimensional (3D) models to simulate MWA for liver tumors, incorporating patient-specific characteristics. The primary objective is to validate the predicted ablation zones compared to clinical outcomes, offering insights into MWA before therapy to facilitate accurate treatment planning. Contrast-enhanced CT images from three patients were used to create 3D models. The simulations used coupled electromagnetic wave propagation and bioheat transfer to estimate the temperature distribution, predicting tumor destruction and ablation margins. The findings indicate that prolonged ablation does not significantly improve tumor destruction once an adequate margin is achieved, although it increases tissue damage. There was a substantial overlap between the clinical ablation zones and the predicted ablation zones. For patient 1, the Dice score was 0.73, indicating high accuracy, with a sensitivity of 0.72 and a specificity of 0.76. For patient 2, the Dice score was 0.86, with a sensitivity of 0.79 and a specificity of 0.96. For patient 3, the Dice score was 0.8, with a sensitivity of 0.85 and a specificity of 0.74. Patient-specific 3D models demonstrate potential in accurately predicting ablation zones and optimizing MWA treatment strategies.

Lenvatinib delivery using a Gd/Fe bimetallic MOF: Enhancing antitumor immunity following microwave-based thermal therapy

Microwave (MW) thermal therapy has been developed as an effective clinical strategy that can achieve pronounced antitumor activity and also has the potential to trigger antitumor immunity. However, patients generally face high rates of tumor recurrence following MW treatment, limiting the long-term benefits of such treatment. The combination of MW treatment and immunomodulatory strategies may represent a promising means of reprogramming the immunosuppressive tumor microenvironment (TME) in a manner conducive to lower recurrence rates. In this study, a Lenvatinib-loaded Gd/Fe metal-organic framework (Gd/FeMOF) was designed as a promising approach to enhancing such antitumor immunity. MW-enhanced dynamic Gd/FeMOF sensitization can facilitate high levels of reactive oxygen species production under MW irradiation, resulting in stronger immunogenic tumor cell death. In parallel, the Lenvatinib released from Gd/FeMOF preparations can serve as an immune adjuvant that suppresses programmed death ligand 1 (PD-L1) expression and drives the reprogramming of the immunosuppressive TME. The Gd and Fe present within this MOF preparation also imbue it with magnetic resonance imaging capabilities. Importantly, in vivo animal model experiments confirmed the ability of GdFeMOF treatment to significantly enhance antitumor immunity while protecting against recurrence. Accordingly, this study offers a foundation for promising strategies aimed at the integrated diagnosis and durable treatment of cancer. STATEMENT OF SIGNIFICANCE: High rates of tumor recurrence following MW thermal therapy limit the long-term benefits of such treatment. We found that the administration of Lenvatinib-loaded Gd/FeMOF nanoparticles significantly reduced tumor recurrence after MW thermal therapy. Under MW irradiation, the Gd/FeMOF nanoparticles were found to augment the immune response due to facilitation of the process of immunogenic cell death. In addition, the released Lenvatinib could act as an immune adjuvant to downregulate the expression of PD-L1 and reprogram the immunosuppressive state of the tumor microenvironment, thus further enhancing the immune response. This is significant because MW-induced immune responses are relatively weak and usually fail to effectively prevent tumor recurrence. The combination of MW treatment with an immunomodulatory strategy may solve this problem.

Distinct immunoreactions after a primary tumor microwave ablation using different heating parameters in a VX2 tumor model

BACKGROUND

Thermal ablation of solid tumors in situ can activate the immune system and produce a specific immune response against the tumor. Microwave ablation (MWA) with different parameters can ablate tumors with similar sizes and cause different local inflammatory effects. Our aim was to determine the immunological effects induced by different energy modes of MWA for a primary tumor.

METHODS

Seventy rabbits with VX2 tumors that were implanted subcutaneously underneath the right second nipple were treated with high-power MWA (40 W for 1 min), low-power MWA (20 W for 2 min), or surgical resection or were left without treatment (control). Survival time was evaluated by log-rank test. On day 14 after ablation, immunohistochemistry and flow cytometry were used to evaluate the T-cell immune responses. In addition, the cytokine patterns were identified by enzyme-linked immunosorbent assay.

RESULTS

Tumor eradication was achieved completely in the MWA groups, as proven by nicotinamide adenine dinucleotide diaphorase staining. Compared with the three treatment groups, the control group had a significantly higher number of pulmonary metastases and worse survival; however, no significant difference was observed among the three treatment groups. More intra-tumoral and systemic CD4+ and CD8+ T-cells were induced in the MWA groups than in the control group. Compared with operation, MWA induced more systemic CD4+ T-cells. More intra-tumoral CD4+ and CD8+ T-cells and systemic CD4+ T-cells were induced by high-power MWA than by low-power MWA. Moreover, MWA increased the interleukin 2 (IL2) and IL12 levels and decreased the IL4, IL6, and IL10 levels. Importantly, the serum IL12 level was significantly higher after high-power MWA than after low-power MWA.

CONCLUSION

High-power MWA enhanced the type 1 T helper immune response and may be selected for the treatment of solid tumors. Future studies are needed to confirm our results.

Inducing the Abscopal Effect in Liver Cancer Treatment: The Impact of Microwave Ablation Power Levels and PD-1 Antibody Therapy

Microwave ablation (MWA) is an effective treatment for liver cancer (LC), but its impact on distant tumors remains to be fully elucidated. This study investigated the abscopal effects triggered by MWA treatment of LC, at different power levels and with or without combined immune checkpoint inhibition (ICI). We established a mouse model with bilateral subcutaneous LC and applied MWA of varied power levels to ablate the right-sided tumor, with or without immunotherapy. Left-sided tumor growth was monitored to assess the abscopal effect. Immune cell infiltration and distant tumor neovascularization were quantified via immunohistochemistry, revealing insights into the tumor microenvironment and neovascularization status. Th1- and Th2-type cytokine concentrations in peripheral blood were measured using ELISA to evaluate systemic immunological changes. It was found that MWA alone, especially at lower power, promoted distant tumor growth. On the contrary, combining high-power MWA with anti-programmed death (PD)-1 therapy promoted CD8+ T-cell infiltration, reduced regulatory T-cell infiltration, upregulated a Th1-type cytokine (TNF-α) in peripheral blood, and inhibited distant tumor growth. In summary, combining high-power MWA with ICI significantly enhances systemic antitumor immune responses and activates the abscopal effect, offering a facile and robust strategy for improving treatment outcomes.

Perfluoropentane/apatinib-encapsulated metal-organic framework nanoparticles enhanced the microwave ablation of hepatocellular carcinoma

Microwave ablation (MWA) is a promising minimally invasive therapy for hepatocellular carcinoma (HCC). However, the efficiency of MWA in treating HCC is evidently limited by the incomplete ablation of large tumors and tumors in high-risk locations. Here we designed an iron-based metal-organic framework nanomedicine (PFP-Apa-MOF) by loading perfluoropentane (PFP) and apatinib (Apa). After being absorbed by HCC, iron could induce ferroptosis. PFP could be activated into bubbles and act as an ultrasound agent for detecting the ablation margin. As an effective antiangiogenic drug, Apa could inhibit tumor residual growth after MWA. The high efficiency of PFP-Apa-MOF was fully demonstrated in vitro and in vivo. The results showed that MWA combined with PFP-Apa-MOF clearly enhanced the ablation efficiency, leading to apparent tumor inhibition, and increased tumor apoptosis and lipid peroxide. PFP-Apa-MOF could play a valuable role in enhancing MWA to achieve better therapeutic efficacy in HCC.

Comparable and Complimentary Modalities for Treatment of Small-Sized HCC: Surgical Resection, Radiofrequency Ablation, and Microwave Ablation

BACKGROUND

Over the past decade, there has been continual improvement in both ablative and surgical technologies for the treatment of hepatocellular carcinoma (HCC). The efficacy of ablative therapy compared to surgical resection for HCC has not been thoroughly evaluated using multiple large-scale randomized controlled trials. By international consensus, if a patient is eligible, surgery is the primary curative treatment option, as it is believed to confer superior oncologic control.

OBJECTIVE

to determine the efficacies of percutaneous ablative therapies and surgical resection (SR) in the treatment of HCC. Data sources, study appraisal, and synthesis methods: A meta-analysis using 5 online databases dating back to 1989 with more than 31,000 patients analyzing patient and tumor characteristics, median follow-up, overall survival, and complication rate was performed.

RESULTS

Ablative therapies are suitable alternatives to surgical resection in terms of survival and complication rates for comparable patient populations. For the entire length of the study from 1989-2019, radiofrequency ablation (RFA) produced the highest 5-year survival rates (59.6%), followed by microwave ablation (MWA) (50.7%) and surgical resection (SR) (49.9%). In the most recent era from 2006 to 2019, surgical resection has produced the highest 5-year survival rate of 72.8%, followed by RFA at 61.7% and MWA at 50.6%. Conclusions and key findings: Depending on the disease state and comorbidities of the patient, one modality may offer superior overall survival rates over the other available techniques. Interventional ablative methods and surgical resection should be used in conjunction for the successful treatment of small-sized HCC.

Ultrasound-guided microwave ablation in the treatment of early-stage tongue cancer

Background

Tongue cancer is a common malignant tumor of the head and neck. Its treatment methods include surgery, radiotherapy, and chemotherapy. However, these treatments have serious side effects and poor cosmetic effect, so it is urgent to find new treatment methods. We pioneered the use of microwave ablation (MWA) in the treatment of early tongue cancer and achieved good results.

Case Presentation

A 67-year-old woman (Han nationality) was admitted to the hospital because of progressive aggravation of tongue pain. She had a history of tongue pain of more than 1 year. Pathological biopsy showed squamous cell carcinoma; following this, radical operation of the tongue cancer was planned. The preoperative examination showed thyroid occupation in the upper mediastinum region compressing the airway; hence, the risk of general anesthesia was high. Consent was obtained from the patient and her family. Ultrasound-guided MWA was successfully performed under the lingual nerve block. The patient was followed for 1 year. She recovered well with no dysphagia and unclear articulation symptoms, and the cosmetic effect was excellent.

Conclusion

To our knowledge, this is the first case of using MWA for the treatment of early-stage tongue cancer (ESTC). Ultrasound-guided MWA may be used for ESTC that can completely ablate the tumor and retain the function of the tongue, further improving the quality of life of the patient. However, it is only a case report and needs more research to verify the use of MWA in ESTC.

Hepatic resection versus microwave ablation for the treatment of early hepatocellular carcinoma: a comparative analysis of treatment outcomes and survival predictors

Introduction

Liver resection and local ablation are the two primary curative treatments for early-stage hepatocellular carcinoma (HCC). Microwave ablation (MWA) shows promising performance in terms of early tumor response, recurrence, and survival. This study aims to determine whether MWA would be comparable to liver resection in treating early-stage HCC.

Methods

This study included patients with hepatitis C-related HCC attending the multidisciplinary HCC clinic, Kasr Al-Ainy Hospital (March 2018 to September 2020). We included adults with early-stage HCC (BCLC stages 0-A). We studied patients and tumor characteristics, HCC treatment response, recurrence, and overall survival.

Results

Thirty-one patients were treated with liver resection and 41 patients were treated with MWA, including 4 patients who received intraoperative MWA. By the end of the study, 21 patients (28.77%) died. Patients who underwent MWA were younger compared to the hepatectomy group with lower baseline AFP (21 (6.7–54) versus 77 (31.3–136.0), respectively, (P value 0.024) and tumor size (2.78 (0.87) cm versus 3.77 (0.97) cm, respectively, (P value < 0.001). We found no differences between the studied groups in terms of treatment response, post-treatment decompensation, recurrence, or overall survival. One-year survival probability in the MWA and resection groups was 75.5% and 76.3% respectively. Post-procedure hepatic decompensation was the only independent predictor of lower survival by multivariate logistic regression analysis (OR 37.74, 95%CI 6.251–227.87, P value < 0.001) after adjusting for age, AFP, and tumor size.

Conclusion

Liver resection and MWA showed similar satisfactory results in the treatment of early-stage HCC, in terms of treatment response, recurrence, and overall survival.

Impact and Novel Perspective of Immune Checkpoint Inhibitors in Patients with Early and Intermediate Stage HCC

Surgery and radiofrequency ablation remain the gold standard to achieve cure in patients with hepatocellular carcinoma (HCC). After a decade in which only sorafenib was available for advanced and metastatic HCC, the emergence of other molecularly targeted drugs and immune checkpoint inhibitors (ICIs) has significantly improved the patients` prognosis. In particular, the use of ICIs has shown promising results and has revolutionized the treatment algorithm in HCC patients. Indeed, preclinical and clinical data have documented a high density of immunosuppressive cells and an increased expression of the programmed death-1 (PD-1) receptor and cytotoxic T-cell associated protein-4 (CTLA-4) in HCC. However, despite these observations, no validated biomarker is available and the molecular groundwork responsible for response to ICIs remains elusive. The anti-CTLA4 monoclonal antibody tremelimumab and the anti-PD-1 monoclonal antibodies nivolumab and pembrolizumab were the first ICIs to be tested in HCC. Recently, the combination of the anti-programmed death-ligand 1 (PD-L1) inhibitor atezolizumab and the anti-vascular endothelial growth factor (VEGF) antibody bevacizumab demonstrated an improvement in patient outcome compared to sorafenib, becoming the standard of care in the frontline setting of advanced disease. Other immunotherapeutic agents such as pembrolizumab or the combination nivolumab-ipilimumab have shown promising results that have to be confirmed in phase III studies. Currently, the combination of different ICIs (i.e., ipilimumab, durvalumab) and anti-angiogenic agents (i.e., regorafenib, lenvatinib) is currently being tested in several trials and will hopefully revolutionize the treatment of HCC. To date, numerous studies are underway evaluating ICIs in adjuvant and neoadjuvant settings to improve survival in early and intermediate stages. Thus, this review focuses on the rationale for ICIs and their potential use for early or intermediate HCC stages.

Operative Microwave Ablation for Hepatocellular Carcinoma Within 3 cm and 3 Nodules: Experience in 559 Patients

BACKGROUND

There are few published data regarding long-term outcome survival after microwave ablation (MWA) for hepatocellular carcinoma (HCC) within 3 cm and 3 nodules. The aim of this study was to examine long-term outcomes after operative MWA for HCC within 3 cm and 3 nodules.

METHODS

This cohort of this retrospective study comprised 559 patients who underwent operative MWA for HCC within 3 cm and 3 nodules in our institute between 1996 and 2017. We analyzed overall survival (OS) and recurrence-free survival (RFS), and evaluated factors related to prognosis.

RESULTS

Median follow-up time was 69 months for the entire cohort. OS rates were 1-year: 98%, 3-year: 87%, 5-year: 73%, and 10-year:39%; RFS rates were 1-year: 91%, 3-year: 60%, 5-year: 42%, and 10-year: 21%. Multivariate analysis revealed that hepatitis C virus (HCV)-positive status, ALBI grade 2 or 3, maximum tumor diameter ≥ 20 mm, and multiple nodules were independent risk factors for both OS and RFS. A prognostic staging model using one point for each risk factor provided a well-categorized predictive model. The 5-year OS rates were 93%, 81%, and 57% for scores of 0, 1 or 2, and 3 or 4, respectively (P < 0.001). The 5-year RFS rates were 70%, 48%, and 28% for scores of 0, 1 or 2, and 3 or 4, respectively (P < 0.001).

CONCLUSIONS

Our results revealed good long-term outcomes after operative MWA for HCC within 3 cm and 3 nodules.

Discontinuous moving shot technique for conformal thermal ablation in an ex vivo porcine liver model

PURPOSE

We aimed to determine the ablation characteristics of discontinuous moving shot technique (DMST) in microwave ablation (MWA), radiofrequency ablation (RFA) and laser ablation (LA), and analyze the differences compared with fixed electrode technique (FET) in an ex vivo porcine liver model.

METHODS

FET was defined as the ablation needle remaining fixed during ablation. In DMST, ablation needle moved backward for a fixed distance twice along the long axis during ablation. Four moving distances (0.5 cm, 0.75 cm, 1 cm and 2 cm) were used in DMST. Long-axis diameter (LAD) and short-axis diameter (SAD) of ablation zones were measured. The ratio of LAD/SAD was calculated.

RESULTS

The shape and size of ablation zones were different between DMST and FET. Compared with FET, DMST could achieve greater LAD when the moving distance became long enough. In MWA with DMST, SAD decreased with the extension of moving distance and finally became smaller than the SAD in FET. While in LA and RFA, the change of moving distance did not affect SAD significantly.

CONCLUSION

In MWA, RFA and LA, the characteristics of ablation zone of DMST were different from that of FET. This unique ablation technique may be suitable for conformal thermal ablation.

Locoregional Combined With Systemic Therapies for Advanced Hepatocellular Carcinoma: An Inevitable Trend of Rapid Development

Despite the application of antiviral drugs and improved surveillance tools, the number of patients diagnosed with hepatocellular carcinoma (HCC) at an advanced stage and with a dismal prognosis is still on the rise. Systemic treatment with multiple multitargeted tyrosine kinase inhibitors (TKIs), such as sorafenib, has been a widely utilized approach for a decade. In addition, the use of a combination of TKIs with other types of compounds, including immune checkpoint inhibitors (ICIs) and antiangiogenic inhibitors, has shown efficacy in treating advanced HCC. However, the presence of intolerable adverse events, low disease response and control rates, and relative short overall survival of such combinatory therapies makes novel or optimized therapies for advance HCC urgently needed. Locoregional therapy (transarterial chemoembolization, and thermal ablation) can destroy primary tumors and decrease tumor burden and is widely used for HCC management. This type of treatment modality can result in local hypoxia and increased vascular permeability, inducing immunogenic effects by releasing tumor antigens from dying cancer cells and producing damage-associated molecular patterns that facilitate antiangiogenic therapy and antitumor immunity. The combination of systemic and locoregional therapies may further produce synergistic effects without overlapping toxicity that can improve prognoses for advanced HCC. In preliminary studies, several combinations of therapeutic modes exhibited promising levels of safety, feasibility, and antitumor effects in a clinical setting and have, thus, garnered much attention. This review aims to provide a comprehensive, up-to-date overview of the underlying mechanisms of combined systemic and locoregional therapies in the treatment of advanced HCC, commenting on both their current status and future direction.

A review on radiofrequency, microwave and high-intensity focused ultrasound ablations for hepatocellular carcinoma with cirrhosis

Importance

Hepatocellular carcinoma (HCC) is usually accompanied by liver cirrhosis, which makes treatment of this disease challenging. Liver transplantation theoretically provides an ultimate solution to the disease, but the maximal surgical stress and the scarcity of liver graft make this treatment option impossible for some patients. In an ideal situation, a treatment that is safe and effective should provide a better outcome for patients with the dilemma.

Objective

This article aims to give a comprehensive review of various types of loco-ablative treatment for HCC.

Evidence Review

Loco-ablative treatment bridges the gap between surgical resection and transarterial chemotherapy. Various types of ablative therapy have their unique ability, and evidence-based outcome analysis is the most important key to assisting clinicians to choose the most suitable treatment modality for their patients.

Findings

Radiofrequency ablation (RFA) has a relatively longer history and more evidence to support its effectiveness. Microwave ablation (MWA) is gaining momentum because of its shorter ablation time and consistent ablation zone. High-intensity focused ultrasound (HIFU) ablation is a relatively new technology that provides non-invasive treatment for patients with HCC. It has been carried out at centers of excellence and it is a safe and effective treatment option for selected patients with HCC and liver cirrhosis.

Conclusion and Relevance

Selective use of different loco-ablative therapies will enhance clinicians' treatment options for treatment of HCC.

Radiomics Model Based on Gadoxetic Acid Disodium-Enhanced MR Imaging to Predict Hepatocellular Carcinoma Recurrence After Curative Ablation

Background

A practical prognostic prediction model is absent for hepatocellular carcinoma (HCC) patients after curative ablation. We aimed to develop a radiomics model based on gadoxetic acid disodium-enhanced magnetic resonance (MR) images to predict HCC recurrence after curative ablation.

Methods

We retrospectively enrolled 132 patients with HCC who underwent curative ablation. Patients were randomly divided into the training (n = 92) and validation (n = 40) cohorts. Radiomic features were extracted from gadoxetic acid disodium-enhanced MR images of the liver before curative ablation, and various baseline clinical characteristics were collected. Cox regression and random survival forests were used to construct models that incorporated radiomic features and/or clinical characteristics. The predictive performance of the different models was compared using the concordance index (C-index) and decision curves analysis (DCA). A cutoff derived from the combined model was used for risk categorization, and recurrence-free survival (RFS) was compared between groups using the Kaplan-Meier survival curve analysis.

Results

Twenty radiomic features and four clinical characteristics were identified and used for model construction. The radiomics model constructed by tumoral and peritumoral radiomic features had better predictive performance (C-index 0.698, 95% confidence interval [CI] 0.640-0.755) compared with the clinical model (C-index 0.614, 95% CI 0.499-0.695), while the combined model had the best predictive performance (C-index 0.706, 95% CI 0.638-0.763). A better net benefit was observed with the combined model compared with the other two models according to the DCA. Distinct RFS distributions were observed when patients were categorized based on the cutoff derived from the combined model (Log rank test, p = 0.007).

Conclusion

The radiomics model which combined radiomic features extracted from gadoxetic acid disodium-enhanced MR images with clinical characteristics could predict HCC recurrence after curative ablation.

Combined therapy with conventional trans-arterial chemoembolization (cTACE) and microwave ablation (MWA) for hepatocellular carcinoma >3-<5 cm

PURPOSE

To compare safety and efficacy of combined therapy with conventional transarterial chemoembolization (cTACE)+microwave ablation (MWA) versus only TACE or MWA for treatment of hepatocellular carcinoma (HCC) >3-<5 cm.

METHODS

This randomized controlled trial (NCT04721470) screened 278 patients with HCC >3-<5 cm. Patients were randomized into three groups: 90 underwent TACE (Group 1); 95 underwent MWA (Group 2); and 93 underwent combined therapy (Group 3). Patients were followed-up with contrast-enhanced CT or MRI. Images were evaluated and compared for treatment response and adverse events based on modified response evaluation criteria in solid tumor. Serum alpha-fetoprotein (AFP) concentration was measured at baseline and during every follow-up visit.

RESULTS

Final analysis included 265 patients (154 men, 111 women; mean age = 54.5 ± 11.8 years; range = 38-76 years). Complete response was achieved by 86.5% of patients who received combined therapy compared with 54.8% with only TACE and 56.5% with only MWA (p = 0.0002). The recurrence rate after 12 months was significantly lower in Group 3 (22.47%) than Groups 1 (60.7%) and 2 (51.1%) (p = 0.0001). The overall survival rate (three years after therapy) was significantly higher in Group 3 (69.6%) than Groups 1 (54.7%) and 2 (54.3%) (p = 0.02). The mean progression-free survival was significantly higher in Group 3 than groups 1 and 2 (p < 0.001). A decrease in AFP concentration was seen in 75%, 63%, and 48% patients of Group 3, 2, and 1, respectively.

CONCLUSIONS

Combined therapy with cTACE + MWA is safe, well-tolerated, and more effective than TACE or MWA alone for treatment of HCC >3-<5 cm.

Treatment Options for Early-Stage Hepatocellular Carcinoma

Patients with early stage hepatocellular carcinoma have good prognosis and are treated with curative intent. Although this cohort of patients is generally defined by limited tumor burden, good liver function, and preserved functional status, there remains utility in further stratification to optimize overall survival and limit post-operative morbidity and mortality. Transplant, resection, ablation, transarterial radioembolization, and transarterial chemoembolization, either as monotherapy or in combination, may play a crucial role in treating this cohort of patients depending on a multitude of factors. In this section, we review each treatment modality and provide general guidelines for patient selection.

Combined use of microwave ablation and cell immunotherapy induces nonspecific immunity of hepatocellular carcinoma model mice

Microwave ablation (MWA) has been widely used in the treatment of solid tumors. Studies have been less conducted on the efficacy of MWA used with cell immunotherapy in treating hepatocellular carcinoma (HCC). The current study aimed at exploring the efficacy of MWA in combination with cell immunotherapy in treating HCC. Hepa1-6 HCC mice were treated by MWA, blockade, or the combined therapy (MWA used with blockade), or left untreated. Survival rates of the mice were plotted by Kaplan-Meier Curve, followed by log-rank test. 25 days after the operation, surviving mice were monitored for tumor recurrence, and tumor volumes were calculated every 5 days. Immunohistochemistry and flow cytometry were performed to detect the numbers of CD4⁺ and CD8⁺ cells in the tumors and spleens of mice. The expressions of related cytokines were detected and measured by ELISPOT and ELISA. The results showed that MWA combined with anti-PD-1/anti-CTLA-4 not only increased the survival time, protected the mice against tumor recurrence, but also enhanced the intratumoral infiltration of cytotoxic T lymphocyte and systemic T-cell immune responses induced by MWA through activation of synergistically specific antitumor immunity. In addition, the combined therapy increased T-helper 1 cell (Th1-type) cytokines, but reduced Th2-type cytokines, resulting in the polarization of Th1 cells. T-cell immune responses of HCC cells were activated by MWA. In addition, the combined therapy of MWA and anti-PD-1/anti-CTLA-4 induced Th1-type immune response, and showed specific antitumor immunity.

Predicting the survival rate of patients with hepatocellular carcinoma after thermal ablation by nomograms

Background

To accurately predict the survival rate of patients with hepatocellular carcinoma (HCC) undergoing thermal ablation using nomograms taking early recurrence into account as a risk factor.

Methods

A total of 591 patients receiving percutaneous thermal ablation were included in this study. The overall survival (OS) and recurrence-free survival (RFS) rate was analyzed. Two prognostic nomograms with or without taking early recurrence into account as a risk factor were constructed using the independent predictors assessed by the multivariate Cox proportional hazard model. The performance of the nomograms, in terms of discrimination and calibration, was evaluated.

Results

The cumulative RFS and OS rates at 1-, 3- and 5-year are 82.2%, 52.5%and 38.4%, 96.6%, 83.6% and 65.5%, respectively. Multivariate analysis without considering the early recurrence shows that tumor number, α-fetoprotein (AFP) level, liver function, and GGT level are associated with OS. The early recurrence, tumor number, AFP level, and liver function are considered associated with the OS when considering early recurrence. Two different nomograms were developed from the above two results. Internal validation with 1,000 bootstrapped sample sets of the two nomograms shows the concordance indexes of 0.69 (95% CI: 0.624-0.748) for the baseline nomogram and 0.81 (95% CI: 0.754-0.857) for the early recurrence-based nomogram, with the latter significantly better in discriminating performance (Z statistics =92.19, P<0.0001).

Conclusions

The survival rate of patients with HCC undergoing radical thermal ablation can be reliably predicted by the nomogram presented in this study, which was developed by taking early recurrence into account.

Locoregional Therapies for Hepatocellular Carcinoma: What Has Changed in the Past Ten Years?

The evolution of locoregional therapies in the last decade has been refined with improved patient selection and a development of a more personalized approach. In doing so, there has been associated improved outcomes and less toxicity. With the rapidly changing landscape of systemic therapy, the role of locoregional therapies alone or in combination for downstaging and curative intent will continue to evolve.

The effect of tumor location on long-term results of microwave ablation for early-stage hepatocellular carcinoma

BACKGROUND

To analyze the influence of tumor location, including tumor adjacency and located segments on long-term survival outcomes for patients with solitary hepatocellular carcinoma (HCC) after microwave ablation (MWA).

METHODS

This retrospective study evaluated 850 patients. The hepatic segments where the tumor is located, tumor adjacency (important tissues adjacent to tumor) and other clinical characteristics were collected. Overall survival (OS), local tumor progression (LTP) and disease-free survival (DFS) were compared and analyzed. Influence of tumor location was evaluated by multi-models and the effect of adjacency for OS, LTP, and DFS in different segments was analyzed by stratification analysis.

RESULTS

The OS, LTP, and DFS rates were similar in different hepatic segments, so were in high risk and safe locations. In multi-models, HCC in segment 8 showed lower death rate of 43% than that in segment 2 (HR 0.57; P = 0.01) and tumors in segment 6 seemed to have lower LTP rate. Tumors in high-risk locations were risk factors for OS, LTP, and DFS compared with tumors in safe locations, but all differences were not significant in different models. The effects of tumor adjacency on survival outcomes among subgroups of segments were limited.

CONCLUSION

The tumor adjacency was not a prognostic factor of survival outcomes for patients with solitary tumors after MWA, but tumors in segment 8 seemed to better OS rate than tumors in other segments.

A Pilot Study of the Impact of Microwave Ablation on the Dielectric Properties of Breast Tissue

Percutaneous microwave ablation (MWA) is a promising technology for patients with breast cancer, as it may help treat individuals who have less aggressive cancers or do not respond to targeted therapies in the neoadjuvant or pre-surgical setting. In this study, we investigate changes to the microwave dielectric properties of breast tissue that are induced by MWA. While similar changes have been characterized for relatively homogeneous tissues, such as liver, those prior results are not directly translatable to breast tissue because of the extreme tissue heterogeneity present in the breast. This study was motivated, in part by the expectation that the changes in the dielectric properties of the microwave antenna’s operation environment will be impacted by tissue composition of the ablation target, which includes not only the tumor, but also its margins. Accordingly, this target comprises a heterogeneous mix of malignant, healthy glandular, and adipose tissue. Therefore, knowledge of MWA impact on breast dielectric properties is essential for the successful development of MWA systems for breast cancer. We performed ablations in 14 human ex-vivo prophylactic mastectomy specimens from surgeries that were conducted at the UW Hospital and monitored the temperature in the vicinity of the MWA antenna during ablation. After ablation we measured the dielectric properties of the tissue and analyzed the tissue samples to determine both the tissue composition and the extent of damage due to the ablation. We observed that MWA induced cell damage across all tissue compositions, and found that the microwave frequency-dependent relative permittivity and conductivity of damaged tissue are lower than those of healthy tissue, especially for tissue with high fibroglandular content. The results provide information for future developments on breast MWA systems.

Ultrasound-guided percutaneous microwave ablation of hepatocellular carcinoma in challenging locations: oncologic outcomes and advanced assistive technology

Purpose: To assess the oncologic outcomes of the hepatocellular carcinoma (HCC) patients in challenging locations (CLs) underwent ultrasound-guided percutaneous microwave ablation (US-PMWA) and the efficacy and safety of the advanced assistive technology (AAT).Materials and methods: Data for 489 treatment-naïve patients with HCC who met Milan criteria and subsequently underwent US-PMWA were reviewed from March 2012 to November 2016. According to the distance (<5 mm) between the tumor and surrounding structures, the patients were divided into two groups: a CL group and a non-CL group. Regarding MWA assisted by AAT, the CL group was further subdivided into two groups: an AAT group and a non-AAT group. Technique effectiveness, complications and survival outcomes (i.e., overall survival [OS] and recurrence-free survival [RFS]) were compared between CL and non-CL groups. Local tumor progression (LTP) was compared between AAT and non-AAT groups.Results: Technique effectiveness and complications in the CL group were similar to those in the non-CL group (p = .873 and p = .828, respectively). The OS and RFS in six types of CL groups were comparable with those in non-CL group (p = .131-.117) including adjacent vital structures, gallbladder, hepatic hilar regions, major vessels, diaphragm and capsule, respectively. The LTP rates in the AAT group were significantly higher than those in the non-AAT group (p = .001).Conclusions: US-PMWA assisted by AAT to treat HCC lesions in CLs was safe and effective; also, this technique had comparable success and survival outcomes with those of patients in non-CL.

Feasibility and safety of surgical microwave ablation for hepatocellular carcinoma in elderly patients: a single center analysis in Japan

The feasibility and safety of microwave ablation in elderly hepatocellular carcinoma (HCC) patients remains unknown. The aim of this study was to evaluate the feasibility and safety of surgical microwave ablation for HCC in patients older than 80 years of age. This retrospective study enrolled consecutive 114 patients older than 80 years of age who underwent surgical microwave ablation for HCC between July 1994 and December 2017. We analyzed perioperative outcomes and long-term outcomes to clarify the prognostic factors. The 1-, 3-, 5-year overall survival and recurrence-free survival rates were 97.3%, 76.0%, 49.2% and 84.2%, 44.7%, and 32.5%, respectively. The overall major morbidity rates (Clavien–Dindo grade IIIA or above) were 2.6%. There were no cases of mortality. Multivariate analysis showed that hepatitis C virus antibody (HCV-Ab) positivity and the presence of multiple tumors were independent prognostic factors for long-term outcomes. The overall survival rate of patients with HCV-Ab negative and single tumor was better than that of other patients (p = 0.026). Surgical microwave ablation was feasible and safe for elderly patients with HCC. Elderly patients with HCV-Ab negative and single tumor would be expected to have better long-term outcomes after surgical microwave ablation.

Locoregional Therapy Approaches for Hepatocellular Carcinoma: Recent Advances and Management Strategies

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and third leading cause of cancer-related mortality worldwide. While surgical resection and transplantation are the standard first-line treatments for early-stage HCC, most patients do not fulfill criteria for surgery. Fortunately, catheter-directed and percutaneous locoregional approaches have evolved as major treatment modalities for unresectable HCC. Improved outcomes have been achieved with novel techniques which can be employed for diverse applications ranging from curative-intent for small localized tumors, to downstaging or bridging to resection and transplantation for early and intermediate disease, and locoregional control and palliation for advanced disease. This review explores recent advances in liver-directed techniques for HCC including bland transarterial embolization, chemoembolization, radioembolization, and ablative therapies, with a focus on patient selection, procedural technique, periprocedural management, and outcomes.

Prognosis of microwave ablation for hepatocellular carcinoma: does age make a difference?

Objective: Hepatocellular carcinoma (HCC) is a notable threat to the longevity of elderly people. However, there is no trial to study the prognosis of these elderly patients after microwave ablation (MWA) treatment. This study investigated whether elderly patients with HCC benefit from MWA similar to younger patients.Materials and methods: Patients who underwent ultrasound-guided percutaneous MWA were included and divided into four age groups and the prognosis was compared. The senior group (Group S, ≥75 years) was then compared with the younger group (Group Y, <75 years) after a 1:1 propensity score matching was applied. The prognostic outcomes were evaluated and Cox analysis was performed to determine the factors associated with survival.Results: The four age groups showed a statistically different distribution in terms of sex, size of liver nodules, and the Charlson comorbidity index. Although Group S had a higher Charlson comorbidity index, no significant differences were found between Group S and Group Y in the rates of complete ablation and major complications as well as overall survival and progression-free survival after matching. Cox analysis demonstrated that the size of tumors and Child Pugh grade rather than age or Charlson comorbidity index were significant prognostic factors for overall survival.Conclusion: The elderly patients with HCC, even though associated with more comorbidities, may achieve acceptable prognostic outcomes following MWA, which are not worse than their younger counterparts.

Comparison of radiofrequency and microwave ablation and identification of risk factors for primary treatment failure and local progression

PURPOSE

To compare percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) for treatment of Hepatocellular carcinoma (HCC) and to identify risk factors for treatment failure and local progression.

METHODS

145 unique HCC [87 (60%) RFA, 58 (40%) MWA] were retrospectively reviewed from a single tertiary medical center. Adverse events were classified as severe, moderate, or mild according to the Society of Interventional Radiology Adverse Event Classification system. Primary and secondary efficacy, as well as local progression, were determined using mRECIST. Predictors of treatment failure and time to local progression were analyzed using generalized estimating equations and Cox regression, respectively.

RESULTS

Technical success was achieved in 143/145 (99%) HCC. There were 1 (0.7%) severe and 2 (1.4%) moderate adverse events. Of the 143 technically successful initial treatments, 136 (95%) completed at least one follow-up exam. Primary efficacy was achieved in 114/136 (84%). 9/22 (41%) primary failures underwent successful repeat ablation, so secondary efficacy was achieved in 128/136 (90%) HCC. Local progression occurred in 24 (19%) HCC at a median of 25 months (95% CI = 19-32 months). There was no difference in technical success, primary efficacy, or time to local progression between RFA and MWA. In HCC treated with MWA, same-day biopsy was associated with primary failure (RR = 9.0, 95% CI: 1.7-47, P = 0.015), and proximity to the diaphragm or gastrointestinal tract was associated with local progression (HR = 2.40, 95% CI:1.5-80, P = 0.017).

CONCLUSION

There was no significant difference in primary efficacy or time to local progression between percutaneous RFA and MWA.

Predictors for hepatocellular carcinoma recurrence after microwave ablation

Aim of the study

Microwave ablation (MWA) for treatment of hepatocellular carcinoma (HCC) is a new promising modality. The prognosis after treatment is mainly linked to the recurrence. We aimed to investigate the predictive value of α-fetoprotein (AFP) score and Aurora B kinase (AURKB) in HCC recurrence after MWA.

Material and methods

A cross-sectional study where 25 early-stage HCC patients (Barcelona Clinic Liver Cancer 0/A-B) were treated with MWA. Tumor biopsies were obtained just prior to MWA and assessed for WHO pathological grade and AURKB expression by immunohistochemistry. AFP score was calculated and a cut-off value of 2 classifies patients into high and low risk of recurrence. After achieving complete ablation, patients were followed every 3 months for 1 year by triphasic CT to detect recurrence.

Results

Child-Pugh classification has no significant impact on prognosis of HCC after MWA (χ² = 1.924, p = 0.165). Serum AFP level and AFP score can effectively predict the response to MWA among HCC patients (χ² = 6.451, ^MCp = 0.031) (χ² = 9.0, p = 0.003), respectively. AFP score was strongly associated with the pathological grade of the tumor (r = 0.467, p = 0.019). AURKB was over-expressed in tumoral more than non-tumoral specimens (p < 0.001). It was correlated with the size of the tumor, the number of tumor nodules and the pathological grade of the tumor (p < 0.05) but has no role in predicting recurrence after MWA (p = 0.869).

Conclusions

AFP score but not AURKB can predict the risk of recurrence of HCC after MWA.

Efficacy of surgical microwave ablation for recurrent hepatocellular carcinoma after curative hepatectomy

BACKGROUND

Little evidence exists regarding postrecurrence survival after microwave ablation for recurrent hepatocellular carcinoma (HCC) after curative hepatectomy; we aimed to evaluate the feasibility of surgical microwave ablation.

METHODS

In this retrospective review, we enrolled patients who underwent curative hepatectomy for primary HCC in our department and had intrahepatic recurrence. We analyzed overall survival according to treatment modality to clarify the prognostic factors for survival.

RESULTS

Of 257 patients, 119 had intrahepatic recurrence. Three patients underwent repeat hepatectomy; 75 patients underwent surgical microwave ablation, and 34 patients underwent transcatheter arterial chemoembolization or hepatic arterial infusion chemotherapy. The median postrecurrence survival time and 5-year postrecurrence survival after surgical microwave ablation were 37.4 months and 55.4%, respectively. The major complication rate (Clavien-Dindo classification IIIa or above) after surgical microwave ablation was 5.3% with no mortality. Multivariate analysis showed that microvascular invasion at primary tumors, and recurrent tumors within 3 cm and 3 nodules were independent prognostic factors for overall survival after surgical microwave ablation for recurrent HCC.

CONCLUSION

Our results suggested that surgical microwave ablation is safe and feasible for recurrent intrahepatic HCC after curative hepatectomy. Close follow-up and further curative treatment could be important for improving postrecurrence survival.

Transcatheter arterial chemoembolization combined with simultaneous DynaCT-guided microwave ablation in the treatment of small hepatocellular carcinoma

PURPOSE

To evaluate the method and effectiveness of transcatheter arterial chemoembolization (TACE) combined with simultaneous DynaCT-guided Microwave ablation (MWA) for the treatment of small hepatocellular carcinoma (SHCC).

MATERIALS AND METHODS

From June 2015 to May 2017, a total of 28 consecutive patients with SHCC received single treatment of TACE and 23 subjects received a combination treatment of TACE with simultaneous DynaCT-guided MWA. Following 1 month of treatment, the tumor response was assessed using the mRECIST criteria and the outcomes were analyzed including intervention-associated complications, changes in liver function, imaging response, and progression-free survival (PFS).

RESULTS

The technical success rate was 100%. The rates of CR (65%) in the combined TACE and MWA group were higher than those of the TACE group (46%). The rate of common adverse events, such as liver abscess, spontaneous bacterial peritonitis and liver dysfunction, in the combined TACE and MWA group (56%) was comparable to the corresponding rate of the TACE group (P > 0.411). The median and mean PFS of the TACE group were significantly lower than those of the combined TACE and MWA group (19.00 months vs. 29.00 months, 21.076 months vs. 24.693 months, p = 0.019, log-rank test).

CONCLUSION

Stereotactic DynaCT-guided MWA is a safe and effective method for the treatment of SHCC, which usually provides an effective tumor puncture path, notably for lesions that cannot be detected following TACE. Overall, the data suggested that this treatment method could improve the clinical outcome of patients with SHCC.

Subsequent cooling-circulation after radiofrequency and microwave ablation avoids secondary indirect damage induced by residual thermal energy

PURPOSE

We aimed to investigate the exact role of residual thermal energy following microwave ablation (MWA) and radiofrequency ablation (RFA) at the final ablation and transition zones and determine whether residual thermal energy could be dissipated by subsequent cooling-circulation.

METHODS

In an ex vivo study, MWA and RFA were performed on fresh porcine liver, and central and border temperatures were compared. In an in vivo study, MWA and RFA were performed to the livers of New Zealand white rabbits. Tissue samples were stained with α-NADH-diaphorase. The coagulation zones (NADH-negative) and transition zones (lightly NADH-stained) of different groups were compared at different time points.

RESULTS

In the ex vivo model, the residual thermal energy after MWA and RFA could be dispersed by subsequent cooling-circulation due to the temperature decreasing rapidly. In the in vivo study, the coagulation volume in the ablation group was larger than that in the cooling-circulation group (P < 0.05) 2 days after ablation. In the ablation group, the damaged zone (the transition zone plus the coagulation zone) on α-NADH-diaphorase-stained images increased rapidly within 2 hours after ablation and slowly reached the maximum on day 2. However, the damaged zones did not change significantly at the three time points observed in the cooling-circulation group.

CONCLUSION

The residual thermal energy in MWA and RFA induced secondary damage beyond the direct coagulation zone, and it could be dissipated by subsequent cooling-circulation, contributing to smaller ablation and transition zones.

Renal Cell Carcinoma Ablation: Preprocedural, Intraprocedural, and Postprocedural Imaging

The rising incidence of renal cell carcinoma (RCC) in recent decades necessitates careful consideration of additional treatment options, especially for patients who may be poor surgical candidates. An emerging body of evidence suggests that ablation may be performed effectively and safely even in patients with multiple comorbidities. Accordingly, clinical guidelines now include thermal ablation as an alternative for such patients with localized tumors that are 4.0 cm or smaller. Recent experience with these minimally invasive techniques has led to a greater understanding of the imaging findings that merit close attention when ablation is anticipated, or after it is performed. These imaging findings may guide the interventionalist's perception of the risks, technical challenges, and likelihood of treatment success associated with RCC ablation. The present review provides an overview of clinically relevant radiologic findings during the preprocedural, intraprocedural, and postprocedural period in the context of image-guided renal ablation. Keywords: Interventional-Body, Kidney, Percutaneous, Urinary © RSNA, 2019.

Theranostic liposomes as nanodelivered chemotherapeutics enhanced the microwave ablation of hepatocellular carcinoma

Aim: This study aimed to develop indocyanine green- and doxorubicin-loaded liposomes (DILPs) as theranostic nanoplatform for the detection of hepatocellular carcinoma (HCC) and as an efficient chemotherapeutic to enhance microwave ablation. Materials & methods: DILPs were synthesized and thoroughly characterized. Biocompatibility, tumor uptake and accumulation, and synergistic ablation-chemotherapeutic efficiency were systematically explored in them. In addition, human HCC surgical samples were used to test the affinity of DILPs for HCC. Results: The combination of microwave ablation and DILPs enhanced the ablation efficiency of HCC with apparent tumor inhibition. DILPs exhibited excellent diagnostic ability and could detect 2.5-mm HCC lesions via optoacoustic tomography imaging. DILPs had better affinity for human HCC surgical samples compared with normal liver tissue. Conclusion: Theranostic DILPs could serve as promising nanoparticles for treatment and management of HCC in the clinic.

Gold-Curcumin Nanostructure in Photo-thermal Therapy on Breast Cancer Cell Line: 650 and 808 nm Diode Lasers as Light Sources

Background:

Au nanoparticles (AuNPs) exhibit very unique physiochemical and optical properties, which now are extensively studied in a range of medical diagnostic and therapeutic applications. AuNPs can be used for cancer clinical treatment with minimal invasion. On the other hand, curcumin is a polyphenol derived from turmeric which is used for medical purposes due to its anti-cancer, anti-microbial, anti-oxidant and anti-inflammatory properties. Despite these potential properties of curcumin, its usage is limited in medicine due to low solubility in water. Conjugation of curcumin to AuNPs (Au-Cur nanostructure) can be increasing its solubility. Photo-thermal therapy (PTT) is a novel kind of cancer treatment which involves two major components: laser and photo-thermoconversion agents.

Materials and Methods:

Here, diode lasers emitting 808 nm and 650 nm were utilized as light sources, and synthesized Au-Cur nanostructure was applied as a photo-thermo conversion agent. UV-vis absorbance spectroscopy and dynamic light scattering (DLS) were applied to study the maximum absorption of particles, size stability of the samples and their zeta potential. The synthesized Au-Cur nanostructure under irradiation of laser is used for PPT on 4T1 cells. The cytotoxicity activity of Au-Cur nanostructure and laser irradiation on 4T1 cells was evaluated by MTT assay.

Results:

Synthesized Au-Cur nanostructure showed λ_max at 540 nm and a mean hydrodynamic diameter of 25.8 nm. 4T1 cells were exposed to an 808 nm diode laser (1.5 W cm², 10 min) in the presence of different concentrations of Au-Cur nanostructure. Next, 4T1 cells with Au-Vur nanostructure were exposed to diode laser beam (650 nm, 1.5 W cm²) for 10 min. The results revealed that Au-Cur nanostructure under laser irradiation of 808 nm more decreased cell viability of 4T1 cells compared to laser irradiation of 650 nm.

Conclusion:

It was concluded that combining an 808-nm laser at a power density of 1.5W/cm² with Au-Cur nanostructure has a destruction effect on 4T1 breast cancer cells in vitro experiments compared to laser irradiation of 650 nm.

Actual 10-Year Survival After Surgical Microwave Ablation for Hepatocellular Carcinoma: A Single-Center Experience in Japan

BACKGROUND

Little evidence exists regarding long-term survival after microwave ablation for hepatocellular carcinoma (HCC). The aim of this study is to determine actual 10-year survival and clarify the clinicopathological features of patients surviving ≥ 10 years after surgical microwave ablation.

PATIENTS AND METHODS

This retrospective study identified 459 patients who underwent surgical microwave ablation for HCC with curative intent between 2001 and 2008. We compared 100 patients who survived ≥ 10 years with 321 patients who died within 10 years.

RESULTS

Median overall survival and recurrence-free survival rates were 5.5 and 2.4 years, respectively. The actual 10-year overall survival rate was 23.8%, and the actual 10-year recurrence-free survival rate was 8.1%. Multivariate analysis showed that age > 70 years [odds ratio 1.87, P = 0.029], hepatitis C virus positivity (OR 2.30, P = 0.004), Child-Pugh class B (OR 3.28, P = 0.003), and platelet count < 10 × 10⁴ /µL (OR 1.93, P = 0.033) were independent risk factors for actual 10-year survival. During 10-year follow-up, 66% of the ≥ 10-year survivors developed recurrence, and 91% of these patients underwent further curative treatment, including hepatic resection or local ablation, for HCC recurrence.

CONCLUSION

Ten-year survival after surgical microwave ablation for HCC can be expected in approximately 24% of patients, even though nearly 2/3 of our 10-year survival patients experienced recurrence. Close postoperative follow-up and further curative treatment for recurrence are important for improving long-term survival.

Hepatic resection versus operative microwave ablation for single hepatocellular carcinoma ≤5 cm: A propensity score-matched analysis

BACKGROUND

Little evidence exists regarding the perioperative and oncologic benefits of microwave ablation for hepatocellular carcinoma. The aim of this study was to compare the efficacy of hepatic resection and operative microwave ablation (microwave coagulo-necrotic therapy) for single hepatocellular carcinoma ≤5 cm.

METHODS

Between 1994 and 2015, a total of 551 patients with a single hepatocellular carcinoma ≤5 cm were treated in our institution (hepatic resection: n = 128; microwave coagulo-necrotic therapy: n = 423). We compared overall survival and recurrence-free survival between hepatic resection and microwave coagulo-necrotic therapy. Propensity score matching analysis identified 94 matched pairs of patients to compare outcomes.

RESULTS

After propensity score matching, baseline variables, including liver function and tumor size, were well-balanced between the 2 groups. The 5- and 10-year overall survival rates were 76% and 47% for hepatic resection and 77% and 48% for microwave coagulo-necrotic therapy, respectively (P = .865). The 5- and 10-year recurrence-free survival rates were 55% and 41% for hepatic resection and 47% and 32% for microwave coagulo-necrotic therapy, respectively (P = .377). In the subgroup analysis, the hepatic resection group had better recurrence-free survival than the microwave coagulo-necrotic therapy group in patients with tumor size >3 cm, with 5-year recurrence-free survival rates of 56.5% and 32.4% in the hepatic resection and microwave coagulo-necrotic therapy group, respectively (P = .029).

CONCLUSION

Our propensity score matching study confirmed no statistically significant differences in both overall survival and recurrence-free survival between hepatic resection and microwave coagulo-necrotic therapy for single hepatocellular carcinoma ≤5 cm; however, hepatic resection is recommended for hepatocellular carcinoma with tumor size >3 cm when patients have good liver function.

Current State of Tumor Ablation Therapies

The most common primary liver malignancy, hepatocellular carcinoma (HCC), has a high likelihood of mortality, and much effort into early detection and treatment has occurred. Multiple staging systems have surfaced of which some guide treatment. Curative intent is a goal of early-staged HCC treatment, and this can be achieved with surgical resection, liver transplantation, and minimally invasive percutaneous therapies such as tumor ablation. Many of the newer ablation techniques have evolved from shortcomings of prior methods which have resulted in an expanded number of applications for tumor ablation. Our review focuses on current mainstream image-guided percutaneous ablation modalities which are commonly performed as an alternative to surgery.

Evaluation of Probe Angles for Synchronous Waveform 915-MHz Microwave Ablation

BACKGROUND

The purpose of this study is to compare the ablation performance between a synchronous microwave ablation (MWA) system and a commercially available asynchronous system in ex vivo bovine liver and evaluate the efficacy of ablation at varying entrance angles.

MATERIALS AND METHODS

Two 915-MHz MWA systems were used in bench top ex vivo bovine livers with various conditions (synchronous versus asynchronous). Using synchronous technology ablations to liver, kidney, or lung at angles of 0, 15, 30, and 90° were evaluated.

RESULTS

Synchronous and asynchronous MWA systems created mean ablation zone volumes of 26.4 and 15.8 cm³, 62.9 and 45.4 cm³, 90.8 and 56.4, and 75.7 and 54.8 cm³ with single, double (2 microwave probes in use simultaneous) (2 cm spacing), and triple (three probes in use simultaneously) (2 cm and 3 cm spacing) antennae configurations, respectively; adjusted P-values ≤ 0.006. Ablation defects were similar across all groups when evaluated for entrance angle. Specifically, when comparing 0-degree angle to all other angles, achieved zones of ablation (ZA) were similar (mean ± standard deviation for 0-degree versus all other angles: 8.72 ± 4.84 versus 9.38 ± 4.11 cm², P = 0.75). The use of the long-tip probe resulted in a statistically significant increase in the achieved ZA when compared to the short tip probe (10.9 ± 4.3 versus 6.5 ± 2.4, respectively; P = 0.01).

CONCLUSIONS

Newly developed synchronous microwave technology creates significantly larger ablation zones when compared to an existing asynchronous commercially available system. The angle of approach does not affect the resulting ZA. This is clinically relevant as true 0-degree angle is often difficult to obtain.

Microwave vs radiofrequency ablation for hepatocellular carcinoma within the Milan criteria: a propensity score analysis

BACKGROUND

Whether microwave ablation (MWA) challenges the standard role of radiofrequency ablation (RFA) in treating early-stage hepatocellular carcinoma (HCC) remains unclear.

AIM

To compare the efficacy of MWA vs RFA for treating primary HCC within the Milan criteria.

METHODS

From January 2002 to January 2017, the oncological outcomes after MWA (126 patients) and RFA (436 patients) were analysed by propensity score matching.

RESULTS

Before propensity score matching, for overall patients, MWA resulted in similar 5-year overall survival to RFA (80.1% vs 75.8%, P = 0.190) but better 5-year recurrence-free survival (28.1% vs 19.6%, P = 0.036). For solitary HCC ≤ 3 cm, MWA resulted in comparable 5-year overall survival (81.8% vs 77.1%, P = 0.170) to RFA but better 5-year recurrence-free survival (34.6% vs 24.0%, P = 0.042). After propensity score matching, MWA resulted in better 5-year overall survival (79.3% vs 68.4%, P = 0.021) and 5-year recurrence-free survival (27.9% vs 6.4%, P < 0.001) than RFA for HCC. For solitary HCC ≤3 cm, MWA resulted in comparable 5-year overall survival (81.2% vs 66.3%, P = 0.062) and 5-year recurrence-free survival (37.7% vs 17.4%, P = 0.088) to RFA. In Cox analysis, RFA modality, tumours located in risk areas and low serum albumin levels were unfavourable prognostic factors for overall survival. RFA modality, multiple tumours, tumour size and low serum albumin levels were unfavourable prognostic factors for recurrence-free survival (all P < 0.05).

CONCLUSIONS

RFA is inferior to MWA for treating HCC within the Milan criteria, but has comparable efficacy to MWA for solitary HCC ≤ 3 cm.

Determinants of survival following hepatocellular carcinoma in Egyptian patients with untreated chronic HCV infection in the pre-DAA era

BACKGROUND AND STUDY AIMS

In this study we assessed rates and determinants of survival in people with untreated chronic HCV infection and hepatocellular carcinoma (HCC) in an Egyptian liver clinic setting.

PATIENTS AND METHODS

This is a prospective cohort study of patients diagnosed with HCV-related HCC and undergoing HCC management at a national liver centre in Egypt in 2013-2014 and with a follow-up through 2016.

RESULTS

A total of 345 patients diagnosed with HCV-related liver cirrhosis complicated by HCC were included. Median age at diagnosis was 57 years (IQR = 52, 62), the majority were male (78%) and Child-Turcotte-Pugh (CTP) class A (64%). At diagnosis Barcelona Clinic Liver Cancer staging (BCLC) was 0 (8%), A (48%), B (20%), C (17%), and D (7%). Most common HCC management modalities were transarterial chemoembolization (TACE) (42%), and radiofrequency ablation (RFA) (21%). Median survival following HCC was 22.8 months. Factors associated with poorer survival in adjusted analyses were INR (HR = 1.81, p = 0.01), alpha-foeto protein (AFP) ≥200 (HR = 1.41, p = 0.02), higher CTP score (HR = 2.48, p < 0.01), and advanced BCLC stage (HR = 1.85, p < 0.01). One year survival in patients with CTP A, B, and C was 85%, 71% and 32%, respectively. One year survival following RFA, TACE, combination RFA/TACE, and sorafenib was 93%, 79%, 80% and 60%, respectively.

CONCLUSION

Survival following HCV-HCC in Egyptian patients undergoing HCC management in a specialised clinic setting is poor, although similar to high income country settings. CTP score is a key determinant of survival, even following adjustment for BCLC stage and HCC management.

Enhanced antitumor efficacy through microwave ablation in combination with immune checkpoints blockade in breast cancer: A pre-clinical study in a murine model

PURPOSE

The purpose of this study was to investigate the therapeutic efficacy of the combination of microwave ablation (MWA) in combination with immune checkpoints blockade in the treatment of breast cancer using the 4T1 tumor-bearing mice model.

MATERIALS AND METHODS

We treated tumor-bearing mice with MWA, programmed cell death protein1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) blockade (P+C), MWA plus PD-1 and CTLA-4 blockade (combination therapy), or no-treatment. Survival time was evaluated with the Kaplan-Meyer method comparing survival curves by log-rank test. On day 15 after MWA, five mice from the combination therapy group received tumor rechallenge with 4T1 or CT26 cells and the volumes of rechallenge tumor were calculated every 5 days. Immune cells were identified by immunohistochemistry and flow cytometry, and the concentrations of plasma interferon-γ (IFN-γ) were identified by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The combination therapy significantly prolonged tumor-bearing mice survival compared to no-treatment group, P+C group or MWA group (P<0.001, P<0.001 and P=0.01, respectively) and protected most surviving mice from 4T1 tumor rechallenge (P=0.002) but not CT26 tumor rechallenge (P=0.905). Both local and systemic CD8+ T-cell responses were induced by MWA (all P<0.05) and further augmented by subsequent administration of PD-1 and CTLA-4 blockade (all P<0.05). Plasma IFN-γ concentrations were significantly elevated in the combination therapy group compared to no-treatment group, P+C group or MWA group (P<0.001, P<0.001 and P=0.01, respectively).

CONCLUSION

MWA combined with immune checkpoints blockade could synergistically enhance antitumor efficacy with augmented specific immune responses, and the combination therapy is a promising approach to treat breast cancer.

MoS2 nanosheets encapsulated in sodium alginate microcapsules as microwave embolization agents for large orthotopic transplantation tumor therapy

In recent years, it is prevalent to treat various kinds of the tumors through microwave ablation method. However, it is still very difficult to ablate large tumors by the traditional microwave ablation therapy. In this work, an effective microwave embolization agent designed by encapsulating molybdenum sulfide nanosheets in the sodium alginate microcapsules, denoted as MSMCs, was prepared for the effective therapy of large tumor. The toxicity evaluation showed that MSMC had a good biocompatibility in vitro. The in vitro and in vivo experiments demonstrated that the MSMC was an excellent embolic and microwave susceptible agent that could be used for dual-enhanced microwave ablation therapy. As such, the MSMC showed excellent tumor therapeutic effect with 5 times larger ablation zone observed by magnetic resonance (MR) imaging than the microwave alone after 3 days treating. Besides, the tumor is nearly completely ablated and can not be recurrent due to the persistent hyperthermia. Moreover, MSMCs have a good biocompatibility and can be degraded and cleared from the body. It is believed that the MSMC is demonstrated to be a promising multifunctional theranostic agent used for treating the larger tumor via the synergistic therapy of enhanced microwave ablation and transcatheter arterial embolization (TAE).

Liposomes loading sodium chloride as effective thermo-seeds for microwave ablation of hepatocellular carcinoma

Microwave ablation (MWA) is a promising minimally invasive therapy that has been widely used to treat hepatocellular carcinoma (HCC). However, the efficiency of MWA in treating HCC is evidently limited by the incomplete ablation of large tumors and tumors in high-risk locations. Here, we report the value of using liposomes packed with sodium chloride (NaCl-LPs) as effective thermo-seeds for MWA of HCC. The prepared liposomes exhibited excellent heat conversion ability by showing a more rapid temperature increase than free NaCl medium, blank liposomes or water under microwave irradiation. The high efficiency of this new microwave sensitization strategy was fully demonstrated in vitro in subcutaneous and orthotopic tumors. The results showed that MWA combined with NaCl-LPs clearly enhanced the ablation efficiency, leading to apparent tumor inhibition and low recurrence. What's more, we verified the susceptibility of NaCl-LPs on orthotopic tumors. Based on the unique properties of NaCl-LPs, sublethal MWA was used to mimic the transitional zone, and large-scale necrosis was observed in tumors combined with NaCl-LPs. In addition, HE staining and blood hematology analysis revealed no noticeable toxicity of NaCl-LPs in vivo, which confirmed that NaCl-LPs possessed good biocompatibility.

CONCLUSION

The effective nanoparticles could play a valuable role in enhancing the thermo-sensitizing effect of MWA for achieving better therapeutic efficacy.

Microwave ablation for treatment of hepatic neoplasia in five dogs

CASE DESCRIPTION 5 dogs between 9 and 11 years of age were evaluated for treatment of primary (n = 2) or metastatic (3) hepatic neoplasia. CLINICAL FINDINGS Patients were evaluated on an elective (n = 3) or emergency (2) basis. Two dogs with primary hepatic neoplasia were evaluated because of lethargy and inappetence. One dog was referred after an enlarged anal sac was detected via palpation per rectum during a routine physical examination. Two dogs were evaluated on an emergency basis because of lethargy and weakness, and hemoabdomen in the absence of a history of trauma was detected. All 5 dogs underwent thoracic radiography and abdominal ultrasonography, with CT performed in both dogs with primary hepatic neoplasia. All dogs had preoperative evidence of abdominal neoplasia, and none had evidence of thoracic metastasis. TREATMENT AND OUTCOME All dogs underwent ventral midline laparotomy and had diffuse hepatic neoplasia that precluded complete resection. Locoregional treatment with MWA was applied to hepatic lesions (0.5 to 2.5 cm diameter) without procedural complications. Histopathologic diagnoses were biliary adenocarcinoma (n = 1), hemangiosarcoma (2), hepatocellular carcinoma (1), and apocrine gland adenocarcinoma (1). CLINICAL RELEVANCE MWA is being increasingly used as an adjunct in the surgical treatment of human patients with primary and metastatic liver disease. Results of the present small case series suggested that MWA is feasible and potentially effective as an adjunctive treatment for appropriately selected dogs with nonresectable hepatic tumors. Further investigation is indicated.

Monitoring Microwave Ablation of Ex Vivo Bovine Liver Using Ultrasonic Attenuation Imaging

Thermal ablation of soft tissue changes the tissue microstructure and, consequently, induces changes in its acoustic properties. Although B-mode ultrasound provides high-resolution and high-frame-rate images of ablative therapeutic procedures, it is not particularly effective at delineating boundaries of ablated regions because of poor contrast in echogenicity between ablated and surrounding normal tissue. Quantitative ultrasound techniques can provide quantitative estimates of acoustic properties, such as backscatter and attenuation coefficients, and differentiate ablated and unablated regions more effectively, with the potential for monitoring minimally invasive thermal therapies. In this study, a previously introduced attenuation estimation method was used to create quantitative attenuation coefficient maps for 11 microwave ablation procedures performed on refrigerated ex vivo bovine liver. The attenuation images correlate well with the pathologic images of the ablated region. The mean attenuation coefficient for regions of interest drawn inside and outside the ablated zones were 0.9 (±0.2) and 0.45 (±0.15) dB/cm/MHz, respectively. These estimates agree with reported values in the literature and establish the usefulness of non-invasive attenuation imaging for monitoring therapeutic procedures in the liver.

Early assessment of coagulation necrosis after hepatic microwave ablation: a comparison of non-enhanced and enhanced T1-weighted images

PURPOSE

To compare the technical success and accuracy of hepatic microwave ablation (MWA) using non-enhanced and enhanced T1-weighted imaging early after ablation. Patients were evaluated with regard to the ablation zone and local tumor progression (LTP).

METHODS

This retrospective study conducted between September 2014 and December 2015 which consisted of 56 patients with 56 hepatic malignant lesions who underwent percutaneous MWA. Non-enhanced and contrast-enhanced T1-weighted imagings were performed within 2 days after tumor ablation. The efficacy of ablation assessed according to the hyperintense middle zone on non-enhanced T1-weighted images and the non-enhanced area on contrast-enhanced T1-weighted images were compared. The development of LTP during ≥7 months of follow-up served as the end point.

RESULTS

On the non-enhanced T1-weighted images, the ablated region had a characteristic two-zone structure featuring a hyperintense middle zone and a surrounding hypointense band. Among the 56 patients, LTP developed in ten including seven lesions, in which both the non-enhanced T1-weighted and portal-phase images showed incomplete tumor ablation. In two of the remaining three patients, incomplete tumor ablation was detected on the non-enhanced T1-weighted images, whereas the corresponding portal-phase images showed complete ablation. In the remaining patient, no residual tumor was detected on either the non-enhanced T1-weighted or the portal-phase images. In the 46 patients without LTP, there was no evidence of residual tumor on the non-enhanced T1-weighted or portal-phase images obtained early after ablation.

CONCLUSIONS

Non-enhanced T1-weighted images are useful in assessing the therapeutic efficacy of MWA of liver tumors early after the procedure.