High-powered microwave ablation of larger hepatocellular carcinoma: evaluation of recurrence rate and factors related to recurrence

TGF-β1 inhibitor enhances the therapeutic effect of microwave ablation on hepatocellular carcinoma

BACKGROUND

Microwave ablation (MWA) is a widely adopted treatment technique for hepatocellular carcinoma (HCC). However, MWA alone is of limited use and has a high recurrence rate. Transforming growth factor-β1 (TGF-β1) is recognized as a potential therapeutic target for HCC patients. Therefore, this study was designed to investigate whether the TGF-β1 inhibitor could increase the efficacy of MWA therapy for HCC treatment.

METHODS

In vitro, HCC cells challenged with TGF-β1 inhibitor (SB-525334), or normal saline were then heated by microwave. Methyl tetrazolium assays were performed to detect cell survival rate and half-maximal drug inhibitory concentration (IC50). Cell viability and apoptosis were detected by cell counting kit-8 assays, flow cytometry and western blotting. In vivo, the mice injected with HepG2 cells received oral gavage of SB-525334 (20 mg/kg) or normal saline and MWA at a power of 15 W. Tumor volume was recorded. Expression of Ki67 and apoptosis-related proteins were detected by immunohistochemistry and western blotting. TUNEL assays were used to detect cell death ratio. Histopathological changes were examined by hematoxylin and eosin staining. The mechanisms associated with the function of MWA combined with TGF-β1 inhibitor in HCC development were explored by western blotting.

RESULTS

Combination of MWA and SB-525334 decreased the survival rate and promoted the apoptosis of HCC cells compared with MWA alone. SB-525334 enhanced the suppressive effect of MWA on tumor growth and amplified cell apoptosis. Mechanistically, MWA collaborated with SB-525334 inhibitor inactivated the TGF-β1/Smad2/Smad3 pathway.

CONCLUSION

TGF-β1 inhibitor enhances the therapeutic effect of MWA on HCC.

Achieving Complete Tumor Clearance: A Minimalist Manganese Hydrogel for Magnetic Resonance Imaging-Guided Synergetic Microwave Ablation and Chemodynamic Therapy

The combination of microwave ablation (MWA) and chemodynamic therapy (CDT) presents a promising strategy for complete eradication of residual tumor after MWA. However, it remains challenging and urgent to develop a facile, biocompatible, and imaging-guided platform for the achievement of this goal. Herein, a minimalist manganese hydrogel (ALG-Mn hydrogel) is proposed for synergistic MWA and CDT to completely eradicate tumor in vivo. The ALG-Mn hydrogel is prepared using a simple mixing method and exhibits excellent syringeability, remarkable microwave sensitivity, and potent Fenton-like activity. By assisting in MWA procedures, the ALG-Mn hydrogel enables both elimination of primary tumor mass through enhanced MWA efficacy and eradication of potential residual tumor tissues via robust CDT. This approach achieves complete tumor clearance without additional drug loading. Furthermore, the paramagnetic Mn2+ component allows real-time dynamic visualization of the ALG-Mn hydrogel at the tumor site via magnetic resonance imaging. To the best of knowledge, the proposed ALG-Mn hydrogel represents the minimalist biocompatible platform for imaging-guided synergistic MWA and CDT toward achieving complete tumor clearance.

Thermal/ultrasound-triggered release of liposomes loaded with Ganoderma applanatum polysaccharide from microbubbles for enhanced tumour ablation

The effectiveness of thermal ablation for the treatment of liver tumours is limited by the risk of incomplete ablation, which can result in residual tumours. Herein, an enhancement strategy is proposed based on the controlled release of Ganoderma applanatum polysaccharide (GAP) liposome-microbubble complexes (GLMCs) via ultrasound (US)-targeted microbubble destruction (UTMD) and sublethal hyperthermic (SH) field. GLMCs were prepared by conjugating GAP liposomes onto the surface of microbubbles via biotin-avidin linkage. In vitro, UTMD promotes the cellular uptake of liposomes and leads to apoptosis of M2-like macrophages. Secretion of arginase-1 (Arg-1) and transforming growth factor-beta (TGF-β) by M2-like macrophages decreased. In vivo, restriction of tumour volume was observed in rabbit VX2 liver tumours after treatment with GLMCs via UTMD in GLMCs + SH + US group. The expression levels of CD68 and CD163, as markers of tumour-associated macrophages (TAMs) in the GLMCs + SH + US group were reduced in liver tumour tissue. Decreased Arg-1, TGF-β, Ki67, and CD31 factors related to tumour cell proliferation and angiogenesis was evident on histological analysis. In conclusion, thermal/US-triggered drug release from GLMCs suppressed rabbit VX2 liver tumour growth in the SH field by inhibiting TAMs, which represents a potential approach to improve the effectiveness of thermal ablation.

Clinical Results, Risk Factors, and Future Directions of Ultrasound-Guided Percutaneous Microwave Ablation for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide, with a relatively poor prognosis, especially for advanced HCC. With the availability of a variety of treatment options, the treatment strategies for HCC have become more and more diversified. Microwave ablation (MWA) has gradually been considered as a viable alternative to surgical resection (SR) owing to its comparable long-term survival, reduced complications, and greater preservation of hepatic parenchyma. However, clinical outcomes, tumor progression, and recurrence of HCC after MWA remain major concerns. Here, after reviewing the current therapeutic options for HCC, we focus on MWA, describing the advantages and challenges of MWA and the clinical results after treatment. We then focused on prognostic factors that influence post-ablation clinical outcomes and briefly presented the strategy of MWA for future clinical treatment.

Rational Design of Biomaterials to Potentiate Cancer Thermal Therapy

Cancer thermal therapy, also known as hyperthermia therapy, has long been exploited to eradicate mass lesions that are now defined as cancer. With the development of corresponding technologies and equipment, local hyperthermia therapies such as radiofrequency ablation, microwave ablation, and high-intensity focused ultrasound, have has been validated to effectively ablate tumors in modern clinical practice. However, they still face many shortcomings, including nonspecific damages to adjacent normal tissues and incomplete ablation particularly for large tumors, restricting their wide clinical usage. Attributed to their versatile physiochemical properties, biomaterials have been specially designed to potentiate local hyperthermia treatments according to their unique working principles. Meanwhile, biomaterial-based delivery systems are able to bridge hyperthermia therapies with other types of treatment strategies such as chemotherapy, radiotherapy and immunotherapy. Therefore, in this review, we discuss recent progress in the development of functional biomaterials to reinforce local hyperthermia by functioning as thermal sensitizers to endow more efficient tumor-localized thermal ablation and/or as delivery vehicles to synergize with other therapeutic modalities for combined cancer treatments. Thereafter, we provide a critical perspective on the further development of biomaterial-assisted local hyperthermia toward clinical applications.

Long-term efficacy and safety of microwave ablation for hepatocellular carcinoma adjacent to the gallbladder with a diameter ≤ 5 cm: a multicenter, propensity score matching study

OBJECTIVE

To compare the long-term efficacy and safety of microwave ablation (MWA) as first-line therapy for hepatocellular carcinoma (HCC) adjacent versus nonadjacent to the gallbladder.

MATERIALS AND METHODS

From 2006 to 2018, 657 patients with ≤5 cm HCC who underwent percutaneous ultrasound-guided MWA as first-line therapy from 5 hospitals were enrolled in this retrospective study. Patients were grouped into the adjacent group (n = 49) and the nonadjacent group (n = 608) according to whether the tumor was adjacent to the gallbladder. Propensity score matching (PSM) was used to balance baseline variables between the two groups.

RESULTS

Forty-eight patient pairs were matched after PSM. For the PSM cohort, during a median follow-up time of 60 months, there were no differences in PFS (hazard ratio [HR], 1.011; 95% confidence interval [CI], 0.647-1.578; p = 0.963) or OS (HR 0.925; 95% CI 0.522-1.639; p = 0.789) between the adjacent and nonadjacent groups. Univariate and multivariate analyses revealed that the tumor adjacent to the gallbladder was not an independent risk factor for PFS or OS (all p > 0.05). Subgroup analysis showed comparable PFS and OS between the two groups in the <3 cm subgroup and the 3-5 cm subgroups (all p > 0.05). In addition to more use of assistive technology (p < 0.05), the adjacent group shared comparable local tumor progression, complications, technical success rate, and hospital stay (all p > 0.05) to the nonadjacent group.

CONCLUSION

There were comparable long-term efficacy and complications between patients with HCC adjacent and nonadjacent to the gallbladder treated with MWA.

ACR Appropriateness Criteria® Management of Liver Cancer: 2022 Update

The treatment and management of hepatic malignancies can be complex because it encompasses a variety of primary and metastatic malignancies and an assortment of local and systemic treatment options. When to use each of these treatments is critical to ensure the most appropriate care for patients. Interventional radiologists have a key role to play in the delivery of a variety of liver directed treatments including percutaneous ablation, transarterial embolization with bland embolic particles alone, transarterial chemoembolization (TACE) with injection of a chemotherapeutic emulsion, and transarterial radioembolization (TARE). Based on 9 clinical variants, the appropriateness of each treatment is described in this document. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Three-dimensional assessment of vascular cooling effects on hepatic microwave ablation in a standardized ex vivo model

The aim of this study was a three-dimensional analysis of vascular cooling effects on microwave ablation (MWA) in an ex vivo porcine model. A glass tube, placed in parallel to the microwave antenna at distances of 2.5, 5.0 and 10.0 mm (A-V distance), simulated a natural liver vessel. Seven flow rates (0, 1, 2, 5, 10, 100, 500 ml/min) were evaluated. Ablations were segmented into 2 mm slices for a 3D-reconstruction. A qualitative and quantitative analysis was performed. 126 experiments were carried out. Cooling effects occurred in all test series with flow rates ≥ 2 ml/min in the ablation periphery. These cooling effects had no impact on the total ablation volume (p > 0.05) but led to changes in ablation shape at A-V distances of 5.0 mm and 10.0 mm. Contrary, at a A-V distance of 2.5 mm only flow rates of ≥ 10 ml/min led to relevant cooling effects in the ablation centre. These cooling effects influenced the ablation shape, whereas the total ablation volume was reduced only at a maximal flow rate of 500 ml/min (p = 0.002). Relevant cooling effects exist in MWA. They mainly depend on the distance of the vessel to the ablation centre.

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

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

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

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

ARID1A expression in hepatocellular carcinoma and relation to tumor recurrence after microwave ablation

Aim of the study

AT-rich interactive domain 1A (ARID1A) is a subunit of the switch/sucrose non-fermentable chromatin remodeling complex, which is commonly mutated in human cancers. The clinical and pathological significance of ARID1A alteration in hepatocellular carcinoma (HCC) has not yet been clarified. The present study aimed to evaluate the clinical significance of the ARID1A gene signature in HCC and its relation to the likelihood of tumor recurrence after microwave ablation (MWA).

Material and methods

This study included 50 patients with cirrhotic HCC of Barcelona Clinic Liver Cancer stages 0/A eligible for MWA. Tumor and peri-tumor biopsies were obtained just prior to MWA and assessed for tumor pathological grade and ARID1A expression by immunohistochemistry. Patients were followed for one year after complete tumor ablation to detect any recurrence.

Results

Tumor size (^MCp = 0.010) and α-fetoprotein level (p = 0.013) can effectively predict the response to MWA. Nuclear expression of ARID1A was significantly lower in HCC compared to the corresponding peri-tumor cirrhotic liver tissues (p = 0.002), but no significant difference in ARID1A cytoplasmic expression was found. Nuclear ARID1A expression level in HCC showed a significantly negative relation to tumor size (^MCp = 0.006), pathological grade (^MCp = 0.046) and post-MWA tumor recurrence (^FEp = 0.041).

Conclusions

ARID1A loss may enhance HCC aggressiveness and post-MWA tumor recurrence. ARID1A could be a potential target to select HCC patients for future therapies.

Proposal and Validation of a Novel Scoring System for Hepatocellular Carcinomas Beyond Curability Borders

Optimal scoring system for clinical prognostic factors in patients with unresectable hepatocellular carcinoma (HCC) is currently uncertain. We aimed to develop and externally validate an easy to use tool, particularly for this population, and named it the "unresectable hepatocellular carcinoma prognostic index" (UHPI). We evaluated the data of patients with treatment-naive unresectable HCC who were diagnosed in the training center from 2010 to 2019 (n = 209). A simple prognostic model was developed by assigning points for each covariate in proportion to the beta coefficients in the Cox multivariable model. Predictive performance and distinction ability of the UHPI were further evaluated in an independent European validation cohort (n = 147) and compared with 11 other available models. A simple scoring system was derived, assigning 0.5/1/2 scores for six independent covariates including, the Child-Pugh score, Eastern Cooperative Oncology Group performance status, maximum tumor size, vascular invasion or extrahepatic metastasis, lymph node involvement, and alpha-fetoprotein. The UHPI score, ranging from 0 to 6, showed superior performance in prognosis prediction and outperformed 11 other staging or prognostic models, giving the highest homogeneity (c-index, 6-month and 1-year area under the receiver operator characteristic curves), lowest Akaike information criterion, and -2 log-likelihood ratio values. The UHPI score allocated well the risk of patients with unresectable HCC for mortality within the first year, using two cut-off values (low-risk, <0.5; intermediate-risk, 0.5-2; high-risk, >2). Conclusion: The UHPI score can predict prognosis better than other systems in subjects with unresectable HCC and can be used in clinical practice or trials to estimate the 6-month and 1-year survival probabilities for this group.

Percutaneous Thermal Ablation Therapy of Hepatocellular Carcinoma (HCC): Microwave Ablation (MWA) versus Laser-Induced Thermotherapy (LITT)

The purpose of this study is to compare the efficacy and safety of microwave ablation (MWA) versus laser-induced thermotherapy (LITT) as a local treatment for hepatocellular carcinoma (HCC,) with regard to therapy response, survival rates, and complication rates as measurable outcomes. This retrospective study included 250 patients (52 females and 198 males; mean age: 66 ± 10 years) with 435 tumors that were treated by MWA and 53 patients (12 females and 41 males; mean age: 67.5 ± 8 years) with 75 tumors that were treated by LITT. Tumor response was evaluated using CEMRI (contrast-enhanced magnetic resonance imaging). Overall, 445 MWA sessions and 76 LITT sessions were performed. The rate of local tumor progression (LTP) and the rate of intrahepatic distant recurrence (IDR) were 6% (15/250) and 46% (115/250) in the MWA-group and 3.8% (2/53) and 64.2% (34/53) in the LITT-group, respectively. The 1-, 3-, and 5-year overall survival (OS) rates calculated from the date of diagnosis were 94.3%, 65.4%, and 49.1% in the MWA-group and 96.2%, 54.7%, and 30.2% in the LITT-group, respectively (p-value: 0.002). The 1-, 2-, and 3-year disease-free survival (DFS) rates were 45.9%, 30.6%, and 24.8% in the MWA-group and 54.7%, 30.2%, and 17% in the LITT-group, respectively (p-value: 0.719). Initial complete ablation rate was 97.7% (425/435) in the MWA-group and 98.7% (74/75) in the LITT-group (p-value > 0.99). The overall complication rate was 2.9% (13/445) in the MWA-group and 7.9% (6/76) in the LITT-group (p-value: 0.045). Based on the results, MWA and LITT thermal ablation techniques are well-tolerated, effective, and safe for the local treatment of HCC. However, MWA is recommended over LITT for the treatment of HCC, since the patients in the MWA-group had higher survival rates.

Ablation Difficulty Score: Proposal of a new tool to predict success rate of percutaneous ablation for hepatocarcinoma

PURPOSE

Identify the factors related to failure ablation after percutaneous ultrasound guided single electrode radiofrequency ablation (RFA) for hepatocarcinoma (HCC) and propose a score for improving patient selection and treatment allocation.

METHODS

From 2010 to 2020 585 HCC nodules treated with RFA were prospectively collected. Ablation Difficulty Score (ADS) was built-up according to clinical and radiological factors related to failure ablation identified by Cox-logistic regression analysis. The study population was stratified in low risk (ADS 0), intermediate risk (ADS 1), and high risk (ADS ≥ 2) of failure ablation.

RESULTS

Overall ablation success rate was 85.5%. Morbidity and mortality rates were 3.5% and 0.0%. According to per nodule analysis the following factors resulted related to failure ablation: size > 20 mm (p = 0.002), sub-capsular location (p = 0.008), perivascular location (p = 0.024), isoechoic appearance (p = 0.008), and non-cirrhotic liver (p = 0.009). The ablation success rate was 93.5% in ADS 0, 85.8% in ADS 1 and 71.3% in ADS ≥ 2 (p < 0.001). The 1-year local tumor progression (LTP) free survival was 90.2% in ADS 0, 80.6% in ADS 1, and 72.3% in ADS ≥ 2 (p = 0.009). Nodule's size > 20 mm (p = 0.014), isoechoic appearance (p = 0.012), perivascular location (p = 0.012) resulted related to lower LTP free survival.

CONCLUSION

Ablation Difficulty Score could be a simple and useful tool for guiding the treatment decision making of HCC. RFA in high risk nodules (ADS ≥ 2) should be carefully evaluated and reserved for patients not suitable for surgery or liver transplantation.

A combined miR-34a and arsenic trioxide nanodrug delivery system for synergistic inhibition of HCC progression after microwave ablation

Background

Microwave ablation (MWA) has become an alternative treatment for unresectable hepatocellular carcinoma (HCC), but it does not eliminate the risk of recurrence and metastasis after treatment. Recent studies have demonstrated that miR-34a presents decreased gene expression in residual tumours after ablation therapy and can increase the therapeutic effect of arsenic trioxide against HCC, which brings new opportunities for HCC treatment.

Methods

A pH-sensitive charge inversion material was used to construct a nanotargeted delivery system based on the synergistic effects of miR-34a and As2O3. We established in vitro and in vivo models of HCC microwave ablation and performed in-depth research on the dual-drug system to inhibit the rapid progression and induce pyroptosis in HCC cells after microwave ablation.

Results

The antitumour effects were enhanced with the dual-drug nanoparticles relative to the single-drug formulations, and the therapeutic efficacy of the nanoparticles was more significant in a weakly acidic environment. The dual-drug nanoparticles increased the N-terminal portion of GSDME and decreased the expression of Cyt-c and c-met.

Conclusions

Dual-drug nanoparticles may improve the therapeutic efficacy of HCC treatment after insufficient ablation through Cyt-c and GSDME-N and decrease the expression levels of c-met. These nanoparticles are expected to provide new treatment methods for residual HCC after MWA, prolong the survival of patients and improve their quality of life.

Biomedical nanobubbles and opportunities for microfluidics

The use of bulk nanobubbles in biomedicine is increasing in recent years, which is attributable to the array of therapeutic and diagnostic tools promised by developing bulk nanobubble technologies. From cancer drug delivery and ultrasound contrast enhancement to malaria detection and the diagnosis of acute donor tissue rejection, the potential applications of bulk nanobubbles are broad and diverse. Developing these technologies to the point of clinical use may significantly impact the quality of patient care. This review compiles and summarizes a representative collection of the current applications, fabrication techniques, and characterization methods of bulk nanobubbles in biomedicine. Current state-of-the-art generation methods are not designed to create nanobubbles of high concentration and low polydispersity, both characteristics of which are important for several bulk nanobubble applications. To date, microfluidics has not been widely considered as a tool for generating nanobubbles, even though the small-scale precision and real-time control offered by microfluidics may overcome the challenges mentioned above. We suggest possible uses of microfluidics for improving the quality of bulk nanobubble populations and propose ways of leveraging existing microfluidic technologies, such as organ-on-a-chip platforms, to expand the experimental toolbox of researchers working to develop biomedical nanobubbles.

The use of bulk nanobubbles in biomedicine is increasing in recent years. This translates into new opportunities for microfluidics, which may enable the generation of higher quality nanobubbles that lead to advances in diagnostics and therapeutics.

Differential Imaging of Liver Tumors before and after Microwave Ablation with Electrode Displacement Elastography

Liver cancer is a leading cause of cancer-related deaths; however, primary treatment options such as surgical resection and liver transplant may not be viable for many patients. Minimally invasive image-guided microwave ablation (MWA) provides a locally effective treatment option for these patients with an impact comparable to that of surgery for both cancer-specific and overall survival. MWA efficacy is correlated with accurate image guidance; however, conventional modalities such as B-mode ultrasound and computed tomography have limitations. Alternatively, ultrasound elastography has been used to demarcate post-ablation zones, yet has limitations for pre-ablation visualization because of variability in strain contrast between cancer types. This study attempted to characterize both pre-ablation tumors and post-ablation zones using electrode displacement elastography (EDE) for 13 patients with hepatocellular carcinoma or liver metastasis. Typically, MWA ablation margins of 0.5-1.0 cm are desired, which are strongly correlated with treatment efficacy. Our results revealed an average estimated ablation margin inner quartile range of 0.54-1.21 cm with a median value of 0.84 cm. These treatment margins lie within or above the targeted ablative margin, indicating the potential to use EDE for differentiating index tumors and ablated zones during clinical ablations. We also obtained a high correlation between corresponding segmented cross-sectional areas from contrast-enhanced computed tomography, the current clinical gold standard, when compared with EDE strain images, with r2 values of 0.97 and 0.98 for pre- and post-ablation regions.

Evaluation of the efficacy and postoperative outcomes of hydrodissection-assisted microwave ablation for subcapsular hepatocellular carcinoma and colorectal liver metastases

PURPOSE

To explore the effect of hydrodissection assisted percutaneous microwave ablation (MWA) on the primary technique efficacy (PTE) and local tumor progression (LTP) of subcapsular hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM).

METHODS

A retrospective review of 135 patients with 181 hepatic subcapsular HCC and CRLM that underwent MWA with (hydrodissection group) and without the use of hydrodissection (control group). The PTE, cumulative LTP rate, and postoperative complications were compared between the two groups.

RESULTS

Amongst the 135 patients with 181 tumors, 60 patients with 72 tumors were in the hydrodissection group and 75 patients with 109 tumors were in the control group. The PTEs were 97.2% and 85.3% in hydrodissection and control groups, respectively (P = 0.019). Multivariate analysis showed that hydrodissection significantly improved the PTE of MWA [odds ratio (OR) 0.147; 95% confidence interval (CI) 0.031-0.703; P = 0.016). Among the tumors which achieved complete response at the first (1 month) follow-up, the overall LTP rates were 8.6% (6/70) and 11.8% (11/93) in the hydrodissection and control groups, respectively. The 1- and 2-year cumulative LTP rates were 3.0% and 5.0% for the hydrodissection group and 6.8% and 13.5% in the control group, respectively (P = 0.391). No significant differences were observed in major postoperative complications between the two groups.

CONCLUSION

Hydrodissection-assisted MWA had a significantly higher PTE than MWA alone in hepatic subcapsular HCC and CRLM. Hydrodissection did not significantly impact the cumulative LTP rate or the incidence of postoperative complications.

Ultrasound-guided percutaneous microwave ablation for hepatocellular carcinoma originating in the caudate lobe: A pilot clinical study

Objective

This study aimed to evaluate the efficacy, feasibility, and tolerability of ultrasound (US)-guided percutaneous microwave ablation (MWA) for treating hepatocellular carcinoma (HCC) originating in the caudate lobe.

Materials and Methods

The treatment and survival parameters of 32 patients with HCC in the caudate lobe, who met the inclusion criteria and had received US-guided percutaneous MWA in our department from November 2010 to October 2015, were retrospectively analyzed. Imaging examination (contrast-enhanced computed tomography or magnetic resonance) 1 month after MWA was used to evaluate the efficacy of US-guided MWA.

Results

Thirty-two patients underwent percutaneous MWA for caudate lobe HCC. The average tumor size was 3.42 ± 0.27 (range: 1-6.8) cm. The initial complete ablation (CA) rate was 87.5% (28/32), and the total CA rate was 96.88% (31/32). Furthermore, the median length of hospitalization was 4 days (range: 2-10 days), and no major complication was observed in this study. The overall survival rates were 87.5%, 50%, and 28.13% at 1, 2, and 3 years, respectively. The progression-free survival after MWA was 93.75%, 53.15%, and 28.13% at 6, 12, and 18 months, respectively.

Conclusions

US-guided percutaneous MWA was a safe and effective treatment. It is a promising alternative therapy for HCC originating in the caudate lobe.

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.

Percutaneous US-guided MWA of small liver HCC: predictors of outcome and risk factors for complications from a single center experience

The aim of the present study was to identify predictors of outcome and complications in patients with small hepatocellular carcinoma (HCC) treated by percutaneous microwave ablation (MWA). Patients with non-previously treated small (≤ 3 cm) HCCs who underwent ultrasound (US)-guided percutaneous MWA between July 2016 and January 2019 were included. For each patient, the following variables were registered: age, sex, albumin, platelet count, INR/PT, PTT ratio, total bilirubin, liver status, etiology of liver disease, Child-Pugh classification, tumor dimension, margin, and hepatic segment, tumor subcapsular, perihilar or perivascular location, HCC focality, ascites. During follow-up, complications and outcomes were registered. Variables were then analyzed in relation to both outcomes and complications. 74 patients were included. Mean CT follow-up was 6.2 months (range 1-24 months). At least one complication occurred in 48% of patients, the majority being asymptomatic imaging findings not requiring intervention. One major complication was registered (duodenal perforation: 1.3%). The occurrence of complications was associated with HCC multifocality and abnormal INR/PT, duodenal wall edema with tumor dimension, portal vein thrombosis with Child Pugh score, perihepatic free fluid with abnormal platelet count and comorbidities. Incomplete response rate at 1 month was 18.9%. Local tumor progression and new HCC nodules rates were 13.5% and 27%, respectively. Incomplete response at 1 month was associated with both alcoholic etiology of liver disease and II segment tumor location, new HCC nodules with PBC. Despite the small series analyzed, significant factors related with complications and outcomes may be kept in mind when planning the best treatment for each patient.

Early Outcomes with Single-antenna High-powered Percutaneous Microwave Ablation for Primary and Secondary Hepatic Malignancies: Safety, Effectiveness, and Predictors of Ablative Failure

Objective:

Microwave ablation (MWA) of liver malignancies has gained much traction over the past 5 years. However, MWA carries relatively higher rates of residual disease compared to resection. Likelihood of MWA success is multifactorial and newer devices with more reliable ablation zones are being developed to overcome these drawbacks. This manuscript is a review of our first 100 liver ablations with the newer single antenna high powered MWA system.

Materials and Methods:

Retrospective chart review of patients that underwent MWA for either primary or secondary hepatic malignancies between March 2015 and July 2016 was conducted. The complete ablation rates, rate of new lesions, complications, and short-term survival were analyzed. Multiple statistical tests, including multivariate regression, were used to assess risk factors for local residual and recurrent disease.

Results:

Fifty-three patients (median age 61 ± 9 years, 39 males) underwent 100 MWAs. Of the 100 lesions ablated, 76 were hepatocellular cancers (HCCs) and 24 were metastases. Median lesion size was 16 ± 9 mm. Seventy- five of these patients had multifocal disease targeted in the same session. Seventy patients had cirrhosis (median model for end-stage liver disease score 9 ± 3; Child-Pugh B and C in 42%). An 83% complete lesion ablation rate was seen on follow-up imaging with liver protocol magnetic resonance imaging/computed tomography (median follow-up of 1 year). The minor complication rate was 9.4% with no major complications or 30-day mortality. Despite this, evidence of new foci of hepatic disease was found in 47% of patients, the majority (80%) of which were in HCC patients (P < 0.01) and most of these new lesions were in a different hepatic segment (64%). Degree of cirrhosis (P < 0.01), presence of non-alcoholic steatohepatitis (NASH) (P = 0.01) and lesion’s subcapsular location (P = 0.03) was significant predictors of residual disease. With the subset analysis of only HCC lesions larger than 1 cm, only the presence of NASH remained significant.

Conclusion:

The single probe high power MWA of malignant hepatic lesions is safe and effective with minimal morbidity. Degree of cirrhosis, NASH, and subcapsular location was associated with an increased rate of residual disease on short-term follow-up.

3D visualization ablation planning system assisted microwave ablation for hepatocellular carcinoma (Diameter >3): a precise clinical application

Background

The aim of this retrospective study was to compare the feasibility and efficiency of ultrasound-guided percutaneous microwave ablation (US-PMWA) assisted by three-dimensional visualization ablation planning system (3DVAPS) and conventional 2D planning for hepatocellular carcinoma (HCC) (diameter > 3 cm).

Methods

One hundred thirty patients with 223 HCC nodules (5.0 ± 1.5 cm in diameter, [3.0–10.0 cm]) who met the eligibility criteria divided into 3D and 2D planning group were reviewed from April 2015 to August 2018. Ablation parameters and oncological outcomes were compared, including overall survival (OS), recurrence-free survival (RFS), and local tumor progression (LTP). Multivariate analysis was performed on clinicopathological variables to identify the risk factors for OS and LTP.

Results

The median follow-up period was 21 months (range 3–44). Insertion number (5.4 ± 1.2 VS. 4.5 ± 0.9, P = 0.034), ablation time (1249.2 ± 654.2 s VS. 1082.4 ± 584.7 s, P = 0.048), ablation energy (57,000 ± 11,892 J VS. 42,600 ± 10,271 J, P = 0.038) and success rate of first ablation (95.0% VS. 85.7%, P = 0.033) were higher in the 3D planning group compared with those in 2D planning group. There was no statistical difference in OS, and RFS between the two groups (P = 0.995, P = 0.845). LTP rate of 3D planning group was less than that of 2D planning group (16.5% VS 41.2%, P = 0.003). Multivariate analysis showed tumor maximal diameters (P < 0.001), tumor number (P = 0.003) and preoperative TACE (P < 0.001) were predictors for OS and sessions (P = 0.024), a-fetoprotein level (P = 0.004), and preoperative planning (P = 0.002) were predictors for LTP, respectively.

Conclusions

3DVAPS improves precision of US guided ablation resulting in lower LTP and higher 5 mm-AM for patients with HCC lesions larger than 3 cm in diameter.

Laparoscopic Microwave Ablation of Hepatocellular Carcinoma at Liver Surface: Technique Effectiveness and Long-Term Outcomes

Background and Aims:

To evaluate long-term outcomes and prognostic factors of laparoscopic microwave ablation as a first-line treatment for hepatocellular carcinoma located at the liver surface not feasible for percutaneous ablation.

Methods:

51 consecutive patients receiving laparoscopic microwave ablation in our center between January 11, 2012, and July 31, 2014, were enrolled. Technique effectiveness (complete ablation or incomplete ablation) was evaluated 1 month postprocedure. Procedure-related complications were recorded. The influences of patients’ baseline characteristics on recurrence-free survival and overall survival were analyzed after a median follow-up of 34.0 (ranging 19.0-49.0) months.

Results:

Complete ablation was gained in 47 (92.2%) of the 51 patients. No patients died within 30 days of microwave ablation procedure. A total of 3 (5.9%) cases of complications were observed. Tumor progression/recurrence were observed in 40 patients (78.4%). The median recurrence-free survival and median overall survival of the total cohort was 11.0 months (95% confidence interval: 7.573-14.427) and 34.0 months (95% confidence interval: 27.244-40.756), respectively. Multivariate analysis identified alanine transaminase level and tumor number as independent significant prognosticators of recurrence-free survival whereas α-fetoprotein level as significant prognosticators of overall survival.

Conclusions:

As a first-line treatment, laparoscopic microwave ablation provides high technique effectiveness rate and is well tolerated in patients with hepatocellular carcinoma located at liver surface. Alanine transaminase and tumor number were significant predictors of recurrence-free survival, whereas α-fetoprotein level was significant predictor of overall survival. Laparoscopic microwave ablation might serve as a rational treatment option for patients with hepatocellular carcinoma with tumors at the liver surface, which merits validation in future perspective studies.

Percutaneous Microwave Ablation Under CT Guidance for Hepatocellular Carcinoma: a Single Institutional Experience

BACKGROUND

Microwave ablation (MWA) is an emerging treatment for treatment of patients with hepatocellular carcinoma (HCC) not amenable of surgical resection.

PATIENTS AND METHODS

We searched for patients diagnosed as having small-, medium-, and large HCCs treated with MWA under CT guidance between 2010 and 2014. The main outcomes of interest were rates of complete ablation, complications, and overall survival. Rates of complete ablation were compared with Chi-square test, and estimated survival rates were calculated by means of Kaplan-Meier method.

RESULTS

Thirty-two patients with 45 HCC nodules received MWA. Seventeen (37.8%) nodules were <3 cm (small), 15 (33.3%) between 3 and 5 cm (medium), and 13 (28.9%) > 5 cm (large). Complete ablation was obtained in 94.1% of small tumors, 80% of medium tumors, and 53.8% of large tumors (p = 0.03). Two patients had HCC located in risk area (paracardiac position). Minor complications occurred after seven procedures (15.5%). Estimated median survival was 37 months (95% confidence interval 11.97-62.02). One-year OS was 82.7%, 2-year survival 68.9%, and 3-year survival 55.2%.

CONCLUSION

MWA is a versatile ablative method that can be applied in HCC at various stages, and also in lesions located in risk areas.

Microwave Ablation in Intermediate Hepatocellular Carcinoma in Cirrhosis: An Italian Multicenter Prospective Study

Background and Aims: To report long-term results in treatment of intermediate hepatocellular carcinoma (HCC) in cirrhotics using new high-powered microwaves (MWS) ablation alone. Methods: This multicenter study included 215 cirrhotics (age range: 67-84 years; 137 males; 149 Child A, 66 Child B) who underwent percutaneous ultrasound-guided high-powered MWS ablation instead of transarterial chemoembolization. Among the patient population, 109 had a single nodule (Ø 5.3-8 cm) [group A], 70 had 2 nodules (Ø 3-6 cm) [group B] and 36 had 3-5 nodules (Ø 1.5-6.8 cm) [group C]. MWS ablation efficacy was evaluated using enhanced-computed tomography and/or magnetic resonance imaging. Primary end-point was 5-year cumulative overall survival (OS). Results: On enhanced-computed tomography and/or magnetic resonance imaging, complete ablation rates were 100% for 1.5-3.5 cm nodules. In nodules >3.5-5 cm, it was 89% for the first ablation and 100% for the second. For lesions >5-8 cm, ablation was up to 92%. Overall, 1-, 3- and 5-year survival rates were 89, 60, and 21%, respectively. The cumulative OS rate of group A was 89%, 66% and 34% at 1, 3 and 5 years. The cumulative OS rate of group B was 88%, 60% and 11% at 1, 3 and 5 years. The cumulative OS rate of group C was 86%, 55% and 0%. The 5-year survival rate was significantly different among the groups (p <0.001). One patient died from rupture of HCC. Upon multivariate analysis, preablation total bilirubin >1.5 mg/dL was an independent factor for predicting lower survival. Conclusions: Percutaneous MWS ablation of intermediate HCC is safe and effective in inducing large volume of necrosis in intermediate HCC nodules, providing long-term survival rates similar to transarterial chemoembolization. Preablation total bilirubin >1.5 mg/dL as expression of liver function reserve is the main factor predicting a worse outcome.

Role of interventional radiology in managing pediatric liver tumors : Part 2: percutaneous interventions

Hepatoblastoma and hepatocellular carcinoma (HCC) are the most common pediatric liver malignancies, with hepatoblastoma occurring more commonly in younger children and HCC occurring more commonly in older children and adolescents. Although surgical resection (including transplant when necessary) and systemic chemotherapy have improved overall survival rate for hepatoblastoma to approximately 80% from 30%, a number of children with this tumor type are not eligible for operative treatment. In contradistinction, pediatric HCC continues to carry a dismal prognosis with an overall 5-year survival rate of 30%. The Paediatric Hepatic International Tumour Trial (PHITT) is an international trial aimed at evaluating both existing and emerging oncologic therapies for primary pediatric liver tumors. Interventional radiology offers a number of minimally invasive procedures that aid in diagnosis and therapy of pediatric liver tumors. For diagnosis, the PHITT biopsy guidelines emphasize and recommend percutaneous image-guided tumor biopsy. Additionally, both percutaneous and endovascular procedures provide therapeutic alternatives that have been, to this point, only minimally utilized in the pediatric population. Specifically, percutaneous ablation offers a number of cytotoxic technologies that can potentially eradicate disease or downstage children with unresectable disease. Percutaneous portal vein embolization is an additional minimally invasive procedure that might be useful to induce remnant liver hypertrophy prior to extended liver resection in the setting of a primary liver tumor. PHITT offers an opportunity to collect data from children treated with these emerging therapeutic options across the world. The purpose of this manuscript is to describe the potential role of minimally invasive percutaneous transhepatic procedures, as well as review the existing data largely stemming from the adult HCC experience.

Percutaneous treatment of hepatocellular carcinoma: State of the art and innovations

Percutaneous treatment of hepatocellular carcinoma (HCC) encompasses a vast range of techniques, including monopolar radiofrequency ablation (RFA), multibipolar RFA, microwave ablation, cryoablation and irreversible electroporation. RFA is considered one of the main curative treatments for HCC of less than 5 cm developing on cirrhotic liver, together with surgical resection and liver transplantation. However, controversies exist concerning the respective roles of ablation and liver resection for HCC of less than 3 to 5 cm on cirrhotic liver. In line with the therapeutic algorithm of early HCC, percutaneous ablation could also be used as a bridge to liver transplantation or in a sequence of upfront percutaneous treatment, followed by transplantation if the patient relapses. Moreover, several innovations in ablation methods may help to efficiently treat early HCC, initially considered as "non-ablatable", and might, in some cases, extend ablation criteria beyond early HCC, enabling treatment of more patients with a curative approach.

Percutaneous microwave thermosphere ablation of pancreatic tumours

Background

In oncologic field, thermo-ablative procedures have spread more and more. Percutaneous microwave ablation (MWA) showed same benefits and some advantages over radiofrequency ablation (RFA). To date, a disadvantage of both was the not totally predictable size and shape of ablation volume. The aim of this study was to assess feasibility and safety of MWA in nonresectable pancreatic head cancer using a new technology of MW with high power (100 W) and frequency of 2,450 MH.

Methods

Five patients with pancreatic head cancer treated with percutaneous MWA under ultrasound guidance were retrospectively reviewed. Mean lesion diameter was 27.8 mm (range, 25-32 mm). Follow-up was performed by CT after 1, 3, 6 and, when possible, 12 months. The shape of the ablation volume was evaluated with multiplanar reformatting (MPR) using roundness index (RI): a value near 1 represents a more spherical ablation zone shape, and a value distant from 1 implies an oval configuration. Ablation and procedure times were registered, together with hospital stay. The feasibility, safety and quality of life (QoL) were reported.

Results

The procedure was feasible in all patients (100%). A spherical shape of ablation zone was achieved in all cases (mean RI =0.97). Mean ablation and procedure time were respectively of 2.48 and 28 minutes. Mean hospital stay was 4 days. No major complications were observed. Minor complications resolved during the hospital stay. An improvement in QoL was observed in all patients despite a tendency to return to preoperative levels in the months following the procedure.

Conclusions

Percutaneous MWA is a feasible and safe approach for the palliative treatment of advanced stage tumors of the head of the pancreas, despite its complex anatomic relations. The spherical shape of the ablation volume could be related with an improving of the effectiveness and safety.

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.

Loco-regional treatment of HCC: current status

Hepatocellular carcinoma (HCC) represents one of the few cancers for which locoregional treatments are recognised as being able to cure and/or prolong survival and are included in international guidelines. This is due to the unique nature of HCC, in most cases occurring in patients with underlying virus- or alcohol-related cirrhosis. The treatment choice in patients with HCC is therefore driven not only by tumour staging, as in the great majority of cancers, but also by careful evaluation of liver function and physical status. Another specific feature of HCC is that it is the only tumour that can be cured by organ transplantation, with the aim of treating both the cancer and underlying liver disease. These characteristics configure a complex scenario and prompt the need for close cooperation among interventional oncologists, surgeons, hepatologists, and anaesthesiologists. In patients with limited hepatic disease, preserved hepatic function and good performance status, categorised as very early and early-stage HCC according to the Barcelona Clinic Liver Cancer (BCLC) classification, image-guided tumour ablation is included among the curative treatments. More than half of patients with HCC are, however, diagnosed late, despite the widespread implementation of surveillance programmes, when curative treatments cannot be applied. For patients presenting with multinodular HCC and relatively preserved liver function, absence of cancer-related symptoms, and no evidence of vascular invasion or extrahepatic spread transcatheter arterial chemoembolisation (TACE) is the current standard of care. Although anti-tumour activity and promising survival results has been reported in cohorts of patients with advanced HCC treated with radio-embolisation, systemic treatment with the multi-kinase inhibitor, sorafenib, is still recommended for patients at this stage. In this article, current treatment strategies for HCC according to tumour stage are discussed, underlining the latest advances in the literature and technical developments.

Efficacy and safety of ultrasound-guided percutaneous microwave ablation for the treatment of hepatic alveolar echinococcosis: A preliminary study

The present study aims to assess the efficacy and safety of ultrasound-guided percutaneous microwave ablation (MWA) for hepatic alveolar echinococcosis (HAE) preliminarily.Seventeen patients diagnosed to HAE and treated with MWA (80 watts, 4 min) were retrospectively analyzed. The upper abdominal computed tomography (CT) was performed at 1, 6, 12 months after the MWA treatment. The complications were evaluated to assess the safety.The diameters of the lesions in the HAE patients ranged from 1.9 to 4.7 cm. The patients included 10 males and 7 females, aged 26 to 70 (45.82 ± 13.36) years, 5 patients infecting with chronic hepatitis viral B and 8 patients with positive hydatid antibody (IgG). The lesions observed in the postoperative CT (1, 6, 12 months) were calcified compared with those observed in the preoperative CT and without relapse. No serious treatment-related complications occurred after treatment.MWA is a novel and effective therapeutic method for HAE with a single lesion (diameter≤=5 cm). Further studies based on prospective random control trials to confirm our findings are necessary.

Clinical analysis on 113 patients with lung cancer treated by percutaneous CT-guided microwave ablation

BACKGROUND

Lung Cancer is a primary tumor with poor prognosis. For early stage lung cancer, treatment options include surgical resection and microwave techniques. Percutaneous ablative techniques emerged as best therapeutic options for nonsurgical patients.

METHODS

The aim of this study was to retrospectively analyze the clinical effect of CT-guided microwave ablation (MWA) treatment for patients with lung cancer who were not eligible for surgical resection. MWA was used to treat the tumor lesion of 113 patients with lung cancer who were in our hospital from Jan, 2013 to Jun, 2015. The median diameter of tumors was 3.1 cm (0.7-6 cm). Follow-up were paid to all the patients who received MWA therapy. The average follow-up was 22.1±8.6 months, and the median follow-up was 18 (7-40) months.

RESULTS

All of 113 cases of patients with lung cancer experienced MWA therapy, and their tumors were found to have vacuolization, lower density and much smaller distinct shrinkage of tumor size with varying degrees. The local progression rate or relapse rate of the whole group was 15.9%. The counterpart of patients in the early-stage group was 5.7% (2/35), and the diameter of tumors in the two patients was more than 3 cm. The local progression rate or relapse rate of patients in advanced-stage group was 20.5%, wherein, 81.3% of local progression or relapse occurred to the patients with a tumorous diameter of more than 3 cm. The results indicated that the patients in advanced-stage group were vulnerable to local progression or relapse, the tumorous with greater diameter had higher incidence of local relapse. No mortality occurred within 30 days after surgery, the survival rate of patients in early-stage group at first, second, third year was respectively 97.1%, 94.1% and 84.7%. The counterpart of patients in advanced-stage group was respectively 93.6%, 87.7% and 71.7%. The difference of survival rate between both groups was not statistically significant (P=0.576). No perioperative deaths occurred, and the main complications i.e., fever, pneumothorax, pleural effusion, hemoptysis, pneumonia, and pain were slight and tolerable.

CONCLUSIONS

MWA is an effective, safe and minimally invasive treatment for the patients with lung cancer who cannot be tolerated by surgical resection.

High-Frequency Irreversible Electroporation: Safety and Efficacy of Next-Generation Irreversible Electroporation Adjacent to Critical Hepatic Structures

Irreversible electroporation (IRE) is a nonthermal ablation modality employed to induce in situ tissue-cell death. This study sought to evaluate the efficacy of a novel high-frequency IRE (H-FIRE) system to perform hepatic ablations across, or adjacent to, critical vascular and biliary structures. Using ultrasound guidance H-FIRE electrodes were placed across, or adjacent to, portal pedicels, hepatic veins, or the gall bladder in a porcine model. H-FIRE pulses were delivered (2250 V, 2-5-2 pulse configuration) in the absence of cardiac synchronization or intraoperative paralytics. Six hours after H-FIRE the liver was resected and analyzed. Nine ablations were performed in 3 separate experimental groups (major vessels straddled by electrodes, electrodes placed adjacent to major vessels, electrodes placed adjacent to gall bladder). Average ablation time was 290 ± 63 seconds. No electrocardiogram abnormalities or changes in vital signs were observed during H-FIRE. At necropsy, no vascular damage, coagulated-thermally desiccated blood vessels, or perforated biliary structures were noted. Histologically, H-FIRE demonstrated effective tissue ablation and uniform induction of apoptotic cell death in the parenchyma independent of vascular or biliary structure location. Detailed microscopic analysis revealed minor endothelial damage within areas subjected to H-FIRE, particularly in regions proximal to electrode insertion. These data indicate H-FIRE is a novel means to perform rapid, reproducible IRE in liver tissue while preserving gross vascular/biliary architecture. These characteristics raise the potential for long-term survival studies to test the viability of this technology toward clinical use to target tumors not amenable to thermal ablation or resection.

Status and advancement of microwave ablation in China

Tumour ablation is defined as the direct application of chemical or thermal therapy to eradicate or substantially destroy a tumour. Currently, minimally invasive ablation techniques are available for the local destruction of focal tumours in multiple organ sites. Microwave ablation (MWA) is premised on the biological response of solid tumours to tissue hyperthermia, and it is a relatively low-risk procedure. Due to several advantages of MWA, including higher thermal efficiency, higher capability for coagulating blood vessels, faster ablation time and the simultaneous application of multiple antennae, MWA could be a promising minimally invasive ablation technique for the treatment of solid tumours. Therefore, the use of MWA has developed rapidly in China during the last decade. Many successful studies have been performed, and widespread use has been achieved for multiple types of tumours in China, especially for liver cancer. This review will describe the state-of-the-art of MWA in China, including the development of MWA equipment and its application in the treatment of multiple types of tumours.

Treatment efficacy of CT-guided percutaneous microwave ablation for primary hepatocellular carcinoma

AIM

To evaluate the treatment efficacy and potential complications of computed tomography (CT)-guided microwave ablation for primary hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Data were collected and analysed from 220 HCC patients treated with CT-guided microwave ablation and followed up for 2 years. Independent risk factors for overall survival and progression-free survival (PFS) were analysed.

RESULTS

Among all cases followed, the cumulative overall survival rates at 1 and 2 years were 95.45% and 89.09%. The cumulative 1- and 2-year PFS rates were 80.90% and 62.73%. For patients with Barcelona Clinic Liver Cancer (BCLC) class C (n=60), the cumulative 1- and 2-year overall survival rates were 89.09% and 74.54%. In this group, patients with tumour invasion of blood vessels or tumour-related symptoms suffered a worse overall survival compared to those without (p=0.011). No fatal complications were observed. Child-Pugh score (p=0.030) and BCLC class (p=0.012) were independent risk factors for overall survival. The number of tumour nodules was an independent risk factor for reoccurrence.

CONCLUSION

CT-guided percutaneous microwave ablation could be an effective and safe treatment option for HCC patients.

Microwave ablation of hepatocellular carcinoma as first-line treatment: long term outcomes and prognostic factors in 221 patients

This retrospective study aimed at evaluating the long-term outcomes and prognostic factors of microwave ablation (MWA) as a first-line treatment for hepatocellular carcinoma (HCC). 221 consecutive patients receiving MWA in our center between October 11, 2010 and December 31, 2013 were enrolled. Technique effectiveness was evaluated one month post-ablation. Initial complete ablation (CA1^st) was gained in 201 (90.95%) patients, secondary CA (CA2^nd) in 8 (3.62%) patients and the remaining 12 (5.43%) patients suffered from incomplete ablation (IA2^nd) after two sessions of MWA. Patients with tumor size >5 cm were less likely to gain CA1^st. Procedure-related complications were recorded and no procedure-related death occurred. 22 (10.4%) complications occurred with 8 (3.8%) being major ones. Tumor characteristics (size, number, location) do not significantly influence complication rates. After a median follow-up of 41.0 (ranging 25.0–63.5) months, the median RFS and OS was 14.0 months (95% CI: 9.254–18.746) and 41.0 months (95% CI: 33.741–48.259) respectively. Multivariate analysis identified two significant prognosticators (levels of alpha fetal protein [AFP] and gamma-glutamyl transpeptidase [GGT]) of RFS and five significant prognosticators (tumor number, tumor size, AFP, GGT and recurrence type) of OS. In conclusion, MWA provides high technique effectiveness rate and is well tolerated in patients with HCC as a first-line treatment.

Microwave ablation in primary and secondary liver tumours: technical and clinical approaches

Thermal ablation is increasingly being utilised in the treatment of primary and metastatic liver tumours, both as curative therapy and as a bridge to transplantation. Recent advances in high-powered microwave ablation systems have allowed physicians to realise the theoretical heating advantages of microwave energy compared to other ablation modalities. As a result there is a growing body of literature detailing the effects of microwave energy on tissue heating, as well as its effect on clinical outcomes. This article will discuss the relevant physics, review current clinical outcomes and then describe the current techniques used to optimise patient care when using microwave ablation systems.

Evaluation of tolerability and efficacy of irreversible electroporation (IRE) in treatment of Child-Pugh B (7/8) hepatocellular carcinoma (HCC)

INTRODUCTION

Few studies have assessed the tolerability and efficacy of irreversible electroporation (IRE) in the treatment of Child-Pugh B (7/8) patients with hepatocellular carcinoma (HCC). Based on its mechanism of action, we hypothesized that IRE would be superior to microwave (MW) ablation and compared the liver tolerance and ablation success rates of these therapies in Child-Pugh B patients with HCC.

METHODS

55 patients with Child-Pugh B (7/8) HCC were treated with either MW ablation (n = 25) or IRE (n = 30). Tolerance and ablation success were evaluated at 30 and 90 days and 90 days and 6 months, respectively. Tolerance was defined as stable liver function and absence of increased ascites or worsening portal hypertension. Ablation success was defined as tumor eradication on triple phase contrasted computed tomography (CT).

RESULTS

Patients undergoing IRE had shorter length of stay (p = 0.05) and 90 day readmission rate (p = 0.03) than those undergoing MW ablation. Additionally, IRE was better tolerated than MW ablation at 30 and 90 days. IRE and MW ablation resulted in 6 month success rates of 97% and 100%.

CONCLUSION

Treatment of Child-Pugh B (7/8) HCC with IRE results in equivalent ablation success with improved liver tolerance compared with MW ablation and other ablative modalities.

Microwave ablation for liver tumors

Surveillance programs and widespread use of medical imaging have increased the detection of hepatic tumors. When feasible, surgical resection is widely accepted as the curative treatment of choice, but surgical morbidity and mortality has spurred the development of minimally invasive ablative technologies over the last 2 decades. Microwave ablation has emerged as a promising thermal ablation modality with improving oncologic efficacy due to technical improvements and image guidance strategies. This article provides an overview of microwave application in liver tumors, and we discuss currently available equipment, clinical efficacy, and safety and provide comparisons with other commonly used therapies. This article also introduces advanced ablative techniques and combination therapies that may help achieve precise ablation and further enhance the efficacy of microwave ablation.

Technical Aspects of Orthotopic Liver Transplantation for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) remains a significant malignancy and is the second leading cause of cancer death worldwide. Multiple therapeutic strategies exist for patients with HCC including locoregional therapy, liver resection, and liver transplantation. In many instances locoregional therapy is used to decrease tumor burden and "bridge" patients to liver transplant. Surgical technique during liver transplantation may need to be altered in light of these preoperative therapies used for treating HCC. In this review we discuss the technical aspects of liver transplantation and how they are impacted in patients with HCC.