Operative microwave ablation for hepatocellular carcinoma: complications, recurrence, and long-term outcomes

Analysis of technical failure after 1,613 surgical microwave ablations: A propensity score-matched analysis

BACKGROUND

Microwave ablation is becoming increasingly common for the treatment of liver tumors. Despite numerous studies aimed at identifying risk factors for local recurrence after microwave ablation, a consensus on modifiable risk factors for failure remains elusive, partly because of the limited statistical power of these studies. This study investigated the incidence of technical failure after microwave ablation, encompassing both incomplete ablation and local recurrence, and aimed to identify modifiable factors that reduce technical failure.

METHODS

This retrospective review included patients who underwent surgical microwave ablation at a high-volume institution between October 2006 and March 2023. Univariate analysis, multivariate analysis, and propensity score matching were performed to identify risk factors for technical failure.

RESULTS

A total of 1,613 surgical microwave ablations were performed on 3,035 tumors, with 226 instances (14% per procedure, 7.4% per tumor) of technical failure. Incomplete ablation occurred at a rate of 1.7% per tumor, whereas local recurrence was identified in 6.5% of ablations in per-tumor analysis. Body mass index >25 was significant for failure (odds ratio, 1.50; 95% confidence interval, 1.07-2.11; P < .05), suggesting that more difficult targeting may lead to increased technical failure rates. African American race (odds ratio, 1.62; 95% confidence interval, 1.16-2.27; P < .05), pre-microwave ablation transarterial chemoembolization (odds ratio, 1.54; 95% confidence interval, 1.08-2.21; P < .05), and previous ablation (odds ratio, 1.58; 95% confidence interval, 1.09-2.29; P < .05) were found to be statistically significant.

CONCLUSION

On the basis of the largest microwave ablation database available to date, this study identified novel modifiable and nonmodifiable risk factors of microwave ablation failure. These results can lead to decreasing technical failure rates after microwave ablation.

A Retrospective Cohort Analysis of Transarterial Chemoembolization for Hepatocellular Cancer at a Tertiary Center in Switzerland

Background/Objectives: International guidelines recommend transarterial chemoembolization (TACE) for intermediate-stage hepatocellular carcinoma (HCC). However, it is used outside these recommendations and has proven beneficial in prolonging survival. Since the role of TACE outside BCLC stage B is unclear, the present study analyzed the results of TACE performed at a tertiary center in Switzerland for different treatment groups, and aims to highlight the treatment outcomes for these groups. Methods: This retrospective cohort study includes 101 HCC patients undergoing TACE at our center. Patients were further subdivided into groups according to therapy combinations (therapies applied before and after index TACE). Kaplan-Meier survival curves were calculated for the Barcelona Center for Liver Cancer (BCLC) subgroups. Results: After TACE, the median survival was 28.1 months for BCLC 0, 31.5 months for BCLC A, 20.5 months for BCLC B, 10.8 for BCLC C, and 7.5 months for BCLC D. A lesion size larger than 55 mm was negatively associated with survival (HR 2.8, 95% CI 1.15-6.78). Complications occurred after TACE procedures: Clavien-Dindo I + II = 30, Clavien-Dindo > 3 = 2. Conclusions: TACE was performed in a substantial part of our cohort outside of routinely used treatment guidelines. The combination of the survival data and complication rate in these patients suggests it was a safe and beneficial strategy. Furthermore, our data show that in our cohort, the survival benefit associated with TACE was restricted to patients with a lesion size smaller than 55 mm.

HPB ultrasound guidance techniques - Targeting

Ultrasound is an indispensable tool for intraoperative assessment and treatment of hepatopancreatobiliary pathology. As minimally invasive approaches to HPB surgery continue to expand and the benefits of parenchymal-sparing liver surgery are increasingly appreciated, skillful targeting will play an even bigger role in HPB surgical practice. Techniques for intraoperative targeting of liver lesions for the purposes of biopsy and ablation, particularly in the laparoscopic setting, are the focus of this chapter. Current evidence supports the use of ablation for a variety of liver lesions including hepatocellular carcinoma and metastatic colorectal cancer, particularly for smaller lesions. Successful targeting requires optimization of patient position and port placement. When targeting multiple lesions, thoughtful treatment sequencing is critical to maintaining visualization and optimizing outcomes.

Surgical microwave ablation for the treatment of hepatocellular carcinoma in 791 operations

INTRODUCTION

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality and often arises in the setting of cirrhosis. The present series reviews outcomes following 791 operations.

METHODS

Retrospective review surgical MWA for HCC from March 2007 through December 2022 at a high-volume institution was performed using a prospective database. Primary outcome was overall survival.

RESULTS

A total of 791 operations in 623 patients and 1156 HCC tumors were treated with surgical MWA. Median tumor size was 2 cm (range 0.25-10 cm) with an average of 1 tumor ablated per operation (range 1-7 tumors). Nearly 90 % of patients had cirrhosis with a median MELD score of 8 (IQR = 6-11). Mortality within 30 days occurred in 13 patients (1.6 %). Per tumor, the rate of incomplete ablation was 2.25 % and local recurrence was 2.95 %. Previous ablation and tumor size were risk factors for recurrence. One-year overall survival was 82.0 % with a median overall survival of 36.5 months (95 % CI 15.7-93.7) and median disease-free survival of 15.9 months (range 5.7-37.3 months).

CONCLUSION

Surgical MWA offers a low-morbidity approach for treatment of HCC, affording low rates of incomplete ablation and local recurrence.

Intratumoral perfusion may affect microwave ablation area of hepatocellular carcinoma

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Patient Selection and Outcomes of Laparoscopic Microwave Ablation of Hepatocellular Carcinoma

Background: Laparoscopic microwave ablation (MWA) of hepatocellular carcinoma is underutilized and predictors of survival in this setting are not well characterized. Methods: The prognostic value of clinicopathologic variables was evaluated on progression-free survival (PFS) and overall survival (OS) by univariate and multivariate analyses. The aim of this study was to evaluate a preferred laparoscopic MWA approach in HCC patients that are not candidates for percutaneous ablation and further classify clinicopathologic factors that may predict survival outcomes following operative MWA in the setting of primary HCC. Results: 184 patients with HCC (median age 66, (33–86), 70% male) underwent laparoscopic MWA (N = 162, 88% laparoscopic) compared to 12% undergoing open MWA (N = 22). Median PFS was 29.3 months (0.2–170) and OS was 44.2 months (2.8–170). Ablation success was confirmed in 100% of patients. Ablation recurrence occurred in 3% (6/184), and local/hepatic recurrence occurred in 34%, at a median time of 19 months (9–18). Distant progression was noted in 8%. Median follow up was 34.1 months (6.4–170). Procedure-related complications were recorded in six (9%) patients with one 90-day mortality. Further, >1 lesion, AFP levels ≥ 80 ng/mL, and an “invader” on pre-operative radiology were associated with increased risk of progression (>1 lesion HR 2.92, 95% CI 1.06 –7.99, p = 0.04, AFP ≥ 80 ng/mL HR 4.16, 95% CI 1.71–10.15, p = 0.002, Invader HR 3.16, 95% CI 1.91–9.15, p = 0.002 ) and mortality (>1 lesion HR 3.62, 95% CI 1.21–10.81, p = 0.02], AFP ≥ 80 ng/mL HR 2.87, 95% CI 1.12–7.35, p = 0.01, Invader HR 3.32, 95% CI 1.21–9.81, p = 0.02). Conclusions: Preoperative lesion number, AFP ≥ 80 ng/mL, and an aggressive imaging characteristic (Invader) independently predict PFS and OS following laparoscopic operative MWA.

Predictive Factors of Local Recurrence after Colorectal Cancer Liver Metastases Thermal Ablation

Background: Identify risk factors for local recurrence (LR) after radiofrequency (RFA) and microwave (MWA) thermoablations (TA) of colorectal cancer liver metastases (CCLM). Methods: Uni- (Pearson’s Chi2 test, Fisher’s exact test, Wilcoxon test) and multivariate analyses (LASSO logistic regressions) of every patient treated with MWA or RFA (percutaneously and surgically) from January 2015 to April 2021 in Centre Georges François Leclerc in Dijon, France. Results: Fifty-four patients were treated with TA for 177 CCLM (159 surgically, 18 percutaneously). LR rate was 17.5% of treated lesions. Univariate analyses by lesion showed factors associated with LR: sizes of the lesion (OR = 1.14), size of nearby vessel (OR = 1.27), treatment of a previous TA site LR (OR = 5.03), and non-ovoid TA site shape (OR = 4.25). Multivariate analyses showed that the size of the nearby vessel (OR = 1.17) and the lesion (OR = 1.09) remained significant risk factors of LR. Conclusions: The size of lesions to treat and vessel proximity are LR risk factors that need to be considered when making the decision of thermoablative treatments. TA of an LR on a previous TA site should be reserved to specific situations, as there is an important risk of another LR. An additional TA procedure can be discussed when TA site shape is non-ovoid on control imaging, given the risk of LR.

Impact of Covid-19 on gastrointestinal cancer surgery: A National Survey

Purpose

To understand the actual impact of the Covid-19 pandemic and frame the future strategies, we conducted a pan India survey to study the impact on the surgical management of gastrointestinal cancers.

Methods

A national multicentre survey in the form of a questionnaire from 16 tertiary care gastrointestinal oncology centres across India was conducted from January 2019 to June 2021 that was divided into a 15-month pre-Covid era and a similar period of active Covid pandemic era.

Results

There was significant disruption of services; 13 (81%) centres worked as dedicated Covid care centres and 43% reported suspension of essential care for more than 6 months. In active Covid phase, there was a 14.5% decrease in registrations and proportion of decrease was highest in the centres from South zone (22%). There was decrease in resections across all organ systems; maximum reduction was noted in hepatic resections (33%) followed by oesophageal and gastric resections (31 and 25% respectively). There was minimal decrease in colorectal resections (5%). A total of 584 (7.1%) patients had either active Covid-19 infection or developed infection in the post-operative period or had recovered from Covid-19 infection. Only 3 (18%) centres reported higher morbidity, while the rest of the centres reported similar or lower morbidity rates when compared to pre-Covid phase; however, 6 (37%) centres reported slightly higher mortality in the active Covid phase.

Conclusion

Covid-19 pandemic resulted in significant reduction in new cancer registrations and elective gastrointestinal cancer surgeries. Perioperative morbidity remained similar despite 7.1% perioperative Covid 19 exposure.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00423-022-02675-6.

COVID-19 and Liver Surgery: How the Pandemic Affected an Italian Medium-Volume HBP Center

Introduction

While the COVID-19 pandemic is still ongoing, it is even more evident that victims of the pandemic are not only those who contract the virus, but also the countless patients suffering from other serious diseases (i.e., tumor) who have undergone delayed potentially life-saving surgery due to a lack of beds. Like many hospitals, ours also initially blocked all elective oncologic surgery, but these operations were “recovered” and reintegrated in a relatively short time, thanks to the establishment of COVID-free wards and operating rooms with staff dedicated to oncological surgery. In tis context, our aim is to assess whether and how the severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) pandemic has impacted our hepatobiliary surgery unit.

Methods

From our prospective database, we retrospectively took data from patients undergoing liver surgery in 2018–2019 (pre-COVID) and 2020–2021 (COVID period). Patients admitted to COVID-free wards must necessarily have a negative nasal swab from the previous 24 h.

Results

Between January 1, 2018, and December 31, 2019 (Group 1), 101 patients were treated; during the pandemic [January 1, 2020, and December 31, 2021 (Group 2)], 126 patients were treated. There was no statistical difference between the groups. The median postoperative hospital stay was 7 days for both groups; 7 patients had major complications (Clavien-Dindo > 3) in Group 1 and 11 in Group 2 (p = 0.795). A total of 4 patients died in Group 1 and 6 during the pandemic (p = 0.754). Tumor burden was significantly greater in Group 2 where nodule size, lymphadenectomy, and extrahepatic disease were significantly greater (p = 0.011, p = 0.004, and p = 0.026, respectively).

Conclusion

During the COVID pandemic, our HPB unit managed to offer a volume of tertiary-center hepatobiliary surgery without a significant impact in terms of length of stay, morbidity, or mortality despite the increase in tumor burden during the pandemic years.

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.

Pulsed Microwave Liver Ablation: An Additional Tool to Treat Hepatocellular Carcinoma

Simple Summary

Hepatocellular carcinoma (HCC) is the seventh most frequent neoplasm and the second most common oncologic cause of death, mostly in patients with end-stage liver disease. HCC treatment is complex and different solutions are available, ranging from liver transplants to local therapies. In this study, we analyze the role of pulsed microwave liver ablation as an additional treatment option.

Abstract

This study aimed to analyze the outcomes of HCC patients treated with a novel technique—pulsed microwave ablation (MWA)—in terms of safety, local tumor progression (LTP), intrahepatic recurrence (IHR), and overall survival (OS). A total of 126 pulsed microwave procedures have been performed in our center. We included patients with mono- or multifocal HCC (BCLC 0 to D). The LTP at 12 months was 9.9%, with an IHR rate of 27.8% at one year. Survival was 92.0% at 12 months with 29.4% experiencing post-operative complications (28.6% Clavien–Dindo 1–2, 0.8% Clavien–Dindo 3–4). Stratifying patients by BCLC, we achieved BCLC 0, A, B, C, and D survival rates of 100%, 93.2%, 93.3%, 50%, and 100%, respectively, at one year, which was generally superior to or in line with the expected survival rates among patients who are started on standard treatment. The pulsed MWA technique is safe and effective. The technique can be proposed not only in patients with BCLC A staging but also in the highly selected cases of BCLC B, C, and D, confirming the importance of the concept of stage migration. This procedure, especially if performed with a minimally invasive technique (laparoscopic or percutaneous), is repeatable with a short postoperative hospital stay.

Haemobilia secondary to an arterio-biliary fistula: A rare complication of intra-operative microwave ablation of hepatocellular carcinoma

A rare case of arterio-biliary fistula and haemobilia complicating intra-operative microwave ablation of hepatocellular carcinoma in a 58-year-old woman with cirrhosis.

CT-based quantification of short-term tissue shrinkage following hepatic microwave ablation in an in vivo porcine liver model

BACKGROUND

Microwave ablation (MWA) is a minimally invasive treatment option for solid tumors and belongs to the local ablative therapeutic techniques, based on thermal tissue coagulation. So far there are mainly ex vivo studies that describe tissue shrinkage during MWA.

PURPOSE

To characterize short-term volume changes of the ablated zone following hepatic MWA in an in vivo porcine liver model using contrast-enhanced computer tomography (CECT).

MATERIAL AND METHODS

We performed multiple hepatic MWA with constant energy parameters in healthy, narcotized and laparotomized domestic pigs. The volumes of the ablated areas were calculated from venous phase CT scans, immediately after the ablation and in short-term courses of up to 2 h after MWA.

RESULTS

In total, 19 thermally ablated areas in 10 porcine livers could be analyzed (n = 6 with two volume measurements during the measurement period and n = 13 with three measurements). Both groups showed a statistically significant but heterogeneous volume reduction of up to 12% (median 6%) of the ablated zones in CECT scans during the measurement period (P < 0.001 [n = 13] and P = 0.042 [n = 6]). However, the dimension and dynamics of volume changes were heterogenous both absolutely and relatively.

CONCLUSION

We observed a significant short-term volume reduction of ablated liver tissue in vivo. This volume shrinkage must be considered in clinical practice for technically successful tumor treatment by MWA and therefore it should be further investigated in in vivo studies.

Operative Microwave Ablation for the Multimodal Treatment of Neuroendocrine Liver Metastases

Background and Purpose: Operative microwave ablation (MWA) is a safe modality for treating hepatic tumors. The aim of this study is to present our 10-year, single-center experience of operative MWA for neuroendocrine liver metastases (NLM). Methods: A single-institution retrospective review of patients who underwent operative MWA for NLM was performed (2008-2018). Demographics, primary tumor site, operative approach, combined surgical operations, and carcinoid symptoms were recorded. Clinical outcomes for major complications, readmission, and mortality were analyzed 30 days postoperatively. Postablation imaging was evaluated for incomplete ablation/missed lesions, and surveillance imaging reviewed for local, regional, and metastatic recurrence. Results: Of the 50 patients (166 targeted lesions) who received MWA for NLM, 41 (82%) were treated with a minimally invasive approach, and 22 (44%) underwent MWA concomitant with hepatectomy and/or primary tumor resection. Within the study cohort 70% of patients were treated with curative intent with a 77% (27/35) success rate. Carcinoid symptoms were reported in 40% (20/50) of patients preoperatively, and MWA treatment improved symptoms in 19/20 patients. Incomplete ablation occurred in 1/166 treated lesions. Recurrence-free survival at 1 and 5 years was 86% and 28%, respectively. Overall survival at 1 and 5 years was 94% and 70%, respectively (median follow-up 32 months, range 0-116 months). Conclusion: Operative MWA is a versatile modality, which can be safe and effectively performed alone or combined with hepatectomy for NLM, preferably using a minimally invasive approach, to achieve symptom control and possibly improve survival.

Impact of ablation algorithm versus tumor-dependent parameters on local control after microwave ablation of malignant liver tumors

BACKGROUND

The aim of this study is to assess the effect of tumor versus ablation-algorithm dependent parameters on local recurrence (LR) after microwave ablation (MWA) of liver malignancies.

METHODS

This was an institutional review board-approved study of patients who underwent laparoscopic or open MWA of malignant liver tumors. The impact of ablation algorithm (stepwise or direct heating, single or overlapping ablations, and ablation margin) and tumor-dependent (type, size, location, and blood vessel proximity) parameters on LR was analyzed using Kaplan-Meier and Cox proportional hazards.

RESULTS

A total of 179 patients with 602 liver tumors underwent 200 MWA procedures. Colorectal liver metastasis (CLM) was the most frequent tumor type followed by neuroendocrine liver metastasis (NELM), other metastatic tumors, and hepatocellular cancer (HCC). For patients followed at least a year with imaging, LR rate was 8.8% per lesion and 13.1%,1.3%, 11.7%, and 12.6%, for CLM, NELM, HCC, and other tumor types, respectively. On multivariate analysis, independent predictors of LR included tumor type, tumor size, and ablation margin.

CONCLUSION

LR after MWA for malignant liver tumors is predicted by both tumor and surgeon-dependent factors. Variations in the ablation algorithm did not affect LR, leaving the ablation margin as the only parameter that could be modified to optimize local tumor control.

Gastrointestinal tract injuries after thermal ablative therapies for hepatocellular carcinoma: A case report and review of the literature

BACKGROUND

Radiofrequency ablation (RFA) and microwave ablation (MWA) represent the standard of care for patients with early hepatocellular carcinoma (HCC) who are unfit for surgery. The incidence of reported adverse events is low, ranging from 2.4% to 13.1% for RFA and from 2.6% to 7.5% for MWA. Gastrointestinal tract (GIT) injury is even more infrequent (0.11%), but usually requires surgery with an unfavourable prognosis. Due to its low incidence and the retrospective nature of the studies, the literature reporting this feared complication is heterogeneous and in many cases lacks information on tumour characteristics, comorbidities and treatment approaches.

CASE SUMMARY

A 77-year-old man who had undergone extended right hepatectomy for HCC was diagnosed with early disease recurrence with a small nodule compatible with HCC in the Sg4b segment of the liver with a subcapsular location. He was treated with percutaneous RFA and a few week later he was urgently admitted to the Surgery ward for abdominal pain and fever. A subcutaneous abscess was diagnosed and treated by percutaneous drainage. A fistulous tract was then documented by the passage of contrast material from the gastric antrum to the abdominal wall. The oesophagogastroduodenoscopy confirmed a circular wall defect at the lesser curvature of gastric antrum, leading directly to the purulent abdominal collection. An over-the-scope clip (OTSC) was used to successfully close the defect

CONCLUSION

This is the first reported case of RFA-related GIT injury to have been successfully treated with an OTSC, which highlights the role of this endoscopic treatment for the management of this complication.

Des-gamma-carboxy prothrombin affects the survival of HCC patients with marginal liver function and curative treatment: ACRoS1402

PURPOSE

Considering the initial treatment of hepatocellular carcinoma (HCC), the best prognostic index for Child-Pugh classes B and C (CP-BC) patients has not been yet established. This study aimed to elucidate the risk factors for disease-free survival (DFS) and overall survival (OS) in multicenter patients with a poor liver functional reserve after curative treatment.

METHODS

Between April 2000 and April 2014, 212 CP-BC patients who received treatment in five high-volume centers in Japan were included in this study. CP-B and C patients were 206 and 6, respectively. Cox proportional hazard regression analyses for DFS and OS were performed to estimate the risk factors.

RESULTS

The mean observation time was 1132 days. Mean Child-Pugh score and indocyanine green retention rate at 15 min were 7.5 and 31.5%, respectively. Histological chronic hepatitis and liver cirrhosis were observed in 20% and 74% patients, respectively. In the multivariate analysis, the risk factors for DFS were des-gamma-carboxy prothrombin (DCP) [hazard ratio (HR), 1.6; P = 0.012] and treatment without liver transplantation. Moreover, DCP was identified as an independent risk factor for OS (HR, 1.7; P = 0.01). Tumor size, number, tumor thrombus, Milan criteria, liver cirrhosis, and treatment without liver transplantation were not identified as risk factors for OS. The 5-year OS in patients with high serum DCP levels (< 90 mAU/mL) was significantly better than that in those with low serum DCP levels (P = 0.003).

CONCLUSIONS

Serum DCP value before treatment predicted both DFS and OS in CP-BC patients with HCC.

Laparoscopic thermoablation for hepatocellular carcinoma in patients with liver cirrhosis: an effective procedure for tricky tumors

The optimal treatment for hepatocellular carcinoma (HCC) is surgical resection. However, only a small percentage of patients are amenable to this option. Percutaneous radiofrequency interstitial thermal ablation (TA) proved to be effective in the treatment of unresectable HCC. Recent advances in laparoscopic ultrasound have improved the accuracy in detecting small intrahepatic HCC nodules missed by pre-operative imaging techniques. Our objective was to evaluate an operative combination of laparoscopic ultrasound with laparoscopic thermoablation (LTA) in the treatment of HCC not amenable to liver resection. The aim of our review was to evaluate the advantages and limits of the laparoscopic approach according the criteria of the evidence-based medicine. LTA of HCC proved to be a safe and effective technique both in the short- and long-term follow-up period. This technique may be indicated in selected cases when the percutaneous approach to the lesion is very difficult or contraindicated.

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.

Simplified Non-Thermal Tissue Ablation With a Single Insertion Device Enabled by Bipolar High-Frequency Pulses

OBJECTIVE

To demonstrate the feasibility of a single electrode and grounding pad approach for delivering high frequency irreversible electroporation treatments (H-FIRE) in in-vivo hepatic tissue.

METHODS

Ablations were created in porcine liver under surgical anesthesia by adminstereing high frequency bursts of 0.5-5.0 μs pulses with amplitudes between 1.1-1.7 kV in the absence of cardiac synchronization or intraoperative paralytics. Finite element simulations were used to determine the electric field strength associated with the ablation margins (E_Lethal) and predict the ablations feasible with next generation electronics.

RESULTS

All animals survived the procedures for the protocol duration without adverse events. E_Lethal of 2550, 1650, and 875 V/cm were found for treatments consisting of 100x bursts containing 0.5 μs pulses and 25, 50, and 75 μs of energized-time per burst, respectively. Treatments with 1 μs pulses consisting of 100 bursts with 100 μs energized-time per burst resulted in E_Lethal of 650 V/cm.

CONCLUSION

A single electrode and grounding pad approach was successfully used to create ablations in hepatic tissue. This technique has the potential to reduce challenges associated with placing multiple electrodes in anatomically challenging environments.

SIGNIFICANCE

H-FIRE is an in situ tumor ablation approach in which electrodes are placed within or around a targeted region to deliver high voltage electrical pulses. Electric fields generated around the electrodes induce irrecoverable cell membrane damage leading to predictable cell death in the relative absence of thermal damage. The sparing of architectural integrity means H-FIRE offers potential advantages compared to thermal ablation modalities for ablating tumors near critical structures.

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.

Radiofrequency Ablation and Microwave Ablation in Liver Tumors: An Update

This article provides an overview of radiofrequency ablation (RFA) and microwave ablation (MWA) for treatment of primary liver tumors and hepatic metastasis. Only studies reporting RFA and MWA safety and efficacy on liver were retained. We found 40 clinical studies that satisfied the inclusion criteria. RFA has become an established treatment modality because of its efficacy, reproducibility, low complication rates, and availability. MWA has several advantages over RFA, which may make it more attractive to treat hepatic tumors. According to the literature, the overall survival, local recurrence, complication rates, disease-free survival, and mortality in patients with hepatocellular carcinoma (HCC) treated with RFA vary between 53.2 ± 3.0 months and 66 months, between 59.8% and 63.1%, between 2% and 10.5%, between 22.0 ± 2.6 months and 39 months, and between 0% and 1.2%, respectively. According to the literature, overall survival, local recurrence, complication rates, disease-free survival, and mortality in patients with HCC treated with MWA (compared with RFA) vary between 22 months for focal lesion >3 cm (vs. 21 months) and 50 months for focal lesion ≤3 cm (vs. 27 months), between 5% (vs. 46.6%) and 17.8% (vs. 18.2%), between 2.2% (vs. 0%) and 61.5% (vs. 45.4%), between 14 months (vs. 10.5 months) and 22 months (vs. no data reported), and between 0% (vs. 0%) and 15% (vs. 36%), respectively. According to the literature, the overall survival, local recurrence, complication rates, and mortality in liver metastases patients treated with RFA (vs. MWA) are not statistically different for both the survival times from primary tumor diagnosis and survival times from ablation, between 10% (vs. 6%) and 35.7% (vs. 39.6), between 1.1% (vs. 3.1%) and 24% (vs. 27%), and between 0% (vs. 0%) and 2% (vs. 0.3%). MWA should be considered the technique of choice in selected patients, when the tumor is ≥3 cm in diameter or is close to large vessels, independent of its size. IMPLICATIONS FOR PRACTICE: Although technical features of the radiofrequency ablation (RFA) and microwave ablation (MWA) are similar, the differences arise from the physical phenomenon used to generate heat. RFA has become an established treatment modality because of its efficacy, reproducibility, low complication rates, and availability. MWA has several advantages over RFA, which may make it more attractive than RFA to treat hepatic tumors. The benefits of MWA are an improved convection profile, higher constant intratumoral temperatures, faster ablation times, and the ability to use multiple probes to treat multiple lesions simultaneously. MWA should be considered the technique of choice when the tumor is ≥3 cm in diameter or is close to large vessels, independent of its size.

Comparison of parallel and crossed placement of antennas in microwave ablation of 3-5 cm hepatocellular carcinoma

PURPOSE

To evaluate the effects of ablation strategies on local tumor progression (LTP) after microwave ablation (MWA) of hepatocellular carcinomas (HCCs) measuring 3-5 cm.

MATERIALS AND METHODS

Between December 2011 and May 2017, 71 HCC patients with 71 nodules treated by ultrasound(US)-guided percutaneous MWA were divided into parallel (group A) and crossed (group B) antenna placement groups. All patients underwent MWA using two antennas with four insertions. LTP and overall survival (OS) rates were compared between the two groups.

RESULTS

The median follow-up time was 16.8 months. There was no significant difference in the complete ablation rate and treatment sessions between the two groups. LTP was diagnosed in 8 of 48 nodules (16.7%) in group A and 1 of 23 nodules (4.3%) in group B, with no significant difference between two groups (P = 0.115). The 1-, 2-, and 3-year OS rates were 88.5%, 79%, and 71.8% in group A and 93.8%, 87.5%, and 87.5% in group B, respectively (P = 0.236). Multivariate analysis showed that the tumor diameter (P = 0.017), the distance between the antennas (P = 0.032), and the total emission time (P = 0.015) were associated with LTP.

CONCLUSIONS

There were trends with lower LTP and improved OS in group B, despite the lack of statistically significant differences between the two strategies at a level of P < 0.05. The increase of distance between antennas and total emission time will facilitate reductions in LTP rate.

Comparison of Displacement Tracking Algorithms for in Vivo Electrode Displacement Elastography

Hepatocellular carcinoma and liver metastases are common hepatic malignancies presenting with high mortality rates. Minimally invasive microwave ablation (MWA) yields high success rates similar to surgical resection. However, MWA procedures require accurate image guidance during the procedure and for post-procedure assessments. Ultrasound electrode displacement elastography (EDE) has demonstrated utility for non-ionizing imaging of regions of thermal necrosis created with MWA in the ablation suite. Three strategies for displacement vector tracking and strain tensor estimation, namely coupled subsample displacement estimation (CSDE), a multilevel 2-D normalized cross-correlation method, and quality-guided displacement tracking (QGDT) have previously shown accurate estimations for EDE. This paper reports on a qualitative and quantitative comparison of these three algorithms over 79 patients after an MWA procedure. Qualitatively, CSDE presents sharply delineated, clean ablated regions with low noise except for the distal boundary of the ablated region. Multilevel and QGDT contain more visible noise artifacts, but delineation is seen over the entire ablated region. Quantitative comparison indicates CSDE with more consistent mean and standard deviations of region of interest within the mass of strain tensor magnitudes and higher contrast, while Multilevel and QGDT provide higher CNR. This fact along with highest success rates of 89% and 79% on axial and lateral strain tensor images for visualization of thermal necrosis using the Multilevel approach leads to it being the best choice in a clinical setting. All methods, however, provide consistent and reproducible delineation for EDE in the ablation suite.

Feasibility study of modeling liver thermal damage using minimally invasive optical method adequate for in situ measurement

Liver thermal ablation techniques have been widely used for the treatment of liver cancer. Kinetic model of damage propagation play an important role for ablation prediction and real-time efficacy assessment. However, practical methods for modeling liver thermal damage are rare. A minimally invasive optical method especially adequate for in situ liver thermal damage modeling is introduced in this paper. Porcine liver tissue was heated by water bath under different temperatures. During thermal treatment, diffuse reflectance spectrum of liver was measured by optical fiber and used to deduce reduced scattering coefficient (μ^'_s ). Arrhenius parameters were obtained through non-isothermal heating approach with damage marker of μ^'_s . Activation energy (E_a ) and frequency factor (A) was deduced from these experiments. A pair of averaged value is 1.200 × 10⁵  J mol^-1 and 4.016 × 10¹⁷  s^-1 . The results were verified for their reasonableness and practicality. Therefore, it is feasible to modeling liver thermal damage based on minimally invasive measurement of optical property and in situ kinetic analysis of damage progress with Arrhenius model. These parameters and this method are beneficial for preoperative planning and real-time efficacy assessment of liver ablation therapy.

Local recurrence after microwave thermosphere ablation of malignant liver tumors: results of a surgical series

BACKGROUND

Microwave thermosphere ablation is a new treatment modality that creates spherical ablation zones using a single antenna. This study aims to analyze local recurrence associated with this new treatment modality in patients with malignant liver tumors.

METHODS

This is a prospective clinical study of patients who underwent microwave thermosphere ablation of malignant liver tumors between September 2014 and March 2017. Clinical, operative, and oncologic parameters were analyzed using Kaplan-Meier survival and Cox proportional hazards model.

RESULTS

One hundred patients underwent 301 ablations. Ablations were performed laparoscopically in 87 and open in 13 patients. Pathology included neuroendocrine liver metastasis (n = 115), colorectal liver metastasis (n = 100), hepatocellular cancer (n = 21), and other tumor types (n = 65). Ninety-day morbidity was 7% with one not procedure-related mortality. Median follow-up was 16 months with 65% of patients completing at least 12 months of follow-up. The rate of local tumor recurrence rate per lesion was 6.6% (20/301). Local tumor, new hepatic, and extrahepatic recurrences were detected in 15%, 40%, and 40% of patients, respectively. Local recurrence rate per pathology was 12% for both colorectal liver metastasis (12/100) and other metastatic tumors (8/65). No local recurrence was observed to date in the neuroendocrine liver metastasis and in the limited number of patients with hepatocellular cancers. Tumor size >3 cm and tumor type were independent predictors of local recurrence.

CONCLUSION

This is the first study to analyze local recurrence after microwave thermosphere ablation of malignant liver tumors. Short-term local tumor control rate compares favorably with that reported for radiofrequency and other microwave technologies in the literature.

A novel 3-dimensional electromagnetic guidance system increases intraoperative microwave antenna placement accuracy

BACKGROUND

Failure to locate lesions and accurately place microwave antennas can lead to incomplete tumor ablation. The Emprint™ SX Ablation Platform employs real-time 3D-electromagnetic spatial antenna tracking to generate intraoperative laparoscopic antenna guidance. We sought to determine whether Emprint™ SX affected time/accuracy of antenna-placement in a laparoscopic training model.

METHODS

Targets (7-10 mm) were set in agar within a laparoscopic training device. Novices (no surgical experience), intermediates (surgical residents), and experts (HPB-surgeons) were asked to locate and hit targets using a MWA antenna (10-ultrasound only, 10-Emprint™ SX). Time to locate target, number of attempts to hit the target, first-time hit rate, and time from initiating antenna advance to hitting the target were measured.

RESULTS

Participants located 100% of targets using ultrasound, with experts taking significantly less time than novices and intermediates. Using ultrasound only, successful hit-rates were 70% for novices and 90% for intermediates and experts. Using Emprint™ SX, successful hit rates for all 3-groups were 100%, with significantly increased first-time hit-rates and reduced time required to hit targets compared to ultrasound only.

DISCUSSION

Emprint™ SX significantly improved accuracy and speed of antenna-placement independent of experience, and was particularly beneficial for novice users.

Imaging-guided synergetic therapy of orthotopic transplantation tumor by superselectively arterial administration of microwave-induced microcapsules

It is an ambitious target to improve overall Hepatocellular Carcinoma therapeutic effects. Recently, MW ablation has emerged as a powerful thermal ablation technique, affording favorable survival with excellent local tumor control. To achieve better therapeutic effects of MW ablation, MW sensitizers are prepared for enhanced MW ablation to preferentially heat tumor territory. However, it is still not practicable for treatment of the orthotopic transplantation tumor. Herein, biocompatible and degradable methoxy poly(ethylene glycol)-poly(lactic-co-glycolic acid) (mPEG-PLGA) microcapsules with hierarchical structure have been designed for microwave-induced tumor therapy. Chemical drug doxorubicin hydrochloride (DOX·HCl), microwave (MW) sensitizers and CT imaging contrast MoS₂ nanosheets and MR imaging contrast Fe₃O₄ nanoparticles are co-incorporated into the microcapsules. In vitro/vivo MR/CT dual-modal imaging results prove the potential application for guiding synergetic therapy and predicting post-therapy tumor progression in the orthotopic transplantation tumor model. After blocking the tumor-feeding arteries, these microcapsules not only exclude the cooling effect by cutting off the blood flow but also enhance MW heating conversion at tumor site. The focused MW heating makes microcapsules mollescent or ruptured and releases DOX·HCl from the microcapsules, achieving the controlled release of drugs for chemical therapy. Compared with MW ablation, 29.4% increase of necrosis diameter of normal liver in rabbit is obtained under MW ablation combined with transcatheter arterial blocking, and the average size of necrosis and inhibition rate of VX-2 liver orthotopic transplantation tumor in rabbit has increased by 129.33% and 73.46%. Moreover, it is proved that the superselectively arterial administration of the as-prepared microcapsules has no recognizable toxicity on the animals. Therefore, this research provides a novel strategy for the construction of MW-induced microcapsules for orthotopic transplantation tumor ablation with the properties of MW sensitizing, superselective arterial blocking, control release and enhanced accumulation of DOX·HCl, and MR/CT dual-modal imaging, which exhibits great potential applications in the field of HCC therapy.

Operative microwave ablation for hepatocellular carcinoma: a single center retrospective review of 219 patients

BACKGROUND

Microwave ablation (MWA) of hepatocellular carcinoma (HCC) offers local regional treatment that can be safely and effectively performed, even in patients with advanced liver disease. We update results from our group's previous analysis of operative MWA for HCC.

METHODS

Retrospective review was performed of all patients who underwent operative MWA for HCC from 2007-2014. Patient demographics, operative characteristics and complications were recorded. Follow up imaging was reviewed to determine rates of complete ablation, local, regional and metastatic recurrence.

RESULTS

Two hundred and nineteen patients were included with a total of 340 tumors treated with operative MWA. Median tumor size was 3.2 cm (range, 1-6 cm). Cirrhosis was present in 89.5% of patients, 60.7% had hepatitis C, and 8.2% had hepatitis B. Thirty-five point nine percent were Child-Pugh class B/C. Ninety-six point eight percent of MWA procedures were performed laparoscopically. Four deaths occurred within 30 days (1.8%). Clavien-Dindo grade III complications occurred in 3.2% of patients. Complete ablation was identified in 97.1% of tumors, with local recurrence rates of 8.5% at 10.9 months median follow up (0-80 months). Regional recurrence occurred in 34.8% of patients at 10.9 months median follow up and metastatic recurrence was seen in 8.1% of patients. One year overall survival was 80.0% and 2-year survival was 61.5%.

CONCLUSIONS

We propose that laparoscopic MWA offers a low morbidity approach for treatment of HCC affording low rates of local recurrence even for patients with significant underlying liver dysfunction. This large series offers insight into outcomes of this modality as definitive treatment for patients with HCC.

Post-Procedure Evaluation of Microwave Ablations of Hepatocellular Carcinomas Using Electrode Displacement Elastography

Microwave ablation has been used clinically as an alternative to surgical resection. However, lack of real-time imaging to assess treated regions may compromise treatment outcomes. We previously introduced electrode displacement elastography (EDE) for strain imaging and verified its feasibility in vivo on porcine animal models. In this study, we evaluated EDE on 44 patients diagnosed with hepatocellular carcinoma, treated using microwave ablation. The ablated region was identified on EDE images for 40 of the 44 patients. Ablation areas averaged 13.38 ± 4.99 cm² on EDE, compared with 7.61 ± 3.21 cm² on B-mode imaging. Contrast and contrast-to-noise ratios obtained with EDE were 232% and 98%, respectively, significantly higher than values measured on B-mode images (p < 0.001). This study indicates that EDE is feasible in patients and provides improved visualization of the ablation zone compared with B-mode ultrasound.

Hepatic Tumor Ablation

Tumor ablation is a safe and effective treatment available in the multidisciplinary care of the surgical oncology patient. The role of ablation is well established in the treatment of hepatocellular carcinoma and is becoming more accepted in the treatment of various malignancies metastatic to the liver, in particular colorectal cancer. Understanding the underlying technology, achieving appropriate applicator placement, using maximum energy delivery to create margins, and performing necessary adjunctive maneuvers are all required for successful tumor ablation.

Induction of rapid, reproducible hepatic ablations using next-generation, high frequency irreversible electroporation (H-FIRE) in vivo

INTRODUCTION

Irreversible electroporation (IRE) offers an alternative to thermal tissue ablation in situ. High-frequency IRE (H-FIRE), employing ultra-short bipolar electrical pulses, may overcome limitations associated with existing IRE technology to create rapid, reproducible liver ablations in vivo.

METHODS

IRE electrodes (1.5 cm spacing) were inserted into the hepatic parenchyma of swine (n = 3) under surgical anesthesia. In the absence of paralytics or cardiac synchronization five independent H-FIRE ablations were performed per liver using 100, 200, or 300 pulses (2250 V, 2-5-2 μs configuration). Animals were maintained under isoflurane anesthesia for 6 h prior to analysis of ablation size, reproducibility, and apoptotic cell death.

RESULTS

Mean ablation time was 230 ± 31 s and no EKG abnormalities occurred during H-FIRE. In 1/15 HFIRE's minor muscle twitch (rectus abdominis) was recorded. Necropsy revealed reproducible ablation areas (34 ± 4 mm(2), 88 ± 11 mm(2) and 110 ± 11 mm(2); 100-, 200- and 300-pulses respectively). Tissue damage was predominantly apoptotic at pulse delivery ≤200 pulses, after which increasing evidence of tissue necrosis was observed.

CONCLUSION

H-FIRE can be used to induce rapid, predictable ablations in hepatic tissue without the need for intraoperative paralytics or cardiac synchronization. These advantages may overcome limitations that restrict currently available IRE technology for hepatic ablations.

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.

Mortality in hepatectomy: Model for End-Stage Liver Disease as a predictor of death using the National Surgical Quality Improvement Program database

BACKGROUND

The predictive value of the Model for End-stage Liver Disease (MELD) for mortality after hepatectomy is unclear. This study aimed to evaluate whether MELD score predicts death after hepatectomy and to identify the most useful score type for predicting mortality. We hypothesized that an increase in this score is correlated with 30-day mortality in patients undergoing hepatic resection.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried for hepatectomy. Original MELD, United Network of Organ Sharing-modified MELD (uMELD), integrated MELD (i-MELD), and sodium-corrected MELD (MELD-Na) scores were calculated. Mortality was analyzed by multivariate logistic regression. MELD types were compared using receiver operating characteristic (ROC) curves.

RESULTS

From 2005 to 2011, 11,933 hepatic resections were performed, including 7,519 partial, 2,104 right, and 1,210 left resections, and 1,100 trisectionectomies. The mean duration of stay was 8.4 ± 22.0 days, and there were 275 deaths (2.4%). The 30-day mortality rates were 1.8%, 6.9%, 15.4%, and 25% according to uMELD strata of 0-9, 10-19, 20-29, and ≥ 30, respectively. Multivariate analysis revealed that increasing MELD stratum was independently associated with higher mortality (P < .001) for all MELD types. The uMELD had the largest effect size (odds ratio [OR], 1.16; 95% CI, 1.10-1.20), whereas i-MELD had the narrowest CI (OR, 1.13; 95% CI, 1.10-1.17) and largest area under the ROC curve.

CONCLUSION

The postoperative 30-day mortality after hepatectomy increases with increasing MELD score across all MELD types. There is a 16% increase in the odds of mortality for each point increase in uMELD.

Microwave ablation: state-of-the-art review

This paper reviews state-of-the-art microwave ablation (MWA) of tumors. MWA is a novel method for treating inoperable tumors, ie, tumors that cannot be treated surgically. However, patients generally choose removal of the tumor by conventional techniques. A literature review of MWA for breast, liver, lung, and kidney tumors is reported here, with tabulation of our findings according to the type of technique used, with a detailed description of the time, type of microwave generator used, and number of patients treated with MWA. In some cases, the subjects were not human patients, but pig or bovine liver specimens. MWA is a technique that has proved to be promising and likely to be used increasingly in the ablation of cancerous tumors. However, MWA needs to be used more widely to establish itself as a common tool in the treatment of inoperable tumors.

Percutaneous treatment of Hepatocellular carcinoma exceeding 3 cm: combined therapy or microwave ablation? Preliminary results

PURPOSE

To compare MWA and RFA combined with TACE for HCC nodules exceeding 3 cm.

METHODS

19 lesions submitted to MWA (G1) were retrospectively compared with a combined treatment group (G2) matching by tumor characteristics (mean size 43 and 45 mm in G1 and G2, respectively). Technical success, complications, complete ablation (CA), and maintained CA (mCA) were evaluated.

RESULTS

Technical success was achieved in all cases. Overall mortality was zero, both in G1 and G2. No significant differences were found in complications rates (3 in G1 and 2 in G2). CA was obtained in 11 (58 %) HCC in G1 and 15 (79 %) in G2 (p = n.s.). CA was obtained in 75.5 % (G1) and 89 % (G2) nodules up to 4 cm, 45 % and 70 % nodules >4 cm, respectively. At statistical analysis, size resulted as predictor for CA only in G1 (mean diameter of CA vs non-CA 39.9 vs. 47.7 mm, p = 0.021). During follow-up (13.1 and 14.4 months in G1 and G2), mCA occurred in 6/19 (32 %) nodules in G1, 8/19 (42 %) in G2.

CONCLUSION

MWA and combined therapy are comparable as for safety. No significant differences were found in terms of technique effectiveness. Larger randomized studies should be designed to confirm MWA as a valid alternative to combined therapy.

MR-PET evaluation of 1-month post-ablation therapy for hepatocellular carcinoma: preliminary observations

PURPOSE

The purpose of the study was to evaluate the feasibility and protocol optimization of whole-body hybrid MR-PET system performed 1-month after post-locoregional thermoablative procedures for hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

Eight patients (6 men and 2 women; mean age, 56.6 ± 5.5 years) with 9 ablated HCCs constituted our study population. Three readers interpreted the studies to determine the presence or absence of residual malignancy. Two readers independently assessed the fused MR-PET images to compare registration accuracy of two types of T2-weighted (triggered T2 half-Fourier acquisition single-shot turbo spin-echo and turbo spin-echo) and T1-weighted [Cartesian and radial 3D gradient echo (GRE)]. Image quality evaluation of both 3D-GRE T1-weighted sequences was evaluated. Kappa statistics were used to measure inter-observer agreement. Non-parametric Kruskal-Wallis and Wilcoxon signed-rank tests were used for qualitative data analysis.

RESULTS

Definite residual tumor was observed in 3/9 ablations; two were PET positive. All residual tumors were isovascular on MRI. Radial 3D-GRE demonstrated significantly superior MR-PET subjective co-registration in comparison with the remaining sequences and showed a non-significant trend toward higher image quality scores than Cartesian GRE.

CONCLUSION

Whole-body hybrid MR-PET is feasible as a part of 1-month follow-up post-locoregional thermoablative treatment for HCC. Radial 3D-GRE offers improved co-registration with PET data, with overall good image quality.

Predictors of thrombosis in hepatic vasculature during microwave tumor ablation of an in vivo porcine model

PURPOSE

To evaluate and model the risk of in vivo thrombosis in each hepatic vessel type during hepatic microwave ablation as a function of vessel diameter, velocity, and vessel-antenna spacing.

MATERIALS AND METHODS

A single microwave ablation antenna was inserted into a single porcine lobe (n = 15 total) adjacent to a hepatic artery, hepatic vein, or portal vein branch. Conventional ultrasound and Doppler ultrasound were used to measure the vessel diameter, blood flow velocity, and vessel-antenna spacing. A microwave ablation zone was created at 100 W for 5 minutes. Thrombus formation was evaluated on ultrasound performed immediately after the procedure. Logistic regression was used to evaluate the predictive value of vessel diameter, blood flow velocity, and vessel-antenna spacing on vascular thrombosis.

RESULTS

Thrombosis was identified in 53% of portal veins, 13% of hepatic veins, and 0% of hepatic arteries. The average peak blood flow rate of the hepatic artery was significantly greater than the average peak blood flow rate of the hepatic vein and portal vein. Peak blood flow velocity < 12.45 cm/s, vessel diameter < 5.10 mm, and vessel-antenna spacing < 3.75 mm were strong predictors of hepatic vein thrombosis. However, these individual factors were not predictive of the more common portal vein thrombosis.

CONCLUSIONS

Hepatic arteries do not appear to be at risk for thrombosis during microwave ablation procedures. Portal vein thrombosis was more common than hepatic vein thrombosis during microwave ablation treatments but was not as predictable based on vessel diameter, flow velocity, or vessel-antenna spacing alone.

Survival analysis of patients with stage I and II hepatocellular carcinoma after a liver transplantation or liver resection

INTRODUCTION

Liver transplantation (LT) is a treatment option in select patients with hepatocellular carcinoma (HCC). The aim of the present study was to compare survival in Stage I or II HCC patients undergoing either liver transplant (LT) or a liver resection (LR).

METHOD

The study is a retrospective analysis of the National Cancer Data Base (1998-2011). In total, 148,882 patients with liver cancer were identified, of which 5-year survival data (1998-2006) were available for 64,227 patients. Patients were stratified by the American Joint Committee on Cancer (AJCC) clinical stage I and II. Kaplan-Meier curves and log-rank tests were used for statistical analysis.

RESULTS

3340 HCC patients met analysis criteria. Among stage I HCC, 860 had LT and 871 had LR. Among stage II HCC, 833 had LT and 776 LR. In stage I patients the median survival for LT and LR were 127.9 and 56.7 months, respectively, (P < 0.0001) and in stage II patients the median survival was 110.8 and 42.8 months (P < 0.0001). Unlike LT patients, LR patients with Stage I HCC had a longer median survival compared with Stage II patients (P = 0.0002).

CONCLUSION

Liver transplantation offers a survival advantage compared with a liver resection among patients with Stage I and II HCC. LT is the best surgical treatment for early stage (I/II) HCC in patients with advanced fibrosis or cirrhosis, whereas LR provides equivalent outcomes to LT in patients without advanced fibrosis and should be considered as the first surgical option.

Local tumour progression after ultrasound-guided microwave ablation of liver malignancies: risk factors analysis of 2529 tumours

OBJECTIVES

To identify the incidence and risk factors that predict local tumour progression (LTP) after ultrasound-guided percutaneous microwave ablation (MWA) of liver malignancies.

MATERIALS AND METHODS

One thousand two hundred and nine patients with 2,529 malignant nodules (mean size 2.8 ± 1.4 cm, range 0.9-8.0 cm) were treated by MWA between July 2005 and December 2012. The influence of 11 factors on the risk of LTP was assessed. Univariate Kaplan-Meier and Cox proportional hazard models were used for statistical analysis.

RESULTS

The overall LTP was 4.2 % per tumour and 8.6 % per patient with a median follow-up of 20.3 months. LTP per tumour was 4.3 % for primary liver cancer and 4.1 % for metastases (p = 0.32). The survival of LTP and free-LTP patients at 1, 3, and 5 years was 92.4 %, 71.6 %, and 45.1 %, respectively, and 92.9 %, 70.1 %, and 52.4 %, respectively (p = 0.93). By univariate analysis, tumour location, size and ablation time were significant risk factors of LTP. Multivariate analysis identified tumour size (>3.0 cm) to be the only independent predictor of LTP.

CONCLUSIONS

MWA of liver malignancies achieves a relatively low-incidence LTP, although LTP risk significantly increases if tumour size >3.0 cm. The technique seems to be appropriate even for patients with a tumour at a risk location.

KEY POINTS

• Microwave ablation of liver malignancies achieves a low incidence local tumour progression. • LTP risk significantly increases if the tumour size is >3.0 cm. • MWA seems to be appropriate even for patients with a tumour at a risk location.

Ablative technologies for hepatocellular, cholangiocarcinoma, and metastatic colorectal cancer of the liver

A wide array of ablation technologies, in addition to the progressive sophistication of imaging technologies and percutaneous, laparoscopic, and open surgical techniques, have allowed us to expand treatment options for patients with liver tumors. In this article, technical considerations of chemical and thermal ablations and their application in hepatic oncology are reviewed.