Laparoscopic-assisted microwave ablation for hepatocellular carcinoma: safety and efficacy in comparison with radiofrequency ablation

Laparoscopic ultrasound-guided microwave ablation of hepatocellular carcinoma in a dog

OBJECTIVE

The aim of the study was to describe laparoscopic ultrasound (LUS) to guide microwave ablation (MWA) of hepatocellular carcinoma (HCC) in a dog.

ANIMALS

A 13-year-old female spayed Husky.

STUDY DESIGN

Case report.

METHODS

The dog was referred for laparoscopic MWA of a caudate lobe HCC measuring 2.7 cm × 1.9 cm× 2.3 cm. Laparoscopic ultrasound was used to guide percutaneous placement of a MWA probe within the caudate lobe mass. LUS was used to determine the tumor margins for placement of the probe within the medial and lateral aspects as well as the center of the mass. Additionally, LUS allowed visualization of vessels within the tumor so they could be avoided during probe placement.

RESULTS

Safe ablation was accomplished, and the dog recovered uneventfully with no complications. Follow-up computed tomography (CT) 3- and 12-months postoperatively revealed complete ablation of the caudate lobe mass. However, progressive increase in size of the right medial lobe mass occurred. Right medial liver lobectomy was performed 13 months after MWA, with a histopathologic diagnosis of HCC. The dog was euthanized 777 days post MWA and 1445 days post initial left lateral lobectomy for HCC.

CONCLUSION

Laparoscopic ultrasound was useful in guiding complete and safe MWA of an HCC in this dog. Laparoscopic ultrasound should be considered when performing laparoscopic MWA of liver lesions in dogs.

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.

SAGES/AHPBA guidelines for the use of microwave and radiofrequency liver ablation for the surgical treatment of hepatocellular carcinoma or colorectal liver metastases less than 5 cm

BACKGROUND

Primary hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM) represent the liver's two most common malignant neoplasms. Liver-directed therapies such as ablation have become part of multidisciplinary therapies despite a paucity of data. Therefore, an expert panel was convened to develop evidence-based recommendations regarding the use of microwave ablation (MWA) and radiofrequency ablation (RFA) for HCC or CRLM less than 5 cm in diameter in patients ineligible for other therapies.

METHODS

A systematic review was conducted for six key questions (KQ) regarding MWA or RFA for solitary liver tumors in patients deemed poor candidates for first-line therapy. Subject experts used the GRADE methodology to formulate evidence-based recommendations and future research recommendations.

RESULTS

The panel addressed six KQs pertaining to MWA vs. RFA outcomes and laparoscopic vs. percutaneous MWA. The available evidence was poor quality and individual studies included both HCC and CRLM. Therefore, the six KQs were condensed into two, recognizing that these were two disparate tumor groups and this grouping was somewhat arbitrary. With this significant limitation, the panel suggested that in appropriately selected patients, either MWA or RFA can be safe and feasible. However, this recommendation must be implemented cautiously when simultaneously considering patients with two disparate tumor biologies. The limited data suggested that laparoscopic MWA of anatomically more difficult tumors has a compensatory higher morbidity profile compared to percutaneous MWA, while achieving similar overall 1-year survival. Thus, either approach can be appropriate depending on patient-specific factors (very low certainty of evidence).

CONCLUSION

Given the weak evidence, these guidelines provide modest guidance regarding liver ablative therapies for HCC and CRLM. Liver ablation is just one component of a multimodal approach and its use is currently limited to a highly selected population. The quality of the existing data is very low and therefore limits the strength of the guidelines.

Ablative and non-surgical therapies for early and very early hepatocellular carcinoma: a systematic review and network meta-analysis

Background

A wide range of ablative and non-surgical therapies are available for treating small hepatocellular carcinoma in patients with very early or early-stage disease and preserved liver function.

Objective

To review and compare the effectiveness of all current ablative and non-surgical therapies for patients with small hepatocellular carcinoma (≤ 3 cm).

Design

Systematic review and network meta-analysis.

Data sources

Nine databases (March 2021), two trial registries (April 2021) and reference lists of relevant systematic reviews.

Review methods

Eligible studies were randomised controlled trials of ablative and non-surgical therapies, versus any comparator, for small hepatocellular carcinoma. Randomised controlled trials were quality assessed using the Cochrane Risk of Bias 2 tool and mapped. The comparative effectiveness of therapies was assessed using network meta-analysis. A threshold analysis was used to identify which comparisons were sensitive to potential changes in the evidence. Where comparisons based on randomised controlled trial evidence were not robust or no randomised controlled trials were identified, a targeted systematic review of non-randomised, prospective comparative studies provided additional data for repeat network meta-analysis and threshold analysis. The feasibility of undertaking economic modelling was explored. A workshop with patients and clinicians was held to discuss the findings and identify key priorities for future research.

Results

Thirty-seven randomised controlled trials (with over 3700 relevant patients) were included in the review. The majority were conducted in China or Japan and most had a high risk of bias or some risk of bias concerns. The results of the network meta-analysis were uncertain for most comparisons. There was evidence that percutaneous ethanol injection is inferior to radiofrequency ablation for overall survival (hazard ratio 1.45, 95% credible interval 1.16 to 1.82), progression-free survival (hazard ratio 1.36, 95% credible interval 1.11 to 1.67), overall recurrence (relative risk 1.19, 95% credible interval 1.02 to 1.39) and local recurrence (relative risk 1.80, 95% credible interval 1.19 to 2.71). Percutaneous acid injection was also inferior to radiofrequency ablation for progression-free survival (hazard ratio 1.63, 95% credible interval 1.05 to 2.51). Threshold analysis showed that further evidence could plausibly change the result for some comparisons. Fourteen eligible non-randomised studies were identified (n ≥ 2316); twelve had a high risk of bias so were not included in updated network meta-analyses. Additional non-randomised data, made available by a clinical advisor, were also included (n = 303). There remained a high level of uncertainty in treatment rankings after the network meta-analyses were updated. However, the updated analyses suggested that microwave ablation and resection are superior to percutaneous ethanol injection and percutaneous acid injection for some outcomes. Further research on stereotactic ablative radiotherapy was recommended at the workshop, although it is only appropriate for certain patient subgroups, limiting opportunities for adequately powered trials.

Limitations

Many studies were small and of poor quality. No comparative studies were found for some therapies.

Conclusions

The existing evidence base has limitations; the uptake of specific ablative therapies in the United Kingdom appears to be based more on technological advancements and ease of use than strong evidence of clinical effectiveness. However, there is evidence that percutaneous ethanol injection and percutaneous acid injection are inferior to radiofrequency ablation, microwave ablation and resection.

Study registration

PROSPERO CRD42020221357.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment (HTA) programme (NIHR award ref: NIHR131224) and is published in full in Health Technology Assessment; Vol. 27, No. 29. See the NIHR Funding and Awards website for further award information.

Indocyanine Green as a Navigational Adjunct for Laparoscopic Ablation of Liver Tumors

BACKGROUND

Minimally invasive operative approaches for resection and thermal ablation (eg, microwave, radiofrequency) of hepatocellular carcinoma (HCC) have been successfully implemented over the last two decades, although identifying tumors can be challenging. Successfully performing laparoscopic ablation requires real-time visualization and ultrasonography skills for direct placement of the ablation probe.

METHODS

In this study, we introduce a novel adjunct to ultrasound imaging for tumors located near or on the surface of the liver via intravenous delivery of indocyanine green (ICG) dye. Non-resectable lesion(s) not amenable to percutaneous ablation were considered for laparoscopic microwave ablation. Each patient initially received a dose of .3125 mg ICG via peripheral IV.

RESULTS

A total of 17 patients were included. There was brisk uptake of ICG throughout the liver parenchyma in under 2 minutes in 15 of 17 patients; the remaining 2 required a second dose of ICG. In 14 cases, a hypo-fluorescent perfusion pattern in the tumor was clearly identified.

DISCUSSION

Integrating ICG and fluorescent imaging provides a complementary adjunct to ultrasound in identifying HCC nodules. While previous applications of ICG typically require injections several days prior to surgery or segmental injections, this study demonstrates a novel real-time application of ICG to aid surgeons with various experiences in laparoscopic-assisted ablation procedures for HCC.

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.

Navigation Improves Tumor Ablation Performance: Results From a Novel Liver Tumor Simulator Study

BACKGROUND

The efficacy of microwave ablation in treating hepatic tumors requires advanced ultrasound skills. Failure of proper technique has the potential for either under- or over-treatment and possible harm to the patient. Emprint SX™ navigation provides surgeons with intra-operative, real-time navigation through augmented reality localization of the ablation antenna and the expected ablation zone. We hypothesize that incorporating this technology leads to improved targeting and optimizes ablation coverage. This study utilizes a simulated model to evaluate ablation outcomes using Emprint SX™ navigation vs standard ultrasound.

METHODS

Surgical residents and faculty were recruited from a single institution. Using a novel tumor ablation simulator, participants performed ablations via 2 modes: standard ultrasound guidance (STD) and Emprint SX™ navigation (NAV). Primary outcome was the percentage of under-ablation. Secondary outcomes included percentage of over-ablation, time to complete trial, and number of attempts to position antenna.

RESULTS

281 trials were performed by fifteen participants, with 47% female and 60% novice ablationists. Under-ablation volume decreased by a mean of 16.3% (SEM ±12.9, P < .001) with NAV compared to STD. Over-ablation volume decreased by a mean of 14.0% (±8.2, P < .001). NAV time was faster by a mean of 32 seconds (±24.9, P < .001) and involved fewer antenna placement attempts by a mean of 1.3 (±1.0, P < .001). For novice ablationists, all outcomes were improved with NAV and novices saw larger improvements compared to experienced ablationists (P = .018).

DISCUSSION

In a simulated model, NAV improves ablation efficacy and efficiency, with novices gaining the greatest benefit over standard ultrasound.

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.

The latest research progress on minimally invasive treatments for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related death worldwide. Due to the high prevalence of hepatitis B virus (HBV) infection in China, the incidence of HCC in China is high, and liver cirrhosis caused by chronic hepatitis also brings great challenges to treatment. This paper reviewed the latest research progress on minimally invasive treatments for HCC, including percutaneous thermal ablation and new nonthermal ablation techniques, and introduced the principles, advantages, and clinical applications of various therapeutic methods in detail.

DATA SOURCES

The data of treatments for HCC were systematically collected from the PubMed, ScienceDirect, American Chemical Society and Web of Science databases published in English, using "minimally invasive" and "hepatocellular carcinoma" or "liver cancer" as the keywords.

RESULTS

Percutaneous thermal ablation is still a first-line strategy for the minimally invasive treatment of HCC. The effect of microwave ablation (MWA) on downgrading treatment before liver transplantation is better than that of radiofrequency ablation (RFA), while RFA is more widely used in the clinical practice. High-intensity focused ultrasound (HIFU) is mainly used for the palliative treatment of advanced liver cancer. Electrochemotherapy (ECT) delivers chemotherapeutic drugs to the target cells while reducing the blood supply around HCC. Irreversible electroporation (IRE) uses a microsecond-pulsed electric field that induces apoptosis and necrosis and triggers a systemic immune response. The nanosecond pulsed electric field (nsPEF) has achieved a good response in the ablation of mice with HCC, but it has not been reported in China for the treatment of human HCC.

CONCLUSIONS

A variety of minimally invasive treatments provide a sufficient survival advantage for HCC patients. Nonthermal ablation will lead to a new wave with its unique advantage of antitumor recurrence and metastasis.

Surgical approach to microwave and radiofrequency liver ablation for hepatocellular carcinoma and colorectal liver metastases less than 5 cm: a systematic review and meta-analysis

BACKGROUND

Primary hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM) represent the two most common malignant neoplasms of the liver. The objective of this study was to assess outcomes of surgical approaches to liver ablation comparing laparoscopic versus percutaneous microwave ablation (MWA), and MWA versus radiofrequency ablation (RFA) in patients with HCC or CRLM lesions smaller than 5 cm.

METHODS

A systematic review was conducted across seven databases, including PubMed, Embase, and Cochrane, to identify all comparative studies between 1937 and 2021. Two independent reviewers screened for eligibility, extracted data for selected studies, and assessed study bias using the modified Newcastle Ottawa Scale. Random effects meta-analyses were subsequently performed on all available comparative data.

RESULTS

From 1066 records screened, 11 studies were deemed relevant to the study and warranted inclusion. Eight of the 11 studies were at high or uncertain risk for bias. Our meta-analyses of two studies revealed that laparoscopic MW ablation had significantly higher complication rates compared to a percutaneous approach (risk ratio = 4.66; 95% confidence interval = [1.23, 17.22]), but otherwise similar incomplete ablation rates, local recurrence, and oncologic outcomes. The remaining nine studies demonstrated similar efficacy of MWA and RFA, as measured by incomplete ablation, complication rates, local/regional recurrence, and oncologic outcomes, for both HCC and CRLM lesions less than 5 cm (p > 0.05 for all outcomes). There was no statistical subgroup interaction in the analysis of tumors < 3 cm.

CONCLUSION

The available comparative evidence regarding both laparoscopic versus percutaneous MWA and MWA versus RFA is limited, evident by the few studies that suffer from high/uncertain risk of bias. Additional high-quality randomized trials or statistically matched cohort studies with sufficient granularity of patient variables, institutional experience, and physician specialty/training will be useful in informing clinical decision making for the ablative treatment of HCC or CRLM.

Outcomes of microwave versus radiofrequency ablation for hepatocellular carcinoma: A systematic review and meta-analysis

BACKGROUND

Studies to date comparing outcomes of microwave ablation (MWA) with radiofrequency ablation (RFA) on patients with hepatocellular carcinoma have yielded conflicting results, with no clear superiority of one technique over the other. The aim of this systematic review and meta-analysis was to compare the efficacy and safety of MWA with RFA.

AIM

To perform a systematic review and meta-analysis comparing the efficacy and safety of MWA with RFA.

METHODS

A systematic literature search was performed using Ovid Medline, Embase, PubMed, Reference Citation Analysis, Cochrane Central and Cochrane Systematic Review databases, and Web of Science. Abstracts and full manuscripts were screened for inclusion utilising predefined inclusion and exclusion criteria comparing outcomes of MWA and RFA. A random-effects model was used for each outcome. Meta-regression analysis was performed to adjust for the difference in follow-up period between the studies. Primary outcome measures included complete ablation (CA) rate, local recurrence rate (LRR), survival [local recurrence-free survival (LRFS), overall survival (OS)] and adverse events.

RESULTS

A total of 42 published studies [34 cohort and 8 randomised controlled trials (RCT)] with 6719 patients fulfilled the selection criteria. There was no significant difference in tumour size between the treatment groups. CA rates between MWA and RFA groups were similar in prospective cohort studies [odds ratio (OR) 0.95, 95% confidence interval (CI) 0.28–3.23] and RCTs (OR 1.18, 95%CI 0.64–2.18). However, retrospective studies reported higher rates with MWA (OR 1.29, 95%CI 1.06–1.57). Retrospective cohort studies reported higher OS (OR 1.54, 95%CI 1.15–2.05 and lower LRR (OR 0.67, 95%CI 0.51–0.87). No difference in terms of LRFS or 30-d mortality was observed between both arms. MWA had an increased rate of adverse respiratory events when compared to RFA (OR 1.99, 95%CI 1.07–3.71, P = 0.03).

CONCLUSION

MWA achieves similar CA rates and as good or better longer-term outcomes in relation to LRR and OS compared to RFA. Apart from an increased rate of respiratory events post procedure, MWA is as safe as RFA.

Efficacy and safety of microwave ablation and radiofrequency ablation in the treatment of hepatocellular carcinoma: A systematic review and meta-analysis

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. Surgical resection is often only possible in the early stages of HCC and among those with limited cirrhosis. Radiofrequency ablation and Microwave ablation are 2 main types of percutaneous thermal ablation for the treatment of HCC. The efficacy and safety between these 2 therapy methods are still under a debate.

OBJECTIVE

To compare the efficacy and safety of Radiofrequency ablation and Microwave ablation in treating HCC.

METHODS

PubMed, EMBASE, the Cochrane databases and Web of Science were systematically searched. We included randomized controlled trials and cohort studies comparing the efficacy and safety of Radiofrequency ablation and Microwave ablation in HCC patients. Outcome measures on local tumor progression, complete ablation, disease-free survival, overall survival, or major complications were compared between the 2 groups. The random effect model was used when there was significant heterogeneity between studies, otherwise the fixed effect model was used.

RESULTS

A total of 33 studies, involving a total of 4589 patients were identified, which included studies comprised 7 RCTs, 24 retrospective observational trials, and 2 prospective observational trial. Microwave ablation had a lower local tumor progression than Radiofrequency ablation in cohort studies (OR = 0.78, 95% CI 0.64-0.96, P = .02). Complete ablation rate of Microwave ablation was higher than that of Radiofrequency ablation in cohort studies (OR = 1.54, 95% CI 1.05-2.25, P = .03). There was no significant difference in overall survival and disease-free survival between the 2 groups. Meta-analysis showed that there was no significant difference in the main complications between Microwave ablation and Radiofrequency ablation.

CONCLUSIONS

Microwave ablation has higher complete ablation and lower local tumor progression than Radiofrequency ablation in the ablation treatment of HCC nodules. There was no significant difference in overall survival between the 2 therapy methods.

Multimodality Imaging Assessment of Desmoid Tumors: The Great Mime in the Era of Multidisciplinary Teams

Desmoid tumors (DTs), also known as desmoid fibromatosis or aggressive fibromatosis, are rare, locally invasive, non-metastatic soft tissue tumors. Although histological results represent the gold standard diagnosis, imaging represents the fundamental tool for the diagnosis of these tumors. Although histological analysis represents the gold standard for diagnosis, imaging represents the fundamental tool for the diagnosis of these tumors. DTs represent a challenge for the radiologist, being able to mimic different pathological conditions. A proper diagnosis is required to establish an adequate therapeutic approach. Multimodality imaging, including ultrasound (US), computed tomography (CT) and Magnetic Resonance Imaging (MRI), should be preferred. Different imaging techniques can also guide minimally invasive treatments and monitor their effectiveness. The purpose of this review is to describe the state-of-the-art multidisciplinary imaging of DTs; and its role in patient management.

Complications Risk Assessment and Imaging Findings of Thermal Ablation Treatment in Liver Cancers: What the Radiologist Should Expect

One of the major fields of application of ablation treatment is liver tumors. With respect to HCC, ablation treatments are considered as upfront treatments in patients with early-stage disease, while in colorectal liver metastases (CLM), they can be employed as an upfront treatment or in association with surgical resection. The main prognostic feature of ablation is the tumor size, since the goal of the treatment is the necrosis of all viable tumor tissue with an adequate tumor-free margin. Radiofrequency ablation (RFA) and microwave ablation (MWA) are the most employed ablation techniques. Ablation therapies in HCC and liver metastases have presented a challenge to radiologists, who need to assess response to determine complication-related treatment. Complications, defined as any unexpected variation from a procedural course, and adverse events, defined as any actual or potential injury related to the treatment, could occur either during the procedure or afterwards. To date, RFA and MWA have shown no statistically significant differences in mortality rates or major or minor complications. To reduce the rate of major complications, patient selection and risk assessment are essential. To determine the right cost-benefit ratio for the ablation method to be used, it is necessary to identify patients at high risk of infections, coagulation disorders and previous abdominal surgery interventions. Based on risk assessment, during the procedure as part of surveillance, the radiologists should pay attention to several complications, such as vascular, biliary, mechanical and infectious. Multiphase CT is an imaging tool chosen in emergency settings. The radiologist should report technical success, treatment efficacy, and complications. The complications should be assessed according to well-defined classification systems, and these complications should be categorized consistently according to severity and time of occurrence.

Percutaneous thermal ablation of hepatic tumors: local control efficacy and risk factors for artificial ascites failure

OBJECTIVE

To investigate the risk factors affecting the technical failure of artificial ascites (AA) formation and to evaluate the local control efficacy of percutaneous thermal ablation assisted by the AA for hepatic tumors.

METHODS

A total of 341 patients with 362 hepatic tumors who underwent thermal ablation assisted by AA were reviewed retrospectively. The technical success of AA, the volume of liquid, and local efficacy after ablation were assessed. Predictive factors for the technical failure of AA formation and local tumor progression (LTP) were analyzed using univariate and multivariate analysis.

RESULTS

The technical success rate of AA formation was 81.8% (296/362). The amount of fluid was higher when the tumor was located in the left lobe of the liver than when it was located in the right lobe (median 950 ml versus 700 ml, p < 0.001). Previous hepatic resection (OR: 12.63, 95% CI: 2.93-54.45, p < 0.001), ablation (OR: 6.48, 95% CI: 1.36-30.92, p = 0.019) and upper-abdomen surgery (OR: 11.34, 95% CI: 1.96-65.67, p = 0.007) were the independent risk factors of AA failure. In the AA success group, the complete ablation rate was higher and the LTP rate was lower than that in the AA failure group (98.7 versus 92.4%, p = 0.012; 8.8 versus 21.2%, p = 0.004). Multivariate analysis identified AA failure (p = 0.004), tumor size (>3.0 cm) (p = 0.002) and metastatic liver tumor (p = 0.008) as independent risk factors for LTP.

CONCLUSION

History of hepatic resection, ablation and upper abdomen surgery were significant predictive factors affecting the technical failure of AA formation. Successful introduction of AA before thermal ablation can achieve better local tumor control efficacy.

Microwave ablation compared with radiofrequency ablation for the treatment of liver cancer: a systematic review and meta-analysis

BACKGROUND

Guidelines have reported that although microwave ablation (MWA) has potential advantages over radiofrequency ablation (RFA), superiority in efficacy and safety remain unclear. Aim of the study is to compare MWA with RFA in the treatment of liver cancer.

METHODS

Meta-analysis was conducted according to the PRISMA guidelines for studies published from 2010 onwards. A random-effects model was used for the meta-analyses. Complete ablation (CA), local tumor progression (LTP), intrahepatic distant recurrence (IDR), and complications were analyzed.

RESULTS

Four randomized trials and 11 observational studies with a total of 2,169 patients met the inclusion criteria. Although overall analysis showed no significant difference in LTP between MWA and RFA, subgroup analysis including randomized trials for patients with hepatocellular cancer (HCC) demonstrated statistically decreased rates of LTP in favor of MWA (OR, 0.40; 95% CI, 0.18-0.92; p = 0.03). No significant differences were found between the two procedures in CA, IDR, complications, and tumor diameter less or larger than 3 cm.

CONCLUSIONS

MWA showed promising results and demonstrated better oncological outcomes in terms of LTP compared to RFA in patients with HCC. MWA can be utilized as the ablation method of choice in patients with HCC.

Treatment of spontaneously ruptured hepatocellular carcinoma: use of laparoscopic microwave ablation and washout

BACKGROUND

Ruptured, or bleeding, hepatocellular carcinoma (rHCC) is a relatively rare disease presentation associated with high acute mortality rates. This study sought to evaluate outcomes following laparoscopic microwave ablation (MWA) and washout in rHCC.

METHODS

A retrospective single-center review was performed to identify patients with rHCC (2008-2018). The treatment algorithm consisted of transarterial embolization (TAE) or trans-arterial chemoembolization (TACE) followed by laparoscopic MWA and washout.

RESULTS

Fifteen patients with rHCC were identified (n = 5 single lesion, n = 5 multifocal disease, n = 5 extrahepatic metastatic disease). Median tumor size was 83 mm (range 5-228 mm), and 10 of 15 underwent TAE or TACE followed by laparoscopic MWA/washout. One patient required additional treatment for bleeding after MWA with repeat TAE. Thirty-day mortality was 6/15. For those patients discharged (n = 9), additional treatments included chemotherapy (n = 5), TACE (n = 3), and/or partial lobectomy (n = 2). Median follow-up was 18.2 months and median survival was 431 days (range 103-832) (one-year survival n = 7; two-year survival n = 4; three-year survival n = 3). Six patients had post-operative imaging from which one patient demonstrated recurrence.

CONCLUSION

Using laparoscopic MWA with washout may offer advantage in the treatment of ruptured HCC. It not only achieves hemostasis but also could have oncologic benefit by targeting local tumor and decreasing peritoneal carcinomatosis risk.

Radiofrequency ablation versus microwave ablation for early stage hepatocellular carcinoma: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

Several randomized control trials (RCTs) were conducted to compare microwave ablation (MWA) and radiofrequency ablation (RFA) in the treatment of hepatocellular carcinoma (HCC) over the years. The purpose of this study was to compare the efficacy of RFA and MWA for early stage HCC.

METHODS

Studies were systematically searched on Emabse, Ovid Medline, PubMed, and Cochrane Library until March 20, 2020. Continuous variables and dichotomous variables were compared using weighted mean difference (WMD) and odds ratio (OR), respectively. For the comparison of overall survival (OS) and disease-free survival (DFS), the hazard ratio (HR) and 95% confidence interval (CI) were extracted from univariate analysis or survival plots.

RESULTS

A total of 26 studies (5 RCTs and 21 cohorts) with 4396 patients (2393 patients in RFA and 2003 patients in MWA) were included in our study. Of these patients, 47% received treatment under general anesthesia in the MWA group and 84% in the RFA group (OR = 0.529, P < .001). The median ablation time was reduced in the MWA group (12 minutes) compared with RFA group (29 minutes) (WMD = -15.674, P < .001). In total, 17.6% patients exhibited progression during follow-up in the MWA group compared with 19.5% in the RFA group (OR = 0.877, P = .225). No statistically significant differences were observed between MWA and RFA groups in terms of OS and DFS (HR = 0.891 and 1.014, P = .222 and .852, respectively).

CONCLUSIONS

MWA exhibited similar therapeutic effects as RFA in the treatment of early stage HCC. Given the shorter ablation time, MWA can be performed under local anesthesia.

Local therapies for liver metastases of rare head and neck cancers: a monoinstitutional case series

INTRODUCTION

Transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) are established procedures for treating hepatocellular cancer and selected malignancies with liver metastasis. The aim of this study is to describe a monoinstitutional case series of local approaches in patients with liver metastases from rare head and neck cancers (HNCs).

METHODS

This is a retrospective series of adult patients with HNC treated with liver locoregional approaches (TACE or RFA) at our institution from 2007 to 2018. In case of chemoembolization, the preferred chemotherapeutic drug was doxorubicin. Response according to RECIST (Response Evaluation Criteria in Solid Tumors) was assessed with contrast-enhanced computed tomography scans.

RESULTS

Thirty-four patients were treated (20 men, median age 58 years) with TACE (27), transarterial embolization (2), or RFA (7). Primary tumours were salivary gland (21), thyroid (6), nasopharyngeal (5), and sinonasal cancers (2). Seventeen patients (50%) had a single metastatic liver nodule; 70% of the remaining 17 patients had at least three liver metastases. The median diameter of the metastatic liver mass undergoing treatment was 39 mm (range 11-100 mm). Median follow-up was 27.6 months. Response rate was 35% (3% complete, 32% partial response). Median progression-free survival and overall survival were 6.9 and 19.6 months, respectively. Treatment-related adverse events occurred in 59% of patients (21% grade ⩾ 3; no grade 5).

DISCUSSION

This retrospective case series demonstrates that locoregional radiologic approaches for rare HNCs with liver metastases are feasible. These procedures deserve further prospective studies before being considered safe and active in these malignancies where the availability of effective systemic treatments is lacking.

Applications of Elastography in Ablation Therapies: An Animal Model In Vivo Study

Background: Ablation therapies are one of the main local treatments for solid organ tumors. After applying any ablation therapy, few days should be waited to perform an imaging study and analyze the result. In this work, we analyzed the correlation between elastography monitoring after procedure and the result of ablation. The objective of this study is to determine tissue changes in vivo in short term after the application of ablation systems using different diagnostic imaging methods. Materials and Methods: Descriptive study in an in vivo swine model. Different types of ablation therapies (radiofrequency ablation, microwave ablation [MWA], and LASER ablation [LA]) were applied in the liver and kidneys. We compared their results by medical image monitoring (ultrasound, computed tomography, elastography) and macroscopic analysis. Results: All the animals survived the procedures. No major intraoperative complications were reported. We determined the characteristics of each procedure. MWA session was faster than the other types of ablation therapies. Regarding ablation area diameters, the largest was achieved with MWA and the smallest with LA. Macroscopically, we observed a central ablation zone, a peripheral ablation zone, and surrounding normal tissue. It was correlated with elastography images. Conclusion: Monitoring of the results of ablation therapies shortly after their application is possible through imaging studies. It allows determining the size of the ablation zone, its characteristics, ruling out complications, and its early results. Elastography could efficiently support this goal.

A pre-operative platelet transfusion algorithm for patients with cirrhosis and hepatocellular carcinoma undergoing laparoscopic microwave ablation

BACKGROUND

Thrombocytopenia is a common finding in patients with chronic liver disease. It is associated with poor clinical outcomes due to increased risk of bleeding after even minor procedures. We sought to determine an algorithm for pre-operative platelet transfusion in patients with cirrhosis and hepatocellular carcinoma (HCC) undergoing laparoscopic microwave ablation (MIS-MWA).

METHODS

A retrospective review identified all patients with cirrhosis and HCC who underwent MIS-MWA at a single tertiary institution between 2007 and 2019. Demographics, pre-operative and post-operative laboratory values, transfusion requirements, and bleeding events were collected. The analyzed outcome of bleeding risk included any transfusion received intra-operatively or a transfusion or surgical intervention post-operatively. Logistic regression models were created to predict bleeding risk and identify patients who would benefit from pre-operative transfusion.

RESULTS

There were 433 patients with cirrhosis and HCC who underwent MIS-MWA identified; of these, 353 patients had complete laboratory values and were included. Bleeding risk was evaluated through bivariate analysis of statistically and clinically significant variables. The accuracy of both models was substantiated through bootstrap validation for 500 iterations (model 1: ROC 0.8684, Brier score 0.0238; model 2: ROC 0.8363, Brier score 0.0252). The first model captured patients with both thrombocytopenia and anemia: platelet count < 60 × 10⁹ / L (OR 7.75, p 0.012, CI 1.58-38.06) and hemoglobin < 10 gm/dL (OR 5.76, p 0.032, CI 1.16-28.63). The second model captured patients with thrombocytopenia without anemia: platelet count < 30 × 10⁹/L (OR 8.41, p 0.05, CI 0.96-73.50) and hemoglobin > 10 gm/dL (OR 0.16, p 0.026, CI 0.031-0.80).

CONCLUSION

The prediction of patients with cirrhosis and HCC requiring pre-operative platelet transfusions may help to avoid bleeding complications after invasive procedures. This study needs to be prospectively validated and ultimately may be beneficial in assessment of novel therapies for platelet-based clinical treatment in liver disease.

Microwave ablation of liver cancer: An updated review

The treatment methods for early liver cancer include surgical resection, liver transplantation, and local ablation. Among them, microwave ablation (MWA) is widely used in clinical practice because of its outstanding advantages, such as minimal invasiveness, radical curative effect, short treatment time, few complications, and no heat-sink effect, especially for the treatment of tumors adjacent to major vessels and hepatic metastases. However, MWA also has limitations such as unpredictable size and shape of the ablation area. This review systematically illustrates the effectiveness and safety of MWA in the treatment of liver cancer. Meanwhile, the relative superiority of the new generation of MWA is discussed, with an aim to provide reference for MWA of liver cancer.

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.

A review of conventional and newer generation microwave ablation systems for hepatocellular carcinoma

Although microwave ablation (MWA) exhibits a high thermal efficiency, the major limitation of conventional MWA systems is the lack of predictability of the ablation zone size and shape. Therefore, a specific newer generation MWA system, The Emprint™ Ablation System with Thermosphere™ Technology, was designed to create predictable large spherical zones of ablation that are not impacted by varying tissue environments. The time required for ablation with MWA systems is short, and the shape of the necrosis is elliptical with the older systems and spherical with the new system. In addition, because MWA has no heat-sink effect, it can be used to ablate tumors adjacent to major vessels. Although these factors yield a large ablation volume and result in good local control, excessive ablation of liver tissue and unexpected ablation of surrounding organs are possible. Therefore, MWA should be carefully performed. This review highlights the efficacy and complications of MWA performed with conventional systems and the newer generation system in patients with hepatocellular carcinoma (HCC). MWA with the newer generation system seems to be a promising treatment option for large HCCs and secondary hepatic malignancies, with several advantages over other available ablation techniques, including conventional MWA. However, further randomized controlled trials are necessary to fully clarify the benefits and pitfalls of this new system.

Microwave ablation compared with radiofrequency ablation for treatment of hepatocellular carcinoma and liver metastases: a systematic review and meta-analysis

Purpose

Percutaneous ablation techniques, including microwave ablation (MWA) and radiofrequency ablation (RFA), have become important minimally invasive treatment options for liver cancer. This systematic review compared MWA with RFA for treatment of liver cancer.

Methods

The systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic search of MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials was conducted for randomized and observational studies published from 2006 onwards. A random-effects model was used for meta-analyses and local tumor progression (LTP), technique efficacy, overall survival (OS), disease-free survival (DFS), intrahepatic de novo lesions (IDL), extrahepatic metastases (EHM), length of stay (LOS), and complications were analyzed. Subgroup and sensitivity analyses were also conducted.

Results

Of 1379 studies identified, 28 randomized and observational studies met inclusion criteria. The main analysis demonstrated that LTP was significantly reduced by 30% with MWA versus RFA (RR=0.70; P=0.02) (all studies) and by 45% with MWA versus RFA (RR=0.55; P=0.007) (randomized studies only). There were no significant differences between MWA and RFA for other efficacy and safety outcomes. Higher frequency (2450 MHz) and larger tumor size (≥2.5 cm) are amongst variables that may be associated with improved outcomes for MWA. Sensitivity analyses were generally congruent with the main results.

Conclusion

MWA is at least as safe and effective as RFA for treating liver cancer and demonstrated significantly reduced LTP rates. Future studies should assess time and costs associated with these two treatment modalities.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

MRI-Guided Cryoablation of Hepatic Dome Hepatocellular Carcinomas Using 1-T Open High-Field-Strength Scanner

OBJECTIVE. The objective of our study was to prospectively evaluate the feasibility, safety, and effectiveness of 1-T open MRI-guided percutaneous cryoablation of hepatic dome hepatocellular carcinomas (HCCs). SUBJECTS AND METHODS. Thirty-seven patients with 37 hepatic dome HCCs underwent MRI-guided percutaneous cryoablations. MR fluoroscopy with a freehand technique was applied in the procedure. All lesions ranged in size from 8 to 38 mm. Patients were followed for at least 12 months after cryoablation or until death. Survival period, local tumor control, and complications were recorded. RESULTS. MRI-guided percutaneous cryoablation procedures were successfully performed on all 37 lesions. The technical success rate was 100%. The median follow-up time was 21.0 months (range, 10-26 months). Two patients with local tumor progression at the 4th and 11th month after the procedure were treated with a supplementary cryoablation. One patient died of upper gastrointestinal hemorrhage at the 10th month after cryoablation. Local tumor progression and overall survival rates were 2.7% (1/37) and 100% (37/37) at 6 months and 5.4% (2/37) and 97.3% (36/37) at 1 year, respectively. Postoperative hydrothorax that required chest tube drainage occurred in two patients; no other severe complications occurred. CONCLUSION. Cryoablation of hepatic dome HCCs with 1-T open MRI guidance is a feasible, safe, and effective therapy method.

Radiofrequency ablation following artificial ascites and pleural effusion creation may improve outcomes for hepatocellular carcinoma in high-risk locations

PURPOSE

To investigate the outcomes of radiofrequency ablation (RFA) following artificial ascites (AA) and artificial pleural effusion (AP) creation for hepatocellular carcinoma (HCC) in high-risk locations.

MATERIALS AND METHODS

Eligible patients were divided into 2 study periods (non-AAAP and AAAP groups) with AAAP performed in the latter period. Local tumor progression, primary technique effectiveness and complications were compared between patients with and without AAAP. Cumulative probability of local tumor progression and overall survival were estimated with Kaplan-Meier curves.

RESULTS

One hundred thirty-eight patients with 195 tumors were evaluated. AAAP was performed in 48 patients with 76 tumors. Local tumor progression rates at 12 and 24 months were 9.3% and 22.2% in the non-AAAP group versus 5.5% and 9% in the AAAP group (p < 0.0001). Primary technique effectiveness was achieved in 76.5% of the non-AAAP group versus 89.5% of the AAAP group (p = 0.046). Night (7.6%) major complications occurred in the non-AAAP group and 2 (2.6%) cases occurred in the AAAP group. Therapy-oriented severity grading system after RFA was lower in the AAAP group (p = 0.02). Overall survival rates at 12 and 24 months were 85.6% and 77.7% in the non-AAAP group versus 97.2% and 89.7% in the AAAP group (p = 0.033).

CONCLUSION

RFA following AA and AP for high-risk located HCC may improve outcomes.

Comparison of microwave ablation and radiofrequency ablation for hepatocellular carcinoma: a systematic review and meta-analysis

BACKGROUND

Microwave ablation (MWA) has several advantages over radiofrequency ablation (RFA) for the treatment of hepatocellular carcinoma (HCC). We aimed to compare the efficacy and safety of MWA with those of RFA for HCC from the perspectives of percutaneous and laparoscopic approaches.

METHODS

PubMed/MEDLINE, Embase, the Cochrane library, and China Biology Medicine databases were searched. Studies comparing the efficacy and safety of MWA with those of RFA in patients with HCC were considered eligible. Complete ablation (CA), local recurrence (LR), disease-free survival (DFS), overall survival (OS), and the major complication rate were compared between MWA and RFA.

RESULTS

Four randomized controlled trials and 10 cohort studies were included. For percutaneous ablation, no significant difference was found between MWA and RFA regarding CA, LR, DFS, OS, and the major complication rate. A subgroup analysis of tumors measuring ≥3 cm revealed no difference in CA and LR for percutaneous ablation. For laparoscopic ablation, a significantly lower LR rate and a non-significant trend toward a higher major complication rate were observed for the MWA group (odds ratio [OR] 2.16, 95% confidence interval [CI] 1.16-4.02, p = .01 for LR; OR 0.21, 95% CI 0.04-1.03, p = .05 for major complication rate). CA, DFS, and OS were similar between the two groups.

CONCLUSIONS

Percutaneous (P)-MWA had similar therapeutic effects compared with P-RFA for HCC. Patients undergoing laparoscopic MWA had a lower LR rate; however, their major complication rate appeared to be higher. The superiority of MWA over RFA remains unclear and needs to be confirmed by high-quality evidence.

Defeating Cancers' Adaptive Defensive Strategies Using Thermal Therapies: Examining Cancer's Therapeutic Resistance, Ablative, and Computational Modeling Strategies as a means for Improving Therapeutic Outcome

BACKGROUND

Diverse thermal ablative therapies are currently in use for the treatment of cancer. Commonly applied with the intent to cure, these ablative therapies are providing promising success rates similar to and often exceeding "gold standard" approaches. Cancer-curing prospects may be enhanced by deeper understanding of thermal effects on cancer cells and the hosting tissue, including the molecular mechanisms of cancer cell mutations, which enable resistance to therapy. Furthermore, thermal ablative therapies may benefit from recent developments in computer hardware and computation tools for planning, monitoring, visualization, and education.

METHODS

Recent discoveries in cancer cell resistance to destruction by apoptosis, autophagy, and necrosis are now providing an understanding of the strategies used by cancer cells to avoid destruction by immunologic surveillance. Further, these discoveries are now providing insight into the success of the diverse types of ablative therapies utilized in the clinical arena today and into how they directly and indirectly overcome many of the cancers' defensive strategies. Additionally, the manner in which minimally invasive thermal therapy is enabled by imaging, which facilitates anatomical features reconstruction, insertion guidance of thermal probes, and strategic placement of thermal sensors, plays a critical role in the delivery of effective ablative treatment.

RESULTS

The thermal techniques discussed include radiofrequency, microwave, high-intensity focused ultrasound, laser, and cryosurgery. Also discussed is the development of thermal adjunctive therapies-the combination of drug and thermal treatments-which provide new and more effective combinatorial physical and molecular-based approaches for treating various cancers. Finally, advanced computational and planning tools are also discussed.

CONCLUSION

This review lays out the various molecular adaptive mechanisms-the hallmarks of cancer-responsible for therapeutic resistance, on one hand, and how various ablative therapies, including both heating- and freezing-based strategies, overcome many of cancer's defenses, on the other hand, thereby enhancing the potential for curative approaches for various cancers.

Utility of endoscopic ultrasound and endoscopy in diagnosis and management of hepatocellular carcinoma and its complications: What does endoscopic ultrasonography offer above and beyond conventional cross-sectional imaging?

Hepatocellular carcinoma constitutes over 90% of the primary liver tumors, the rest being cholangiocarcinoma. It has an insidious presentation, which is responsible for the delayed presentation. Hence, the management strategy relies on screening to diagnose it an early stage for curative resection and/or treatment with local ablative techniques or chemotherapy. However, even with different screening programs, more than 60% of tumors are still detected at an advanced stage, leading to an unchanged mortality rate, thereby implying a room for improvement in the screening and diagnostic process. In the last few years, there has been evolution of utility of endoscopy, specifically endoscopic ultrasonography along with Fine needle aspiration, for this purpose, which we comprehensively review in this article.

Microwave ablation for treatment of hepatic neoplasia in five dogs

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

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.

Oligometastatic Disease in Pancreatic Cancer - How to Proceed?

BACKGROUND

Pancreatic cancer is a highly aggressive malignancy and will become the second leading cause of cancer-related death in the USA and also in Germany by 2030. Furthermore, the majority of patients with pancreatic ductal adenocarcinoma (PDAC) will present with distant metastases, limiting surgical management in this population as there is little evidence available to support surgical or ablative treatment options for advanced-stage disease. However, highly selected patients suffering from synchronous and metachronous oligometastatic PDAC may potentially benefit from a surgical resection with an acceptable morbidity.

METHODS

This review summarizes and discusses the current literature on the management of oligometastatic disease regarding PDAC, focusing on para-aortic lymph nodes as well as isolated hepatic and pulmonary metastases.

RESULTS AND CONCLUSION

In order to further investigate the feasibility and efficacy of such an approach, a prospective multicenter trial, in which survival and quality of life after metastatic resection and systemic chemotherapy is evaluated, has to be initiated. Additionally, local and locoregional ablation techniques or stereotactic body radiation therapy as therapeutic options for isolated metastases in PDAC need further research in order to determine their significance and benefit.

Current role of microwave ablation in the treatment of small hepatocellular carcinomas

Percutaneous radiofrequency ablation (RFA) can be as effective as surgical resection in terms of overall survival and recurrence-free survival rates in patients with small hepatocellular carcinoma (HCC). Effectiveness of RFA is adversely influenced by heat-sink effect. Other ablative therapies could be considered for larger tumors or for tumors located near the vessels. In this regard, recent improvements in microwave energy delivery systems seem to open interesting perspectives to percutaneous ablation, which could become the ablation technique of choice in the near future. Microwave ablation (MWA) has the advantages of possessing a higher thermal efficiency. It has high efficacy in coagulating blood vessels and is a relatively fast procedure. The time required for ablation is short and the shape of necrosis is elliptical with the older systems and spherical with the new one. There is no heat-sink effect and it can be used to ablate tumors adjacent to major vessels. These factors yield a large ablation volume, and result in good local control and fewer complications. This review highlights the most relevant updates on MWA in the treatment of small (<3 cm) HCC. Furthermore, we discuss the possibility of MWA as the first ablative choice, at least in selected cases.

MWA Versus RFA for Perivascular and Peribiliary CRLM: A Retrospective Patient- and Lesion-Based Analysis of Two Historical Cohorts

Purpose

To retrospectively analyse the safety and efficacy of radiofrequency ablation (RFA) versus microwave ablation (MWA) in the treatment of unresectable colorectal liver metastases (CRLM) in proximity to large vessels and/or major bile ducts.

Method and Materials

A database search was performed to include patients with unresectable histologically proven and/or ¹⁸F–FDG–PET avid CRLM who were treated with RFA or MWA between January 2001 and September 2014 in a single centre. All lesions that were considered to have a peribiliary and/or perivascular location were included. Univariate logistic regression analysis was performed to assess the distribution of patient, tumour and procedure characteristics. Multivariate logistic regression was used to correct for potential confounders.

Results

Two hundred and forty-three patients with 774 unresectable CRLM were ablated. One hundred and twenty-two patients (78 males; 44 females) had at least one perivascular or peribiliary lesion (n = 199). Primary efficacy rate of RFA was superior to MWA after 3 and 12 months of follow-up (P = 0.010 and P = 0.022); however, after multivariate analysis this difference was non-significant at 12 months (P = 0.078) and vanished after repeat ablations (P = 0.39). More CTCAE grade III complications occurred after MWA versus RFA (18.8 vs. 7.9 %; P = 0.094); biliary complications were especially common after peribiliary MWA (P = 0.002).

Conclusion

For perivascular CRLM, RFA and MWA are both safe treatment options that appear equally effective. For peribiliary CRLM, MWA has a higher complication rate than RFA, with similar efficacy. Based on these results, it is advised to use RFA for lesions in the proximity of major bile ducts.

A Recent Advance in Image-Guided Locoregional Therapy for Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the third most common cause of cancer-related deaths. Hepatic resection and liver transplantation are considered to be the preferred treatment for HCC. However, as novel therapeutic options such as image-guided locoregional therapies have emerged and been refined, the manner in which HCC is treated has changed dramatically compared with what it was considered just 2 decades earlier.

SUMMARY

This study reviews the current results of various image-guided locoregional therapies for treating HCC, especially focusing on thermal ablative and transarterial techniques.

KEY MESSAGE

Advances in image-guided locoregional therapies, including local ablative therapy and transarterial therapy, have led to a major breakthrough in the management of HCC. Both survival rates and cure rates of patients with HCC have improved markedly since the introduction of these techniques.

PRACTICAL IMPLICATIONS

Radiofrequency ablation is currently considered as an alternative to surgical resection for patients with early-stage HCC. A newer technique of ablation such as microwave ablation is increasingly being used, especially for large HCC. Transarterial chemoembolization has become a standard care for asymptomatic patients with multinodular tumors in intermediate-stage disease, and transarterial radioembolization has become the method of choice in HCC cases with portal vein thrombosis. Moreover, combination treatment modalities, such as thermal-based ablation combined with transarterial chemoembolization or ¹²⁵I seed implant brachytherapy, may further broaden their clinical indications for HCC. Moreover, use of localized radiation in combination with thermal ablation has been reported to improve tumor control and long-term survival.

Interventional oncology: pictorial review of post-ablation imaging of liver and renal tumors

Percutaneous image-guided ablation is now commonly performed in many institutions for the treatment of hepatocellular carcinoma, liver metastases, and renal cell carcinoma in select patients. Accurate interpretation of post-ablation imaging is of supreme importance because treatment algorithms for these diseases rely heavily on imaging to guide management decisions. The purpose of this pictorial essay is to provide abdominal imagers with a review of the indications for percutaneous ablation in the abdomen, a basic overview of ablation modalities in clinical use today, the expected post-ablation imaging findings in the liver and kidney, and potential complications of hepatic and renal ablation procedures.

CT-Guided Percutaneous Microwave Ablation of Tumors in the Hepatic Dome: Assessment of Efficacy and Safety

PURPOSE

To evaluate the technique, efficacy, safety, and clinical outcomes of CT-guided microwave ablation of tumors in the hepatic dome.

MATERIALS AND METHODS

Retrospective review was conducted of 46 consecutive patients (31 men and 15 women; mean age, 64 y) treated with CT-guided microwave ablation for hepatic-dome tumors between June 2011 and December 2014. Baseline demographics of sex, tumor diagnosis, tumor location, tumor size, and technical details were recorded. Technical success was evaluated. Treatment response was assessed per European Association for the Study of the Liver criteria. Overall success and overall survival were calculated, and complications were recorded.

RESULTS

Forty-eight tumors were treated. Tumor locations included segments VIII (n = 32), VII (n = 10), and VIa (n = 6). Mean tumor size was 2.4 cm (range, 0.9-5.2 cm). Thirty-four tumors (70%) were treated following creation of artificial ascites with 0.9% normal saline solution (mean volume, 1,237 mL; range, 300-3,000 mL). The technical success rate was 100%, and the complete response rate was 94%. Overall survival rate was 73.9% over 24.7 months of follow-up. There were no major complications. Two patients experienced small, asymptomatic pneumothoraces that were aspirated at the time of the procedure and required no further treatment.

CONCLUSIONS

CT-guided microwave ablation of tumors in the hepatic dome is associated with a high technical success rate, high complete response rate, and low complication rate.

Percutaneous thermal ablation for primary hepatocellular carcinoma: A systematic review and meta-analysis

BACKGROUND AND AIM

Percutaneous thermal ablation using radiofrequency ablation (RFA) and microwave ablation (MWA) are both widely available curative treatments for hepatocellular carcinoma. Despite significant advances, it remains unclear which modality results in better outcomes. This meta-analysis of randomized controlled trials (RCT) and observational studies was undertaken to compare the techniques in terms of effectiveness and safety.

METHODS

Electronic reference databases (Medline, EMBASE and Cochrane Central) were searched between January 1980 and May 2014 for human studies comparing RFA and MWA. The primary outcome was the risk of local tumor progression (LTP). Secondary outcomes were complete ablation (CA), overall survival, and major adverse events (AE). The ORs were combined across studies using the random-effects model.

RESULTS

Ten studies (two prospective and eight retrospective) were included, and the overall LTP rate was 13.6% (176/1298). There was no difference in LTP rates between RFA and MWA [OR (95% CI): 1.01(0.67-1.50), P = 0.9]. The CA rate, 1- and 3-year overall survival and major AE were similar between the two modalities (P > 0.05 for all). In subgroup analysis, there was no difference in LTP rates according to study quality, but LTP rates were lower with MWA for treatment of larger tumors [1.88(1.10-3.23), P = 0.02]. There was no significant publication bias or inter-study heterogeneity (I(2) < 50% and P > 0.1) observed in any of the measured outcomes.

CONCLUSION

Overall, both RFA and MWA are equally effective and safe, but MWA may be more effective compared to RFA in preventing LTP when treating larger tumors. Well-designed, larger, multicentre RCTs are required to confirm these findings.

Microwave ablation versus radiofrequency ablation for the treatment of hepatocellular carcinoma: A systematic review and meta-analysis

PURPOSE

Radiofrequency ablation (RFA) and microwave ablation (MWA) are the two main percutaneous techniques for the treatment of unresectable hepatocellular carcinoma (HCC). However, to date, studies comparing the two therapies have provided discordant results. The aim of this meta-analysis is to evaluate the efficacy and safety of the two treatments for HCC patients.

MATERIALS AND METHODS

A computerised bibliographic search was performed on PubMed/MEDLINE, Embase, Google Scholar and Cochrane library databases. The rates of complete response (CR), local recurrence (LRR), 3-year survival (SR) and major complications were compared between the two treatment groups by using the Mantel-Haenszel test in cases of low heterogeneity or the DerSimonian and Laird test in cases of high heterogeneity. Sources of heterogeneity were investigated using subgroup analyses. In order to confirm our finding, sensitivity analysis was performed restricting the analysis to high-quality studies.

RESULTS

One randomised controlled trial (RCT) and six retrospective studies with 774 patients were included in the meta-analysis. A non-significant trend of higher CR rates in the patients treated with MWA was found (odds ratio (OR) = 1.12, 95% confidence interval (CI) 0.67-1.88, p = 0.67]. Overall LRR was similar between the two treatment groups (OR 1.01, 95% CI 0.53-1.87, p = 0.98) but MWA outperformed RFA in cases of larger nodules (OR 0.46, 95% CI 0.24-0.89, p = 0.02). 3-year SR was higher after RFA without statistically significant difference (OR 0.95, 95% CI 0.58-1.57, p = 0.85). Major complications were more frequent, although not significantly, in MWA patients (OR 1.63, 95% CI 0.88-3.03, p = 0.12).

CONCLUSIONS

Our results indicate a similar efficacy between the two percutaneous techniques with an apparent superiority of MWA in larger neoplasms.

Liver Ablation: Best Practice

Tumor ablation in the liver has evolved to become a well-accepted tool in the management of increasing complex oncologic patients. At present, percutaneous ablation is considered first-line therapy for very early and early hepatocellular carcinoma and second-line therapy for colorectal carcinoma liver metastasis. Because thermal ablation is a treatment option for other primary and secondary liver tumors, an understanding of the underlying tumor biology is important when weighing the potential benefits of ablation. This article reviews ablation modalities, indications, patient selection, and imaging surveillance, and emphasizes technique-specific considerations for the performance of percutaneous ablation.

Surgery for oligometastasis of pancreatic cancer

The incidence of pancreatic adenocarcinoma (PDAC) has steadily increased over the past several decades. The majority of PDAC patients will present with distant metastases, limiting surgical management in this population. Hepatectomy and pulmonary metastasectomy (PM) has been well established for colorectal cancer patients with isolated, resectable hepatic or pulmonary metastatic disease. Recent advancements in effective systemic therapy for PDAC have led to the selection of certain patients where metastectomy may be potentially indicated. However, the indication for resection of oligometastases in PDAC is not well defined. This review will discuss the current literature on the surgical management of metastatic disease for PDAC with a specific focus on surgical resection for isolated hepatic and pulmonary metastases.