Comparison of Laparoscopic Microwave to Radiofrequency Ablation of Small Hepatocellular Carcinoma (≤3 cm)

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.

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.

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

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

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.

Outcome of Near-infrared Fluorescence-navigated Pulmonary Metastasectomy for Hepatocellular Carcinoma

OBJECTIVES

Pulmonary metastasectomy for hepatocellular carcinoma (HCC) is suitable in highly selected patients. However, complete resection is challenging in HCC patients with multiple lung metastases. We aimed to describe the clinical utility and survival outcome of indocyanine green (ICG) fluorescence-navigated resection of HCC lung metastases.

METHODS

From October 2015 to March 2021, 15 HCC patients with pulmonary metastasis underwent NIR fluorescence imaging thoracoscopic surgery. ICG was administered through peripheral veins preoperatively. All suspected lesions detected by palpation, white-light thoracoscopy or near-infrared (NIR) imaging were resected. After metastasectomy, all patients were followed up at regular intervals of 6-12 months.

RESULTS

A total of 90 metastatic HCC nodules were resected in 15 patients. All patients received sublobar resections, during which 89 lesions were removed by wedge resection and 1 lesion was managed via segmentectomy. Under NIR fluorescence imaging, 81 nodules successfully demonstrated fluorescence during the surgery, while 9 metastatic nodules were undetected. The median signal-to-background ratio (SBR) of the nodules was 3.34. Five patients died and 7 patients relapsed by the end of observation. The median overall survival (OS) and disease-free survival (DFS) were 47.1 months and 17.3 months, respectively. The 1-year OS and DFS rates were 71.1% and 57.8%, respectively.

CONCLUSIONS

ICG fluorescence imaging technology is useful for visualization of the peripheral tumours to assist in pulmonary metastasectomy for HCC. In addition, this technology has the potential to detect the small tumour that are missed in preoperative examinations, which might be beneficial for HCC patients with multiple lung metastases.

Analysis of the efficacy of microwave ablation in the treatment of early hepatic alveolar echinococcosis: A propensity score matching based study

BACKGROUND

To explore the efficacy of microwave ablation (MWA) in the treatment of hepatic alveolar echinococcosis (HAE) with a diameter of ≤5 cm.

METHOD

From June 2014 to January 2020, patients diagnosed with HAE were retrospectively analyzed. After balancing the confounding factors by propensity score matching (PSM) , the patients were divided into MWA group (n = 20) and radical operation group (n = 20) by 1:1 matching. The safety and effectiveness of MWA were assessed by comparing the differences between the two groups in terms of postoperative general laboratory indices, grading of postoperative complications, length of postoperative hospitalization, the outcome of treatment, and disease recurrence.

RESULT

After PSM, all confounders were not statistically different (P>0.05) . Compared with the radical surgery group, patients in the MWA group had lower postoperative ALT and WBC elevations (P<0.001) , shorter postoperative hospital stay (P<0.001) ) , lower hospital costs (P<0.001) . The effective rate of the two groups was 100%. There was no statistical difference in the incidence of postoperative complications and recurrence rate (P>0.05).

CONCLUSION

MWA is a safe and effective means of treating HAE ≤ 5 cm in diameter.

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.

Efficacy and safety of various primary treatment strategies for very early and early hepatocellular carcinoma: a network meta-analysis

BACKGROUND

Several treatments are available for treatment of early and very early-stage Hepatocellular Carcinoma, also known as small Hepatocellular Carcinoma (SHCC). However, there is no consensus with regards to the efficacies of these methods. We aimed at identifying the most effective initial treatment strategy for SHCC through Bayesian network meta-analyses.

METHODS

Studies published between January, 2010, and February, 2021 were searched in EMBASE, Cochrane Library, PubMed and Web of science databases, and conference proceedings for trials. The included studies reported the survival outcomes of very early and early Hepatocellular Carcinoma patients subjected to radiofrequency ablation (RFA), microwave ablation (MWA), surgical resection (SR), transarterial chemoembolization (TACE), percutaneous ethanol injection (PEI), minimally invasive liver surgery (MIS), stereotactic body radiotherapy (SBRT) and cryoablation (CA). Then, data were extracted from studies that met the inclusion criteria. Patient survival data were retrieved from the published Kaplan-Meier curves and pooled. A Bayesian random-effects model was used to combine direct and indirect evidence.

RESULTS

A total of 2058 articles were retrieved and screened, from which 45 studies assessing the efficacies of 8 different treatments in 11,364 patients were selected. The included studies had high methodological quality. Recurrence free survival* (progression/recurrence/relapse/disease/tumor-free survival were combined and redefined as RFS*) and overall survival (OS) outcomes were highest in MIS-treated patients (HR 0·57, 95% confidence intervals [CI] 0·38-0·85; HR 0.48,95% CI 0.36-0.64, respectively), followed by SR-treated patients (HR 0.60, 95% CI 0.50-0.74; HR 0.62, 95% CI 0.55-0.72, respectively). TACE was highly efficacious (58.9%) at decreasing the rates of major complications. Similar findings were obtained through sensitivity analysis, and in most of the prognostic subgroups.

CONCLUSIONS

MIS and SR exhibited the highest clinical efficacies, however, they were associated with higher rates of complications. Ablation is effective in small tumors, whereas SBRT is a relatively promising treatment option for SHCC. More well-designed, large-scale randomized controlled trials should be performed to validate our findings.

Image-guided locoregional non-intravascular interventional treatments for hepatocellular carcinoma: Current status

Hepatocellular carcinoma (HCC) is one of the most deadly and frequent cancers worldwide, although great advancement in the treatment of this malignancy have been made within the past few decades. It continues to be a major health issue due to an increasing incidence and a poor prognosis. The majority of patients have their HCC diagnosed at an intermediate or advanced stage in theUSA or China. Curative therapy such as surgical resection or liver transplantation is not considered anoption of treatment at these stages.

Transarterial chemoembolization (TACE), the most widely used locoregional therapeutic approach, used to be the mainstay of treatment for cases with unresectable cancer entities. However, for those patients with hypovascular tumors or impaired liver function reserve, TACE is a suboptimal treatment option. For example, embolization does not result in complete coverage of a hypovascular tumor, and may rather promotes postoperative tumor recurrence, or leave residual tumor, in these TACE-resistance patients. In addition, TACE carries a higher risk of hepatic decompensation in patients with poor liver function or reserve.

Non-vascular interventional locoregional therapies for HCC include radiofrequency ablation (RFA), microwave ablation (MWA), high-intensity focused ultrasound (HIFU), laser-induced thermotherapy (LITT), cryosurgical ablation (CSA), irreversible Electroporation (IRE), percutaneous ethanol injection (PEI), and brachytherapy. Recent advancements in these techniques have significantly improved the treatment efficacy of HCC and expanded the population of patients who qualify for treatment. This review embraces the current status of imaging-guided locoregional non-intravascular interventional treatments for HCCs, with a primary focus on the clinical evaluation and assessment of the efficacy of combined therapies using these interventional techniques.

Transcatheter Arterial Chemoembolization Combined with Simultaneous Cone-beam Computed Tomography-guided Microwave Ablation in the Treatment of Small Hepatocellular Carcinoma: Clinical Experiences From 50 Procedures

RATIONALE AND OBJECTIVES

To investigate the technical success, safety and outcomes of transcatheter arterial chemoembolization (TACE) combined with simultaneous cone-beam computed tomography (CBCT)-guided microwave ablation (MWA) in small hepatocellular carcinoma (SHCC).

MATERIALS AND METHODS

Retrospective analysis of 66 lesions in 50 patients (38 men, 12 women) who underwent TACE combined with simultaneous CBCT-guided MWA for SHCC. After 1 month of treatment, the tumor responses were assessed using the mRECIST criteria, along with interventional-related complications and changes in hepatic and renal function. Moreover, progression-free survival (PFS) and overall survival (OS) were calculated.

RESULTS

All patients achieved technical success. The mean target tumor size was 3.4 ± 0.7 (range, 2.2-4.9) cm. The mean energy, ablation duration per tumor, and the mean safety margin were 51.3  ±  8.4  kJ, 6.7  ±  0.8  minutes and 1.4 ± 0.6 cm, respectively. The 1-, 3-, and 5-year PFS rates were 90.0%, 65.4%, and 35.7%, respectively, with a mean PFS of 43.46 months; and the 1-, 3-, and 5-year OS rates were 98.0%, 89.8%, and 74.3%, respectively, with a mean OS of 54.90 months. Multivariate Cox regression analysis further illustrated that TACE combined with MWA in the treatment of a single tumor with a diameter of less than 3 cm was an independent protective factor for PFS and OS (p < 0.001). The patients had no major complications. Among the exceptions, one patient (2%) had an asymptomatic perihepatic effusion that resolved spontaneously, two patients (4%) developed massive right pleural effusion, requiring thoracic drainage, and another patient (2%) developed a hepatic subcapsular hemorrhage required interventional embolization.

CONCLUSION

CBCT-guided TACE combined with simultaneous MWA was a safe and successful treatment of SHCC with a high technical efficacy.

A novel prognostic nomogram for hepatocellular carcinoma after thermal ablation

It remains impossible to accurately assess the prognosis after thermal ablation in patients with hepatocellular carcinoma (HCC). Our aim was to build a nomogram to predict the survival rate of HCC patients after thermal ablation. We developed and validated a nomogram using data of 959 HCC patients after thermal ablation from two centers. Harrell's concordance index (C-index), calibration plot and Decision curve analysis (DCA) were used to measure the performance of the nomogram, and we compared it with the Barcelona Clinic Liver Cancer (BCLC) staging system and a previous nomogram. Six variables including age, serum albumin, operation method, risk area, tumor number and early recurrence were selected to construct the nomogram. In the training cohort, internal validation cohort, and external validation cohort, the nomogram all had a higher C-index to predict survival rate than both the BCLC staging system and the previous nomogram (0.736, 0.558 and 0.698, respectively; 0.763, 0.621 and 0.740, respectively; and 0.825, 0.551 and 0.737, respectively). Calibration plots showed a high degree of consistency between prediction and actual observation. Decision curve analysis (DCA) presented that compared with BCLC system and the previous nomogram, our nomogram had the highest net benefit. In all three cohorts, the nomogram could accurately divide patients into three subgroups according to predicted survival risk. A nomogram was developed and validated to predict survival of HCC patients who underwent thermal ablation, which is helpful for prognostic prediction and individual surveillance in clinical practice.

Efficacy of microwave ablation versus radiofrequency ablation for hepatocellular carcinoma: a propensity score analysis

Purpose

To evaluate the efficacy and safety of radiofrequency ablation (RFA) and new-generation microwave ablation (MWA) for the treatment of hepatocellular carcinoma (HCC).

Methods

The propensity score matching method was applied to patients with HCC treated with MWA (93 patients) or RFA (156 patients) at a single institution from January 2014 to April 2020. The local tumor progression (LTP), intrahepatic distant recurrence (IDR), and recurrence-free survival (RFS) of the two matched therapies were analyzed using the Kaplan–Meier method. Cox proportional hazard models were used to identify risk factors for LTP and RFS. The therapeutic effects and complications of the two treatments were also compared.

Results

The LTP, IDR, and RFS of MWA and RFA were equivalent (LTP: hazard ratio [HR] = 0.87; 95% confidence interval [95% CI] 0.36- 2.07; P = 0.746, IDR: HR = 1.03; 95% CI 0.61–1.73; P = 0.890, RFS: HR = 1.15; 95% CI 0.69–1.91; P = 0.566). Para-vessel lesions was the only risk factor for LTP, whereas age, previous treatment, Albumin-Bilirubin score, and tumor diameter were risk factors for RFS. On the other hand, the ablation time per nodule (6.79 ± 2.73 and 9.21 ± 4.90 min; P = 0.008) and number of sessions per nodule required to achieve technical success (1.16 ± 0.39 and 1.34 ± 0.57; P = 0.009) were significantly lower in MWA than in RFA. The major complication rate of MWA and RFA was also equivalent.

Conclusion

MWA and RFA have similar therapeutic effects and safety, although MWA has advantages over RFA regarding efficacy, including shorter ablation time and fewer sessions required.

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

Importance

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

Objective

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

Evidence Review

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

Findings

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

Conclusion and Relevance

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

Recurrence of Hepatocellular Carcinoma in Hepatitis C Virus (HCV) Liver Transplant Recipients Treated with Pretransplant Direct-Acting Antiviral (DAA) Therapy

Background

Direct-acting antivirals (DAAs) have revolutionized the treatment of hepatitis C virus (HCV). The impact of DAAs on recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) remains uncertain.

Objective

We aimed to evaluate the risk of HCC recurrence in LT recipients cleared of HCV with DAAs at the time of LT compared to a control group of LT recipients who were viremic at the time of LT.

Methods

The study was a single-center, retrospective cohort study of patients undergoing LT for HCV-related HCC from 2002 to 2017. We compared time to post-LT HCC recurrence in patients with a sustained virological response (SVR) from DAAs prior to LT (DAA group) to patients who were viremic at LT (HCV+ group) using Kaplan-Meier analysis. We performed a secondary analysis comparing post-LT HCC recurrence in the DAA group to LT recipients with SVR from interferon-based treatment prior to LT (IFN group).

Results

One hundred fifty-one patients underwent LT for HCC related to HCV: 34 patients in DAA group, 95 patients in HCV+ group, and 22 in IFN group. Kaplan-Meier estimates of being HCC free were 96.2, 96.2, and 78.8% at 6, 12, and 24 months in DAA group, respectively, and 100, 98.6, and 95.8% at 6, 12, and 24 months in the HCV+ group, respectively; p = 0.08. There was no difference observed for HCC recurrence between the DAA and IFN groups. In a multivariate Cox proportional hazards model, DAA use increased the risk of post-LT HCC recurrence (HR 5.2, 95% CI 0.9-29.81, p = 0.07).

Conclusions

A strong trend was observed on both Kaplan-Meier and multivariate analyses toward increased post-LT HCC recurrence in patients who achieved SVR prior to LT with DAAs compared to patients who were viremic at LT. Caution is required when considering pre-LT treatment of HCV with DAAs in patients with HCC.

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.

Prospective double-blinded randomized controlled trial of Microwave versus RadioFrequency Ablation for hepatocellular carcinoma (McRFA trial)

BACKGROUND

Microwave (MWA) and radiofrequency ablation are the commonly used local ablation for hepatocellular carcinoma (HCC). Studies comparing both techniques are scarce. The aim of this study was to compare the efficacy of MWA versus RFA as a treatment for HCC.

METHODS

Patients with HCC who were suitable for local ablation were randomized into MWA or RFA. All patients were followed up regularly with contrast-enhanced computed tomography (CT) performed at 1, 3, 6 and 12 months after ablation. Both patients and the radiologists who interpreted the post-procedure CT scans were blinded to the treatment allocation. Treatment-related morbidity, overall and disease-free survivals were analyzed.

RESULTS

A total of 93 patients were recruited. Among them, 47 and 46 patients were randomized to MWA and RFA respectively. Patients in two groups were comparable in baseline demographics and tumor characteristics. With a median follow-up of around 30 months, there were no significant difference in the treatment-related morbidity, overall and disease-free survivals. MWA had a significantly shorter overall ablation time when compared with RFA (12 min vs 24 min, p < 0.001).

CONCLUSIONS

MWA is no different to RFA with respect to completeness of ablation and survivals. It is, however, as safe and effective as RFA in treating small HCC.

Radiofrequency ablation with four electrodes as a building block for matrix radiofrequency ablation: Ex vivo liver experiments and finite element method modelling. Influence of electric and activation mode on coagulation size and geometry

PURPOSE

Radiofrequency ablation (RFA) is increasingly being used to treat unresectable liver tumors. Complete ablation of the tumor and a safety margin is necessary to prevent local recurrence. With current electrodes, size and shape of the ablation zone are highly variable leading to unsatisfactory local recurrence rates, especially for tumors >3 cm. In order to improve predictability, we recently developed a system with four simple electrodes with complete ablation in between the electrodes. This rather small but reliable ablation zone is considered as a building block for matrix radiofrequency ablation (MRFA). In the current study we explored the influence of the electric mode (monopolar or bipolar) and the activation mode (consecutive, simultaneous or switching) on the size and geometry of the ablation zone.

MATERIALS AND METHODS

The four electrode system was applied in ex vivo bovine liver. The electric and the activation mode were changed one by one, using constant power of 50 W in all experiments. Size and geometry of the ablation zone were measured. Finite element method (FEM) modelling of the experiment was performed.

RESULTS

In ex vivo liver, a complete and predictable coagulation zone of a 3 × 2 × 2 cm block was obtained most efficiently in the bipolar simultaneous mode due to the combination of the higher heating efficacy of the bipolar mode and the lower impedance by the simultaneous activation of four electrodes, as supported by the FEM simulation.

CONCLUSIONS

In ex vivo liver, the four electrode system used in a bipolar simultaneous mode offers the best perspectives as building block for MRFA. These results should be confirmed by in vivo experiments.

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.

[Image-guided, minimally invasive surgery and other local therapeutic procedures for primary liver tumors]

BACKGROUND

The incidence of primary liver tumors is rising. Modern minimally invasive, image-guided procedures offer a potentially curative therapy option.

OBJECTIVE

The aim of this study was to evaluate the multitude of image-guided minimally invasive procedures concerning their evidence-based effect on local tumor control and overall survival.

MATERIAL AND METHODS

A systematic search of MEDLINE focused on hepatocellular cancer, minimally invasive treatment, local ablative therapy, therapeutic stratification and comparative studies was performed.

RESULTS

The level of evidence varied greatly depending on the procedure used. The highest quality evidence including prospective randomized studies was found for radiofrequency ablation (RFA) of hepatocellular cancer. The RFA is superior with respect to local tumor control and overall survival in comparison to other ablative procedures. Prospective randomized studies comparing surgery and RFA showed diverging and contradictory results. Microwave ablation and robotic stereotactic irradiation showed sufficient potential in retrospective studies in comparison to RFA and surgery in order to confirm the techniques in randomized studies. There is only anecdotal evidence concerning high intensity focused ultrasound (HIFU) and irreversible electroporation. Percutaneous ethanol injection (PEI), cryoablation and laser-induced thermal therapy (LITT) were inferior techniques to RFA in most studies.

CONCLUSION

Minimally invasive resection and local ablative therapies based on structured imaging and image reporting can improve the prognosis of patients with hepatocellular cancer even in patients that exceed the BCLC 0/A stage.

Safety and effective of laparoscopic microwave ablation for giant hepatic hemangioma: A retrospective cohort study

Introduction

The purpose of this study was to evaluate the advantages and disadvantages of laparoscopic microwave ablation (LMWA) as compared with conventional open resection (ORES) for the treatment of giant hepatic hemangioma.

Methods

and analysis: A retrospective chart review was conduct on patients with hepatic hemangioma underwent LMWA or ORES between 2014 and 2016.

Results

Of 131 patients, 37 patients underwent ORES and 94 patients underwent LMWA. Blood loss, operative time, postoperative hospital stay, hospital cost (RMB) were significantly different between two groups. Patients after LMWA experienced significantly less pain than those patients undergoing ORES. At a mean follow-up period of 12.8 ± 3.6 months in ORES group and 13.5 ± 2.5 months in LMWA group, no long-term complication was observed.

Conclusion

Compared with ORES, LMWA is a safe and effective minimally invasive for treating giant hepatic hemangioma.

•

Retrospectively analysed the clinical data of patients with hepatic haemangioma and investigated the efficacy of operation.

•

Technical aspects of laparoscopic microwave ablation for giant hepatic haemangioma were listed base on operation experience.

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.

Design of a Novel Electrode of Radiofrequency Ablation for Large Tumors: In Vitro Validation and Evaluation

In the present study, a monopolar expandable electrode (MEE) in radiofrequency ablation (RFA) proposed in our previous study was validated and evaluated using the in vitro experiment and computer simulation. Two commercial RF electrodes (conventional electrode, CE and umbrella electrode, UE) was used to compare the ablation results with MEE using the in vitro egg white model (experiment and computer simulation) and in vivo liver tumor model (computer simulation) to verify the efficacy of MEE in the large tumor ablation. The sharp increase in impedance during RFA procedures was taken as the termination of RFA protocols. The volume and sphericity of ablation zone generated by MEE, CE, and UE in the in vitro egg white experiment were 75.3 1.6 cm3, 2.7 0.4 cm3, 12.4 1.8 cm3 (P <0.001), and 88.1 0.9%, 12.9 1.3%, 62.0 3.0% (P <0.001), respectively. Correspondingly, a similar result was obtained in the egg white simulation. In the liver tumor simulation, the volume and sphpericity of ablation zone generated by MEE, CE, and UE were 35.4 cm3 and 86.8%, 3.7 cm3 and 17.7%, and 12.7 cm3 and 59.6%, respectively. In summary, MEE has the potential to achieve complete ablation in the treatment of large tumors (>3 cm in diameter) compared with CE and UE due to the larger electrode-tissue interface and more round shape of hooks.

Perforation of the esophagus due to thermal injury after laparoscopic radiofrequency ablation for hepatocellular carcinoma: a case for caution

Background

Several reported complications associated with radiofrequency ablation for liver tumors are due to thermal damage of neighboring organs. We herein report a first case of esophageal perforation due to thermal injury of laparoscopic radiofrequency ablation (RFA).

Case presentation

A 75-year-old woman was treated repeatedly with RFA (percutaneous and laparoscopic) and transcatheter arterial chemoembolization for hepatocellular carcinoma. One week after laparoscopic RFA for recurrent HCC located in segment 2 of the liver, dysphagia and thoracic pain occurred. Upper gastrointestinal endoscopy revealed a perforated esophageal ulcer at the esophago-gastric junction. Inflammation was localized because of severe intra-abdominal adhesion due to repeat surgery, so we decided to treat the patient conservatively. The perforation of the esophagus gradually scarred, and exacerbation did not occur after restarting oral intake.

Conclusions

When patients with a history of abdominal surgery or intra-abdominal inflammation undergo thermal ablation therapy, caution is required, as there is a possibility of thermal injury of unexpected organs.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Long-term Survival in Patients Treated with a Robotic Radiosurgical Device for Liver Metastases

Purpose

The treatment of liver metastases with local procedures is a fast progressing field. For the most, long-term survival data is missing raising questions with regard to the efficacy of such modalities when compared to surgical resection. Radiosurgery using the CyberKnife device enables the treatment of liver lesions with a single-session approach. Here we present long-term survival data to explore the curative potential of this strategy.

Materials and Methods

Patients with oligo-metastatic disease limited to the liver have been treated with single-session or hypo-fractioned radiosurgery in curative intent and prospectively followed until death. Follow-up (FU) was performed using magnetic resonance imaging (MRI) 2 months after radiation and at 3-month intervals for the first 2 years. After that annual computed tomography or MRI scans were performed until 5 years post-treatment. Local recurrence in the radiated volume and recurrence outside the treated volume were used to define local and distant progression. Survival times were censored at the time of the last FU.

Results

One hundred twenty-six patients treated between 2005 and 2015 with 194 lesions were included into this study. Median FU was 30.0 months. According to Response Evaluation Criteria in Solid Tumors, 55.2% had a complete remission and 11.3% a partial remission. Seventy-two point two percent recurred outside the radiated lesion and median overall survival was 35.2 months with a 3-year survival rate of 47.7%.

Conclusion

This is currently the largest cohort of stereotactic body radiation therapy treated liver lesions with a median long-term follow of 30 months. Robotic radiosurgery using a single session approach has a high efficacy to control the radiated lesion with the potential to cure patients.

Advances and Future Directions in the Treatment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide. Liver transplant is considered the gold standard for curative therapy for HCC when patients are not candidates for surgical resection or ablation. Because a subset of patients with HCC have a survival rate with liver transplantation that is comparable to that of cirrhotic patients without tumors, the organ allocation system allows for increased priority for transplant in potential recipients within the Milan criteria. With the recent change in the Model for End-Stage Liver Disease exception point allocation, patients with HCC will now need to wait at least 6 months before being awarded extra points. This extension leads to increased time on the transplant waiting list and underscores the importance of locoregional therapy to contain the tumor burden. Fortunately, there has been significant progress in therapy for HCC in the past few decades, namely due to advances in interventional radiology, radiotherapy, and expanded surgical and transplant criteria. Recent advances in immunotherapy also provide promising options for patients who are not candidates for other therapies. This article highlights the major therapeutic options for HCC, including surgical resection, liver transplant, thermal and nonthermal ablation, chemoembolization, radiotherapy, and systemic chemotherapy, as well as discusses the evidence supporting these approaches.