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

Four types of tumor progression after microwave ablation of single hepatocellular carcinoma of ≤5 cm: incidence, risk factors and clinical significance

OBJECTIVES

To evaluate the incidence, risk factors and clinical significance of four types of tumor progression (TP) after microwave ablation (MWA) of single hepatocellular carcinoma (HCC) of <5 cm.

METHODS

The data of 340 treatment-naïve, HCC patients with a single HCC of <5 cm underwent MWA between April 2012 and November 2017 were retrospectively reviewed. TPs including local tumor progression (LTP), intrahepatic distant recurrence (IDR), aggressive intrasegmental recurrence (AIR) and extrahepatic distant recurrence (EDR) were reviewed and compared between BCLC stage 0 and A. Univariate and multivariate analysis were performed on clinicopathological variables and different TPs to identify factors affecting long-term overall survival (OS).

RESULTS

In a median follow-up period of 25.6 months (range, 3.1-61.4 months), the rate of LTP, IDR, AIR and EDR was 6.2% (21/340), 29.1% (98/340), 3.2% (11/340) and 7.9% (27/340). The four types of TP occurrence rates in BCLC stage 0 were comparable to those in BCLC stage A (p = 0.492, 0.971, 0.681 and 0.219). Univariate analysis showed that age (p < 0.001, hazard ratio [HR] = 2.783), comorbidities (p = 0.042, HR = 1.864), IDR, AIR and EDR (p = 0.027, HR = 1.719; p = 0.001, HR = 3.628; p = 0.009, HR = 2.638) were independently associated with OS. Multivariate analysis showed older age (p < 0.001, HR = 2.478), the occurrence of AIR (p < 0.001, HR = 2.648) and the occurrence of EDR (p = 0.002, HR = 2.222), were associated with poor OS.

CONCLUSIONS

The occurrence rate of IDR is the highest of all TPs following MWA of a single HCC of <5cm. Old age, AIR and EDR had an adverse effect on long-term OS.

Radiofrequency versus microwave ablation for hepatocellular carcinoma within the Milan criteria in challenging locations: a retrospective controlled study

PURPOSE

The aim of this study was to compare the safety and efficacy of radiofrequency ablation (RFA) with microwave ablation (MWA) for hepatocellular carcinoma (HCC) within the Milan criteria in challenging locations.

METHODS

This study retrospectively investigated 201 consecutive patients with Milan criteria HCCs who underwent RFA (RFA group, n = 150) or MWA (MWA group, n = 51) between January 2012 and December 2016. Overall survival (OS), recurrence-free survival (RFS), local tumor control, and treatment-related complications were compared between the two groups. Prognostic factors were analyzed using the Cox proportional hazard regression model.

RESULTS

Median follow-up duration was 36.7 months (range: 6.2-64.0 months). Cumulative 1-, 3-, and 5-year OS rates were 97.9%, 92.3%, and 80.6% in the MWA group and 96.4%, 87.4%, and 78.2% in the RFA group, respectively, (P = 0.450). Cumulative RFS rates at 1, 3, and 5 years were 93.2%, 74.4%, and 63.7% in the MWA group and 80.3%, 57.3%, and 49.6% in the RFA group, respectively, (P = 0.097). Multivariate analyses showed that variable categories "patient age above 65 years" (P = 0.004) and "more than one tumor" (P = 0.004) were associated with overall mortality, and "patient age above 65 years" (P = 0.048) and "tumor size greater than 3 cm" (P = 0.009) were associated with inferior RFS. The incidences of major complications were not significantly different between the two groups (3.3% vs 3.9%, P = 0.843).

CONCLUSIONS

RFA and MWA were associated with comparable safety and efficacy for HCC within the Milan criteria in challenging locations. Further study in a large, multi-center patient cohort is necessary to validate the results.

Therapies for hepatocellular carcinoma: overview, clinical indications, and comparative outcome evaluation-part one: curative intention

Hepatocellular carcinoma (HCC) offers unique management challenges as it commonly occurs in the setting of underlying chronic liver disease. The management of HCC is directed primarily by the clinical stage. The most commonly used staging system is the Barcelona-Clinic Liver Cancer system, which considers tumor burden based on imaging, liver function and the patient's performance status. Early-stage HCC can be managed with therapies of curative intent including surgical resection, liver transplantation, and ablative therapies. This manuscript reviews the various treatment options for HCC with a curative intent, such as locablative therapy types, surgical resection, and transplant. Indications, contraindications and outcomes of the various treatment options are reviewed. Multiple concepts relating to liver transplant are discussed including Milan criteria, OPTN policy, MELD exception points, downstaging to transplant and bridging to transplant.

Diagnostic evaluation and ablation treatments assessment in hepatocellular carcinoma

This article provides an overview of diagnostic evaluation and ablation treatment assessment in Hepatocellular Carcinoma (HCC). Only studies, in the English language from January 2010 to January 202, evaluating the diagnostic tools and assessment of ablative therapies in HCC patients were included. We found 173 clinical studies that satisfied the inclusion criteria.HCC may be noninvasively diagnosed by imaging findings. Multiphase contrast-enhanced imaging is necessary to assess HCC. Intravenous extracellular contrast agents are used for CT, while the agents used for MRI may be extracellular or hepatobiliary. Both gadoxetate disodium and gadobenate dimeglumine may be used in hepatobiliary phase imaging. For treatment-naive patients undergoing CT, unenhanced imaging is optional; however, it is required in the post treatment setting for CT and all MRI studies. Late arterial phase is strongly preferred over early arterial phase. The choice of modality (CT, US/CEUS or MRI) and MRI contrast agent (extracelllar or hepatobiliary) depends on patient, institutional, and regional factors. MRI allows to link morfological and functional data in the HCC evaluation. Also, Radiomics is an emerging field in the assessment of HCC patients.Postablation imaging is necessary to assess the treatment results, to monitor evolution of the ablated tissue over time, and to evaluate for complications. Post- thermal treatments, imaging should be performed at regularly scheduled intervals to assess treatment response and to evaluate for new lesions and potential complications.

Microwave Ablation of Very-Early- and Early-Stage HCC: Efficacy Evaluation by Correlation with Histology after Liver Transplantation

Microwave (MW) ablation is a worldwide-diffused technique for the percutaneous ablation of hepatocellular carcinoma (HCC). Nevertheless, the efficacy of this technique still needs to be confirmed in pathological specimens. The purpose of this study was to evaluate the efficacy of MW ablation by correlation with histology in excised liver samples at the time of liver transplantation (LT). All patients with MW-ablated HCC who subsequently underwent LT between 2012 and 2020 were retrospectively evaluated. In the explanted livers, the treated lesions were evaluated at pathology, and the necrosis was classified as complete or partial. Thirty-six HCCs were ablated in 30 patients (20.9 ± 6.1 mm, a range of 10-30 mm). Ablations were performed with a single insertion of a MW antenna under ultrasound or CT guidance. A complete radiological response was demonstrated in 30/36 nodules (83.3%) in 24/30 patients (80%) at imaging performed one-month after MW ablation. At pathology, of the 36 treated nodules, 28 (77.8%) showed a complete necrosis, and 8 (22.2%) showed a pathological partial necrosis. Good agreement was found between the imaging performed one-month after treatment and the complete pathological response (Cohen's k = 0.65). The imaging accuracy in detecting a complete response to treatment was 88.9%. All lesions with complete necrosis did not show recurrence at follow-up imaging until transplantation. The rad-path correlation in the explanted livers showed that MW ablation achieved a high rate of complete necrosis if a macroscopical complete ablation was obtained.

Radiofrequency ablation of hepatocellular carcinoma: Prognostic factors and recent advances

With the improvement of technology and diagnostic level, radiofrequency ablation (RFA) has made rapid progress in the treatment of primary hepatocellular carcinoma (HCC) in the past two decades. Especially, the overall survival after the treatment of small HCCs by RFA can be comparable to that achieved by hepatic resection. The 10-year survival rates of RFA for HCC were 27.3%-46.1%, and for solitary HCC less than 3 cm, the 10-year survival rate is about 74.0%. RFA combined with other therapies can expand the indications of RFA treatment and benefit the survival of patients with HCC. The prognostic model of RFA for HCC provides a powerful tool for individualized clinical diagnosis and treatment.

Liver resection versus radiofrequency ablation for recurrent hepatocellular carcinoma: a systematic review and meta-analysis

BACKGROUND & AIMS

Liver resection (LR) and radiofrequency ablation (RFA) are commonly used for the treatment of recurrent hepatocellular carcinoma (HCC), but the optimal treatment modality remains unclear. We aimed to compare the efficacy and safety of LR vs RFA for recurrent HCC.

METHODS

We searched PubMed, Embase, Web of Science, and the Cochrane Library for relevant studies. The primary outcomes were overall survival (OS) and disease-free survival (DFS). The secondary outcomes were major complications and hospital stay.

RESULTS

Eighteen studies with 1991 patients with recurrent HCC were included. The pooled hazard ratio (HR) for OS demonstrated that LR had significantly better OS than RFA in recurrent HCC (HR, 0.81; 95% confidence interval [CI], 0.68-0.95). Specifically, LR was associated with higher 2-, 3- and 4-year OS rates compared with RFA. The pooled HR for DFS showed no significant difference between LR and RFA during the whole follow-up period (HR, 0.90; 95% CI, 0.76-1.07). However, LR was associated with significantly higher 2- to 5-year DFS rates compared to RFA. LR was also associated with more major complications (p < .001) and longer hospital stay (p < .001). Subgroup analyses demonstrated that LR and RFA had similar efficacy in patients with recurrent tumors less than 3 cm or patients presenting three or fewer recurrent nodules.

CONCLUSION

LR could provide better long-term survival outcomes than RFA for recurrent HCC patients, while RFA has a higher safety profile. RFA can be a good alternative to LR for patients with small-sized recurrence or patients with a limited number of recurrent nodules. However, as tumor size increases, LR tends to be more efficacious.

Microwave ablation determines similar survival outcomes as compared to radiofrequency ablation for the treatment of hepatocellular carcinoma

OBJECTIVES

It is still unclear whether microwave ablation (MWA) outperforms radiofrequency ablation (RFA) in the treatment of hepatocellular carcinoma (HCC). Aim of this manuscript is to compare the two treatments through a meta-analysis of randomized-controlled trials (rcts).

METHODS

Computerized bibliographic search was performed on main databases through August 2020. The primary outcome was the complete response rate, with survival rate, disease-free survival rate, and adverse event rate as secondary outcomes. Results were expressed in terms of risk ratio (RR) and 95% confidence interval (CI).

RESULTS

Seven rcts enrolling 1143 patients were included. Rates of complete response were similar (RR 1.01, 95% CI 0.99-1.02); likewise, survival rates were constantly similar, with rrs ranging from 1.05 (0.96-1.15) at 1-year to 0.91 (0.81-1.03) at 5-year. Disease-free survival at 1-, 2-, and 3-year was similar between the two groups with RR 1.00 (0.96-1.04), 0.94 (0.84-1.06), and 1.06 (0.93-1.21), respectively. On the other hand, RR for disease-free survival at 5-year was significantly in favor of MWA (3.66, 1.32-42.27). Adverse event rate was similar between the two treatments (RR 1.06, 0.48-2.34), with bleeding and hematoma as most frequent complications.

CONCLUSIONS

MWA seems to determine similar outcomes as compared to RFA.

Percutaneous radiofrequency ablation of HCC: reduced ablation duration and increased ablation size using single, internally cooled electrodes with an optimized pulsing algorithm

PURPOSE

To assess the use of optimized radiofrequency (RF) to achieve larger, spherical ablation volumes with short application duration for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Twenty-two patients (M:F = 17:5, median age 69.6 year, range 63-88) with 28 HCCs due to HCV + liver cirrhosis underwent RFA. 20/28 (71.4%) were tumors ≤3cm diameter, and 8/28 (28.6%) ranged from 3.2 to 4.2 cm. RF was applied using up to 2500mA via an optimized pulsing algorithm with real-time ultrasound monitoring to detect hyperechogenic changes. Single insertions of an internally cooled electrode were performed using exposed tips of 2 or 3 cm for 13 HCCs and 4 cm for 15 HCCs. All patients were followed-up for a minimum of 5 years with contrast-enhanced computed tomography (CECT).

RESULTS

Technical success was achieved without adverse events in all cases. The mean ablation time was 8.5 ± 2.6 min. In 21/28 (75%), ablation duration ranged from 3 to 9 min, with 12 min duration applied in only 7/28 (25%). Mean coagulation diameters were 2.4 ± 0.14, 3.3 ± 0.62, and 4.4 ± 1.0, for 2, 3 and 4 cm electrodes, respectively (p < 0.01). The sphericity index was 74.9 ± 12.8 for 4 cm electrodes and 81.9 ± 8.0 for shorter electrodes (p = 0.091). At 5-year follow-up, no tumor ≤3 cm had recurrence and only 2/8 (25%) >3 cm tumors developed local progression. One patient had multifocal disease with no local progression.

CONCLUSION

Efficient delivery of RF energy can considerably decrease the ablation time in many instances while achieving larger, relatively spherical, and reproducible areas of ablation with extremely low rates of local tumor progression and adverse events.

Heating technology for malignant tumors: a review

The therapeutic application of heat is very effective in cancer treatment. Both hyperthermia, i.e., heating to 39-45 °C to induce sensitization to radiotherapy and chemotherapy, and thermal ablation, where temperatures beyond 50 °C destroy tumor cells directly are frequently applied in the clinic. Achievement of an effective treatment requires high quality heating equipment, precise thermal dosimetry, and adequate quality assurance. Several types of devices, antennas and heating or power delivery systems have been proposed and developed in recent decades. These vary considerably in technique, heating depth, ability to focus, and in the size of the heating focus. Clinically used heating techniques involve electromagnetic and ultrasonic heating, hyperthermic perfusion and conductive heating. Depending on clinical objectives and available technology, thermal therapies can be subdivided into three broad categories: local, locoregional, or whole body heating. Clinically used local heating techniques include interstitial hyperthermia and ablation, high intensity focused ultrasound (HIFU), scanned focused ultrasound (SFUS), electroporation, nanoparticle heating, intraluminal heating and superficial heating. Locoregional heating techniques include phased array systems, capacitive systems and isolated perfusion. Whole body techniques focus on prevention of heat loss supplemented with energy deposition in the body, e.g., by infrared radiation. This review presents an overview of clinical hyperthermia and ablation devices used for local, locoregional, and whole body therapy. Proven and experimental clinical applications of thermal ablation and hyperthermia are listed. Methods for temperature measurement and the role of treatment planning to control treatments are discussed briefly, as well as future perspectives for heating technology for the treatment of tumors.

The (Eternal) Debate on Microwave Ablation Versus Radiofrequency Ablation in BCLC-A Hepatocellular Carcinoma

BACKGROUND/AIM

While percutaneous radiofrequency ablation (RFA) is considered the standard ablative modality for the treatment of early-stage hepatocellular carcinoma (HCC), percutaneous microwave ablation (MWA) is being increasingly used in recent years. We performed a systematic review and meta-analysis to compare percutaneous MWA versus percutaneous RFA in BCLC-A HCC across randomized controlled trials (RCTs).

PATIENTS AND METHODS

Eligible studies included RCTs assessing MWA versus RFA in BCLC-A HCC. Outcomes of interest included: complete ablation (CA) rate, local recurrence (LR) rate, 1-year overall survival (OS) rate, 3-year OS rate and major complications rate.

RESULTS

We retrieved all the relevant RCTs through PubMed/Medline, Cochrane library and EMBASE; five eligible studies involving a total of 794 patients (MWA: 409; RFA: 385) and 1008 nodules of HCC (MWA: 519; RFA: 489) were included in our analysis. No significant differences were found between MWA and RFA regarding CA, LR, 3-year OS and major complications rate. Regarding 1-year OS, a higher rate was observed in the MWA group.

CONCLUSION

MWA and RFA are effective and safe techniques in early stage, BCLC-A, HCCMWA resulted in better 1-year OS, although this benefit was not confirmed in the 3-year analysis.

Applications of Microwave Energy in Medicine

Microwaves are a highly utilized electromagnetic wave, used across a range of industries including food processing, communications, in the development of novel medical treatments and biosensor diagnostics. Microwaves have known thermal interactions and theorized non-thermal interactions with living matter; however, there is significant debate as to the mechanisms of action behind these interactions and the potential benefits and limitations of their use. This review summarizes the current knowledge surrounding the implementation of microwave technologies within the medical industry.

Percutaneous microwave ablation applications for liver tumors: recommendations for COVID-19 patients

Microwave ablation (MWA) is an alternative locoregional therapy to surgical resection of solid tumors in the treatment of malignancies, and is widely used for hepatic tumors. It has a slightly higher overall survival (OS) rate compared to external beam radiation therapy (EBRT), and proton beam therapy (PBT), and better long-term recurrence-free OS rate compared to radiofrequency ablation (RFA). In this paper, current commercial devices, most recent noncommercial designs, and the principles behind them alongside the recently reported developments and issues of MWA are reviewed. The paper also provides microscopic insights on effects of microwave irradiation in the body. Our review shows that MWA is a safe and effective, minimally invasive method with high ablation completion rates. However, for large tumors, the completion rates slightly decrease, and recurrences increase. Thus, for large tumors we suggest using a cooled shaft antenna or multiple antenna placements. Comparisons of the two common ablation frequencies 915 MHz and 2.45 GHz have shown inconsistent results due to non-identical conditions. This review suggests that 915 MHz devices are more effective for ablating large tumors and the theory behind MWA effects corroborates this proposition. However, for small tumors or tumors adjacent to vital organs, 2.45 GHz is suggested due to its more localized ablation zone. Among the antenna designs, the double-slot antenna with a metallic choke seems to be more effective by localizing the radiation around the tip of the antenna, while also preventing backward radiation towards the skin. The review also pertains to the use of MWA in COVID-19 patients and risk factors associated with the disease. MWA should be considered for COVID-19 patients with hepatic tumors as a fast treatment with a short recovery time. As liver injury is also a risk due to COVID-19, it is recommended to apply liver function tests to monitor abnormal levels in alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, and other liver function indicators.

Higher Efficiency of Percutaneous Microwave (MWA) Than Radiofrequency Ablation (RFA) in Achieving Complete Response in Cirrhotic Patients with Early Hepatocellular Carcinoma

BACKGROUND

Contrasting data are available in the literature regarding the superiority of percutaneous microwave ablation (MWA) or radiofrequency ablation (RFA) in very early or early (BCLA 0 or A) hepatocellular carcinoma (HCC).

AIMS

The primary outcome was to compare the efficacy of RFA and MWA in achieving complete response in cirrhotic patients with early and very early HCC. The secondary outcomes were to evaluate the overall survival and the recurrence rate.

METHODS

A retrospective, observational, single-center study was performed. Inclusion criteria were liver cirrhosis, new diagnosis of a single node of HCC measuring a maximum of 50 mm or up to three nodules with diameter up to 35 mm, treatment with RFA or MWA. Radiological response was evaluated with multiphasic contrast-enhanced Computed Tomography or Magnetic Resonance Imaging at 5-7 weeks after thermal ablation. Complete response was defined when no vital tissue was detected after treatment.

RESULTS

Overall, 251 HCC patients were included in this study; 81 patients were treated with MWA and 170 with RFA. The complete response rate was similar in MWA and RFA groups (out of 331 nodules, 87.5% (91/104) were treated with MWA and 84.2% (186/221) were treated with RFA, p = 0.504). Interestingly, a subanalysis demonstrated that for 21-35 mm nodules, the probability to achieve a complete response using MWA was almost 5 times higher than for RFA (OR = 4.88, 95% CI 1.37-17.31, p = 0.014). Moreover, recurrence rate in 21-35 mm nodules was higher with RFA with respect to MWA (31.9% versus 13.5%, p = 0.019). Overall survival was 80.4% (45/56) when treated with MWA and 62.2% (56/90) when treated with RFA (p = 0.027). No significant difference was observed between MWA and RFA treatment in the 15-20 mm nodules group.

CONCLUSION

This study showed that MWA is more efficient than RFA in achieving complete response in HCC nodules with 21 to 35 mm diameter.

Single-nodule hepatitis B virus-associated hepatocellular carcinoma smaller than 3 cm: two phenotypes defined by cluster analysis and their association with the outcome of ablation as the first-line therapy

OBJECTIVES

Hepatocellular carcinoma (HCC) is a heterogeneous disease. This study aimed to identify the heterogeneity related to the prognosis of ablation in patients with single-nodule hepatitis B virus (HBV)-associated HCC ≤3 cm.

METHODS

A total of 359 patients with single-nodule HBV-associated HCC ≤3 cm treated with curative thermal ablation were retrospectively investigated. Hierarchical cluster analysis was applied to obtain more homogeneous patient clusters concerning demographic and physiological characteristics. Discriminant analysis was performed to identify the relatively important variables for cluster analysis. Multiple correspondence analysis (MCA) was used to clarify the relationship between clusters and categorical variables. Overall survival (OS) was compared among clusters using the Kaplan-Meier model.

RESULTS

A two-cluster model was identified. Cluster 1 (n = 85) showed a higher percentage of female and older patients, higher inflammation response (higher prognostic nutritional index [PNI] and Glasgow prognostic score [GPS]), worse liver function (higher albumin-bilirubin grade and Child-Pugh grade), and relatively poorer immune status (higher neutrophil-to-lymphocyte ratio [NLR]) than cluster 2 (n = 274). NLR and GPS were the two most influential variables for cluster analysis (p < .0001). Cluster 2 had a significantly better prognosis than cluster 1. MCA revealed a clear negative correlation between inflammation status and liver function. Compared with cluster 1, the hazard ratios for OS of cluster 2 were 0.47 and 0.52 before and after adjusting for age, respectively (p < .05).

CONCLUSIONS

This study identified two sub-phenotypes of patients with single-nodule HBV-associated HCC ≤3 cm and their association with the outcome of thermal ablation alone as the first-line therapy. Key points Thermal ablation alone as the first-line therapy is not suitable for all patients with single-nodule hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) ≤3 cm. Patients with single-nodule HBV-associated HCC ≤3 cm can be identified as two sub-phenotypes associated with the outcome of thermal ablation alone as the first-line therapy, based on key preoperative clinical characteristics, especially inflammatory response and immune status. Patients with single-nodule HBV-associated HCC ≤3 cm characterized by late-onset disease, worse liver function, poorer immune status, and higher inflammatory response (with higher inflammatory response being the most important factor) are not suitable for thermal ablation alone as the first-line therapy. In contrast, patients with single-nodule HBV-associated HCC ≤3 cm characterized by early-onset disease, better liver function, lower inflammatory response, and good immune status (with lower inflammatory response being the most important factor) are particularly suitable for thermal ablation alone. Implications for patient care In the treatment of patients with single-nodule HBV-associated HCC ≤3 cm, thermal ablation alone as the first-line therapy should be carefully considered after recognizing the key clinical characteristics, among which inflammatory response and immune status are the two most important factors involved in clinical heterogeneity, and inflammatory response is closely related to the prognosis of thermal ablation alone as the first-line therapy for these patients.

Clinical Characterisation and Management of the Main Treatment-Induced Toxicities in Patients with Hepatocellular Carcinoma and Cirrhosis

The incidence of hepatocellular carcinoma (HCC) continues to increase worldwide, particularly in Western countries. In almost all cases, HCC develops in subjects with hepatic cirrhosis, often as the result of hepatitis B or C virus infection, alcohol abuse or metabolic forms secondary to non-alcoholic steatohepatitis. Patients with HCC and hepatic symptoms can therefore present symptoms that are attributable to both conditions. These patients require multidisciplinary management, calling for close interaction between the hepatologist and the oncologist. Indeed, the treatment of HCC requires, depending on the disease stage and the degree of hepatic impairment, locoregional therapies that can in turn be broken down into surgical and nonsurgical treatments and systemic treatments used in the event of progression after the administration of locoregional treatments. The past decade has seen the publication of countless papers of great interest that have radically changed the scenario of treatment for HCC. Novel therapies with biological agents and immunotherapy have come to be standard options in the approach to treatment of this cancer, obtaining very promising results where in the past chemotherapy was almost never able to have an impact on the course of the disease. However, in addition to being costly, these drugs are not devoid of adverse effects and their management cannot forgo the consideration of the underlying hepatic impairment. Patients with HCC and cirrhosis therefore require special attention, starting from the initial characterisation needed for an appropriate selection of those to be referred for treatment, as these patients are almost never fit. In this chapter, we will attempt to investigate and clarify the key points of the management of the main toxicities induced by locoregional and systemic treatments for HCC secondary to cirrhosis.

Overall survival and local recurrence following RFA, MWA, and cryoablation of very early and early HCC: a systematic review and Bayesian network meta-analysis

OBJECTIVE

To compare overall survival (OS) and local recurrence (LR) following radiofrequency ablation (RFA), microwave ablation (MWA), and cryoablation (CA) for very early and early hepatocellular carcinoma (HCC).

METHODS

This systematic review was performed according to the PRISMA guidelines. MEDLINE, Embase, and Cochrane databases were searched. Randomized controlled trials (RCTs) and observational studies were included. OS and LR at 1 year and 3 years were assessed. OS was reported as hazard ratio (HR) with 95% credible intervals (CrI) and LR as relative risk (RR) with 95% CrI, to summarize effect of each comparison.

RESULTS

Nineteen studies (3043 patients), including six RCTs and 13 observational studies, met inclusion criteria. For OS at 1 year, as compared to RFA, CA had HR of 0.81 (95% CrI: 0.43-1.51), and MWA had HR of 1.01 (95% CrI: 0.71-1.43). For OS at 3 years, as compared to RFA, CA had HR of 0.90 (95% CrI: 0.48-1.64) and MWA had HR of 1.07 (95% CrI: 0.73-1.50). For LR at 1 year, CA and MWA had RR of 0.75 (95% CrI: 0.45-1.24) and 0.93 (95% CrI: 0.78-1.14), respectively, as compared to RFA. For LR at 3 years, CA and MWA had RR of 0.96 (0.74-1.23) and 0.98 (0.87-1.09), respectively, as compared to RFA. Overall, none of the comparisons was statistically significant. Age of patients and tumor size did not influence treatment effect.

CONCLUSIONS

RFA, MWA, and CA are equally effective for locoregional treatment of very early and early HCC.

KEY POINTS

• There is no significant difference in the OS and LR (at 1 year and 3 years) following ablation of very early and early HCC with RFA, MWA, and CA. • There was no effect of tumor size on the treatment efficacy. • More RCTs comparing CA with RFA and MWA should be performed.

Percutaneous Cryoablation of Liver Tumors: Initial Experience from a Tertiary Care Center in India

BACKGROUND

Percutaneous ablation is an important part of management strategy for liver tumors. While radiofrequency ablation and microwave ablation are the most widely used ablative techniques, cryoablation (CA) has several technical advantages but has been underused till recently. In this study, we report the initial experience with percutaneous CA of liver tumors.

METHODS

This was a retrospective evaluation of consecutive patients with liver tumors who underwent percutaneous CA between October 2018 and August 2019. The ablation procedures were performed under combined ultrasound and computed tomography guidance using argon-helium-based CA systems. The baseline tumor characteristics (including size and location), Barcelona Clinic Liver Cancer stage, and Child-Pugh score were recorded. Each patient underwent a follow-up after 1 month and at 3 months subsequently. Technical success, complete response, local tumor progression, and overall survival were evaluated.

RESULTS

Nine patients (mean age, 62.4 years, median age, 66 years, five men and four women) with 10 liver tumors (mean size, 2.22 cm) underwent CA. Seven (77.8%) patients had hepatocellular carcinoma (HCC), and 2 patients had solitary liver metastasis. One patient with HCC had two lesions, while the rest had only one lesion. Of the two metastatic lesions, one was from carcinoma of the cervix and the other was from jejunal neuroendocrine tumor. Five tumors were located adjacent to the gallbladder, two lesions were adjacent to the right portal vein, two lesions were subcapsular, and one lesion was adjacent to the stomach. Technical success was achieved in all the patients. Complete response was achieved in 7 (77.8%) patients. The median follow-up period was 7 months (range, 3-12 months). There was no local tumor progression and no death during the follow-up period. No procedure-related complication was seen.

CONCLUSION

Percutaneous CA of hepatic tumors is technically feasible and is a safe and effective ablative technique.

Updates on the Diagnosis and Management of Hepatocellular Carcinoma

Introduction

Globally, the incidence, as well as mortality, related to hepatocellular carcinoma (HCC) is on the rise, owing to relatively few curative options. Underlying cirrhosis is the most common etiology leading to HCC, but risk factors of cirrhosis show great regional variability. Over the years, there has been a steady development in the diagnostic and therapeutic modalities of HCC, including the availability of a wide range of systemic chemotherapeutic agents. We aim to review the recent advancements in the diagnostic and therapeutic strategies for HCC.

Methodology

The literature search was done using databases PubMed, Cochrane, and Science Direct, and the latest relevant articles were reviewed.

Findings

Screening of HCC is a pivotal step in the early diagnosis of the disease. Current guidelines recommend using ultrasound and alfa fetoprotein but various new biomarkers are under active research that might aid in diagnosing very small tumors, not picked up by the current screening methods. Treatment options are decided based upon the overall performance of the patient and the extent of the disease, as per the Barcelona classification. There are very few options that offer a cure for the disease, ranging from liver resection and transplantation to tumor ablation. Downstaging has proven to have a significant role in the course of the disease. An attempt to control the disease can be made via radiological interventions, such as transarterial chemoembolization, transarterial radioembolization, or radiation therapy. For advanced disease, sorafenib used to be the only option until a couple of years ago. Recently, many other systemic agents have received approval as first-line and second-line therapies for HCC. Genomics is an area of active clinical research as understanding the mutations and genomics involved in the evolution of HCC might lead to a breakthrough therapy.

How to cite this article

Raees A, Kamran M, Özkan H, et al. Updates on the Diagnosis and Management of Hepatocellular Carcinoma. Euroasian J Hepato-Gastroenterol 2021;11(1):32–40.

Microwave Ablation Versus Radiofrequency Ablation for Treatment of Hepatocellular Carcinoma: A Meta-Analysis of Randomized Controlled Trials

There are limited and discordant results on the comparison between microwave ablation (MWA) and radiofrequency ablation (RFA) for the treatment of hepatocellular carcinoma (HCC). This meta-analysis aims to compare the two treatments in terms of efficacy and safety, based on a meta-analysis of randomized-controlled trials (RCTs). A computerized bibliographic search was performed on the main databases throughout August 2020. The primary outcome was the complete response rate, while survival rate (at 1-, 2-, 3-, and 5-year), disease-free survival rate (at 1-, 2-, 3-, and 5-year), local and distant recurrence rate, adverse event rate, and number of treatment sessions were the secondary outcomes. Seven RCTs enrolling 921 patients were included. No difference in terms of complete response between the two treatments was observed (risk ratio (RR) 1.01, 95% CI 0.99-1.02). Survival rates were constantly similar, with RRs ranging from 1.05 (0.96-1.15) at 1 year to 0.91 (0.81-1.03) at 5 years. While local recurrence rate was similar between MWA and RFA (RR 0.70, 0.43-1.14), distant recurrence rate was significantly lower with MWA (RR 0.60, 0.39-0.92). Disease-free survival at 1, 2, and 3 years was similar between the two groups with RR 1.00 (0.96-1.04), 0.94 (0.84-1.06), and 1.06 (0.93-1.21), respectively. On the other hand, RR for disease-free survival at 5 years was significantly in favor of MWA (3.66, 1.32-42.27). Adverse event rate was similar between the two treatments (RR 1.06, 0.48-2.34), with bleeding and hematoma representing the most frequent complications. Our results indicate a similar efficacy and safety profile between the two techniques. MWA seems to decrease the rate of long-term recurrences, but this finding needs to be confirmed in further trials.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Comparison of transcatheter arterial chemoembolization combined with radiofrequency ablation or microwave ablation for the treatment of unresectable hepatocellular carcinoma: a systemic review and meta-analysis

Background: Transcatheter arterial chemoembolization (TACE), radiofrequency ablation (RFA), and microwave ablation (MWA) are regarded as effective therapies for treating unresectable hepatocellular carcinoma (HCC). We conducted this study to compare the efficiency and safety of TACE combined with RFA (TR group) or MWA (TM group).Method: PubMed, the Cochrane Library, Ovid Medline, Web of Science, Scopus, Embase, ScienceDirect, and Google Scholar were searched. The primary endpoints were overall survival (OS), progression-free survival (PFS), response rates, and complications.Result: Eight cohort studies and one randomized controlled trial were included. The TM group had better OS (Hazard ratio [HR]: 1.55; 95% confidence interval [CI]: 1.09-2.21, p = 0.01) and a better 2- and 3-year OS rate, 24-month PFS rate (Risk ratio [RR]: 0.67; 95% CI: 0.46-0.96, p = 0.03), and complete response rate (RR: 0.87; 95% CI: 0.79-0.96, p = 0.003) than the TR group. Furthermore, the TM and TR groups did not show significant differences in PFS, the disease control rate or complications. The advantage of TM was mainly reflected in younger patients (50-60 years old) compared with patients aged 60-70 years, as well as in patients with larger tumors (≥3 cm) compared with patients with tumors <3 cm. Moreover, patients treated with conventional TACE (cTACE) in the TM group showed longer OS, while patients treated with drug-eluting bead transarterial chemoembolization (DEB-TACE) in the TR group showed a higher overall response rate.Conclusion: TM seems to be a more effective therapy than TR for unresectable HCC, with better survival and similar safety.

Nonsurgical Approaches to Treat Biliary Tract and Liver Tumors

Endoscopic and percutaneous therapies have been shown to prolong life and reduce morbidity for patients with unresectable advanced stages of primary hepatobiliary malignancies. This article reviews pertinent studies published within the last 5 years that involve locoregional techniques to manage hepatocellular carcinoma, perihilar and distal cholangiocarcinoma. A major emphasis is placed on photodynamic therapy, radiofrequency ablation, irreversible electroporation, and microwave ablation. Technical advances, combinational therapies, and postintervention outcomes are discussed. Despite widespread application, high-quality evidence does not show superiority of any particular locoregional technique for treating advanced hepatobiliary cancers.

The efficacy of transarterial chemoembolization combined with microwave ablation for unresectable hepatocellular carcinoma: a systematic review and meta-analysis

Purpose: To evaluate the clinical value of transarterial chemoembolization (TACE) combined with microwave ablation (MWA) for unresectable hepatocellular carcinoma (HCC).Patients and methods: Eligible studies were identified using PubMed, MedLine, Embase, the Cochrane Library, and Web of Science, investigating the synergistic effect of TACE + MWA in the treatment of advanced HCC. Endpoints were the 1-, 2- and 3-year survival rates, local control rate (LCR), objective remission rate (ORR), and adverse event (AE). Odds ratio (OR) with 95% confidence interval (CI) was used to determine the effect size.Results: Nine studies including 351 patients in the TACE + MWA group and 653 patients in the TACE group were enrolled in this meta-analysis. The pooled OR for the 1-, 2-, and 3-year survival rates were in favor of TACE + MWA (OR = 3.29, 95% CI 2.26-4.79; OR = 2.82, 95% CI 2.01-3.95; OR = 4.50, 95% CI 2.96-6.86; respectively). The pooled OR for the ORR and LCR were also in favor of TACE + MWA (OR = 4.64, 95%CI 3.11-6.91; OR = 3.93, 95% CI 2.64-5.87; respectively). No significant difference in the incidence of severe AE was observed between TACE + MWA group and TACE group (p > .05). However, subgroup analysis showed that patients with tumor size >5 cm were more likely to be benefited from TACE + MWA, rather than patients with tumor size ≤5 cm.Conclusion: With the current data, we concluded that combination TACE and MWA was safe, and should be strongly recommended to unresectable patients with tumor size >5 cm, but TACE alone was enough for unresectable patients with tumor size ≤5 cm. However, the conclusion needs further validation.

Curative-Intent Therapies in Localized Hepatocellular Carcinoma

PURPOSE OF REVIEW

The high mortality rate for hepatocellular carcinoma (HCC) relative to its prevalence underscores the need for curative-intent therapies. Image-guided therapies such as ablation and embolization have an established role as primary or neoadjuvants preparing patients for curative treatment.

RECENT FINDINGS

For HCC < 3 cm, percutaneous thermal ablation provides oncologic outcomes similar to surgical resection and is now a recommended first-line therapy in the EASL guidelines. Both ablation and embolization are recommended as bridging therapies for HCC patients awaiting liver transplantation. T3 HCC can be downstaged by embolization to T2, allowing liver transplantation with similar outcomes to patients transplanted within Milan criteria. New and evolving techniques such as SBRT, radiation segmentectomy and lobectomy, and combination therapies show promise but require further prospective data before they can be integrated into treatment algorithms. Combinations of embolic, ablative, and extirpative therapies can increase access to curative-intent treatment of HCC. Multidisciplinary treatment decisions are required to craft optimal treatment strategies considering tumor size, location, and underlying liver cirrhosis.

[Locoregional and local ablative treatment options for liver tumors]

Interventional radiology offers a large variety of locoregional and local ablative treatment options for liver tumors. These can be applied as stand-alone minimally invasive procedures or in combination with other treatment options and with curative as well as palliative intent depending on the respective tumor stage. This review article presents the various locoregional and local ablative treatment techniques and describes the clinical value in the treatment of hepatocellular carcinoma and intrahepatic cholangiocarcinoma.

Pilot in vivo studies on transcutaneous boiling histotripsy in porcine liver and kidney

Boiling histotripsy (BH) is a High Intensity Focused Ultrasound (HIFU) method for precise mechanical disintegration of target tissue using millisecond-long pulses containing shocks. BH treatments with real-time ultrasound (US) guidance allowed by BH-generated bubbles were previously demonstrated ex vivo and in vivo in exposed porcine liver and small animals. Here, the feasibility of US-guided transabdominal and partially transcostal BH ablation of kidney and liver in an acute in vivo swine model was evaluated for 6 animals. BH parameters were: 1.5 MHz frequency, 5–30 pulses of 1–10 ms duration per focus, 1% duty cycle, peak acoustic powers 0.9–3.8 kW, sonication foci spaced 1–1.5 mm apart in a rectangular grid with 5–15 mm linear dimensions. In kidneys, well-demarcated volumetric BH lesions were generated without respiratory gating and renal medulla and collecting system were more resistant to BH than cortex. The treatment was accelerated 10-fold by using shorter BH pulses of larger peak power without affecting the quality of tissue fractionation. In liver, respiratory motion and aberrations from subcutaneous fat affected the treatment but increasing the peak power provided successful lesion generation. These data indicate BH is a promising technology for transabdominal and transcostal mechanical ablation of tumors in kidney and liver.

Treatment Lines in Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer and the second most lethal malignancy worldwide. In the Western world, HCC predominantly develops in patients with liver cirrhosis. Therefore, application of locoregional interventions and systemic agents should be based on an interdisciplinary evaluation, most importantly, taking the functional liver reserve into account. This review summarizes current treatment lines and novel strategies in the management of HCC. For the most part, randomized controlled trials and large meta-analyses are reported, with an emphasis on systemic therapies.

Summary

In patients with limited hepatic disease and sufficient liver function, resection and local ablation are the most frequently employed curative locoregional therapies. Due to recurrence rates of up to 70% within 5 years and in patients with compromised liver function not amenable to these local modalities, liver transplantation remains superior in terms of tumor control and long-term survival. However, its applicability is limited because of the increasing gap between available donor organs and patients on the waiting list. Transarterial chemoembolization is commonly employed to bridge patients to transplantation and also serves as standard of care for patients not suitable for other local therapies. Recently, various phase 3 trials have reported a clinical benefit for the tyrosine kinase inhibitors lenvatinib, regorafenib, and cabozantinib in HCC. In addition, ramucirumab, an angiostatic antibody, also improves survival in second-line systemic therapy. This opens new avenues in the sequential application of treatment lines, and thus early response assessment is necessary to fully utilize the clinical impact of locoregional therapies and systemic therapies and to shift patients to further treatment lines before hepatic deterioration.

Key Messages

Clinical decision-making in hepatocellular carcinoma is based on an interdisciplinary evaluation. Liver transplantation should always be considered as long-term curative treatment option, especially in T2 patients. In palliative treatment, early response assessment is required to advance patients to the next treatment line before decompensation.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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