Radiofrequency ablation of hepatocellular carcinoma: treatment success as defined by histologic examination of the explanted liver

Evaluation of a robotic system for irreversible electroporation (IRE) of malignant liver tumors: initial results

OBJECTIVE

Comparison of conventional CT-guided manual irreversible electroporation (IRE) of malignant liver tumors and a robot-assisted approach regarding procedural accuracy, intervention time, dose, complications, and treatment success.

METHODS

A retrospective single-center analysis of 40 cases of irreversible electroporation of malignant liver tumors in 35 patients (6 females, 29 males, average age 60.3 years). Nineteen of these ablation procedures were performed manually and 21 with robotic assistance. A follow-up (ultrasound, CT, and MRI) was performed after 6 weeks in all patients.

RESULTS

The time from the planning CT scan to the start of the ablation as well as the dose-length product were significantly lower under robotic assistance (63.5 vs. 87.4 min, [Formula: see text]; 2132 vs. 4714 mGy cm, [Formula: see text]). The procedural accuracy, measured as the deviation of the IRE probes with respect to a defined reference probe, was significantly higher using robotic guidance (2.2 vs. 3.1 mm, [Formula: see text]). There were no complications. There was one incomplete ablation in the manual group.

CONCLUSION

Robotic assistance for IRE of liver tumors allows for faster procedure times with higher accuracy while reducing radiation dose as compared to the manual placement of IRE probes.

Dynamic Contrast-Enhanced Magnetic Resonance Imaging With Gadolinium Ethoxybenzyl Diethylenetriamine Pentaacetic Acid for Quantitative Assessment of Vascular Effects on Hepatocellular-Carcinoma Lesions Treated by Transarterial Chemoembolization or Radiofrequency Ablation

PURPOSE

The aim of this study was to investigate the role of dynamic contrast-enhanced magnetic resonance imaging (MRI) in evaluation of blood flow changes related to transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) procedures in patients with hepatocellular carcinoma (HCC) lesions.

METHODS

Fifty-four patients, with biopsy-proven HCC, who underwent TACE or RFA, were evaluated, 1 month after treatment, with upper abdominal MRI examination. Multiplanar T2-weighted, T1-weighted, and dynamic contrast-enhanced sequences were acquired. Dedicated perfusion software (T1 Perfusion Package, Viewforum; Philips Medical Systems, The Netherlands) was used to generate color permeability maps. After placing regions of interest in normal hepatic parenchyma, in successfully treated lesions, and in area of recurrence, the following perfusion parameters were calculated and statistically analyzed: relative arterial, venous, and late enhancement; maximum enhancement; maximum relative enhancement, and time to peak.

RESULTS

Twenty-one of 54 patients had residual disease, and perfusion parameters values measured within tumor tissue were: relative arterial enhancement median, 42%; relative venous enhancement median, 69%; relative late enhancement median, 57.7%; maximum enhancement median, 749.6%; maximum relative enhancement median, 69%; time to peak median, 81.1 seconds. As for all the evaluated parameters, a significant difference (P < 0.05) was found between residual viable tumor tissue and effective treated lesions.

CONCLUSIONS

Dynamic contrast-enhanced MRI represents a complementary noninvasive tool that may offer quantitative and qualitative information about HCC lesions treated with TACE and RFA.

Experimental measurement of microwave ablation heating pattern and comparison to computer simulations

INTRODUCTION

For computational models of microwave ablation (MWA), knowledge of the antenna design is necessary, but the proprietary design of clinical applicators is often unknown. We characterised the specific absorption rate (SAR) during MWA experimentally and compared to a multi-physics simulation.

METHODS

An infrared (IR) camera was used to measure SAR during MWA within a split ex vivo liver model. Perseon Medical's short-tip (ST) or long-tip (LT) MWA antenna were placed on top of a tissue sample (n = 6), and microwave power (15 W) was applied for 6 min, while intermittently interrupting power. Tissue surface temperature was recorded via IR camera (3.3 fps, 320 × 240 resolution). SAR was calculated intermittently based on temperature slope before and after power interruption. Temperature and SAR data were compared to simulation results.

RESULTS

Experimentally measured SAR changed considerably once tissue temperatures exceeded 100 °C, contrary to simulation results. The ablation zone diameters were 1.28 cm and 1.30 ± 0.03 cm (transverse), and 2.10 cm and 2.66 ± -0.22 cm (axial), for simulation and experiment, respectively. The average difference in temperature between the simulation and experiment were 5.6 °C (ST) and 6.2 °C (LT). Dice coefficients for 1000 W/kg SAR iso-contour were 0.74 ± 0.01 (ST) and 0.77 (± 0.03) (LT), suggesting good agreement of SAR contours.

CONCLUSION

We experimentally demonstrated changes in SAR during MWA ablation, which were not present in simulation, suggesting inaccuracies in dielectric properties. The measured SAR may be used in simplified computer simulations to predict tissue temperature when the antenna geometry is unknown.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Loco-regional therapies for patients with hepatocellular carcinoma awaiting liver transplantation: Selecting an optimal therapy

Hepatocellular carcinoma (HCC) is a common, increasingly prevalent malignancy. For all but the smallest lesions, surgical removal of cancer via resection or liver transplantation (LT) is considered the most feasible pathway to cure. Resection - even with favorable survival - is associated with a fairly high rate of recurrence, perhaps since most HCCs occur in the setting of cirrhosis. LT offers the advantage of removing not only the cancer but the diseased liver from which the cancer has arisen, and LT outperforms resection for survival with selected patients. Since time waiting for LT is time during which HCC can progress, loco-regional therapy (LRT) is widely employed by transplant centers. The purpose of LRT is either to bridge patients to LT by preventing progression and waitlist dropout, or to downstage patients who slightly exceed standard eligibility criteria initially but can fall within it after treatment. Transarterial chemoembolization and radiofrequency ablation have been the most widely utilized LRTs to date, with favorable efficacy and safety as a bridge to LT (and for the former, as a downstaging modality). The list of potentially effective LRTs has expanded in recent years, and includes transarterial chemoembolization with drug-eluting beads, radioembolization and novel forms of extracorporal therapy. Herein we appraise the various LRT modalities for HCC, and their potential roles in specific clinical scenarios in patients awaiting LT.

Pretransplant Locoregional Therapy for Hepatocellular Carcinoma: Evaluation of Explant Pathology and Overall Survival

Background and objectives

Liver transplant is an important treatment option for patients with hepatocellular carcinoma (HCC) within Milan criteria. We sought to determine the rate of complete tumor necrosis after bridging therapy.

Methods

The medical records of all 178 patients undergoing liver transplantation between January 1, 2008 and July 31, 2015 were reviewed. Response to therapy by imaging was based on mRECIST criteria (1).

Results

Sixty-three (35%) patients had HCC. Forty-three (68%) were treated with at least one bridging therapy and 14 (22%) were diagnosed incidentally. Eighteen (42%) underwent TACE and 25 (58%) underwent ablation. Twenty (80%) patients who underwent ablation and nine (60%) who underwent TACE had complete response based on imaging. Viable tumor was identified in explant pathology in 32 patients (74%). The presence or absence of viable tumor was not associated with overall survival.

Conclusion

Rates of viable tumor based on pathologic analysis in the hepatic explant were high after bridging therapy, but not associated with worse outcome. We conclude that serial bridging to achieve complete pathologic tumor response is not needed prior to transplant for HCC, and presence of complete response by imaging is adequate. Further studies are needed to determine if cancer cells that appear viable are alive.

RFA plus lyso-thermosensitive liposomal doxorubicin: in search of the optimal approach to cure intermediate-size hepatocellular carcinoma

When heated during a radiofrequency ablation (RFA) procedure to ≥40°C, lyso-thermosensitive liposomal doxorubicin (LTLD) produces high drug concentration in the surrounding margins of the ablation zone. The hypothesis that the RFA + LTLD combination can effectively treat hepatocellular carcinoma (HCC) was investigated in the HEAT study: adding LTLD did not improve the efficacy of normal practice RFA. However, among the 285 patients with a solitary lesion who received at least 45-min RFA dwell time, the hazard ratio for overall survival was 0.63 (95% CI: 0.41-0.96; p = 0.04). The OPTIMA study is currently ongoing to test the hypothesis that adding LTLD to a standardized RFA lasting ≥45 min increases survival compared with standardized RFA alone.

Progress in surgical and nonsurgical approaches for hepatocellular carcinoma treatment

BACKGROUND

Hepatocellular carcinoma (HCC) is a complex and heterogeneous malignancy, frequently occurs in the setting of a chronically diseased organ, with multiple confounding factors making its management challenging. HCC represents one of the leading causes of cancer-related mortality globally with a rising trend of incidence in some of the developed countries, which indicates the need for better surgical and nonsurgical management strategies.

DATA SOURCES

PubMed database was searched for relevant articles in English on the issue of HCC management.

RESULTS

Surgical resection represents a potentially curative option for appropriate candidates with tumors detected at earlier stages and with well-preserved liver function. The long-term outcome of surgery is impaired by a high rate of recurrence. Surgical approaches are being challenged by local ablative therapies such as radiofrequency ablation and microwave ablation in selected patients. Liver transplantation offers potential cure for HCC and also correction of underlying liver disease, and minimizes the risk of recurrence, but is reserved for patients within a set of criteria proposed for a prudent allocation in the shortage of donor organs. Transcatheter locoregional therapies have become the palliative standard allowing local control for intermediate stage patients with noninvasive multinodular or large HCC who are beyond the potentially curative options. The significant survival benefit with the multikinase inhibitor sorafenib for advanced HCC has shifted the direction of research regarding systemic treatment toward molecular therapies targeting the disregulated pathways of hepatocarcinogenesis. Potential benefit is suggested from simultaneous or sequential multimodal therapies, and optimal combinations are being investigated. Despite the striking progress in preclinical studies of HCC immunotherapy and gene therapy, extensive clinical trials are required to achieve successful clinical applications of these innovative approaches.

CONCLUSION

Treatment decisions have become increasingly complex for HCC with the availability of multiple surgical and nonsurgical therapeutic options and require a comprehensive, multidisciplinary approach.

Transcatheter arterial embolization combined with radiofrequency ablation activates CD8(+) T-cell infiltration surrounding residual tumors in the rabbit VX2 liver tumors

Purpose

To evaluate the effect of transcatheter arterial embolization (TAE) combined with radiofrequency ablation (RFA) treatment (TAE + RFA) on the expression of heat shock protein 70 (HSP70) in residual tumors and explore the relationship between the HSP70 and CD8⁺ T-cell infiltrate surrounding residual tumors in the rabbit VX2 liver tumor model.

Materials and methods

Animals with VX2 liver tumors were randomized into four groups (control, TAE, RFA, and TAE + RFA) with 15 rabbits in each group. Five rabbits in each group were sacrificed on days 1, 3, and 7 after treatment. HSP70 expression and infiltration of CD8⁺ T-cells in the liver and residual tumors surrounding the necrosis zone were detected by immunohistochemistry staining. The maximal diameters of tumor necrosis, numbers of metastases, and tumor growth rate were compared on day 7 after treatment.

Results

TAE + RFA achieved larger maximal diameter of tumor necrosis, lower tumor growth rate, and fewer metastatic lesions, compared with other treatments on day 7. The number of CD8⁺ T-cells in the TAE + RFA group was significantly higher than in other groups on days 1, 3, and 7. There was a positive correlation between HSP70 expression level and infiltration of CD8⁺ T-cells surrounding the residual tumor on day 1 (r=0.9782, P=0.012), day 3 (r=0.93, P=0.021), and day 7 (r=0.8934, P=0.034).

Conclusion

In the rabbit VX2 liver tumor model, TAE + RFA activated the highest number of CD8⁺ T-cells surrounding residual tumors. TAE + RFA appears to be a beneficial therapeutic modality for tumor control and antitumor immune response in this model.

Diagnostic criteria for hepatocellular carcinoma ⩽3 cm with hepatocyte-specific contrast-enhanced magnetic resonance imaging

BACKGROUND & AIMS

Current diagnostic imaging criteria for hepatocellular carcinoma (HCC) are dedicated to imaging with nonspecific extracellular contrast agents. This study aimed to evaluate diagnostic criteria for HCC ⩽3 cm on magnetic resonance imaging (MRI) with a hepatocyte-specific contrast agent through an inception cohort study.

METHODS

Of 291 patients with chronic liver disease and new nodules of 1-3 cm in diameter at surveillance ultrasonography, 295 solid nodules (194 HCCs, 98 benign nodules, and three other malignancies) in 198 patients with a confirmed final diagnosis or ⩾24 months follow-up were evaluated on gadoxetic acid-enhanced MRI. Through univariate and multivariate logistic regression analyses, various diagnostic criteria were developed by combining significant MRI findings for diagnosing HCC. The diagnostic performance of each criterion was compared with that of the European Association for the Study of the Liver (EASL) criteria.

RESULTS

Four MRI findings (arterial-phase hyperintensity, transitional-phase hypointensity, hepatobiliary-phase hypointensity, and rim enhancement) were independently significant for diagnosis of HCC ⩽3 cm. For whole nodules, EASL criteria showed the best performance for diagnosing HCC (sensitivity, 83.5%; specificity, 81.2%). For nodules ⩽2 cm in diameter, a new criterion (arterial-phase hyperintensity and hepatobiliary-phase hypointensity) showed a significantly higher sensitivity than that of the EASL criteria (83.0% vs. 74.5%, p=0.008), without a significantly different specificity (76.7% vs. 81.1%, p=0.125).

CONCLUSIONS

EASL criteria exhibit the best diagnostic performance for HCC ⩽3 cm on hepatocyte-specific contrast-enhanced MRI. A newly identified criterion (arterial-phase hyperintensity and hepatobiliary-phase hypointensity) may increase the diagnostic sensitivity of small (⩽2 cm) HCC.

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

BACKGROUND

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

SUMMARY

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

KEY MESSAGE

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

PRACTICAL IMPLICATIONS

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

Phase 2 study of stereotactic body radiotherapy and optional transarterial chemoembolization for solitary hepatocellular carcinoma not amenable to resection and radiofrequency ablation

BACKGROUND

Curative treatment options for patients with early stage hepatocellular carcinoma (HCC) include resection, liver transplantation, and percutaneous ablation therapy. However, even patients with solitary HCC are not always amenable to these treatments. The authors prospectively investigated the clinical outcomes of patients who received stereotactic body radiotherapy (SBRT) for solitary HCC.

METHODS

A phase 2 study involving SBRT and optional transarterial chemoembolization (TACE) was conducted in patients with Child-Pugh grade A or B and underlying, solitary HCC (greatest tumor dimension, ≤4 cm) who were unsuitable candidates for resection and radiofrequency ablation. The prescription dose was 35 to 40 grays in 5 fractions. The primary endpoint was 3-year local tumor control.

RESULTS

From 2007 to 2012, 101 patients were enrolled, and 90 were evaluable with a median follow-up of 41.7 months (range, 6.8-96.2 months). Thirty-two patients were treatment-naïve, 20 were treated for newly diagnosed intrahepatic failure, and 38 were treated for residual or recurrent HCC as salvage therapy. Thirty-two patients did not receive TACE, 48 received insufficient TACE, and 10 attained full lipiodol accumulation. The 3-year local control rate was 96.3%, the 3-year liver-related cause-specific survival rate was 72.5%, and the overall survival rate was 66.7%. Grade 3 laboratory abnormalities were observed in 6 patients, and 8 patients had Child-Pugh scores that worsened by 2 points.

CONCLUSIONS

SBRT achieved high local control and overall survival with feasible toxicities for patients with solitary HCC, despite rather stringent conditions. SBRT can be effective against solitary HCC in treatment-naive, intrahepatic failure, residual disease, and recurrent settings, taking advantage of its distinctive characteristics. Cancer 2016;122:2041-9. © 2016 American Cancer Society.

Potential of Radiofrequency Ablation in Combination with Immunotherapy in the Treatment of Hepatocellular Carcinoma

Radiofrequency ablation (RFA) is an important treatment option for patients with early hepatocellular carcinoma (HCC). RFA offers a reliable, reproducible modality to effectively treat hepatic lesions with minimal collateral damage to the surrounding hepatic parenchyma. In addition to traditional open operative techniques, RFA can be performed percutaneously or laparoscopically to minimize the physiologic insult to the patient. Due to the concomitant hepatic damage and dysfunction that often is present in patients with HCC these factors make RFA a frequently utilized therapeutic option. However, RFA is most efficacious in treating smaller tumors (≤ 2 cm), particularly when an ablation margin of ≥ 4-5 mm can be obtained. RFA has diminishing utility in larger tumors, resulting in reduced three and five year overall survival rates when compared to surgical resection. Multimodal approaches to include RFA with other standard and investigational approaches have become a subject of recent interest. RFA capably produces cellular destruction causing liberation of a substantial amount of antigens, many of which are tumor-specific providing a favorable environment for immune recognition. We propose that utilizing an immunotherapeutic approach in conjunction with RFA is the next logical step in the treatment of HCC. In this review, we summarize how RFA modulates antitumor immunity and works in concert with immunotherapy in the treatment of HCC. The information provided is expected to help the future design of novel RFA-integrated immunotherapies which are able to generate durable and powerful antitumor immune response to achieve optimal tumor control.

Hepatocellular Carcinoma within Milan Criteria: No-Touch Multibipolar Radiofrequency Ablation for Treatment-Long-term Results

Purpose To assess the long-term outcome in 108 consecutive patients treated with no-touch multibipolar radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) that met the Milan criteria. Materials and Methods This retrospective study was approved by the ethical review board, and the need to obtain informed consent was waived. Between November 1, 2006, and December 31, 2011, 132 HCC tumors (diameter, 10-45 mm; 39 tumors ≥ 30 mm) in 108 consecutive patients (106 with cirrhosis) that met Milan criteria were treated with no-touch multibipolar RFA, which consisted of activating, in bipolar mode, three or four electrodes inserted just beyond the tumor margins. Follow-up was performed every 3 months for 2 years and every 6 months thereafter with computed tomographic or magnetic resonance imaging. Survival probabilities were computed by using the Kaplan-Meier method. Predictive factors of tumor progression and overall survival were assessed by using the Cox proportional hazard model. Results No technical failure occurred, and complete ablation was achieved for all the nodules. After a median of 40.5 months (range, 2-84 months) of follow-up, 3- and 5-year local and overall tumor progression-free survival were 96%, 94%, 52%, and 32%, respectively. Neither tumor diameter greater than 30 mm nor location abutting a large vessel were associated with local tumor progression. Tumor diameter greater than 30 mm was the only parameter predictive of overall tumor progression (P = .0036). Independent factors associated with shorter overall survival were Child-Pugh class B disease, age greater than 65 years, and platelet count of less than 150 g/L (P < .003). Three major complications occurred (2.7%): hemothorax in one patient and liver failure in two, with major portal-systemic shunts. One patient (0.9%) died, and one underwent transplantation. Conclusion No-touch multibipolar RFA for HCC tumors that meet Milan criteria provides a high local tumor progression-free survival rate. An ongoing randomized trial might help to clarify the role of this new approach for the treatment of early HCC. (©) RSNA, 2016 Online supplemental material is available for this article. An earlier incorrect version of this article appeared online. This article was corrected on March 30, 2016.

Preliminary Outcome of Microwave Ablation of Hepatocellular Carcinoma: Breaking the 3-cm Barrier?

PURPOSE

To evaluate preliminary outcomes after microwave ablation (MWA) of hepatocellular carcinoma (HCC) up to 5 cm and to determine the influence of tumor size.

MATERIALS AND METHODS

Electronic records were searched for HCC and MWA. Between January 2011 and September 2014, 173 HCCs up to 5 cm were treated by MWA in 129 consecutive patients (89 men, 40 women; mean age, 66.9 y ± 9.5). Tumor characteristics related to local tumor progression and primary and secondary treatment efficacy were evaluated by univariate analysis. Outcomes were compared between tumors ≤ 3 cm and tumors > 3 cm.

RESULTS

Technical success, primary efficacy, and secondary efficacy were 96.5%, 99.4%, and 94.2% at a mean follow-up period of 11.8 months ± 9.8 (range, 0.8-40.6 mo). Analysis of tumor characteristics showed no significant risk factor for local tumor progression, including subcapsular location (P = .176), tumor size (P = .402), and perivascular tumor location (P = .323). The 1-year and 2-year secondary or overall treatment efficacy rates for tumors measuring ≤ 3 cm were 91.2% and 82.1% and for tumors 3.1-5 cm were 92.3% and 83.9% (P = .773). The number of sessions to achieve secondary efficacy was higher in the larger tumor group (1.13 vs 1.06, P = .005). There were three major complications in 134 procedures (2.2%).

CONCLUSIONS

With use of current-generation MWA devices, percutaneous ablation of HCCs up to 5 cm can be achieved with high efficacy.

[Diagnosis and treatment of hepatocellular carcinoma. Update consensus document from the AEEH, SEOM, SERAM, SERVEI and SETH]

Hepatocellular carcinoma is the most common primary malignancy of the liver and one of the most frequent causes of death in patients with liver cirrhosis. Simultaneously with the recognition of the clinical relevance of this neoplasm, in recent years there have been important developments in the diagnosis, staging and treatment of HCC. Consequently, the Asociación Española para el Estudio del Hígado has driven the need to update clinical practice guidelines, continuing to invite all the societies involved in the diagnosis and treatment of this disease to participate in the drafting and approval of the document (Sociedad Española de Trasplante Hepático, Sociedad Española de Radiología Médica, Sociedad Española de Radiología Vascular e Intervencionista y Sociedad Española de Oncología Médica). The clinical practice guidelines published in 2009 accepted as Clinical Practice Guidelines of the National Health System has been taken as reference document, incorporating the most important advances that have been made in recent years. The scientific evidence for the treatment of HCC has been evaluated according to the recommendations of the National Cancer Institute (www.cancer.gov) and the strength of recommendation is based on the GRADE system.

Radiofrequency ablation of hepatocellular carcinoma: Mono or multipolar?

BACKGROUND AND AIMS

Thermo-ablation by radiofrequency is recognized as a curative treatment for early-stage hepatocellular carcinoma. However, local recurrence may occur because of incomplete peripheral tumor destruction. Multipolar radiofrequency has been developed to increase the size of the maximal ablation zone. We aimed to compare the efficacy of monopolar and multipolar radiofrequency for the treatment of hepatocellular carcinoma and determine factors predicting failure.

METHODS

A total of 171 consecutive patients with 214 hepatocellular carcinomas were retrospectively included. One hundred fifty-eight tumors were treated with an expandable monopolar electrode and 56 with a multipolar technique using several linear bipolar electrodes. Imaging studies at 6 weeks after treatment, then every 3 months, assessed local effectiveness. Radiofrequency failure was defined as persistent residual tumor after two sessions (primary radiofrequency failure) or local tumor recurrence during follow-up. This study received institutional review board approval (number 2014/77).

RESULTS

Imaging showed complete tumor ablation in 207 of 214 lesions after the first session of radiofrequency. After a second session, only two cases of residual viable tumor were observed. During follow-up, there were 46 local tumor recurrences. Thus, radiofrequency failure occurred in 48/214 (22.4%) cases. By multivariate analysis, technique (P < 0.001) and tumor size (P = 0.023) were independent predictors of radiofrequency failure. Failure rate was lower with the multipolar technique for tumors < 25 mm (P = 0.023) and for tumors between 25 and 45 mm (P = 0.082). There was no difference for tumors ≥ 45 mm (P = 0.552).

CONCLUSIONS

Compared to monopolar radiofrequency, multipolar radiofrequency improves tumor ablation with a subsequent lower rate of local tumor recurrence.

Ablation techniques for primary and metastatic liver tumors

Ablative treatment methods have emerged as safe and effective therapies for patients with primary and secondary liver tumors who are not surgical candidates at the time of diagnosis. This article reviews the current literature and describes the techniques, complications and results for radiofrequency ablation, microwave ablation, cryoablation, and irreversible electroporation.

Gefitinib Synergizes with Irinotecan to Suppress Hepatocellular Carcinoma via Antagonizing Rad51-Mediated DNA-Repair

Chemotherapy is the only choice for most of the advanced hepatocellular carcinoma (HCC) patients, while few agents were available, making it an urgent need to develop new chemotherapy strategies. A phase II clinical trial suggested that the efficacy of irinotecan in HCC was limited due to dose-dependent toxicities. Here, we found that gefitinib exhibited synergistic activity in combination with SN-38, an active metabolite of irinotecan, in HCC cell lines. And the enhanced apoptosis induced by gefitinib plus SN-38 was a result from caspase pathway activation. Mechanistically, gefitinib dramatically promoted the ubiquitin–proteasome-dependent degradation of Rad51 protein, suppressed the DNA repair, gave rise to more DNA damages, and ultimately resulted in the synergism of these two agents. In addition, the increased antitumor efficacy of gefitinib combined with irinotecan was further validated in a HepG2 xenograft mice model. Taken together, our data demonstrated for the first time that the combination of irinotecan and gefitinib showed potential benefit in HCC, which suggests that Rad51 is a promising target and provides a rationale for clinical trials investigating the efficacy of the combination of topoisomerase I inhibitors and gefitinib in HCC.

CT Appearance of Hepatocellular Carcinoma after Locoregional Treatments: A Comprehensive Review

Hepatocellular carcinoma (HCC) is a major health problem worldwide, affecting more than 600,000 new patients per year. Curative treatments are available in a small percentage of patients, while most of them present in stages requiring locoregional treatments such as thermoablation, transarterial chemoembolization, and/or radioembolization. These therapies result in specific imaging features that the general radiologist has to be aware of in order to assess the response to treatment and to correctly manage the follow-up of treated patients. Multiphasic helical computed tomography has become a popular imaging modality for detecting hypervascular tumors and characterizing liver lesions. On this basis, many staging and diagnostic systems have been proposed for evaluating response to all different existing strategies. Radiofrequencies and microwaves generate thermoablation of tumors, and transarterial chemoembolization exploits the double effect of the locoregional administration of drugs and embolizing particles. Eventually radioembolization uses a beta-emitting isotope to induce necrosis. Therefore, the aim of this comprehensive review is to analyze and compare CT imaging appearance of HCC after various locoregional treatments, with regard to specific indications for all possible procedures.

Liver transplantation for hepatocellular carcinoma - factors influencing outcome and disease-free survival

Hepatocellular carcinoma is one of the leading causes of cancer-related death worldwide. Liver transplantation can be a curative treatment in selected patients. However, there are several factors that influence disease-free survival after transplantation. This review addresses the pre-, intra- and postoperative factors that influence the risk of tumor recurrence after liver transplantation.

Ultrasound-Guided Percutaneous Radiofrequency Ablation of Liver Tumors: How We Do It Safely and Completely

Ultrasound-guided percutaneous radiofrequency (RF) ablation has become one of the most promising local cancer therapies for both resectable and nonresectable hepatic tumors. Although RF ablation is a safe and effective technique for the treatment of liver tumors, the outcome of treatment can be closely related to the location and shape of the tumors. There may be difficulties with RF ablation of tumors that are adjacent to large vessels or extrahepatic heat-vulnerable organs and tumors in the caudate lobe, possibly resulting in major complications or treatment failure. Thus, a number of strategies have been developed to overcome these challenges, which include artificial ascites, needle track ablation, fusion imaging guidance, parallel targeting, bypass targeting, etc. Operators need to use the right strategy in the right situation to avoid the possibility of complications and incomplete thermal tissue destruction; with the right strategy, RF ablation can be performed successfully, even for hepatic tumors in high-risk locations. This article offers technical strategies that can be used to effectively perform RF ablation as well as to minimize possible complications related to the procedure with representative cases and schematic illustrations.

Colorectal liver metastatic disease: efficacy of irreversible electroporation--a single-arm phase II clinical trial (COLDFIRE-2 trial)

Background

Irreversible electroporation (IRE) is a novel image-guided tumor ablation technique that has shown promise for the ablation of lesions in proximity to vital structures such as blood vessels and bile ducts. The primary aim of the COLDFIRE-2 trial is to investigate the efficacy of IRE for unresectable, centrally located colorectal liver metastases (CRLM). Secondary outcomes are safety, technical success, and the accuracy of contrast-enhanced (ce)CT and ¹⁸F-FDG PET-CT in the detection of local tumor progression (LTP).

Methods/design

In this single-arm, multicenter phase II clinical trial, twenty-nine patients with ¹⁸F-FDG PET-avid CRLM ≤ 3,5 cm will be prospectively included to undergo IRE of the respective lesion. All lesions must be unresectable and unsuitable for thermal ablation due to vicinity of vital structures. Technical success is based on ceMRI one day post-IRE. All complications related to the IRE procedure are registered. Follow-up consists of ¹⁸F-FDG PET-CT and 4-phase liver CT at 3-monthly intervals during the first year of follow-up. Treatment efficacy is defined as the percentage of tumors successfully eradicated 12 months after the initial IRE procedure based on clinical follow-up using both imaging modalities, tumor marker and (if available) histopathology. To determine the accuracy of ¹⁸F-FDG PET-CT and ceCT, both imaging modalities will be individually scored by two reviewers that are blinded for the final oncologic outcome.

Discussion

To date, patients with a central CRLM unsuitable for resection or thermal ablation have no curative treatment option and are given palliative chemotherapy. For these patients, IRE may prove a life-saving treatment option. The results of the proposed trial may represent an important step towards the implementation of IRE for central liver tumors in the clinical setting.

Trial registration

Trial registration number: NCT02082782.

Hepatocellular carcinoma: From clinical practice to evidence-based treatment protocols

Hepatocellular carcinoma (HCC) is one of the major malignant diseases in many healthcare systems. The growing number of new cases diagnosed each year is nearly equal to the number of deaths from this cancer. Worldwide, HCC is a leading cause of cancer-related deaths, as it is the fifth most common cancer and the third most important cause of cancer related death in men. Among various risk factors the two are prevailing: viral hepatitis, namely chronic hepatitis C virus is a well-established risk factor contributing to the rising incidence of HCC. The epidemic of obesity and the metabolic syndrome, not only in the United States but also in Asia, tend to become the leading cause of the long-term rise in the HCC incidence. Today, the diagnosis of HCC is established within the national surveillance programs in developed countries while the diagnosis of symptomatic, advanced stage disease still remains the characteristic of underdeveloped countries. Although many different staging systems have been developed and evaluated the Barcelona-Clinic Liver Cancer staging system has emerged as the most useful to guide HCC treatment. Treatment allocation should be decided by a multidisciplinary board involving hepatologists, pathologists, radiologists, liver surgeons and oncologists guided by personalized -based medicine. This approach is important not only to balance between different oncologic treatments strategies but also due to the complexity of the disease (chronic liver disease and the cancer) and due to the large number of potentially efficient therapies. Careful patient selection and a tailored treatment modality for every patient, either potentially curative (surgical treatment and tumor ablation) or palliative (transarterial therapy, radioembolization and medical treatment, i.e., sorafenib) is mandatory to achieve the best treatment outcome.

Optimizing the management of patients with BCLC stage-B hepatocellular carcinoma: Modern surgical resection as a feasible alternative to transarterial chemoemolization

OBJECTIVE

To analyse the impact of liver resection (LR) in patients with Hepatocellular Carcinoma (HCC) within the Barcelona-Clinic-Liver-Cancer (BCLC)-B stage.

METHODS

Analysis of patients with BCLC-B HCC treated with LR or transarterial chemoembolization (TACE) between 2007 and 2012 in our hospital. Survival/recurrence analyses were performed by log-rank tests and Cox multivariate models. Further analyses were specifically obtained for the HCC subclassification (B1-2-3-4) proposed recently.

RESULTS

Eighty patients were treated (44-TACE/36-LR). Number of nodules was [1.8(1.1)], being multinodular in 50% of cases. Although resected patients had a higher hospital stay than those who underwent TACE (14 ± 13 vs 7 ± 6; P = 0.004), the rate and severity of complications was lower measured by Dindo-Clavien scale (P < 0.05). Overall survival was 40% with a median follow-up of 29.5 months (0.07-96.9). Five-years survival rates were 62.9%, 28.1% and 15.4%, respectively (P = 0.004) for B1, B2 and B3-4 stages. Cox model showed that only total bilirubin [OR = 2.055(1.23-3.44)] and BCLC subclassification B3-4 [OR = 2.439(1.04-5.7)] and B2 [OR = 2.79(1.35-5.77)] vs B1 were independent predictors of 5-years-survival. In B1 patients, surgical approach led a significant decrease in 5-years recurrence-rate (25% vs 60%; P = 0.018). In the surgical subgroup analysis, better results were observed if well/moderate differentiation combined with no microvascular-invasion (VI) in 5-years-survival (84.6%; P = 0.001) and -recurrence (23.1%; P = 0.041), respectively. These survival and recurrence trends were remarkable in B1 stages.

CONCLUSIONS

Management of Intermediate BCLC-B HCC stage should be more complex and include updated criteria regarding B-stage subclassifications, VI and tumour differentiation. Modern surgical resection would offer improved survival benefit with acceptable safety in selected BCLC-B stage patients.

Irreversible Electroporation of Malignant Hepatic Tumors--Alterations in Venous Structures at Subacute Follow-Up and Evolution at Mid-Term Follow-Up

Purpose

To evaluate risk factors associated with alterations in venous structures adjacent to an ablation zone after percutaneous irreversible electroporation (IRE) of hepatic malignancies at subacute follow-up (1 to 3 days after IRE) and to describe evolution of these alterations at mid-term follow-up.

Materials and Methods

43 patients (men/women, 32/11; mean age, 60.3 years) were identified in whom venous structures were located within a perimeter of 1.0 cm of the ablation zone at subacute follow-up after IRE of 84 hepatic lesions (primary/secondary hepatic tumors, 31/53). These vessels were retrospectively evaluated by means of pre-interventional and post-interventional contrast-enhanced magnetic resonance imaging or computed tomography or both. Any vascular changes in flow, patency, and diameter were documented. Correlations between vascular change (yes/no) and characteristics of patients, lesions, and ablation procedures were assessed by generalized linear models.

Results

191 venous structures were located within a perimeter of 1.0 cm of the ablation zone: 55 (29%) were encased by the ablation zone, 78 (41%) abutted the ablation zone, and 58 (30%) were located between 0.1 and 1.0 cm from the border of the ablation zone. At subacute follow-up, vascular changes were found in 19 of the 191 vessels (9.9%), with partial portal vein thrombosis in 2, complete portal vein thrombosis in 3, and lumen narrowing in 14 of 19. At follow-up of patients with subacute vessel alterations (mean, 5.7 months; range, 0 to 14 months) thrombosis had resolved in 2 of 5 cases; vessel narrowing had completely resolved in 8 of 14 cases, and partly resolved in 1 of 14 cases. The encasement of a vessel by ablation zone (OR = 6.36, p<0.001), ablation zone being adjacent to a portal vein (OR = 8.94, p<0.001), and the usage of more than 3 IRE probes (OR = 3.60, p = 0.035) were independently associated with post-IRE vessel alterations.

Conclusion

Venous structures located in close proximity to an IRE ablation zone remain largely unaffected by this procedure, and thrombosis is rare.

Microwave Ablation Compared to Radiofrequency Ablation for Hepatic Lesions: A Meta-Analysis

To evaluate the efficacy and safety of microwave (MW) ablation compared with radiofrequency (RF) ablation for hepatic lesions by using meta-analytic techniques. Overall, 16 studies involving 2,062 patients were included. MW ablation was found to have significantly better 6-year overall survival than RF ablation (odds ratio, 1.64, 95% confidence interval, 1.15-2.35), but this was based on a few articles (n = 3 of 16). MW ablation and RF ablation had similar 1-5-year overall survival, disease-free survival, local recurrence rate, and adverse events. Based on similar safety and efficacy outcomes, either MW ablation or RF ablation may be used for effective local hepatic therapy.

Guide for diagnosis and treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is ranked as the 5^th common type of cancer worldwide and is considered as the 3^rd common reason for cancer-related deaths. HCC often occurs on top of a cirrhotic liver. The prognosis is determined by several factors; tumour extension, alpha-fetoprotein (AFP) concentration, histologic subtype of the tumour, degree of liver dysfunction, and the patient’s performance status. HCC prognosis is strongly correlated with diagnostic delay. To date, no ideal screening modality has been developed. Analysis of recent studies showed that AFP assessment lacks adequate sensitivity and specificity for effective surveillance and diagnosis. Many tumour markers have been tested in clinical trials without progressing to routine use in clinical practice. Thus, surveillance is still based on ultrasound (US) examination every 6 mo. Imaging studies for diagnosis of HCC can fall into one of two main categories: routine non-invasive studies such as US, computed tomography (CT), and magnetic resonance imaging, and more specialized invasive techniques including CT during hepatic arteriography and CT arterial portography in addition to the conventional hepatic angiography. This article provides an overview and spotlight on the different diagnostic modalities and treatment options of HCC.

Irreversible Electroporation of Hepatic and Pancreatic Malignancies: Radiologic-Pathologic Correlation

Irreversible electroporation (IRE) is a novel therapy that has shown to be a feasible and promising alternative to conventional ablative techniques when treating tumors near vital structures or blood vessels. The clinical efficacy of IRE has been evaluated using established imaging criteria. This study evaluates the histologic and imaging response of hepatic and pancreatic malignancies that were surgically resected after IRE. In total, 12 lesions ablated with IRE were included, including 3 pancreatic carcinomas, 5 primary tumors of the liver, and 4 metastatic tumors of the liver. The rate of complete response to IRE was 25% based on the histologic evaluation of the resected tumors. Although treatment-related vessel wall changes were noted in several cases in histologic findings, there was no evidence of vascular luminal narrowing or obliteration in any of the specimens. The imaging response to IRE before surgical resection usually resulted in underestimation of disease burden when compared with the histologic response seen on the resected specimens.

Hepatocellular carcinoma: From diagnosis to treatment

Hepatocellular carcinoma (HCC) is the sixth most prevalent malignancy worldwide and is a rising cause of cancer related mortality. Risk factors for HCC are well documented and effective surveillance and early diagnosis allow for curative therapies. The majority of HCC appears to be caused by cirrhosis from chronic hepatitis B and hepatitis C virus. Preventive strategies include vaccination programs and anti-viral treatments. Surveillance with ultrasonography detects early stage disease and improves survival rates. Many treatment options exist for individuals with HCC and are determined by stage of presentation. Liver transplantation is offered to patients who are within the Milan criteria and are not candidates for hepatic resection. In patients with advanced stage disease, sorafenib shows some survival benefit.

Dual-energy CT after radiofrequency ablation of liver, kidney, and lung lesions: a review of features

Early detection of residual tumour and local tumour progression (LTP) after radiofrequency (RF) ablation is crucial in the decision whether or not to re-ablate. In general, standard contrast-enhanced computed tomography (CT) is used to evaluate the technique effectiveness; however, it is difficult to differentiate post-treatment changes from residual tumour. Dual-energy CT (DECT) is a relatively new technique that enables more specific tissue characterisation of iodine-enhanced structures because of the isolation of iodine in the imaging data. Necrotic post-ablation zones can be depicted as avascular regions by DECT on greyscale- and colour-coded iodine images. Synthesised monochromatic images from dual-energy CT with spectral analysis can be used to select the optimal keV to achieve the highest contrast-to-noise ratio between tissues. This facilitates outlining the interface between the ablation zone and surrounding tissue. Post-processing of DECT data can lead to an improved characterisation and delineation of benign post-ablation changes from LTP. Radiologists need to be familiar with typical post-ablation image interpretations when using DECT techniques. Here, we review the spectrum of changes after RF ablation of liver, kidney, and lung lesions using single-source DECT imaging, with the emphasis on the additional information obtained and pitfalls encountered with this relatively new technique.

Teaching Points

•Technical success of RF ablation means complete destruction of the tumour.

•Assessment of residual tumour on contrast-enhanced CT is hindered by post-ablative changes.

•DECT improves material differentiation and may improve focal lesion characterisation.

•Iodine maps delineate the treated area from the surrounding parenchyma well.

Switching bipolar hepatic radiofrequency ablation using internally cooled wet electrodes: comparison with consecutive monopolar and switching monopolar modes

OBJECTIVE

To evaluate whether switching bipolar radiofrequency ablation (SB-RFA) using three internally cooled wet (ICW) electrodes can induce coagulations >5 cm in porcine livers with better efficiency than consecutive monopolar (CM) or switching monopolar (SM) modes.

METHODS

A total of 60 coagulations were made in 15 in vivo porcine livers using three 17-gauge ICW electrodes and a multichannel radiofrequency (RF) generator. RF energy (approximately 200 W) was applied in CM mode (Group A, n = 20) for 24 min, SM mode for 12 min (Group B, n = 20) or switching bipolar (SB) mode for 12 min (Group C, n = 20) in in vivo porcine livers. Thereafter, the delivered RFA energy, as well as the shape and dimension of coagulations were compared among the groups.

RESULTS

Spherical- or oval-shaped ablations were created in 30% (6/20), 85% (17/20) and 90% (18/20) of coagulations in the CM, SM and SB groups, respectively (p = 0.003). SB-RFA created ablations >5 cm in minimum diameter (Dmin) in 65% (13/20) of porcine livers, whereas SM- or CM-RFA created ablations >5 cm in only 25% (5/20) and 20% (4/20) of porcine livers, respectively (p = 0.03). The mean Dmin of coagulations was significantly larger in Group C than in Groups A and B (5.1 ± 0.9, 3.9 ± 1.2 and 4.4 ± 1.0 cm, respectively, p = 0.002) at a lower delivered RF energy level (76.8 ± 14.3, 120.9 ± 24.5 and 114.2 ± 18.3 kJ, respectively, p < 0.001).

CONCLUSION

SB-RFA using three ICW electrodes can create coagulations >5 cm in diameter with better efficiency than do SM- or CM-RFA.

ADVANCES IN KNOWLEDGE

SB-RFA can create large, regular ablation zones with better time-energy efficiency than do CM- or SM-RFA.

Tumoral pulmonary emboli from angioinvasive hepatocellular carcinoma

Tumoral pulmonary emboli from hepatocellular carcinoma (HCC) have rarely been described, although invasion of the portal and hepatic venous systems is a well-known complication. HCC originating in a noncirrhotic liver in the absence of chronic hepatitis B infection is also uncommon. We present a case of a patient with chronic hepatitis C infection without hepatic cirrhosis who developed angioinvasive HCC with intracardiac extension and tumoral pulmonary emboli. Differential considerations, including combined HCC-cholangiocarcinoma, other hepatic mesenchymal tumors, and metastasis, are discussed. Owing to poor prognosis, no resection was attempted. Autopsy was performed because of the unusual clinical presentation, and immunohistochemistry of the hepatic tumor, the intracardiac extension, and the pulmonary emboli were concordant with hepatocellular origin. Even though definitive diagnosis may not affect patient outcome, it is important for radiologists and clinicians to be aware that angioinvasive HCC may arise in the absence of cirrhosis.

Radiotherapy for liver tumors

Many patients with primary hepatic malignancies present with advanced disease that is not suitable for surgical resection, orthotopic liver transplantation, or radiofrequency ablation. Outcomes are particularly dismal in patients with large, unresectable tumors and/or tumor venous thrombosis. Liver-directed radiotherapy, including stereotactic body radiotherapy (SBRT), is able to treat a variety of tumor sizes and tumors with venous involvement and has demonstrated excellent safety and control outcomes. SBRT should be considered a standard option in patients with early-stage hepatocellular carcinoma who are not candidates for surgical resection, orthotopic liver transplantation or radiofrequency ablation. SBRT should be strongly considered in patients with larger tumors and/or tumors with tumor venous thrombosis who have adequate liver function. Radiotherapy should remain a focus of hepatocellular carcinoma research.

Comparison of transarterial chemoembolization and hepatic resection for large solitary hepatocellular carcinoma: a propensity score analysis

PURPOSE

To compare long-term survival after hepatic resection and transarterial chemoembolization of large solitary hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

Analysis of 91 and 68 consecutive patients with large (≥ 5 cm) solitary HCCs who underwent hepatic resection and transarterial chemoembolization, respectively, was performed. Overall survival and time to progression (TTP) were estimated using the Kaplan-Meier method and compared using the Cox proportional hazards model. To control for treatment-selection bias, matched groups of patients were selected using a propensity score matching method, and survival analysis was repeated.

RESULTS

During the follow-up period (median, 60.7 mo; range, 0.5-122.2 mo), 42 (46%) patients in the hepatic resection group and 35 (51%) patients in the transarterial chemoembolization group died. The 1-year, 3-year, and 5-year overall survival rates of the hepatic resection and transarterial chemoembolization groups were 91.1%, 80.0%, and 66.4% (hepatic resection group) and 89.8%, 72.8%, and 49.6% (transarterial chemoembolization group) (P = .023). TTP was significantly longer in patients who underwent hepatic resection (P < .001). Hepatitis B surface antigen positivity and the absence of portal hypertension were independent predictors for favorable overall survival. For patients with platelet counts ≤ 100,000/mm(3), Child-Pugh score of 6, smaller HCCs (≤ 7 cm), or portal hypertension, hepatic resection and transarterial chemoembolization yielded similar overall survival rates. After propensity score matching, transarterial chemoembolization was comparable to hepatic resection in overall survival (P = .293), whereas TTP remained longer in patients who underwent hepatic resection (P = .001).

CONCLUSIONS

Transarterial chemoembolization can lead to results comparable to hepatic resection in the treatment of large solitary HCCs, particularly in patients with clinically presumed portal hypertension.

Factors associated with short-term local recurrence of liver cancer after percutaneous ablation using irreversible electroporation: a prospective single-center study

PURPOSE

To evaluate the risk factors associated with short-term local recurrence of malignant liver lesions after irreversible electroporation (IRE).

MATERIALS AND METHODS

Thirty-nine consecutive patients (79 malignant liver lesions) were treated with IRE, of whom 14 were excluded from the analysis (including 12 without 6 mo of follow-up and two with incomplete ablation). The remaining 25 patients (aged 59.4 y ± 11.2) had 48 malignant liver lesions, including 22 hepatocellular carcinomas (HCCs), six cholangiocellular carcinomas, and 20 metastatic liver cancers. Multivariate analyses were used to evaluate the associations of risk factors with early recurrence. The characteristics of patients, lesions, and IRE procedures were assessed by logistic regression.

RESULTS

Fourteen of the 48 treated lesions (29.2%) showed early local recurrence after 6 months. Tumor volume (< 5 cm(3) vs ≥ 5 cm(3); P = .022) and underlying disease type (HCC, cholangiocellular carcinoma, or metastatic disease; P = .023) were independently associated with early local recurrence. However, distances to the surrounding portal veins (< 0.5 cm vs ≥ 0.5 cm; P = .810), hepatic veins (P = .170), hepatic arteries (P = .761), and bile ducts (P = .226) were not significantly associated with local recurrence.

CONCLUSIONS

Because short distances to the surrounding vessels were not associated with early local recurrence, percutaneous IRE might provide an alternative treatment option for perivascular tumors. However, patients with larger tumor volumes appeared to be poor candidates for percutaneous IRE. Regarding the different types of treated lesions, patients with HCC had significantly better outcomes.

Microwave ablation of focal hepatic malignancies regardless of size: A 9-year retrospective study of 64 patients

PURPOSE

To retrospectively evaluate the safety and efficacy of microwave ablation (MWA) as treatment for single, focal hepatic malignancies.

MATERIALS AND METHODS

Institutional review board approval was obtained for this HIPAA-compliant study. From December 2003 to May 2012, 64 patients were treated with MWA for a single hepatic lesion, in 64 sessions. Hepatocellular carcinoma (HCC) was treated in 25 patients (geometric mean tumor size, 3.33-cm; 95% CI, 2.65-4.18-cm; range, 1.0-12.0-cm), metastatic colorectal cancer (CRC) was treated in 27 patients (geometric mean tumor size, 2.7-cm; 95% CI, 2.20-3.40-cm; range, 0.8-6.0-cm), and other histological-types were treated in 12 patients (geometric mean tumor size, 3.79-cm; 95% CI, 2.72-5.26-cm; range, 1.7-8.0-cm). Kaplan-Meier (K-M) method was used to analyze time event data. Chi-square and correlation evaluated the relationship between tumor size and treatment parameters.

RESULTS

Technical success rate was 95.3% (61/64). Treatment parameters were tailored to tumor size; as size increased more antennae were used (p<0.001), treatment with multiple activations increased (p<0.028), and treatment time increased (p<0.001). There was no statistically significant relationship between time to recurrence and tumor size, number of activations, number of antennae, and treatment time. At one-year, K-M analysis predicted a likelihood of local recurrence of 39.8% in HCC patients, 45.7% in CRC metastases patients, and 70.8% in patients with other metastases. Median cancer specific survivals for patients were 38.3 months for HCC patients, 36.3 months for CRC metastases, and 13.9 months for other histological-types. Complications occurred in 23.4% (15/64) of sessions.

CONCLUSION

In our sample, tumor size did not appear to impact complete ablation rates or local recurrence rates for focal hepatic malignancies treated with MWA.

Heat sink effect on tumor ablation characteristics as observed in monopolar radiofrequency, bipolar radiofrequency, and microwave, using ex vivo calf liver model

Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices.With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored.With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres.Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected.Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5.MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink.

Image-guided ablation of primary liver and renal tumours

Image-guided ablation (IGA) techniques have evolved considerably over the past 20 years and are increasingly used to definitively treat small primary cancers of the liver and kidney. IGA is recommended by most guidelines as the best therapeutic choice for patients with early stage hepatocellular carcinoma (HCC)-defined as either a single tumour smaller than 5 cm or up to three nodules smaller than 3 cm-when surgical options are precluded, and has potential as first-line therapy, in lieu of surgery, for patients with very early stage tumours smaller than 2 cm. With regard to renal cell carcinoma, despite the absence of any randomized trial comparing the outcomes of IGA with those of standard partial nephrectomy, a growing amount of data demonstrate robust oncological outcomes for this minimally invasive approach and testify to its potential as a standard-of-care treatment. Herein, we review the various ablation techniques, the supporting evidence, and clinical application of IGA in the treatment of primary liver and kidney cancers.

Efficacy and survival analysis of percutaneous radiofrequency versus microwave ablation for hepatocellular carcinoma: an Egyptian multidisciplinary clinic experience

BACKGROUND

Hepatocellular carcinoma (HCC) is a primary tumor of the liver with poor prognosis. For early stage HCC, treatment options include surgical resection, liver transplantation, and percutaneous ablation. Percutaneous ablative techniques (radiofrequency and microwave techniques) emerged as best therapeutic options for nonsurgical patients.

AIMS

We aimed to determine the safety and efficacy of radiofrequency and microwave procedures for ablation of early stage HCC lesions and prospectively follow up our patients for survival analysis.

PATIENTS AND METHODS

One Hundred and 11 patients with early HCC are managed in our multidisciplinary clinic using either radiofrequency or microwave ablation. Patients are assessed for efficacy and safety. Complete ablation rate, local recurrence, and overall survival analysis are compared between both procedures.

RESULTS

Radiofrequency ablation group (n = 45) and microwave ablation group (n = 66) were nearly comparable as regards the tumor and patients characteristics. Complete ablation was achieved in 94.2 and 96.1% of patients managed by radiofrequency and microwave ablation techniques, respectively (p value 0.6) with a low rate of minor complications (11.1 and 3.2, respectively) including subcapsular hematoma, thigh burn, abdominal wall skin burn, and pleural effusion. Ablation rates did not differ between ablated lesions ≤ 3 and 3-5 cm. A lower incidence of local recurrence was observed in microwave group (3.9 vs. 13.5% in radiofrequency group, p value 0.04). No difference between both groups as regards de novo lesions, portal vein thrombosis, and abdominal lymphadenopathy. The overall actuarial probability of survival was 91.6% at 1 year and 86.1% at 2 years with a higher survival rates noticed in microwave group but still without significant difference (p value 0.49).

CONCLUSION

Radiofrequency and microwave ablations led to safe and equivalent ablation and survival rates (with superiority for microwave ablation as regards the incidence of local recurrence).

Combination guidance of contrast-enhanced US and fusion imaging in radiofrequency ablation for hepatocellular carcinoma with poor conspicuity on contrast-enhanced US/fusion imaging

PURPOSE

The purpose of this study was to evaluate the usefulness of the combination guidance of contrast-enhanced US (CEUS) and fusion imaging in radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) with poor conspicuity on B-mode US and CEUS/fusion imaging.

MATERIALS AND METHODS

We conducted a retrospective cohort study, which included 356 patients with 556 HCCs that were inconspicuous on B-mode US. A total of 192 patients with 344 HCCs, 123 patients with 155 HCCs, and 37 patients with 57 HCCs underwent RFA under CEUS guidance, fusion imaging guidance, and the combination of CEUS and fusion imaging guidance.

RESULTS

The average number of treatment sessions was 1.1 (range: 1-2) in the CEUS guidance group, 1.1 (range: 1-2) in the fusion imaging guidance group, and 1.1 (range: 1-3) in the combination of CEUS and fusion imaging guidance group. Treatment analysis did not reveal significantly more RFA treatment sessions in the combination guidance group than in the other groups (p = 0.97, Student's t test). During the follow-up period (1.1-85.3 months, mean ± SD, 43.2 ± 59.5), the 3-year local tumor progression rates were 4.9, 7.2, and 5.9% in the CEUS guidance group, the fusion imaging guidance group, and the combination guidance group, respectively (p = 0.84, log-rank test).

CONCLUSION

In spite of selection bias, session frequency and local tumor progression were not different under the combination guidance with CEUS and fusion imaging in RFA. The combination of fusion imaging and CEUS guidance in RFA therapy is an effective treatment for HCC with poor conspicuity on B-mode US and CEUS/fusion imaging.

Tumour eradication using synchronous thermal ablation and Hsp90 chemotherapy with protein engineered triblock biopolymer-geldanamycin conjugates

PURPOSE

Hepatocellular carcinoma (HCC) suffers high tumour recurrence rate after thermal ablation. Heat shock protein 90 (Hsp90) induced post-ablation is critical for tumour survival and progression. A combination therapy of thermal ablation and polymer conjugated Hsp90 chemotherapy was designed and evaluated for complete tumour eradication of HCC.

MATERIALS AND METHODS

A thermo-responsive, elastin-like polypeptide (ELP)-based tri-block biopolymer was developed and conjugated with a potent Hsp90 inhibitor, geldanamycin (GA). The anti-cancer efficacy of conjugates was evaluated in HCC cell cultures with and without hyperthermia (43 °C). The conjugates were also administered twice weekly in a murine HCC model as a single treatment or in combination with single electrocautery as the ablation method.

RESULTS

ELP-GA conjugates displayed enhanced cytotoxicity in vitro and effective heat shock inhibition under hyperthermia. The conjugates alone significantly slowed the tumour growth without systemic toxicity. Four doses of thermo-responsive ELP-GA conjugates with concomitant simple electrocautery accomplished significant Hsp90 inhibition and sustained tumour suppression.

CONCLUSION

Hsp90 inhibition plays a key role in preventing the recurrence of HCC, and the combination of ablation with targeted therapy holds great potential to improve prognosis and survival of HCC patients.

Hepatocellular carcinoma: systemic therapies and future perspectives

Hepatocellular carcinoma is (HCC) the most common primary malignancy of the liver in adults. It is also the fifth most common solid cancer worldwide and the third leading cause of cancer-related deaths. Treatment options for HCC include liver transplantation, surgical resection, locoregional therapies and chemotherapy. The median survival time of patients following the diagnosis of unresectable disease is approximately 6-20 months, whereas the 5-year survival is less than 5%. Given the projected increase in incidence of HCC due to hepatitis C virus infection and obesity related cirrhosis, there is an urgent need for more intensive research in this cancer. In this article, we review the systemic options available for patients with HCC, its molecular pathogenesis and future therapeutic directions with special emphasis on immune-based and molecularly-targeted therapy.