Thermal ablation for hepatocellular carcinoma

Ultrasonography of Hepatocellular Carcinoma: From Diagnosis to Prognosis

Hepatocellular carcinoma (HCC) is a prominent contributor to cancer-related mortality worldwide. Early detection and diagnosis of liver cancer can significantly improve its prognosis and patient survival. Ultrasound technology, serving has undergone substantial advances as the primary method of HCC surveillance and has broadened its scope in recent years for effective management of HCC. This article is a comprehensive overview of ultrasound technology in the treatment of HCC, encompassing early detection, diagnosis, staging, treatment evaluation, and prognostic assessment. In addition, the authors summarized the application of contrast-enhanced ultrasound in the diagnosis of HCC and assessment of prognosis. Finally, the authors discussed further directions in this field by emphasizing overcoming existing obstacles and integrating cutting-edge technologies.

Postoperative SIRS after thermal ablation of HCC: Risk factors and short-term prognosis

Background

We aimed to explore the potential risk factors and short-term prognosis for SIRS after thermal ablation of hepatocellular carcinoma (HCC).

Methods

Data from patients with HCC who underwent thermal ablation in the Third Affiliated Hospital of Sun Yat-sen University between January 2015 and August 2021 were retrieved from the perioperative database. Pre-, intra- and postoperative data between SIRS group and non-SIRS group were compared and multivariate logistic regression analysis was performed to identify the risk factors for SIRS after thermal ablation.

Results

A total of 1491 patients were enrolled and 234 (15.7 %) patients developed SIRS after thermal ablation. Compared with those without SIRS, patients with SIRS had a longer hospital stay, higher hospitalization costs and higher risk of more severe postoperative complications. In the multivariate logistic regression analysis, current smoking (OR 1.58, 95 %CI 1.09-2.29), decreased HCT (OR 1.51,95 %CI 1.11-2.04), NEUT < 1.5 × 109/L(OR 1.74, 95 %CI 1.14-2.65), NEUT% < 0.5 or > 0.7 (OR 1.36, 95 %CI 1.01-1.83) and PT > 16.3s (OR 2.42, 95 %CI 1.57-3.74) were significantly associated with postoperative SIRS.

Conclusions

Current smoking, decreased HCT, neutropenia, abnormal percentage of neutrophils and prolonged PT are the independent risk factors for SIRS after thermal ablation of HCC, which worsens outcomes of patients. This study can help identify high-risk population and guide appropriate care so as to reduce the incidence of postoperative SIRS.

Local Therapies for Hepatocellular Carcinoma and Role of MRI-Guided Adaptive Radiation Therapy

Hepatocellular carcinoma (HCC) is the most common liver tumor, with a continually rising incidence. The curative treatment for HCC is surgical resection or liver transplantation; however, only a small portion of patients are eligible due to local tumor burden or underlying liver dysfunction. Most HCC patients receive nonsurgical liver-directed therapies (LDTs), including thermal ablation, transarterial chemoembolization (TACE), transarterial radioembolization (TARE), and external beam radiation therapy (EBRT). Stereotactic ablative body radiation (SABR) is a specific type of EBRT that can precisely deliver a high dose of radiation to ablate tumor cells using a small number of treatments (or fractions, typically 5 or less). With onboard MRI imaging, MRI-guided SABR can improve therapeutic dose while minimizing normal tissue exposure. In the current review, we discuss different LDTs and compare them with EBRT, specifically SABR. The emerging MRI-guided adaptive radiation therapy has been reviewed, highlighting its advantages and potential role in HCC management.

Application of ablative therapy for intrahepatic recurrent hepatocellular carcinoma following hepatectomy

The post-hepatectomy recurrence rate of hepatocellular carcinoma (HCC) is persistently high, affecting the prognosis of patients. An effective therapeutic option is crucial for achieving long-term survival in patients with postoperative recurrences. Local ablative therapy has been established as a treatment option for resectable and unresectable HCCs, and it is also a feasible approach for recurrent HCC (RHCC) due to less trauma, shorter operation times, fewer complications, and faster recovery. This review focused on ablation techniques, description of potential candidates, and therapeutic and prognostic implications of ablation for guiding its application in treating intrahepatic RHCC.

Hydrogels for Antitumor and Antibacterial Therapy

As a highly absorbent and hydrophobic material with a three-dimensional network structure, hydrogels are widely used in biomedical fields for their excellent biocompatibility, low immunogenicity, adjustable physicochemical properties, ability to encapsulate a variety of drugs, controllability, and degradability. Hydrogels can be used not only for wound dressings and tissue repair, but also as drug carriers for the treatment of tumors. As multifunctional hydrogels are the focus for many researchers, this review focuses on hydrogels for antitumor therapy, hydrogels for antibacterial therapy, and hydrogels for co-use in tumor therapy and bacterial infection. We highlighted the advantages and representative applications of hydrogels in these fields and also outlined the shortages and future orientations of this useful tool, which might give inspirations for future studies.

Contrast-enhanced ultrasound (CEUS) in HCC diagnosis and assessment of tumor response to locoregional therapies

Hepatocellular carcinoma (HCC) is a global problem constituting the second leading cause of cancer deaths worldwide, thereby necessitating an accurate and cost-effective solution for managing care. Ultrasound is well poised to address this need due to its low cost, portability, safety, and excellent temporal resolution. The role of ultrasound for HCC screening has been well established and supported by multiple international guidelines. Similarly, contrast-enhanced ultrasound (CEUS) can be used for the characterization of focal liver lesions in high-risk populations, and standardized criteria for CEUS have been established by the American College of Radiology Liver Imaging Reporting & Data System (LI-RADS). Following HCC identification, CEUS can also be highly beneficial in treatment planning, delivery, and monitoring HCC response to locoregional therapies. Specific advantages of CEUS include providing real-time treatment guidance and improved diagnostic performance for the detection of residual tumor viability or recurrence, thereby identifying patients in need of retreatment substantially earlier than contrast-enhanced CT and MRI. This review provides a primer on ultrasound and CEUS for the screening and characterization of HCC, with an emphasis on assessing tumor response to locoregional therapies.

Effectiveness of Hepatocellular Carcinoma Surveillance and an Optimal Surveillance Interval: Nationwide Cohort of Korea

PURPOSE

To assess associations between surveillance intervals in a national hepatocellular carcinoma (HCC) surveillance program and receiving curative treatment and mortality using nationwide cohort data for Korea.

MATERIALS AND METHODS

Using the National Health Insurance Service Database of Korea, we retrospectively identified 3201852 patients, the target population of the national HCC surveillance program, between 2008 and 2017. After exclusion, a total of 64674 HCC patients were divided based on surveillance intervals: never screened, ≤6 months (6M), 7-12 months (1Y), 13-24 months (2Y), and 25-36 months (3Y). Associations for surveillance interval with the chance to receive curative therapy and all-cause mortality were analyzed.

RESULTS

The 6M group (51.9%) received curative therapy more often than the other groups (1Y, 48.3%; 2Y, 43.8%; 3Y, 41.3%; never screened, 34.5%). Odds ratio for receiving curative therapy among the other surveillance interval groups (1Y, 0.87; 2Y, 0.76; 3Y, 0.77; never screened, 0.57; p<0.001) were significantly lower than that of the 6M group. The hazard ratios (HRs) of all-cause mortality were 1.07, 1.14, and 1.37 for 2Y, 3Y, and never screened groups. The HR for the 1Y group (0.96; p=0.092) was not significantly different, and it was lower (0.91; p<0.001) than that of the 6M group after adjustment for lead-time bias. Curative therapy was associated with survival benefits (HR, 0.26; p<0.001).

CONCLUSION

HCC surveillance, especially at a surveillance interval of 6 months, increases the chance to receive curative therapy.

A review of antenna designs for percutaneous microwave ablation

Microwave (MW) antenna is a key element in microwave ablation (MWA) treatments as the means that energy is delivered in a focused manner to the tumor and its surrounding area. The energy delivered results in a rise in temperature to a lethal level, resulting in cell death in the ablation zone. The delivery of energy and hence the success of MWA is closely dependent on the structure of the antennas. Therefore, three design criteria, such as expected ablation zone pattern, efficiency of energy delivery, and minimization of the diameter of the antennas have been the focus along the evolution of the MW antenna. To further improve the performance of MWA in the treatment of various tumors through inventing novel antennas, this article reviews the state-of-the-art and summarizes the development of MW antenna designs regarding the three design criteria.

Efficacy and safety of US-guided thermal ablation for primary hyperparathyroidism: a systematic review and meta-analysis

Purpose: To summarize the published literature on thermal ablation for primary hyperparathyroidism (PHPT) and to evaluate the effectiveness and safety of thermal ablation as a novel treatment strategy.Materials and methods: Two authors carried out the literature search using four databases independently, including PubMed, Embase, Cochrane, and Web of Science. The meta-analysis included prospective and retrospective data that compared post-ablative outcomes to pre-ablative values. The primary outcomes were parathyroid hormone (PTH), serum calcium and volume of the parathyroid gland (VPG).Results: From the 184 original articles, five studies (4 retrospective studies and 1 prospective study) examining 84 patients met the inclusion criteria. The meta-analysis showed significant reduction of PTH at 3 (standardized mean difference (SMD) =  -1.09, 95% confidence index (CI) =  -1.42 to -0.76, p < 0.001) and 6 months (SMD =  -1.13, 95% CI =  -1.46 to -0.80, p < 0.001) after thermal ablation. Serum calcium level was significantly reduced at 3 (mean difference (MD) =  -0.31, 95% CI =  -0.50 to -0.12, p  =  0.001) and 6 months (MD =  -0.31, 95% CI =  -0.46 to -0.17, p < 0.001) after thermal ablation. There was no significant difference between pre-ablative VPG and that of 6 months after ablation (MD =  -0.30, 95% CI =  -0.70 to 0.09, p  =  0.13). The most common complications were transient dysphonia and subcutaneous edema. No major complications or death occurred.Conclusion: Thermal ablation is effective and safe for treatment of PHPT. PTH and calcium levels were reduced significantly at 3 and 6 months after thermal ablation.

Safety and Local Efficacy of Laser Ablation for the Extrahepatic Metastasis of Hepatocellular Carcinoma: An Available Treatment Strategy

Thermal ablation plays an important role in the treatment of extrahepatic metastasis of hepatocellular carcinoma (HCC). Yet laser ablation (LA), as a safe thermal ablative modality, is less investigated in this field. In this study, the safety and local effectiveness of LA in the treatment for the extrahepatic metastasis of HCC were evaluated. From May 2012 to May 2019, 17 patients (13 males and 4 females; mean age, 54.1 ± 14.6 years; age range, 34–80 years), who underwent LA for treatment of extrahepatic metastasis of HCC at the First Affiliated Hospital of Sun Yat-sen University, were retrospectively enrolled in this study. Local effectiveness, complications, local tumor progression (LTP), and overall survival (OS) were evaluated. Finally, a total of 28 LA treated extrahepatic metastatic lesions of HCC were reviewed. Neither LA-related mortality nor major complication occurred. Complete ablation (CA) was achieved in 20 out of 28 lesions (71.4%). During the follow-up (mean, 19.5 ± 12.8 months; range, 5–42.7 months), LTP developed in 4 out of 20 lesions with CA (20%). Four patients died of tumor progression or multiple organ dysfunction syndrome. The accumulative one- and three-year OS rates were 79.0% and 65.8%, respectively. In conclusion, LA is a safe and effective therapeutic option in the treatment of extrahepatic metastasis of HCC. Further studies are necessary to evaluate the benefit of LA.

Magnetic resonance and ultrasound image-guided navigation system using a needle manipulator

PURPOSE

Image guidance is crucial for percutaneous tumor ablations, enabling accurate needle-like applicator placement into target tumors while avoiding tissues that are sensitive to injury and/or correcting needle deflection. Although ultrasound (US) is widely used for image guidance, magnetic resonance (MR) is preferable due to its superior soft tissue contrast. The objective of this study was to develop and evaluate an MR and US multi-modal image-guided navigation system with a needle manipulator to enable US-guided applicator placement during MR imaging (MRI)-guided percutaneous tumor ablation.

METHODS

The MRI-compatible needle manipulator with US probe was installed adjacent to a 3 Tesla MRI scanner patient table. Coordinate systems for the MR image, patient table, manipulator, and US probe were all registered using an optical tracking sensor. The patient was initially scanned in the MRI scanner bore for planning and then moved outside the bore for treatment. Needle insertion was guided by real-time US imaging fused with the reformatted static MR image to enhance soft tissue contrast. Feasibility, targeting accuracy, and MR compatibility of the system were evaluated using a bovine liver and agar phantoms.

RESULTS

Targeting error for 50 needle insertions was 1.6 ± 0.6 mm (mean ± standard deviation). The experiment confirmed that fused MR and US images provided real-time needle localization against static MR images with soft tissue contrast.

CONCLUSIONS

The proposed MR and US multi-modal image-guided navigation system using a needle manipulator enabled accurate needle insertion by taking advantage of static MR and real-time US images simultaneously. Real-time visualization helped determine needle depth, tissue monitoring surrounding the needle path, target organ shifts, and needle deviation from the path.

The Efficacy and The Safety of Ultrasound-guided Ablation Therapy for Treating Papillary Thyroid Microcarcinoma

The prevalence of papillary thyroid microcarcinoma (PTMC) increases rapidly all around the world, but the management of PTMC hasn't reached a consensus. Recently, ultrasound-guided (US-guided) ablation therapy was introduced as a feasible treatment for low-risk PTMC. The clinical application of US-guided ablation therapy needs doctors' effort to investigate the efficacy and the safety of US-guided ablation in treating PTMC carefully. Although the present evidence showed some limitations, such as short-term study time spans and no randomized control design, in our perspective, US-guided thermal ablation therapy has good short-term efficacy and safety and is a promising PTMC's treatment in future clinical practice.

Histotripsy for Non-Invasive Ablation of Hepatocellular Carcinoma (HCC) Tumor in a Subcutaneous Xenograft Murine Model

Histotripsy fractionates tissue through a mechanical, non-invasive ultrasonic ablation process that precisely controls acoustic cavitation while utilizing real-time ultrasound (US) imaging guidance. This study investigates the potential, feasibility and tumor volume reduction effects of histotripsy for liver cancer ablation in a subcutaneous in vivo murine Hepatocellular Carcinoma (HCC) model. Hep3B tumors were generated in the right flanks of 14 NSG and 7 NOD-SCID mice. The mice were grouped as follows: A (acute, NSG with n=9 treatment and n=1 control), B (chronic, NSG with n=2 treatment and n=2 control) and C (chronic NODSCID, with n=6 treatment and n=1 control). Treatment was performed when the tumor diameters reached >5 mm. 1-2 cycle histotripsy pulses at 100 Hz PRF (p- >30 MPa) were delivered using a custom built 1 MHz therapy transducer attached to a motorized positioner, which scanned the transducer focus to traverse the targeted tumor volume, guided by real-time US imaging. Tumor ablation effectiveness was assessed by obtaining T1, T2 and T2* weighted MR images. Post euthanasia, treated tumor, brain, and lung tissue samples were harvested for histology. Histology of acute group A showed fractionation of targeted region with a sharp boundary separating it from untreated tissue. Groups B and C demonstrated effective tumor volume reduction post treatment on MRI as the homogenate and edema were resorbed within 23 weeks. However, as the tumor was subcutaneous, it was not possible to set adequate treatment margin and since the mice were immune-compromised, residual viable tumor cells eventually developed into tumor regrowth at 3-9 weeks after histotripsy. Groups B and C showed no signs of metastasis in the lung and brain. Our study successfully demonstrated the potential of histotripsy for non-invasive HCC ablation in a subcutaneous murine model. Additional work is ongoing to study the response of histotripsy in immune-competent orthotopic liver tumor models.

Non-Invasive Liver Ablation Using Histotripsy: Preclinical Safety Study in an In Vivo Porcine Model

This study investigates the safety profile for use of histotripsy, a non-invasive ultrasonic ablation method currently being developed for the treatment of liver cancer, for liver ablation in an in vivo porcine model. Histotripsy treatments were applied to the liver and hepatic veins of 22 porcine subjects, with half of the subjects receiving systemic heparinization. Vital signs (heart rate, blood pressure, temperature, electrocardiogram and SpO₂) were monitored throughout the procedure and for 1 h post-treatment. Blood was drawn at six points during the experiment to analyze blood gases, liver function and free hemoglobin levels. All treatments were guided and monitored by real-time ultrasound imaging. After treatment, the tissue was harvested for histological analysis. Results indicated that histotripsy generated well-defined lesions inside the liver and around the treated hepatic veins of all subjects in both treatment groups. Vital signs and blood analysis revealed that animals responded well to histotripsy, with all animals surviving the treatment. One animal in the non-heparinized group had a transient increase in pH and decreases in blood pressure, heart rate and PCO₂ during the 15-min vessel treatment, with these changes returning to baseline levels soon after the treatment. Overall, the results indicate that histotripsy can safely be performed on the liver without the need for systemic heparinization, even in regions containing large hepatic vessels, supporting its future use for the treatment of liver cancer.

Management of people with early- or very early-stage hepatocellular carcinoma: an attempted network meta-analysis

BACKGROUND

Hepatocellular carcinoma (primary liver cancer) is classified in many ways. The Barcelona Clinic Liver Cancer (BCLC) group staging classifies the cancer based on patient's life expectancy. People with very early- or early-stage hepatocellular carcinoma have single tumour or three tumours of maximum diameter of 3 cm or less, Child-Pugh status A to B, and performance status 0 (fully functional). Management of hepatocellular carcinoma is uncertain.

OBJECTIVES

To assess the comparative benefits and harms of different interventions used in the treatment of early or very early hepatocellular carcinoma through a network meta-analysis and to generate rankings of the available interventions according to their safety and efficacy. However, it was not possible to assess whether the potential effect modifiers were similar across different comparisons. Therefore, we did not perform the network meta-analysis and instead assessed the benefits and harms of different interventions versus each other or versus sham or no intervention using standard Cochrane methodology.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Science Citation Index Expanded, and trials registers to September 2016 to identify randomised clinical trials (RCTs) on hepatocellular carcinoma.

SELECTION CRITERIA

We included only RCTs, irrespective of language, blinding, or publication status, in participants with very early- or early-stage hepatocellular carcinoma, irrespective of the presence of cirrhosis, portal hypertension, aetiology of hepatocellular carcinoma, size and number of the tumours, and future remnant liver volume. We excluded trials including participants who were previously liver transplanted. We considered interventions compared with each other, sham, or no intervention.

DATA COLLECTION AND ANALYSIS

We calculated the odds ratio, mean difference, rate ratio, or hazard ratio with 95% confidence intervals using both fixed-effect and random-effects models based on available-participant analysis with Review Manager 5. We assessed the risk of bias according to Cochrane, controlled risk of random errors with Trial Sequential Analysis using Stata, and the quality of the evidence using GRADE.

MAIN RESULTS

Eighteen trials met the inclusion criteria for this review. Four trials (593 participants; 574 participants included for one or more analyses) compared surgery versus radiofrequency ablation in people with early hepatocellular carcinoma, eligible to undergo surgery. Fourteen trials (2533 participants; 2494 participants included for various analyses) compared different non-surgical interventions in people with early hepatocellular carcinoma, not eligible to undergo surgery. Overall, the quality of evidence was low or very low for all outcomes for both comparisons. Surgery versus radiofrequency ablationThe majority of participants had cirrhotic livers, and the hepatocellular carcinoma was of viral aetiology. The trials did not report the participants' portal hypertension status or whether they received adjuvant antiviral treatment or adjuvant immunotherapy. The average follow-up ranged from 29 months to 42 months (3 trials).There was no evidence of a difference in all-cause mortality at maximal follow-up for surgery versus radiofrequency ablation (hazard ratio 0.80, 95% confidence interval (CI) 0.60 to 1.08; 574 participants; 4 trials; I² = 68). Cancer-related mortality was lower in the surgery group (20/115 (17.4%)) than in the radiofrequency ablation group (43/115 (37.4%)) (odds ratio 0.35, 95% CI 0.19 to 0.65; 230 participants; 1 trial). Serious adverse events (number of participants) was higher in the surgery group (14/60 (23.3%)) than in the radiofrequency ablation group (1/60 (1.7%)) (odds ratio 17.96, 95% CI 2.28 to 141.60; 120 participants; 1 trial). The number of serious adverse events was higher in the surgery group (adjusted rate 11.3 events per 100 participants) than in the radiofrequency ablation group (3/186 (1.6 events per 100 participants)) (rate ratio 7.02, 95% CI 2.29 to 21.46; 391 participants; 2 trials; I² = 0%). None of the trials reported health-related quality of life. One trial was funded by a party with vested interests; three trials were funded by parties without any vested. Non-surgical interventionsThe majority of participants had cirrhotic livers, and the hepatocellular carcinoma was of viral aetiology. Most trials did not report the portal hypertension status of the participants, and none of the trials reported whether the participants received adjuvant antiviral treatment or adjuvant immunotherapy. The average follow-up ranged from 6 months to 37 months (11 trials). Trial participants, who were not eligible for surgery, were treated with radiofrequency ablation, laser ablation, microwave ablation, percutaneous acetic acid injection, percutaneous alcohol injection, a combination of radiofrequency ablation with systemic chemotherapy, a combination of radiofrequency ablation with percutaneous alcohol injection, a combination of transarterial chemoembolisation with percutaneous alcohol injection, or a combination of transarterial chemoembolisation with radiofrequency ablation.The mortality at maximal follow-up was higher in the percutaneous acetic acid injection (hazard ratio 1.77, 95% CI 1.12 to 2.79; 125 participants; 1 trial) and percutaneous alcohol injection (hazard ratio 1.49, 95% CI 1.18 to 1.88; 882 participants; 5 trials; I² = 57%) groups compared with the radiofrequency ablation group. There was no evidence of a difference in all-cause mortality at maximal follow-up for any of the other comparisons. The proportion of people with cancer-related mortality at maximal follow-up was higher in the percutaneous alcohol injection group (adjusted proportion 16.8%) compared with the radiofrequency ablation group (20/232 (8.6%)) (odds ratio 2.18, 95% CI 1.22 to 3.89; 458 participants; 3 trials; I² = 0%). There was no evidence of a difference in any of the comparisons that reported serious adverse events (number of participants or number of events). None of the trials reported health-related quality of life. Five trials were funded by parties without any vested interest; the source of funding was not available in the remaining trials.

AUTHORS' CONCLUSIONS

The evidence was of low or very low quality. There was no evidence of a difference in all-cause mortality at maximal follow-up between surgery and radiofrequency ablation in people eligible for surgery. All-cause mortality at maximal follow-up was higher with percutaneous acetic acid injection and percutaneous alcohol injection than with radiofrequency ablation in people not eligible for surgery. There was no evidence of a difference in all-cause mortality at maximal follow-up for the other comparisons. High-quality RCTs designed to assess clinically important differences in all-cause mortality and health-related quality of life, and having an adequate follow-up period (approximately five years) are needed.

Management of people with intermediate-stage hepatocellular carcinoma: an attempted network meta-analysis

BACKGROUND

There is significant uncertainty in the treatment of intermediate-stage hepatocellular carcinoma which is defined by the Barcelona Clinic Liver Cancer (BCLC) as hepatocellular carcinoma stage B with large, multi-nodular, Child-Pugh status A to B, performance status 0 to 2, and without vascular occlusion or extrahepatic disease.

OBJECTIVES

To assess the comparative benefits and harms of different interventions used in the treatment of intermediate-stage hepatocellular carcinoma (BCLC stage B) through a network meta-analysis and to generate rankings of the available interventions according to their safety and efficacy. However, we found only one comparison. Therefore, we did not perform the network meta-analysis, and we assessed the comparative benefits and harms of different interventions versus each other, or versus placebo, sham, or no intervention (supportive treatment only) using standard Cochrane methodology.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Science Citation Index Expanded, World Health Organization International Clinical Trials Registry Platform, and randomised clinical trials registers to September 2016 to identify randomised clinical trials on hepatocellular carcinoma.

SELECTION CRITERIA

We included only randomised clinical trials, irrespective of language, blinding, or publication status, in participants with intermediate-stage hepatocellular carcinoma, irrespective of the presence of cirrhosis, size, or number of the tumours (provided they met the criteria of intermediate-stage hepatocellular carcinoma), of presence or absence of portal hypertension, of aetiology of hepatocellular carcinoma, and of the future remnant liver volume. We excluded trials which included participants who had previously undergone liver transplantation. We considered any of the various interventions compared with each other or with no active intervention (supportive treatment only). We excluded trials which compared variations of the same intervention: for example, different methods of performing transarterial chemoembolisation.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We calculated the hazard ratio (HR) with 95% confidence intervals (CI) using both fixed-effect and random-effects models based on available-participant analysis with Review Manager. We assessed risk of bias according to Cochrane, controlled risk of random errors with Trial Sequential Analysis using Stata, and assessed the quality of the evidence using GRADE.

MAIN RESULTS

Three randomised clinical trials, including 430 participants, met the inclusion criteria for this review; however, data from two trials with 412 participants could be included in only one primary outcome (i.e. mortality). All three trials were at high risk of bias. All three trials included supportive care as cointervention. The comparisons included in the two trials reporting on mortality were: systemic chemotherapy with sorafenib versus no active intervention; and transarterial chemoembolisation plus systemic chemotherapy with sorafenib versus transarterial chemoembolisation alone. The trials did not report the duration of follow-up; however, it appeared that the participants were followed up for a period of about 18 to 30 months. The majority of the participants in the trials had cirrhotic livers. The trials included participants with intermediate-stage hepatocellular carcinoma arising from viral and non-viral aetiologies. The trials did not report the portal hypertension status of the participants. The mortality was 50% to 70% over a median follow-up period of 18 to 30 months. There was no evidence of difference in mortality at maximal follow-up between systemic chemotherapy versus no chemotherapy (hazard ratio 0.85, 95% CI 0.60 to 1.18; participants = 412; studies = 2; I² = 0%; very low quality evidence). A subgroup analysis performed by stratifying the analysis by the presence or absence of transarterial chemoembolisation as cointervention did not alter the results. None of the trials reported on serious adverse events other than mortality, health-related quality of life, recurrence of hepatocellular carcinoma, or length of hospital stay. One of the trials providing data was funded by the pharmaceutical industry, the other did not report the source of funding, and the trial with no data for the review was also funded by the pharmaceutical industry. We found two ongoing trials.

AUTHORS' CONCLUSIONS

Currently, there is no evidence from randomised clinical trials that people with intermediate-stage hepatocellular carcinoma would benefit from systemic chemotherapy with sorafenib either alone or when transarterial chemoembolisation was used as a cointervention (very low quality evidence). We need high-quality randomised clinical trials designed to measure differences in clinically important outcomes (e.g. all-cause mortality or health-related quality of life).

Microwave ablation of hepatocellular carcinoma as first-line treatment: long term outcomes and prognostic factors in 221 patients

This retrospective study aimed at evaluating the long-term outcomes and prognostic factors of microwave ablation (MWA) as a first-line treatment for hepatocellular carcinoma (HCC). 221 consecutive patients receiving MWA in our center between October 11, 2010 and December 31, 2013 were enrolled. Technique effectiveness was evaluated one month post-ablation. Initial complete ablation (CA1^st) was gained in 201 (90.95%) patients, secondary CA (CA2^nd) in 8 (3.62%) patients and the remaining 12 (5.43%) patients suffered from incomplete ablation (IA2^nd) after two sessions of MWA. Patients with tumor size >5 cm were less likely to gain CA1^st. Procedure-related complications were recorded and no procedure-related death occurred. 22 (10.4%) complications occurred with 8 (3.8%) being major ones. Tumor characteristics (size, number, location) do not significantly influence complication rates. After a median follow-up of 41.0 (ranging 25.0–63.5) months, the median RFS and OS was 14.0 months (95% CI: 9.254–18.746) and 41.0 months (95% CI: 33.741–48.259) respectively. Multivariate analysis identified two significant prognosticators (levels of alpha fetal protein [AFP] and gamma-glutamyl transpeptidase [GGT]) of RFS and five significant prognosticators (tumor number, tumor size, AFP, GGT and recurrence type) of OS. In conclusion, MWA provides high technique effectiveness rate and is well tolerated in patients with HCC as a first-line treatment.

Non-Invasive Ultrasound Liver Ablation Using Histotripsy: Chronic Study in an In Vivo Rodent Model

Hepatocellular carcinoma, or liver cancer, has the fastest growing incidence among cancers in the United States. Current liver ablation methods are thermal-based and share limitations due to the heat sink effect from the blood flow through the highly vascular liver. Recently, our group has investigated histotripsy as a non-invasive liver cancer ablation method. Histotripsy is a non-thermal ultrasonic ablation method that fractionates tissue through the control of acoustic cavitation. Previous experiments in an in vivo porcine model show that histotripsy can create well-confined lesions in the liver through ribcage obstruction without damaging the overlying ribs and other tissues. Histotripsy can also completely fractionate liver tissue surrounding major vessels while preserving the vessels. In this study, we investigate the long-term effects of histotripsy liver ablation in a rodent model. We hypothesize that the fractionated histotripsy lesion will be resorbed by the liver, resulting in effective tissue healing. To test this hypothesis, the livers of 20 healthy rats were treated with histotripsy using an 8-element 1-MHz histotripsy transducer. Rats were euthanized after 0, 3, 7, 14 and 28 days (n = 4). In vivo and post mortem results showed histotripsy lesions were successfully generated through the intact abdomen in all 20 rats. Magnetic resonance imaging found primarily negative contrast on day 0, positive contrast on day 3 and rapid normalization of signal intensity thereafter (i.e., signal amplitude returned to baseline levels seen in healthy liver tissue). Histologically, lesions were completely fractionated into an acellular homogenate. The lesions had a maximum cross-sectional area of 17.2 ± 1.9 mm(2) and sharp boundaries between the lesion and the healthy surrounding tissue after treatment. As the animals recovered after treatment, the histotripsy tissue homogenate was almost completely replaced by regenerated liver parenchyma, resulting in a small fibrous lesion (<1 mm(2) maximum cross-section) remaining after 28 d. The results of this study suggest that histotripsy has potential as a non-invasive liver ablation method for effective tissue removal.

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.

Reusable tissue-mimicking hydrogel phantoms for focused ultrasound ablation

The ability of N-isopropylacrylamide (NIPAM)-based hydrogel phantoms to mimic tissues with different acoustic and thermal properties under high-intensity focused ultrasound (HIFU) ablation was investigated. These phantoms were designed to model the formation of thermal lesions in tissues above the threshold temperature of protein denaturation. By adjusting the concentration of acrylic acid (AAc) in the NIPAM-based hydrogel phantoms, the cloud point (i.e., lower critical solution temperature) of the phantoms could be tailored to produce HIFU thermal lesions similar to those formed in different swine tissues in terms of size and shape. Additionally, energy thresholds for inducing transient or permanent bubbles in the phantoms during HIFU ablation were also identified to shed light on the onset of cavitation or material damage. The NIPAM-based hydrogel phantoms developed in this study possess major advantages such as transparent, reusable and tailorable properties, and are practical tools for characterizing an ablative device (or treatment) to determine its efficacy and safety.

Image-guided non-invasive ultrasound liver ablation using histotripsy: feasibility study in an in vivo porcine model

Hepatocellular carcinoma (HCC), or liver cancer, is one of the fastest growing cancers in the United States. Current liver ablation methods are thermal based and share limitations resulting from the heat sink effect of blood flow through the highly vascular liver. In this study, we explore the feasibility of using histotripsy for non-invasive liver ablation in the treatment of liver cancer. Histotripsy is a non-thermal ablation method that fractionates soft tissue through the control of acoustic cavitation. Twelve histotripsy lesions ∼1 cm(3) were created in the livers of six pigs through an intact abdomen and chest in vivo. Histotripsy pulses of 10 cycles, 500-Hz pulse repetition frequency (PRF), and 14- to 17-MPa estimated in situ peak negative pressure were applied to the liver using a 1-MHz therapy transducer. Treatments were performed through 4-6 cm of overlying tissue, with 30%-50% of the ultrasound pathway covered by the rib cage. Complete fractionation of liver parenchyma was observed, with sharp boundaries after 16.7-min treatments. In addition, two larger volumes of 18 and 60 cm(3) were generated within 60 min in two additional pigs. As major vessels and gallbladder have higher mechanical strength and are more resistant to histotripsy, these remained intact while the liver surrounding these structures was completely fractionated. This work shows that histotripsy is capable of non-invasively fractionating liver tissue while preserving critical anatomic structures within the liver. Results suggest histotripsy has potential for the non-invasive ablation of liver tumors.

Radiofrequency ablation of metastatic lesions from breast cancer

INTRODUCTION

Breast cancer (BC) is the most common malignancy in women. Various studies [5,6] have shown that surgical resection of single liver or lung metastases in patients with metastases from BC increases survival. Radiofrequency ablation (RFA) can be an alternative to resection in some patients when resection is not feasible.

MATERIALS AND METHODS

From January 2002 to December 2008, 491 patients with liver metastases underwent US-guided percutaneous RFA. Of these patients 5 (5/491; 1%) had BC. In the same period, 32 patients with pulmonary metastases underwent CT-guided RFA. Of these patients 3 (3/32; 9%) had BC. Mean age was 61.3 years. All patients were postmenopausal and receiving polychemotherapy according to international guidelines. Inclusion criteria for RFA treatment of metastases from BC applied are identical or in some cases more restrictive than those reported in the literature.

RESULTS

There were no deaths or severe complications and no treatment failures. Disease free and overall median survival were respectively 7.65 and 25.7 months after US-guided RFA and 13.4 and 34.8 months after CT-guided RFA. During follow-up (mean follow-up 26 months, range 4-63 months) 5/8 (62.5%) patients exhibited recurrence: 3/5 (60%) had local recurrence and 2/5 (40%) had non-local recurrence; 4/5 patients with recurrence were re-treated.

DISCUSSION

The authors' experience confirms that RFA is an effective, safe and repeatable technique in the treatment of metastases from BC. Metastatic recurrence rate confirms that metastatic BC is a disease which requires a multidisciplinary approach and that the role of chemotherapy is indisputable. Effects on survival are promising but further confirmation is needed through prospective randomized studies.

Repeated radiofrequency ablation for management of patients with cirrhosis with small hepatocellular carcinomas: a long-term cohort study

In most patients with cirrhosis, successful percutaneous ablation or surgical resection of hepatocellular carcinoma (HCC) is followed by recurrence. Radiofrequency ablation (RFA) has proven effective for treating HCC nodules, but its repeatability in managing recurrences and the impact of this approach on survival has not been evaluated. To this end, we retrospectively analyzed a prospective series of 706 patients with cirrhosis (Child-Pugh class ≤ B7) who underwent RFA for 859 HCC ≤ 35 mm in diameter (1-2 per patient). The results of RFA were classified as complete responses (CRs) or treatment failures. CRs were obtained in 849 nodules (98.8%) and 696 patients (98.5%). During follow-up (median, 29 months), 465 (66.8%) of the 696 patients with CRs experienced a first recurrence at an incidence rate of 41 per 100 person-years (local recurrence 6.2; nonlocal 35). Cumulative incidences of first recurrence at 3 and 5 years were 70.8% and 81.7%, respectively. RFA was repeated in 323 (69.4%) of the 465 patients with first recurrence, restoring disease-free status in 318 (98.4%) cases. Subsequently, RFA was repeated in 147 (65.9%) of the 223 patients who developed a second recurrence after CR of the first, restoring disease-free status in 145 (98.6%) cases. Overall, there were 877 episodes of recurrence (1-8 per patient); 577 (65.8%) of these underwent RFA that achieved CRs in 557 (96.5%) cases. No procedure-related deaths occurred in 1,921 RFA sessions. Estimated 3- and 5-year overall and disease-free (after repeated RFAs) survival rates were 67.0% and 40.1% and 68.0 and 38.0%, respectively.

CONCLUSION

RFA is safe and effective for managing HCC in patients with cirrhosis, and its high repeatability makes it particularly valuable for controlling intrahepatic recurrences.

[Liver hemostasis using a dry electrocautery or greased with lidocaine or neomycin or glycerin or vaseline, in rabbit]

OBJECTIVE

To assess the hemostasis and healing of the hepatic parenchyma after segmental hepatectomy, using a dry electrocautery or an electrocautery greased with lidocaine gel, neomycin pomade, glycerin lotion, or a vaseline pomade.

METHODS

Rabbits were submitted to partial hepatectomy and divided into six groups of 10 animals each: Group 1: untreated; Group 2: treated with a dry electrocautery; Group 3: treated with an electrocautery greased with lidocaine gel; Group 4: with neomycin pomade; Group 5: with glycerine lotion; Group 6: with vaseline pomade. Resected liver weight, bleeding volume and time spent to achieve hemostasis were determined. Five rabbits from each group were re-operated upon after 24 hours and five after 7 days in order to obtain a biopsy of the hepatic wound and to explore he abdominal cavity. Red blood cell levels and markers of hepatic function and injury were determined before surgery and before re-operation.

RESULTS

Lidocaine gel and glycerine lotion reduced the bleeding volume and the time to achieve hemostasis and conducted the thermal energy of the electrocautery, causing hydropic cell degeneration after 24 hours and deeper necrosis of hepatic tissue after 7 days. All substances increased the aminotransferase concentrations. These values returned to normal after a maximum of seven days.

CONCLUSION

The electrocautery coated with lidocaine gel and glycerine lotion were the most effective methods for the hemostasis of hepatic parenchyma.

Combination radiofrequency ablation and intravenous radiolabeled liposomal Doxorubicin: imaging and quantification of increased drug delivery to tumors

PURPOSE

To identify, with noninvasive imaging, the zone of radiopharmaceutical uptake after combination therapy with radiofrequency (RF) ablation and intravenous administration of technetium 99m ((99m)Tc) liposomal doxorubicin in a small-animal tumor model, and to quantify and correlate the uptake by using imaging and tissue counting of intratumoral doxorubicin accumulation.

MATERIALS AND METHODS

This study was approved by the animal care committee. Two phases of animal experiments were performed. In the first experiment, a single human head-and-neck squamous cell carcinoma tumor was grown in each of 10 male nude rats. Seven of these animals were treated with intravenous (99m)Tc-liposomal doxorubicin followed by RF tumor ablation at a mean temperature of 70 degrees C + or - 2 for 5 minutes, and three were treated with intravenous (99m)Tc-liposomal doxorubicin only. Combination single photon emission computed tomography-computed tomography (SPECT/CT) was performed at 15 minutes, 4 hours, and 20 hours after therapy. In the second experiment, two tumors each were grown in 11 rats, but only one of the tumors was ablated after intravenous administration of (99m)Tc-liposomal doxorubicin. SPECT/CT and planar scintigraphy were performed at the same posttreatment intervals applied in the first experiment, with additional planar imaging performed at 44 hours. After imaging, tissue counting in the excised tumors was performed. Radiotracer uptake, as determined with imaging and tissue counting, was quantified and compared. In a subset of three animals, intratumoral doxorubicin accumulation was determined with fluorimetry and correlated with the imaging and tissue-counting data.

RESULTS

At both SPECT/CT and planar scintigraphy, increased uptake of (99m)Tc-liposomal doxorubicin was visibly apparent in the ablated tumors. Results of quantitative analysis with both imaging and tissue counting confirmed significantly greater uptake in the RF ablation-treated tumors (P < .001). Intratumoral doxorubicin accumulation correlated closely with imaging (r = 0.9185-0.9871) and tissue-counting (r = 0.995) results.

CONCLUSION

Study results show that increased delivery of intravenous liposomal doxorubicin to tumors combined with RF ablation can be depicted and quantified with noninvasive imaging.

Unresectable hepatocellular carcinoma: serial early vascular and cellular changes after transarterial chemoembolization as detected with MR imaging

PURPOSE

To prospectively assess serial changes in contrast material-enhanced and diffusion-weighted (DW) magnetic resonance (MR) imaging values within 1 month after transarterial chemoembolization (TACE) in patients with unresectable hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Institutional review board approval was obtained for this prospective HIPAA-compliant study. MR imaging was performed before and within 24 hours after TACE in 24 patients with HCC (21 male, three female; mean age, 59 years and 62 years, respectively). Serial MR imaging was subsequently performed 1, 2, 3, and 4 weeks after therapy. The imaging protocol included fast spin-echo T2-weighted MR imaging, breath-hold DW echo-planar MR imaging, and breath-hold unenhanced and contrast-enhanced T1-weighted three-dimensional fat-suppressed gradient-recalled-echo MR imaging in the arterial and portal venous phases. Tumor size, enhancement, and apparent diffusion coefficient (ADC) values were recorded before and sequentially after treatment. Regression models for the correlated data were used to assess changes in these parameters over time after TACE.

RESULTS

Mean tumor size was 7.5 cm and was unchanged up to 4 weeks after therapy. Reduction in tumor enhancement in the arterial phase occurred immediately after TACE, with a consistent reduction occurring 1-3 weeks after therapy (P = .001). Reduction in tumor enhancement in the portal venous phase also occurred immediately after TACE, with a consistent reduction occurring 1-3 weeks after therapy (P = .0003). The increase in tumor ADC value was significant 1-2 weeks after therapy (P = .004), borderline significant 3 weeks after therapy, and insignificant 24 hours and 4 weeks after therapy.

CONCLUSION

Significant reduction in tumor enhancement occurred within 24 hours after TACE and persisted up to 4 weeks after TACE. Lesser changes in the ADC value appeared 1 week after TACE, persisted through 2 weeks after TACE, and became less apparent 3 and 4 weeks after TACE. No change in tumor size was recorded during the follow-up period.

Current situation and progress of local ablation therapy for hepatocellular carcinoma

Local ablation therapy with satisfactory therapeutic effects has been an important combined therapy for hepatocellular carcinoma (HCC). There are mainly two ablation methods available including thermal ablation and chemical ablation. Thermal ablation techniques include microwave ablation, radiofrequency ablation, laser ablation, high intensity focus ultrasound (HIFU) and cryoablation, etc. Chemical ablation methods include mainly ethanol ablation and acetic acid ablation. In this article, our objective was to evaluate the current situation and progress of local ablation therapy in terms of its principles, indications, therapeutic effects, complications, contraindications and pros and cons of various ablation therapies for HCC.

Ultrasound simulation of real-time temperature estimation during radiofrequency ablation using finite element models

Radiofrequency ablation is the most common minimally invasive therapy used in the United States to treat hepatocellular carcinoma and liver metastases. The ability to perform real-time temperature imaging while a patient is undergoing ablation therapy may help reduce the high recurrence rates following ablation therapy. Ultrasound echo signals undergo time shifts with increasing temperature due to sound speed and thermal expansion, which are tracked using both 1D cross correlation and 2D block matching based speckle tracking methods. In this paper, we present a quantitative evaluation of the accuracy and precision of temperature estimation using the above algorithms on both simulated and experimental data. A finite element analysis simulation of radiofrequency ablation of hepatic tissue was developed. Finite element analysis provides a method to obtain the exact temperature distribution along with a mapping of the tissue displacement due to thermal expansion. These local displacement maps were combined with the displacement due to speed of sound changes and utilized to generate ultrasound radiofrequency frames at specified time increments over the entire ablation procedure. These echo signals provide an ideal test-bed to evaluate the performance of both speckle tracking methods, since the estimated temperature results can be compared directly to the exact finite element solution. Our results indicate that the 1D cross-correlation (CC) method underestimates the cumulative displacement by 0.20mm, while the underestimation with 2D block matching (BM) is about 0.14 mm after 360 s of ablation. The 1D method also overestimates the size of the ablated region by 5.4% when compared to 2.4% with the 2D method after 720 s of ablation. Hence 2D block matching provides better tracking of temperature variations when compared to the 1D cross-correlation method over the entire duration of the ablation procedure. In addition, results obtained using 1D cross-correlation diverge from the ideal finite element results after 7 min of ablation and for temperatures greater than 65 degrees C. In a similar manner, experimental results presented using a tissue-mimicking phantom also demonstrate that the maximum percent difference with 2D block matching was 5%, when compared to 31% with the 1D method over the 700 s heating duration on the phantom.

Electromagnetic tracking for thermal ablation and biopsy guidance: clinical evaluation of spatial accuracy

PURPOSE

To evaluate the spatial accuracy of electromagnetic needle tracking and demonstrate the feasibility of ultrasonography (US)-computed tomography (CT) fusion during CT- and US-guided biopsy and radiofrequency ablation procedures.

MATERIALS AND METHODS

The authors performed a 20-patient clinical trial to investigate electromagnetic needle tracking during interventional procedures. The study was approved by the institutional investigational review board, and written informed consent was obtained from all patients. Needles were positioned by using CT and US guidance. A commercial electromagnetic tracking device was used in combination with prototype internally tracked needles and custom software to record needle positions relative to previously obtained CT scans. Position tracking data were acquired to evaluate the tracking error, defined as the difference between tracked needle position and reference standard needle position on verification CT scans. Registration between tracking space and image space was obtained by using reference markers attached to the skin ("fiducials"), and different registration methods were compared. The US transducer was tracked to demonstrate the potential use of real-time US-CT fusion for imaging guidance.

RESULTS

One patient was excluded from analysis because he was unable to follow breathing instructions during the acquisition of CT scans. Nineteen of the 20 patients were evaluable, demonstrating a basic tracking error of 5.8 mm +/- 2.6, which improved to 3.5 mm +/- 1.9 with use of nonrigid registrations that used previous internal needle positions as additional fiducials. Fusion of tracked US with CT was successful. Patient motion and distortion of the tracking system by the CT table and gantry were identified as sources of error.

CONCLUSIONS

The demonstrated spatial tracking accuracy is sufficient to display clinically relevant preprocedural imaging information during needle-based procedures. Virtual needles displayed within preprocedural images may be helpful for clandestine targets such as arterial phase enhancing liver lesions or during thermal ablations when obscuring gas is released. Electromagnetic tracking may help improve imaging guidance for interventional procedures and warrants further investigation, especially for procedures in which the outcomes are dependent on accuracy.

Ultrasound targeted microbubble destruction increases capillary permeability in hepatomas

Ultrasound-targeted microbubble destruction (UTMD) has evolved as a promising tool for organ-specific gene and drug delivery. Taking advantage of high local concentrations of therapeutic substances and transiently increased capillary permeability, UTMD could be used for the treatment of ultrasound accessible tumors. The aim of this study was to evaluate if UTMD can locally increase capillary permeability in a hepatoma model of the rat. Furthermore, we evaluated whether UTMD can transfect DNA into such tumors. Subcutaneous Morris hepatomas were induced in both hind limbs of ACI rats by cell injection. A total of 18 rats were divided into three groups. Only one tumor per rat was treated by ultrasound. The first group received injection of Evans blue, followed by UTMD. The second group received a phosphate-buffered saline solution infusion and ultrasound to the target tumor after Evans blue injection. The third group received UTMD first, followed by Evans blue injection. Tumors and control organs were harvested, and Evans blue extravasation was quantified. Another 12 rats received DNA-loaded microbubbles by UTMD to one tumor, encoding for luciferase. Evans blue injection followed by UTMD showed about fivefold higher Evans blue amount in the target tumors compared with the control tumors. In contrast, no significant difference in Evans blue content was detected between target and control tumors when ultrasound was applied without microbubbles or when UTMD was performed before Evans blue injection. Plasmid transfection was not successful. In conclusion, ultrasound targeted microbubble destruction is able to transiently increase capillary permeability in hepatomas. Using naked DNA, this technique does not seem to be feasible for noninvasive transfection of hepatomas.

Non-invasive ultrasound-based temperature imaging for monitoring radiofrequency heating—phantom results

Minimally invasive therapies (such as radiofrequency ablation) are becoming more commonly used in the United States for the treatment of hepatocellular carcinomas and liver metastases. Unfortunately, these procedures suffer from high recurrence rates of hepatocellular carcinoma ( approximately 34-55%) or metastases following ablation therapy. The ability to perform real-time temperature imaging while a patient is undergoing radiofrequency ablation could provide a significant reduction in these recurrence rates. In this paper, we demonstrate the feasibility of ultrasound-based temperature imaging on a tissue-mimicking phantom undergoing radiofrequency heating. Ultrasound echo signals undergo time shifts with increasing temperature, which are tracked using 2D correlation-based speckle tracking methods. Time shifts or displacements in the echo signal are accumulated, and the gradient of these time shifts are related to changes in the temperature of the tissue-mimicking phantom material using a calibration curve generated from experimental data. A tissue-mimicking phantom was developed that can undergo repeated radiofrequency heating procedures. Both sound speed and thermal expansion changes of the tissue-mimicking material were measured experimentally and utilized to generate the calibration curve relating temperature to the displacement gradient. Temperature maps were obtained, and specific regions-of-interest on the temperature maps were compared to invasive temperatures obtained using fiber-optic temperature probes at the same location. Temperature elevation during a radiofrequency ablation procedure on the phantom was successfully tracked to within +/-0.5 degrees C.

Functional MR imaging assessment of tumor response after 90Y microsphere treatment in patients with unresectable hepatocellular carcinoma

PURPOSE

To assess the utility of functional contrast medium-enhanced and diffusion-weighted magnetic resonance (MR) imaging in the assessment of early (1 month) response of unresectable hepatocellular carcinoma (HCC) to a single treatment with yttrium-90-labeled microspheres.

MATERIALS AND METHODS

The authors evaluated the MR images obtained before and 1 month after single selective (90)Y microsphere treatment in 13 consecutive patients (mean age, 62 years). All patients had cirrhosis and pathologically proved HCC. Images were evaluated by consensus of two radiologists. Tumor size, arterial and venous enhancement, and apparent diffusion coefficient (ADC) were recorded before and after treatment. One targeted tumor in the treated lobe of the liver was included in each patient. In patients who also had lesions in the contralateral lobe of the liver, a second tumor was included as nontargeted tumor.

RESULTS

There were 19 tumors in the 13 patients (mean tumor size, 9.4 cm). The mean tumor burden was 25% of the total liver volume. Targeted tumors (n = 13) demonstrated a mean decrease in arterial enhancement of 22% (P = .013), a mean decrease in venous enhancement of 25% (P = .012), and a mean increase in ADC value of 18% (P < .001). These targeted tumors did not change significantly in size after treatment (P = .492). Six patients had contralateral nontargeted tumors. These nontargeted tumors had no significant change in size (P = 0.100), arterial enhancement (P = .182), venous enhancement (P = .182), or ADC value (P = .105) after treatment.

CONCLUSIONS

Early after treatment with (90)Y microspheres, tumors demonstrated a decrease in enhancement and an increase in ADC, without a statistically significant change in tumor size. These MR findings are useful in the early posttreatment period for assessing treatment response.

Technology insight: Image-guided therapies for hepatocellular carcinoma--intra-arterial and ablative techniques

Locoregional techniques have become the mainstay of therapy for patients with unresectable hepatocellular carcinoma (HCC). Such image-guided interventions include catheter-based approaches (transarterial chemoembolization and yttrium-90 radiotherapy) and locoregional ablative techniques, either chemical (percutaneous ethanol injection), or thermal (radiofrequency ablation, laser ablation, microwave ablation and cryoablation). These therapies are mainly utilized for palliation, but have also been used with curative intent. In selected cases, percutaneous interventional treatments have shown good results (5-year survival 40-50%), but, even when chosen as first-line treatment, have not been able to achieve the response rates and outcomes achieved by surgical options (resection or transplantation). New promising image-guided therapies are continuously emerging, as we attempt to improve tumor targeting, minimize hepatic toxicity and ultimately improve quality of life and survival of patients with HCC. With new technologies in imaging and drug delivery becoming available, it is likely that, in the future, patients with HCC will be best treated by a multidisciplinary team approach, utilizing a combination of techniques to improve patient survival. This review outlines the current status of the most commonly used image-guided locoregional interventions in the treatment of patients with HCC, and describes recent research and advances related to image-guided interventions for liver cancer.

Combination of repeated single-session percutaneous ethanol injection and transarterial chemoembolisation compared to repeated single-session percutaneous ethanol injection in patients with non-resectable hepatocellular carcinoma

AIM: To evaluate the treatment effect of percutaneous ethanol injection (PEI) for patients with advanced, non-resectable HCC compared with combination of transarterial chemoembolisation (TACE) and repeated single-session PEI, repeated single-session PEI alone, repeated TACE alone, or best supportive care.

METHODS: All patients who received PEI treatment during the study period were included and stratified to one of the following treatment modalities according to physical status and tumor extent: combination of TACE and repeated single-session PEI, repeated single-session PEI alone, repeated TACE alone, or best supportive care. Prognostic value of clinical parameters including Okuda-classification, presence of portal vein thrombosis, presence of ascites, number of tumors, maximum tumor diameter, and serum cholinesterase (CHE), as well as Child-Pugh stage, α-fetoprotein (AFP), fever, incidence of complications were assessed and compared between the groups. Survival was determined using Kaplan-Meier and multivariate regression analyses.

RESULTS: The 1- and 3-year survival of all patients was 73% and 47%. In the subgroup analyses, the combination of TACE and PEI (1) was associated with a longer survival (1-, 3-, 5-year survival: 90%, 52%, and 43%) compared to PEI treatment alone (2) (1-, 3-, 5-year survival: 65%, 50%, and 37%). Secondary PEI after initial stratification to TACE (3) yielded comparable results (1-, 3-, 5-year survival: 91%, 40%, and 30%) while PEI after stratification to best supportive care (4) was associated with decreased survival (1-, 3-, 5-year survival: 50%, 23%, 12%). Apart from the chosen treatment modalities, predictors for better survival were tumor number (n < 5), tumor size (< 5 cm), no ascites before PEI, and stable serum cholinesterase after PEI (P < 0.05). The mortality within 2 wk after PEI was 2.8% (n = 3). There were 24 (8.9%) major complications after PEI including segmental liver infarction, focal liver necrosis, and liver abscess. All complications could be managed non-surgically.

CONCLUSION: Repeated single-session PEI is effective in patients with advanced HCC at an acceptable and manageable complication rate. Patients stratified to a combination of TACE and PEI can expect longer survival than those stratified to repeated PEI alone. Furthermore, patients with large or multiple tumors in good clinical status may also profit from a combination of TACE and reconsideration for secondary PEI.

Treatment of unresectable hepatocellular carcinoma with use of 90Y microspheres (TheraSphere): safety, tumor response, and survival

PURPOSE

To present safety and efficacy results obtained in treatment of a cohort of patients with unresectable hepatocellular carcinoma (HCC) with use of 90Y microspheres (TheraSphere).

PATIENTS AND METHODS

Forty-three consecutive patients with HCC were treated with 90Y microspheres over a 4-year period. Patients were treated by liver segment or lobe on one or more occasions based on tumor distribution, liver function, and vascular flow dynamics. Patients were followed for adverse events, objective tumor response, and survival. Patients were stratified into three risk groups according to method of treatment and risk stratification (group 0, segmental; group 1, lobar low-risk; group 2, lobar high-risk) and Okuda and Child-Pugh scoring systems.

RESULTS

Based on follow-up data from 43 treated patients, 20 patients (47%) had an objective tumor response based on percent reduction in tumor size and 34 patients (79%) had a tumor response when percent reduction and/or tumor necrosis were used as a composite measure of tumor response. There was no statistical difference among the three risk groups with respect to tumor response. Survival times from date of diagnosis were different among the risk groups (P < .0001). Median survival times were 46.5 months, 16.9 months, and 11.1 months for groups 0, 1, and 2, respectively. Median survival times of 24.4 months and 12.5 months by Okuda scores of I and II, respectively, were achieved (mean, 25.8 months vs 13.1). Patients had median survival times of 20.5 months and 13.8 months according to Child class A and class B/C disease, respectively (mean, 22.7 months vs 13.6 months). Patients classified as having diffuse disease exhibited decreased survival and reduced tumor response. There were no life-threatening adverse events related to treatment.

CONCLUSIONS

Use of 90Y microspheres (TheraSpheres) provides a safe and effective method of treatment for a broad spectrum of patients presenting with unresectable HCC. Further investigation is warranted.

Differences in the lesion formation process between focused ultrasound and microwave ablations

The objective is to understand the differences in the lesion formation processes between microwave and high-intensity focused ultrasound (HIFU) ablation. The lesions formed by microwaves and HIFU were real-time monitored and compared using transparent tissue-mimicking phantoms at 60 and 70 W of driving electrical power. Microwaves and HIFU produced lesions different in shape, size, and developing processes. For HIFU ablations, the hyperechoic region appeared bigger in ultrasonic images, as compared with the protein denatured region observed optically at the end of 100 s ablations. On the contrary, the hyperechoic signal was only limited to a small region along the antenna of a microwave ablator. Careful monitoring and controlling the lesion formation process is essential for successful microwaves and HIFU thermal ablations.

Percutaneous laser ablation in the treatment of hepatocellular carcinoma with small tumors: analysis of factors affecting the achievement of tumor necrosis

PURPOSE

To identify the factors that affect the achievement of tumor necrosis with percutaneous laser ablation (PLA) in patients with hepatocellular carcinoma (HCC) and tumor size no larger than 4.0 cm.

MATERIALS AND METHODS

Ultrasound-guided biopsy results were retrospectively studied in 99 lesions (range, 0.5-4.0 cm; mean, 2.7 cm) from 82 patients (44 men, 38 women; age range, 50-80 years; median, 68 y) who had undergone PLA.

RESULTS

Complete tumor ablation was obtained in 90 lesions (90.9%). Of the nine cases in which complete tumor necrosis was not achieved, six had tumors located in sites that did not allow the optimal placement of fibers, and five of these had a tumor diameter greater than 3 cm. Early discontinuation of PLA as a result of decompensation of liver cirrhosis was the reason for not achieving a complete tumor ablation in three other cases. There was a clear relationship between the energy delivered and the volume of necrosis achieved (r = 0.56; P < .001) regardless of the initial size of HCC tumors. The number of illuminations required, and consequently the amount of energy delivered, was also affected by tumor location. In fact, lesions adjacent to large vessels (> or = 3 mm) required a greater number of illuminations than the other lesions to achieve complete ablation (2.9 +/- 1.4 vs 2.3 +/- 0.9; P = .043). The eight cases with undifferentiated histology required more illuminations than the cases with other histologic types (3.4 +/- 0.9 vs 2.2 +/- 0.9; P < .001). However, these cases were located in sites that did not allow the optimal placement of fibers, therefore requiring multiple treatments.

CONCLUSION

PLA is a highly effective treatment in HCC with a tumor size of 4.0 cm or smaller. In this setting, two variables, tumor size and tumor location, affect the achievement of complete tumor ablation and the number of treatments required to obtain tumor necrosis.

Hepatocellular carcinoma: therapy and prevention

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. The major etiologies and risk factors for the development of HCC are well defined and some of the multiple steps involved in hepatocarcinogenesis have been elucidated in recent years. Despite these scientific advances and the implementation of measures for the early detection of HCC in patients at risk, patient survival has not improved during the last three decades. This is due to the advanced stage of the disease at the time of clinical presentation and limited therapeutic options. The therapeutic options fall into five main categories: surgical interventions including tumor resection and liver transplantation, percutaneous interventions including ethanol injection and radiofrequency thermal ablation, transarterial interventions including embolization and chemoembolization, radiation therapy and drugs as well as gene and immune therapies. These therapeutic strategies have been evaluated in part in randomized controlled clinical trials that are the basis for therapeutic recommendations. Though surgery, percutaneous and transarterial interventions are effective in patients with limited disease (1-3 lesions, <5 cm in diameter) and compensated underlying liver disease (cirrhosis Child A), at the time of diagnosis more than 80% patients present with multicentric HCC and advanced liver disease or comorbidities that restrict the therapeutic measures to best supportive care. In order to reduce the morbidity and mortality of HCC, early diagnosis and the development of novel systemic therapies for advanced disease, including drugs, gene and immune therapies as well as primary HCC prevention are of paramount importance. Furthermore, secondary HCC prevention after successful therapeutic interventions needs to be improved in order to make an impact on the survival of patients with HCC. New technologies, including gene expression profiling and proteomic analyses, should allow to further elucidate the molecular events underlying HCC development and to identify novel diagnostic markers as well as therapeutic and preventive targets.

Radiofrequency ablation-assisted liver resection: review of the literature and our experience

BACKGROUND

Surgical resection is the best established treatment known to provide long-term survival and possibility of cure for liver malignancy. Intraoperative blood loss has been the major concern during major liver resections, and mortality and morbidity of surgery are clearly associated with the amount of blood loss. Different techniques have been developed to minimize intraoperative blood loss during liver resection. The radiofrequency ablation (RFA) technique has been used widely in the treatment of unresectable liver tumors. This review concentrates on the use of RFA to provide an avascular liver resection plane.

METHODS AND RESULTS

The following review is based on two types of RFA device during liver resection: single needle probe RFA and the In-Line RFA device.

CONCLUSION

Liver resection assisted by RFA is safe and is associated with very limited blood loss.