Incomplete ablation after radiofrequency ablation of hepatocellular carcinoma: analysis of risk factors and prognostic factors

A Blood Hepatocellular Carcinoma Signature Recognizes Very Small Tumor Nodules with Metastatic Traits

Background and Aims

Hepatocellular carcinoma (HCC) cases with small nodules are commonly treated with radiofrequency ablation (RFA), but the recurrence rate remains high. This study aimed to establish a blood signature for identifying HCC with metastatic traits pre-RFA.

Methods

Data from HCC patients treated between 2010 and 2017 were retrospectively collected. A blood signature for metastatic HCC was established based on blood levels of alpha-fetoprotein and des-γ-carboxy-prothrombin, cell-free DNA (cfDNA) mutations, and methylation changes in target genes in frozen-stored plasma samples that were collected before RFA performance. The HCC blood signature was validated in patients prospectively enrolled in 2021.

Results

Of 251 HCC patients in the retrospective study, 33.9% experienced recurrence within 1 year post-RFA. The HCC blood signature identified from these patients included des-γ-carboxy-prothrombin ≥40 mAU/mL with cfDNA mutation score, where cfDNA mutations occurred in the genes of TP53, CTNNB1, and TERT promoter. This signature effectively predicted 1-year post-RFA recurrence of HCC with 92% specificity and 91% sensitivity in the retrospective dataset, and with 87% specificity and 76% sensitivity in the prospective dataset (n=32 patients). Among 14 cases in the prospective study with biopsy tissues available, positivity for the HCC blood signature was associated with a higher HCC tissue score and shorter distance between HCC cells and microvasculature.

Conclusions

This study established an HCC blood signature in pre-RFA blood that potentially reflects HCC with metastatic traits and may be valuable for predicting the disease's early recurrence post-RFA.

Hug sign in intraprocedural cone-beam-CT to predict short-term response to combined treatment of hepatocellular carcinoma

OBJECTIVES

Combined treatment of ablation and chemoembolization for hepatocellular carcinoma represents a promising therapy to increase treatment efficacy and improve patient survival. The "hug sign" is a recently introduced radiological sign consisting in deposition of beads/contrast agent during transarterial chemoembolization in the hyperemic area surrounding the post-ablation volume, seen during intraprocedural unenhanced cone-beam CT, that may indicate intraprocedural success. Aim of our retrospective study was to analyze the usefulness of the "hug sign" at the intraprocedural unenhanced cone-beam CT as an early predictor of response to combined treatment, based on the hug sign angle.

MATERIALS AND METHODS

Between January 2017 and September 2021 all patients with hepatocellular carcinoma which underwent a combined treatment of thermal ablation followed by chemoembolization were enrolled. All treated patients underwent immediate post-procedural unenhanced cone-beam CT to evaluate the deposition of contrast agent, lipiodol or radiopaque beads and to assess the percentage of coverage of the ablated area with the contrast agent (hug sign angle). Patients with missing pre-procedural, intra-procedural and/or post-procedural data/imaging, or with poor-quality post-procedural cone-beam CT images were excluded.

RESULTS

128 patients (mean age, 69.3 years ± 1.1 [standard deviation]; 87 men) were evaluated. Our study evidenced that 84.4% (81/85) of patients with a hug sign angle of 360° had no residual tumor at the first 1-/3-months follow-up examination. A hug sign angle of 360° also showed to be an independent protective factor against residual tumor at multivariate analysis.

CONCLUSION

Unenhanced cone-beam CT performed at the end of a combined treatment with ablation plus chemoembolization can effectively predict an early treatment response on radiological images, when a hug sign angle of 360° was detected.

Can Machine Learning Predict Favorable Outcome After Radiofrequency Ablation of Hepatocellular Carcinoma?

PURPOSE

The standard practice for limited-stage hepatocellular carcinoma (HCC) is the resection or the use of local ablative techniques, such as radiofrequency ablation (RFA). The outcome after RFA depends on a complex interaction between the patient's general condition, hepatic function, and disease stage. In this study, we aimed to explore using a machine learning model to predict the response.

PATIENTS AND METHODS

A retrospective study was conducted for patients with RFA for a localized HCC between 2018 and 2022. The collected clinical, radiologic, and laboratory data were explored using Python and XGBoost. They were split into a training set (70%) and a validation set (30%). The primary end point of this study was to predict the probability of achieving favorable outcomes 12 months after RFA. Favorable outcomes were defined as the patient was alive and HCC was controlled.

RESULTS

One hundred and eleven patients were eligible for the study. Males were 78 (70.3%) with a median age of 57 (range of 43-81) years. Favorable outcome was seen in 62 (55.9%) of the patients. The 1-year survival rate and control rate were 94.6%, and 61.3%, respectively. The final model harbored an accuracy and an AUC of 90.6% and 0.95, respectively, for the training set, while they were 78.9% and 0.80, respectively, for the validation set.

CONCLUSION

Machine learning can be a predictive tool for the outcome after RFA in patients with HCC. Further validation by a larger study is necessary.

Percutaneous microwave ablation for early-stage intrahepatic cholangiocarcinoma: A single-institutional cohort

Objectives

Cholangiocarcinoma (CCA) is the second-most common primary hepatic malignancy with an increasing incidence over the past two decades. CCA arises from the epithelial cells lining the bile ducts and can be classified as intrahepatic, perihilar, or distal based on the site of origin in the biliary tree. Surgical resection is the definitive curative therapy for early-stage intrahepatic CCA; however, only a minority of patients may be ideal surgical candidates. Percutaneous microwave ablation (MWA) is a minimally invasive procedure widely used for hepatocellular carcinoma and colorectal cancer metastases to the liver. Growing evidence suggests MWA can play a role in the management of patients with early-stage intrahepatic CCA. In this study, we aim to describe the safety and efficacy of MWA for the management of intrahepatic CCA.

Material and Methods

A retrospective review of patients with intrahepatic CCA treated with MWA at our tertiary referral medical center was performed. Eight patients were treated between 2014 and 2019. Diagnosis of CCA was made based on histopathological studies of samples obtained by surgical resection or percutaneous liver biopsy. All procedures were performed under computed tomography (CT) guidance using a high-power single antenna MWA system. General anesthesia was used for all procedures. Patient medical history, procedural technical information, outcomes, and follow-up data were reviewed. Progression-free survival was estimated with a Kaplan-Meier curve.

Results

A total of 25 tumors with an average size of 2.2 ± 1.7 cm (range 0.5-7.8) were treated with MWA. Our cohort consisted of eight patients (4 males and 4 females) with an average age of 69.3 ± 5.7 years (range 61-79). Three out of eight (3/8, 37.5%) patients were treated initially with surgical resection. NASH-related cirrhosis was documented in 3/8 (37.5%) patients, while 1/8 (12.5%) had alcoholic cirrhosis; the remaining 4 patients (4/8, 50%) did not have cirrhosis. All patients were discharged within 24 h after ablation. Average total follow-up time was 10.6 ± 11.8 months (range 0-41). The incomplete ablation rate and local recurrence rate were 4% (1/25 lesions) and 12% (3/25 lesions), respectively.

Conclusion

In patients who do not qualify for surgical resection, MWA is a safe alternative therapy for the treatment of intrahepatic CCA.

Radiofrequency ablation for pediatric recurrent hepatocellular carcinoma: a single-center experience

PURPOSE

To summarize our single-center experience with percutaneous ultrasound (US)-guided radiofrequency ablation (RFA) for pediatric recurrent hepatocellular carcinoma (RHCC).

METHODS

From September 2007 to September 2021, patients under 18 who underwent percutaneous US-guided RFA for RHCC were retrospectively enrolled in this study. Local effectiveness, complications, local tumor progression (LTP), progression free survival (PFS), and overall survival (OS) were evaluated.

RESULTS

A total of 10 patients (9 male and 1 female; mean age, 11.7 ± 4 years ; age range, 6-17 years) with 15 intrahepatic RHCC lesions were enrolled in this study. Complete ablation (CA) was achieved in 14 out of 15 lesions (93.3%) after the first RFA. During the follow-up (mean, 63.1 ± 18 months; range, 5.3-123.3 months), LTP did not occur. Five patients died including three with tumor progression and one with liver failure. The accumulative one- and three-year PFS rates were 30% and 10%, respectively. The accumulative one- and three-year OS rates were 77.8% and 44.4%, respectively.

CONCLUSIONS

Our single-center experience suggests the safety and feasibility of percutaneous US-guided RFA for pediatric RHCC.

Drug-Eluting Bead Transarterial Chemoembolization Versus Radiofrequency Ablation as an Initial Treatment of Single Small (≤ 3 cm) Hepatocellular Carcinoma

BACKGROUND

In this study, we aimed to compare the long-term therapeutic outcomes of drug-eluting bead transarterial chemoembolization (DEB-TACE) with those of radiofrequency ablation (RFA) for the initial treatment of a single small (≤ 3 cm) hepatocellular carcinoma (HCC).

METHODS

From January 2010 to December 2021, 259 consecutive patients who underwent DEB-TACE (67 patients) or RFA (192 patients) as a first-line treatment for a single small HCC were enrolled in this retrospective study. The therapeutic outcomes, including cumulative intrahepatic local tumor progression (LTP), progression-free survival (PFS), and long-term overall survival (OS) rates, were compared between the two groups before and after propensity score (PS) matching. Multivariate Cox proportional hazard models were used to evaluate the prognostic factors and differences in OS and PFS between the two groups for all 92 patients after PS matching.

RESULTS

After PS matching, the 1-, 2-, 3-, and 5-year LTP rates were lower in the RFA group than those in the DEB-TACE group (P < 0.001), and the 1-, 2-, 3-, and 5-year PFS rates in the RFA group were higher than those in the DEB-TACE group (P = 0.007). However, the 1-, 2-, 3-, and 5-year OS rates were not significantly different between the RFA and DEB-TACE groups (P = 0.584). Moreover, the OS was not significantly different between the RFA and DEB-TACE groups in the univariate and multivariate analyses, with a hazard ratio (HR) of 0.81. The PFS was significantly higher in the RFA group than that in the DEB-TACE group in the univariate analyses, with a HR of 0.44 (P = 0.009). Multivariate Cox regression analysis showed that albumin (P = 0.019) was an independent prognostic factor for OS. Additionally, the major complication rates were not significantly different between the DEB-TACE and RFA groups (P = 1.000).

CONCLUSION

The LTP and PFS rates of RFA were superior to those of DEB-TACE in the initial treatment of single small HCC after PS matching. However, the OS rates were not significantly different between RFA and DEB-TACE. Therefore, DEB-TACE may be considered an efficient substitute for RFA in some patients with a single small HCC who are ineligible for RFA.

Stimulating Antitumoral Immunity by Percutaneous Cryoablation and Combination Immunoadjuvant Therapy in a Murine Model of Hepatocellular Carcinoma

PURPOSE

To test the hypothesis that antitumoral immunity can be induced after cryoablation (cryo) of hepatocellular carcinoma (HCC) through coadministration of the immunostimulant CpG and an immune checkpoint (programmed cell death 1 [PD-1]) inhibitor.

MATERIALS AND METHODS

Sixty-three immunocompetent C57BL/6J mice were generated with 2 orthotopic HCC tumor foci: 1 for treatment and 1 to observe for antitumoral immunity. Tumors were treated with incomplete cryo alone or intratumoral CpG and/or a PD-1 inhibitor. The primary endpoint was death or when the following criteria for sacrifice were met: tumor > 1 cm (determined using ultrasound) or moribund state. Antitumoral immunity was assessed using flow cytometry and histology (tumor and liver) as well as enzyme-linked immunosorbent assay (serum). Analysis of variance was used for statistical comparisons.

RESULTS

At 1 week, the nonablated satellite tumor growth was reduced by 1.9-fold (P = .047) in the cryo + CpG group and by 2.8-fold (P = .007) in the cryo + CpG + PD-1 group compared with that in the cryo group. Compared with cryo alone, the time to tumor progression to endpoints was also prolonged for cryo + CpG + PD-1 and cryo + CpG mice, with log-rank hazard ratios of 0.42 (P = .031) and 0.27 (P < .001), respectively. Flow cytometry and histology showed increased cytotoxic T-cell infiltration (P = .002) and serum levels of the proinflammatory cytokine interferon-γ (P = .015) in tumors and serum of cryo + CpG mice compared with those in tumors and serum of mice treated with cryo alone. High serum levels of the anti-inflammatory cytokine tumor growth factor-β and the proangiogenesis chemokine C-X-C motif chemokine ligand 1 were correlated with a shorter time to endpoints and faster tumor growth.

CONCLUSIONS

Cryo combined with the immunostimulant CpG promoted cytotoxic T-cell infiltration into tumors, slowed tumor growth, and prolonged the time to progression to endpoints in an aggressive murine HCC model.

In-situ tumor vaccination by percutaneous ablative therapy and its synergy with immunotherapeutics: An update on combination therapy

Percutaneous tumor ablation is now a widely accepted minimally invasive local treatment option offered by interventional radiology and applied to various organs and tumor histology types. It utilizes extreme temperatures to achieve irreversible cellular injury, where ablated tumor interacts with surrounding tissue and host via tissue remodeling and inflammation, clinically manifesting as post-ablation syndrome. During this process, in-situ tumor vaccination occurs, in which tumor neoantigens are released from ablated tissue and can prime one’s immune system which would favorably affect both local and remote site disease control. Although successful in priming the immune system, this rarely turns into clinical benefits for local and systemic tumor control due to intrinsic negative immune modulation of the tumor microenvironment. A combination of ablation and immunotherapy has been employed to overcome these and has shown promising preliminary results of synergistic effect without significantly increased risk profiles. The aim of this article is to review the evidence on post-ablation immune response and its synergy with systemic immunotherapies.

Prognostic Role of Albumin-Bilirubin Grade in Hepatocellular Carcinoma After Ultrasound-guided Percutaneous Radiofrequency Ablation: A Single-center Experience Over a Decade

BACKGROUND

The albumin-bilirubin (ALBI) grade has been proposed to evaluate liver function and predict prognosis in patients with hepatocellular carcinoma (HCC). Data are scarce in terms of the clinical application of ALBI score in patients with HCC undergoing radiofrequency ablation (RFA). The current study sought to assess the prognostic efficacy of ALBI grade in early-stage HCC after RFA.

METHODS

We retrospectively reviewed 344 treatment-naive patients, whereby the overall survival (OS), recurrence-free survival (RFS), local tumor progression, and intrahepatic distant recurrence were assessed using Kaplan-Meier analysis. Predictors determining OS and RFS after RFA were analyzed using Cox proportional hazards analysis.

RESULTS

During a median follow-up time of 48.0 months (range: 2 to 158 mo), 48 patients had died because of tumor progression or liver failure. Patients with ALBI grade 2 had poorer OS (P=0.033) and RFS (P=0.002), and higher intrahepatic distant recurrence rate (P<0.001) than those with ALBI grade 1. Local tumor progression rates were comparable between the 2 groups (P=0.801). Multivariate analyses showed that ABLI grade 2 was the only independent risk factor for poor OS (hazard ratio=1.850, 95% confidence interval: 1.041-3.286, P=0.036) and poor RFS (hazard ratio=1.467, 95% confidence interval: 1.094-1.968, P=0.011) after RFA. For Child-Pugh grade A group, patients divided by ALBI grade 1 versus grade 2 showed significant differences in both OS and RFS (P=0.039 and 0.002).

CONCLUSION

The ALBI grade can be used to discriminate long-term prognosis in patients with HCC following RFA and to further stratify prognosis in those with Child-Pugh grade A.

An Overview of Hepatocellular Carcinoma After Insufficient Radiofrequency Ablation

Radiofrequency ablation (RFA) is a commonly used treatment for hepatocellular carcinoma (HCC), however, various complex conditions in clinical practice may lead to insufficient radiofrequency ablation (IRFA), allowing residual HCC to survive. In clinical practice and laboratory models, IRFA plays an important role in rapid tumor progression. Therefore, targeting the residual HCC and avoiding IRFA were worthwhile methods. A deeper understanding of IRFA is required; IRFA contributes to the improvement of proliferative activity, migration rates, and invasive capacity, and this may be due to the involvement of multiple complex processes or proteins, including epithelial mesenchymal transitions (EMTs), cancer stem cells (CSCs), autophagy, heat shock proteins (HSPs), changes of non-tumor cells and extracellular matrix, altered immune microenvironment, hypoxia-inducible factors (HIFs), growth factors, epigenetic alterations, and metabolic reprogramming. We focus on the processes of the above mechanisms and possible therapeutic approach, with a review of the literature. Additionally, we recapitulated the construction methods of various experimental models of IRFA (in vivo and in vitro).

Risk of intra-abdominal seeding after laparoscopic-assisted thermal ablation of exophytic hepatocellular carcinoma tumors

BACKGROUND

Laparoscopic-assisted thermal ablation has been used successfully to treat early hepatocellular carcinoma (HCC) tumors, defined as < 3 cm in diameter. This approach allows for ablation of tumors located in areas of the liver that are otherwise inaccessible for a percutaneous approach. Thermal ablation of exophytic tumors remains controversial due to a reported increased risk of tumor seeding of the abdominal cavity and incomplete ablation.

METHODS

This cohort study consisted of 663 HCC tumors treated with thermal ablation at a single, quaternary academic medical center between 2/2001 and 1/2021. Post treatment, patients were followed at a defined interval schedule beginning at one month post treatment, then every 3 months for 2 years, every 6 months in year 3, followed by yearly studies. Patients' medical records were reviewed for three years post ablation for evidence of complete ablation and intra-abdominal dissemination of disease.

RESULTS

326 patient records met the inclusion criteria. Comparing the exophytic and non-exophytic groups, there were statistically significant differences in etiology of liver disease (p = 0.048) and TNM stage (p = 0.03), as well as a higher rate of incomplete ablation in the non-exophytic group (10.2% vs 3.3%; p = 0.045). Otherwise, there were no statistically significant differences in baseline characteristics, tumor characteristics, or use of thermal ablation technology. Rates of intra-abdominal dissemination of HCC were low in both groups: 1.1% (n = 1) in the exophytic group and 1.7% (n = 4) in the non-exophytic group. There was no significant difference in intra-abdominal dissemination of HCC between the groups (p > 0.99, RR = 0.66; 95% CI 0.07-5.79). Additionally, no differences were seen in dissemination between microwave ablation and radiofrequency ablation (p > 0.99).

CONCLUSION

This study demonstrates that laparoscopic-assisted thermal ablation of small, exophytic tumors is safe and does not increase the risk for disseminated intra-abdominal HCC disease.

The learning curve of laparoscopic ablation of liver tumors: A technically demanding procedure requiring dedicated training

BACKGROUND

Laparoscopic ablation (LA) of liver tumors is an increasingly performed procedure. However, LA is technically demanding, with inherent difficulties making LA more complex than percutaneous and open surgery ablations. This study aimed to characterize the learning curve (LC) of LAs.

METHODS

All consecutive LAs of malignant liver tumors performed with curative intent by a single surgeon were identified from a prospective database. A risk-adjusted cumulative summative (RA-CUSUM) analysis was used for evaluating the LC of LAs. Incomplete ablation (IA) was the outcomes measure. Performance trends were analyzed using broken-line modeling.

RESULTS

From June 2007 to February 2018, 241 lesions underwent LA during 151 procedures. RA-CUSUM analysis demonstrated an LC of 93 LAs (p < 0.001), with an IA rate decreasing from 12.9% to 4.7% (p = 0.027). Lesions in the posterosuperior segment and those in cirrhotic livers showed an LC of 34 and 45 tumor ablations, respectively (p=<0.001 each). Open ablations performed during the same period showed steady outcomes, indicating already acquired proficiency.

CONCLUSION

Completion of a steep LC is needed to gain proficiency in LAs. Dedicated training should be warranted to novices to smooth the LC and decrease LA failures.

METTL3/IGF2BP1/CD47 contributes to the sublethal heat treatment induced mesenchymal transition in HCC

Microwave ablation is a first-line treatment of small hepatocellular carcinoma (HCC), while incomplete ablation induces recurrence and metastasis. However, its underlying mechanism remains largely unexplored. Here we reported that sublethal heat treatment (46 °C) strongly promoted migration and EMT transition in HCC cells. Mechanistic investigation revealed that compared with 37 °C, HCC cells treated with 46 °C expressed higher level of CD47. Knockdown of CD47 significantly attenuated sublethal heat treatment stimulated migration and EMT transition. In addition, METTL3 which is the key enzyme of m⁶A modification was also induced by 46 °C treatment and triggered CD47 expression in HCC cells. Moreover, CD47 mRNA degradation was further proved to be stabled in the IGF2BP1-dependent manner. Importantly, sublethal heat treatment stimulated CD47 expression and EMT transition were also confirmed in patient-derived organoid. Taken together, our study suggests that METTL3/IGF2BP1/CD47 mediated EMT transition contributes to the incomplete ablation induced metastasis in HCC cells. Moreover, these findings identify the METTL3/IGF2BP1/CD47 axis as a potential therapeutic target for the microwave ablation and shed new lights on the crosstalk between incomplete heat ablation and RNA methylation.

Percutaneous ultrasound guided PEG-coated gold nanoparticles enhanced radiofrequency ablation in liver

To investigate the effects of PEG-coated gold nanoparticles on ablation zone volumes following in vivo radiofrequency ablation of porcine liver. This prospective study was performed following institutional animal care and committee approval was used. Radiofrequency ablations were performed in the livers of ten Sus scrofa domesticus swines. During each ablation, 10 mL (mL) of Peg-coated gold nanoparticles at two different concentrations (0.5 mg/mL and 0.01 mg/mL) were injected through the electrode channel into the target zone. For the control group, 10 mL of physiological saline was used. Five to ten minutes after each ablation, contrast enhanced ultrasound (CEUS) was performed to evaluate the volume of the coagulation zone. On day five we performed another CEUS and the animals were sacrificed. Treated tissues were explanted for quantification of the ablation zones' volumes. Hematoxylin and eosin (H&E) staining was also performed for histologic analysis. A total of 30 ablations were performed in the livers. The mean coagulation zone volume as measured by CEUS on day 5 after RFA was: 21.69 ± 3.39 cm3, 19.22 ± 5.77 cm3, and 8.80 ± 3.33 cm3 for N1, N2 and PS respectively. The coagulation zone volume after N1 and N2 treatments was significantly higher compared to PS treatment (p < 0.001 and p = 0.025 respectively). There was no difference between N1 and N2 treatment (p = 0.60). In our proof-of concept, pilot study we have shown for the first time that when injected directly into the target tissue during RFA, gold nanoparticles can substantially increase the coagulation zone.

Computed tomography-guided percutaneous microwave ablation with artificial ascites for problematic hepatocellular tumors

Background: The aim of this study was to assess the feasibility, safety and efficacy of computed tomography (CT)-guided percutaneous microwave ablation with artificial ascites for problematic hepatocellular tumors.Methods: Forty-eight patients with 61 problematic hepatocellular carcinomas who underwent CT-guided percutaneous microwave ablation with artificial ascites were reviewed retrospectively. Lesions less than 5 mm away from the gastrointestinal system, diaphragm, pericardium or kidney were defined as problematic tumors with the potential risk of thermal damage. Microwave ablation was performed after artificial ascites was established between tumors and the adjacent high-risk organs. The technical effectiveness of microwave ablation, local tumor progression and complications was assessed.Results: Microwave ablation with artificial ascites was successfully performed in all 61 tumors. The technical effectiveness rate was 100% with contrast-enhanced CT performed immediately after the ablation procedure. Local tumor progression occurred in three (6%) of the 48 patients during the follow-up period (mean, 15 months; range, 6-24 months). No major complications related to the procedure occurred.Conclusion: CT-guided percutaneous microwave ablation with artificial ascites is a feasible, safe and effective choice for treating problematic hepatocellular tumors, avoiding potential thermal damage to the adjacent high-risk organs.

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.

Radiofrequency ablation using internally cooled wet electrodes in bipolar mode for the treatment of recurrent hepatocellular carcinoma after locoregional treatment: A randomized prospective comparative study

Objective

This study aimed to compare the efficacy between bipolar radiofrequency ablation (RFA), using twin internally cooled wet (TICW) electrodes, and switching monopolar RFA, using separable clustered (SC) electrodes, in the treatment of recurrent hepatocellular carcinoma (HCC) after locoregional treatment.

Materials and methods

In this single-center, two-arm, parallel-group, randomized controlled study, we performed a 1:1 random allocation on eligible patients with recurrent HCC after locoregional treatment, to receive TICW-RFA or SC-RFA. The primary endpoint was the minimum diameter of the ablation zone per unit ablation time. Secondary endpoints included other technical parameters, complication rate, technical success and technique efficacy, and clinical outcomes.

Results

Enrolled patients were randomly assigned to the TICW-RFA group (n = 40) or SC-RFA group (n = 37). The two groups did not show significant differences in the primary endpoint, the minimum diameter of the ablation zone per unit ablation time was 2.71 ± 0.98 mm/min and 2.61 ± 0.96 mm/min in the TICW-RFA and SC-RFA groups, respectively (p = 0.577). Total RF energy delivery (11.75 ± 9.04 kcal vs. 22.61 ± 12.98 kcal, p < 0.001) and energy delivery per unit time (0.81 ± 0.49 kcal/min vs. 1.45 ± 0.42 kcal/min, p < 0.001) of the TICW-RFA group were less than those of the SC-RFA group. No procedure-related death or major complications occurred. Technical success was achieved in all patients in both groups, and technique efficacy rates were 100% (46/46) in the TICW-RFA group and 95.0% (38/40) in the SC-RFA group (p = 0.213). The 1-year and 2-year cumulative LTP rates were 11.8% and 24.2%, respectively, in the TICW-RFA group, and 8.6% and 18.1%, respectively, in the SC-RFA group (p = 0.661).

Conclusion

In this single-center randomized controlled study from a Korean tertiary referral hospital, TICW-RFA demonstrated similar therapeutic efficacy and safety profile for recurrent HCC after locoregional treatment compared with SC-RFA.

Trial registration

ClinicalTrials.gov (NCT03806218)

Stereotactic Body Radiotherapy as a Salvage Therapy after Incomplete Radiofrequency Ablation for Hepatocellular Carcinoma: A Retrospective Cohort Study

Residual tumor tissue after radiofrequency ablation (RFA) is inevitable in clinical practice, and the optimal management of residual tumor after RFA has not been established. To evaluate the efficiency and toxicity of stereotactic body radiotherapy (SBRT) as a salvage therapy after incomplete RFA for hepatocellular carcinoma (HCC), we retrospectively included 32 HCC patients with an initial incomplete response (iIR) to RFA from May 2011 to August 2018. An iIR was defined as the presence of residual enhancement on CT or MRI one month after RFA treatment. The primary endpoint was local tumor control (LTC); the secondary endpoints included progression-free survival (PFS), overall survival (OS), and toxicity. All patients fulfilled 6 fractions of SBRT as planned, with dosages ranging from 30 Gy to 54 Gy. The objective response rate (ORR) was 50.0%. The 1- and 2-year LTC rates were 86.6% (95% CI, 74.3% to 98.9%) and 74.7% (95% CI, 55.9% to 93.5%), respectively. Fewer times of prior treatments was associated with better LTC (HR = 11.7, P=0.026). The 1- and 2-year PFS rate were 69.9% (95% CI, 53.4% to 86.4%) and 52.7% (95% CI, 33.1% to 72.3%), respectively. A higher Child-Pugh score was the only independent risk factor for tumor progression (HR = 5.17, P=0.012). The 1- and 3-year OS rate were 85.6% and 67.1%, respectively. Only two patients suffered grade 3 adverse events, and none experienced grade 4 or 5 events. In conclusion, for HCC patients confirmed to have an iIR to prior RFA, with compensated liver function, SBRT provided favorable LTC and OS along with acceptable toxicity.

Computed tomography-guided radiofrequency ablation combined with transarterial embolization assisted by a three-dimensional visualization ablation planning system for hepatocellular carcinoma in challenging locations: a preliminary study

OBJECTIVE

To assess the clinical efficacy and safety of computed tomography-guided radiofrequency ablation(CT-RFA) combined with transarterial embolization(TAE) assisted by a three-dimensional visualization ablation planning system(3DVAPS) for hepatocellular carcinoma(HCC) in challenging locations.

METHODS

Data from 62 treatment-naive patients with hepatocellular carcinoma(HCC), with 83 lesions in challenging locations, and who met the Milan criteria and underwent CT-RFA between June 2013 and June 2016 were reviewed. Patients were divided into one of two groups according to different treatment modalities: study group (TAE combined with RFA assisted by 3DVAPS [n = 32]); and control (RFA only [n = 30]). Oncological outcomes included ablation-related complications, local tumor progression (LTP), and overall survival (OS). Univariate and multivariate Cox proportional hazards regression analyses were performed to assess risk factors associated with LTP and OS.

RESULTS

HCC lesions (mean size, 1.9 ± 1.0 mm in diameter) abutting the gastrointestinal tract (n = 25), heart and diaphragm (n = 21), major vessels (n = 13), and gallbladder (n = 3) were treated. A significant difference was detected in LTP between the two groups (P = 0.034), with no significant difference in OS between the two groups (P = 0.193). There were no severe complications related to ablation. Univariate analysis revealed that sex (P = 0.046) and child-turcotte-pugh (CTP) grade (P<0.001) were risk factors for OS, whereas CTP grade and treatment method (P<0.001) were risk factors for LTP. Multivariate analysis revealed that CTP grade B (P = 0.005) was independently associated with poor OS, and RFA alone (P<0.001) was independently associated with poor LTP.

CONCLUSION

CT-RFA combined with TAE assisted by a 3DVAPS provided ideal clinical efficiency for HCC in challenging locations and was a highly safe treatment modality.

Phenotypic alterations in liver cancer cells induced by mechanochemical disruption

Hepatocellular carcinoma (HCC) is a highly fatal disease recognized as a growing global health crisis worldwide. Currently, no curative treatment is available for early-to-intermediate stage HCC, characterized by large and/or multifocal tumors. If left untreated, HCC rapidly progresses to a lethal stage due to favorable conditions for metastatic spread. Mechanochemical disruption of cellular structures can potentially induce phenotypic alterations in surviving tumor cells that prevent HCC progression. In this paper, HCC response to mechanical vibration via high-intensity focused ultrasound and a chemical disruptive agent (ethanol) was examined in vitro and in vivo. Our analysis revealed that mechanochemical disruption caused a significant overproduction of reactive oxygen species (ROS) in multiple HCC cell lines (HepG2, PLC/PRF/5, and Hep3B). This led to a decrease in cell viability and long-term proliferation due to increased expression and activity of death receptors TNFR1 and Fas. The cells that survived mechanochemical disruption had a reduced expression of cancer stem cell markers (CD133, CD90, CD49f) and a diminished colony-forming ability. Mechanochemical disruption also impeded HCC migration and their adhesion to vascular endothelium, two critical processes in hematogenous metastasis. The HCC transformation to a non-tumorigenic phenotype post mechanochemical disruption was confirmed by a lack of tumor spheroid formation in vitro and complete tumor regression in vivo. These results show that mechanochemical disruption inhibits uncontrolled proliferation and reduces tumorigenicity and aggressiveness of HCC cells through ROS overproduction and associated activation of TNF- and Fas-mediated cell death signaling. Our study identifies a novel curative therapeutic approach that can prevent the development of aggressive HCC phenotypes.

Establishment of an insufficient radiofrequency ablation orthotopic nude mouse model of hepatocellular carcinoma to study the invasiveness and metastatic potential of residual cancer

In order to assess the metastatic potential of residual hepatocellular carcinoma (HCC) following insufficient radiofrequency ablation (RFA) and to improve the current animal model, an insufficient RFA orthotopic nude mouse model of HCC was developed in the present study. A human HCC orthotopic nude mouse model was established using HCCLM3 cells, which has a high metastatic potential, labeled with green fluorescent protein. A total of 12 nude mice within the RFA group received insufficient RFA and 12 mice in the control group received RFA needle electrode puncture of the tumor without ablation, 3 weeks after implantation. To investigate tumor growth and metastasis, 4 weeks after RFA, six mice in each group were sacrificed and the remaining mice in each group were maintained until death to evaluate their life span. No mice died following insufficient RFA and the success rate was 100%. Compared with the control group, the intrahepatic and lung metastasis rates were higher in the RFA group, despite the mice having smaller tumor volumes and longer survival times. Lung and intrahepatic metastasis rates in the insufficient RFA group were 100% (6/6) and 66.67% (4/6), respectively, compared with 33.33% (2/6) and 0% (0/6), respectively, in the control group. As part of the study, a safe and reliable method to establish an insufficient RFA orthotopic nude mouse model was developed. The present study revealed that residual cancer following insufficient RFA had exhibited increased invasiveness and metastatic potential.

Robotic versus Freehand Needle Positioning in CT-guided Ablation of Liver Tumors: A Randomized Controlled Trial

Purpose To compare the accuracy of freehand versus robotic antenna placement in CT-guided microwave ablation (MWA) of liver tumors. Materials and Methods This study was conducted as a prospective single-center nonblinded randomized controlled trial (Netherlands Trial Registry, NTR6023). Eligible study participants had undergone clinically indicated CT-guided MWA of liver tumors and were able to receive a CT contrast agent. Randomization was performed per tumor after identification on contrast material-enhanced CT images. The primary outcome was the number of antenna repositionings, which was compared by using the Mann-Whitney U test. Secondary outcomes were lateral targeting error stratified by in-plane and out-of-plane targets and targeting time. Results Between February 14 and November 12, 2017, 31 participants with a mean age of 63 years (range, 25-88 years) were included: 17 women (mean age, 57 years; range, 25-77 years) and 14 men (mean age, 70 years; range, 52-88 years). The freehand study arm consisted of 19 participants, while the robotic study arm consisted of 18 participants; six participants with multiple tumors were included in both arms. Forty-seven tumors were assessed; five tumors were excluded from the analysis because of technical limitations. In the robotic arm, no antenna repositioning was required. In the freehand arm, a median of one repositioning was required (range, zero to seven repositionings; P < .001). For out-of-plane targets, lateral targeting error was 10.1 mm ± 4.0 and 5.9 mm ± 2.9 (P = .007) for freehand and robotic procedures, respectively, and for in-plane targets, lateral targeting error was 6.2 mm ± 2.7 and 7.7 mm ± 5.9, respectively (P = .51). Mean targeting time was 19 minutes (range, 8-55 minutes) and 36 minutes (range, 3-70 minutes; P = .001) for freehand and robotic procedures, respectively. Conclusion Robotic antenna guidance reduces the need for antenna repositioning in microwave ablation to accurately target liver tumors and increases accuracy for out-of-plane targets. However, targeting time was greater with robotic guidance than with freehand targeting. © RSNA, 2019.

Long-term survival after percutaneous irreversible electroporation of inoperable colorectal liver metastases

Background

For colorectal liver metastases (CRLM) that are not amenable to surgery or thermal ablation, irreversible electroporation (IRE) is a novel local treatment modality and additional option.

Methods

This study is a retrospective long-term follow-up of patients with CRLM who underwent IRE as salvage treatment.

Results

Of the 24 included patients, 18 (75.0%) were male, and the median age was 57 (range: 28-75) years. The mean time elapsed from diagnosis to IRE was 37.9±37.3 months. Mean overall survival was 26.5 months after IRE (range: 2.5-69.2 months) and 58.1 months after diagnosis (range: 14.8-180.1 months). One-, three-, and five-year survival rates after initial diagnosis were 100.0%, 79.2%, and 41.2%; after IRE, the respective survival rates were 79.1%, 25.0%, and 8.3%. There were no statistically significant differences detected in survival after IRE with respect to gender, age, T- or N-stage at the time of diagnosis, size of metastases subject to IRE, number of hepatic lesions, or time elapsed between IRE and diagnosis.

Conclusion

For nonresectable CRLM, long-term survival data emphasize the value of IRE as a new minimally invasive local therapeutic approach in multimodal palliative treatment, which is currently limited to systemic or regional therapies in this setting.

Percutaneous ablation for perivascular hepatocellular carcinoma: Refining the current status based on emerging evidence and future perspectives

Various therapeutic modalities including radiofrequency ablation, cryoablation, microwave ablation, and irreversible electroporation have attracted attention as energy sources for effective locoregional treatment of hepatocellular carcinoma (HCC); these are accepted non-surgical treatments that provide excellent local tumor control and favorable survival. However, in contrast to surgery, tumor location is a crucial factor in the outcomes of locoregional treatment because such treatment is mainly performed using a percutaneous approach for minimal invasiveness; accordingly, it has a limited range of ablation volume. When the index tumor is near large blood vessels, the blood flow drags thermal energy away from the targeted tissue, resulting in reduced ablation volume through a so-called “heat-sink effect”. This modifies the size and shape of the ablation zone considerably. In addition, serious complications including infarction or aggressive tumor recurrence can be observed during follow-up after ablation for perivascular tumors by mechanical or thermal damage. Therefore, perivascular locations of HCC adjacent to large intrahepatic vessels can affect post-treatment outcomes. In this review, we primarily focus on physical properties of perivascular tumor location, characteristics of perivascular HCC, potential complications, and clinical outcomes after various locoregional treatments; moreover, we discuss the current status and future perspectives regarding percutaneous ablation for perivascular HCC.

1000 consecutive ablation sessions in the era of computer assisted image guidance - Lessons learned

•

Computer assisted targeting techniques are simple to use and improve results in ablative tumour treatments.

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The indications for ablative soft tissue tumour ablation are increasing.

•

Treatments are superior to resective surgery in terms of complications and hospitalization, oncological non-inferiority remains to be proven.

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An incomplete ablation can be retreated without negative effects on survival.

•

Jet ventilation is an effective technique to minimize organ displacement during percutaneous or laparoscopic ablation.

Background

Ablation therapies for tumours are becoming more used as ablation modalities evolve and targeting solutions are getting better. There is an increasing body of long-term results challenging resection and proving lower morbidities and costs. The aim of this paper is to share the experiences from a high-volume centre in introducing computer assisted targeting solutions and efficient ablation modalities like microwave generators and irreversible electroporation.

Material and methods

One thousand consecutive treatments in one high-volume centre were evaluated retrospectively from prospectively collected data.

Results

The purpose of this paper is to present the benefits of going into computer assisted targeting techniques and microwave technology; pitfalls and overview of outcomes. The main target organ was the liver and the main indications were ablation of hepatocellular carcinomas and colorectal liver metastases. With the assistance of computer assisted targeting the local recurrence rate within 6 months has dropped from 30 to near 10%. The survival of patients with hepatocellular carcinoma and colorectal liver metastases is not worse if the tumour can be retreated after a local recurrence. Multiple colorectal liver metastases can be treated successfully.

Discussion

The incorporation of computer assisted targeting technologies for ultrasound-, ct guided- and laparoscopic tumour ablation has been very successful and without a noticeable learning curve. The same is true for switching from radiofrequency energies to microwave generators and irreversible electroporation.

Conclusion

It is well worthwhile upgrading ablation and targeting technologies to achieve excellent and reproducible results and minimizing operator dependency.

Serum miR-130b level, an ideal marker for monitoring the recurrence and prognosis of primary hepatocellular carcinoma after radiofrequency ablation treatment

OBJECTIVE

This study was aimed to explore the potential roles of miR-130b for the efficacy of radiofrequency ablation (RFA) in patients with primary hepatocellular carcinoma (PHC).

METHODS

The serum sample of 110 PHC patients, which underwent RFA treatment, was collected on 1d pre-operation (Pre 1), 7d (POD 7) and 14d post-operation (POD 14). qRT-PCR was used to detect miR-130b expression. The relationship between miR-130b expression and clinicopathological features, postoperative recurrence and survival rate were analyzed.

RESULTS

The liver function of PHC patients was improved after RFA treatment. The level of alpha fetoprotein (AFP) was gradually reduced on POD 7 and POD 14 (all P <  0.05). Before RFA, the expression of miR-130b in PHC patients was upregulated, while the expression of miR-130b decreased significantly with time after RFA treatment. And high expression of miR-130b was closely related to cirrhosis (P =  0.027) and tumor differentiation degree (P <  0.01). Serum miR-130b levels were significantly higher in patients with recurrence than in patients without recurrence (P <  0.05). Patients were divided into two groups according to miR-130b expression level (median ΔCt), compared with low ΔCt group, the incidence of recurrence in high ΔCt group was significantly higher after RFA (P =  0.020). Kaplan-Meier survival analysis showed that the survival rate of high ΔCt group was significantly shorter than that of low ΔCt group (P <  0.001).

CONCLUSION

Our study provided evidence that serum miR-130b level may be used as an ideal marker for monitoring the recurrence and prognosis of PHC after RFA treatment.

Integrating interventional oncology in the treatment of liver tumors

Background

Percutaneous ablation techniques offer a vast armamentarium for local, minimally invasive treatment of liver tumors, nowadays representing an established therapeutic option, which is integrated in treatment algorithms, especially for non-resectable liver tumors. The results of ablative treatment compare very well to surgical treatment in liver lesions, and confirm that these techniques are a valuable option for bridging for transplantation. Different techniques have been established to perform tumor ablation, and the feasibility varies according to the procedure and technical skills of the operator, depending on the size and location of the liver lesion. In recent years, stereotactic multi-needle techniques using 3D trajectory planning, general anesthesia, and tube disconnection during needle placement have had a strong impact on the application range of ablation for liver tumors.

Conclusion

It is well known that creating a sufficient ablation margin and overlapping ablation zones is one key issue to enable ablation of large liver lesions with tumor-free margins (A0 ablation in analogy to R0 resection). Image fusion during treatment and follow-up assure highly accurate staging procedures and interventional planning.

Novel aspects

Review on the standards in ablation techniques for the treatment of liver tumors. Update on different ablation techniques, indications, and contraindications for percutaneous liver tumor treatment. Summary of recently published reports on liver tumor ablation.

Percutaneous treatment of hepatocellular carcinoma: State of the art and innovations

Percutaneous treatment of hepatocellular carcinoma (HCC) encompasses a vast range of techniques, including monopolar radiofrequency ablation (RFA), multibipolar RFA, microwave ablation, cryoablation and irreversible electroporation. RFA is considered one of the main curative treatments for HCC of less than 5 cm developing on cirrhotic liver, together with surgical resection and liver transplantation. However, controversies exist concerning the respective roles of ablation and liver resection for HCC of less than 3 to 5 cm on cirrhotic liver. In line with the therapeutic algorithm of early HCC, percutaneous ablation could also be used as a bridge to liver transplantation or in a sequence of upfront percutaneous treatment, followed by transplantation if the patient relapses. Moreover, several innovations in ablation methods may help to efficiently treat early HCC, initially considered as "non-ablatable", and might, in some cases, extend ablation criteria beyond early HCC, enabling treatment of more patients with a curative approach.

The relationship between applied energy and ablation zone volume in patients with hepatocellular carcinoma and colorectal liver metastasis

Objectives

To study the ratio of ablation zone volume to applied energy in computed tomography (CT)-guided radiofrequency ablation (RFA) and microwave ablation (MWA) in patients with hepatocellular carcinoma (HCC) in a cirrhotic liver and in patients with colorectal liver metastasis (CRLM).

Methods

In total, 90 liver tumors, 45 HCCs in a cirrhotic liver and 45 CRLMs were treated with RFA or with one of two MWA devices (MWA_A and MWA_B), resulting in 15 procedures for each tumor type, per device. Device settings were recorded and the applied energy was calculated. Ablation volumes were segmented on the contrast-enhanced CT scans obtained 1 week after the procedure. The ratio of ablation zone volume in milliliters to applied energy in kilojoules was determined for each procedure and compared between HCC (R_HCC) and CRLM (R_CRLM), stratified according to ablation device.

Results

With RFA, R_HCC and R_CRLM were 0.22 mL/kJ (0.14–0.45 mL/kJ) and 0.15 mL/kJ (0.14–0.22 mL/kJ; p = 0.110), respectively. With MWA_A, R_HCC was 0.81 (0.61–1.07 mL/kJ) and R_CRLM was 0.43 (0.35–0.61 mL/kJ; p = 0.001). With MWA_B, R_HCC was 0.67 (0.41–0.85 mL/kJ) and R_CRLM was 0.43 (0.35–0.61 mL/kJ; p = 0.040).

Conclusions

With RFA, there was no significant difference in energy deposition ratio between tumor types. With both MWA devices, the ratios were higher for HCCs. Tailoring microwave ablation device protocols to tumor type might prevent incomplete ablations.

Key Points

• HCCs and CRLMs respond differently to microwave ablation

• For MWA, CRLMs required more energy to achieve a similar ablation volume

• Tailoring ablation protocols to tumor type might prevent incomplete ablations

Activated hepatic stellate cells secrete periostin to induce stem cell-like phenotype of residual hepatocellular carcinoma cells after heat treatment

Some evidences show that residual tumor after thermal ablation will progress rapidly. However, its mechanisms remain unclear. Here, we assessed whether activated HSCs could regulate stem cell-like property of residual tumor after incomplete thermal ablation to promote tumor progression. Human HCC cell lines were exposed to sublethal heat treatment to simulate the peripheral zone of thermal ablation. After residual HCC cells were cultured with conditional medium (CM) from activated HSCs, parameters of the stem cell-like phenotypes were analyzed. Nude mice bearing heat-exposed residual HCC cells and HSCs were subjected to metformin treatment to thwarter tumor progression. CM from activated primary HSCs or LX-2 cells significantly induced the stem cell-like phenotypes of residual HCC cells after heat treatment. These effects were significantly abrogated by neutralizing periostin (POSTN) in the CM. POSTN regulated the stemness of heat-exposed residual HCC cells via activation of integrin β1/AKT/GSK-3β/β-catenin/TCF4/Nanog signaling pathway. Metformin significantly inhibited in vivo progression of heat-exposed residual HCC via suppressing POSTN secretion and decreasing cancer stem cell marker expression. Our data propose a new mechanism of activated HSCs promoting the stemness traits of residual HCC cells after incomplete thermal ablation and suggest metformin as a potential drug to reverse this process.

Percutaneous Irreversible Electroporation: Long-term survival analysis of 71 patients with inoperable malignant hepatic tumors

Aim of this retrospective analysis was to evaluate the survival times after percutaneous irreversible electroporation (IRE) in inoperable liver tumors not amenable to thermal ablation. 71 patients (14 females, 57 males, median age 63.5 ± 10.8 years) with 103 liver tumors were treated in 83 interventions using IRE (NanoKnife® system). The median tumor short-axis diameter was 1.9 cm (minimum 0.4 cm, maximum 4.5 cm). 35 patients had primary liver tumors and 36 patients had liver metastases. The Kaplan-Meier method was employed to calculate the survival rates, and the different groups were compared using multivariate log-rank and Wilcoxon tests. The overall median survival time was 26.3 months; the median survival of patients with primary land secondary liver cancer did not significantly differ (26.8 vs. 19.9 months; p = 0.41). Patients with a tumor diameter >3 cm (p < 0.001) or more than 2 lesions (p < 0.005) died significantly earlier than patients with smaller or fewer tumors. Patients with hepatocellular carcinoma and Child-Pugh class B or C cirrhosis died significantly earlier than patients with Child-Pugh class A (p < 0.05). Patients with very early stage HCC survived significantly longer than patients with early stage HCC with a median survival of 22.3 vs. 13.7 months (p < 0.05).

Hong Kong consensus recommendations on the management of hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is particularly prevalent in Hong Kong because of the high prevalence of chronic hepatitis B (CHB) infection; HCC is the fourth commonest cancer in men and the seventh commonest in women, and it is the third leading cause of cancer death in Hong Kong. The full spectrum of treatment modalities for HCC is available locally; however, there is currently no local consensus document detailing how these modalities should be used.

SUMMARY

In a series of meetings held between May and October 2013, a multidisciplinary group of Hong Kong clinicians - liver surgeons, medical oncologists, clinical oncologists, hepatologists, and interventional radiologists - convened to formulate local recommendations on HCC management. These recommendations consolidate the most current evidence pertaining to HCC treatment modalities, together with the latest thinking of practicing clinicians engaged in HCC management, and give detailed guidance on how to deploy these modalities effectively for patients in various disease stages.

KEY MESSAGES

Distinct from other regional guidelines, these recommendations provide guidance on the use of antiviral therapy to reduce the incidence of HCC in CHB patients with cirrhosis and to reduce recurrence of CHB-related HCC.

Salvage treatment for local recurrence of hepatocellular carcinoma after local ablation therapy

AIM

Local recurrence of hepatocellular carcinoma (HCC) after local ablation therapy (LAT) is a serious problem; however, the optimal treatment strategy remains unclear.

METHODS

A retrospective analysis was conducted of 50 patients with local recurrence of HCC after LAT that underwent either salvage hepatectomy (n = 23) or radiofrequency ablation (RFA; n = 27). Their background characteristics, intraoperative data, and postoperative short- and long-term outcome were analyzed.

RESULTS

The RFA group was found to be significantly associated with an impaired liver functional reserve, smaller number and size of tumors. The hepatectomy group showed a significantly longer operation time, greater intraoperative blood loss and more frequent red blood cell transfusion. In-hospital stay mortality and morbidity rate did not significantly differ. The disease-free and overall survival showed no significant difference between the groups. Although local recurrence after salvage treatment was found in zero (0%) for hepatectomy and in seven (25.9%) for RFA, that did not affect the overall survival. The tumor size at the prior LAT was identified as an independent prognostic factor for disease-free survival and serum albumin for overall survival.

CONCLUSION

Whereas salvage hepatectomy for local recurrent HCC is recommended for selected patients in terms of its good local control effect, salvage RFA is also acceptable because it is less invasive and also has a reasonable long-term outcome.

Comparative analysis of Laparoscopic versus open surgical radiofrequency ablation for malignant liver tumors

Backgrounds/Aims

This study aims to evaluate the comparative effectiveness of two surgical approaches on the treatment outcomes of radiofrequency ablation (RFA) for malignant liver tumors.

Methods

Fifty-seven patients with malignant liver tumors, hepatocellular carcinoma, cholangiocarcinoma and liver metastases, who were candidates for RFA, underwent laparoscopic or open surgical treatments.

Results

The patients' characteristics were comparable in the two groups that received open (n=33, 57.9%) and laparoscopic (n=24, 42.1%) surgical treatments. There were no statistically significant differences between the two groups in terms of recurrence rate (p=0.337) and overall survival (p=0.423). However, patients in the laparoscopic RFA group had significantly shorter hospital stay (14.1 vs. 5.9 days, p<0.05) and experienced fewer complications (Grade I: 62.5% vs. 26.3%, p=0.102).

Conclusions

Laparoscopic RFA can be performed for malignant liver tumors with lower morbidity rates, less invasiveness and lower expense compared to open surgical approach.

Synergistic ablation of liver tissue and liver cancer cells with high-intensity focused ultrasound and ethanol

We investigated the combined effect of ethanol and high-intensity focused ultrasound (HIFU), first, on heating and cavitation bubble activity in tissue-mimicking phantoms and porcine liver tissues and, second, on the viability of HepG2 liver cancer cells. Phantoms or porcine tissues were injected with ethanol and then subjected to HIFU at acoustic power ranging from 1.2 to 20.5 W (HIFU levels 1-7). Cavitation events and the temperature around the focal zone were measured with a passive cavitation detector and embedded type K thermocouples, respectively. HepG2 cells were subjected to 4% ethanol solution in growth medium (v/v) just before the cells were exposed to HIFU at 2.7, 8.7 or 12.0 W for 30 s. Cell viability was measured 2, 24 and 72 h post-treatment. The results indicate that ethanol and HIFU have a synergistic effect on liver cancer ablation as manifested by greater temperature rise and lesion volume in liver tissues and reduced viability of liver cancer cells. This effect is likely caused by reduction of the cavitation threshold in the presence of ethanol and the increased rate of ethanol diffusion through the cell membrane caused by HIFU-induced streaming, sonoporation and heating.

Evaluation of the current radiofrequency ablation systems using axiomatic design theory

This article evaluates current radiofrequency ablation systems using axiomatic design theory. Due to its minimally invasive procedure, short-time hospital stay, low cost, and tumour metastasis treatment, the radiofrequency ablation technique has been playing an important role in tumour treatment in recent decades. Although the radiofrequency ablation technique has many advantages, some issues still need to be addressed. Among these issues, the two most important are as follows: (1) the size of tumours to be removed (has to be larger than 3 cm in diameter) and (2) cleanness of the removal. Many device solutions have been proposed to address the two issues. However, there is a lack of knowledge regarding the systematic evaluation of these solutions. This article evaluates these systems in terms of their solution principles (or simply called conceptual design in general product design theory) using a design theory called axiomatic design theory. In addition, with the axiomatic design theory, a better conceptual design in terms of its feasibility to cope with incomplete target tissue necrosis from the large size of tumours has been found. The detailed analysis and simulation of the new conceptual design are conducted using finite element approach. The results in this article are proved by the information of animal experiments and clinical practices obtained from the literature. This study thus contributes to the current knowledge to further developments in radiofrequency ablation systems and procedure guidelines for physicians to perform the radiofrequency ablation operation more effectively.

Perivascular versus nonperivascular small HCC treated with percutaneous RF ablation: retrospective comparison of long-term therapeutic outcomes

PURPOSE

To compare the long-term therapeutic outcomes of radiofrequency (RF) ablation for small perivascular hepatocellular carcinoma (HCC) and nonperivascular HCC.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board. Between December 2004 and April 2008, 241 patients (175 men and 66 women; age range, 32-82 years) with a single early-stage HCC that was 3 cm or smaller in the greatest dimension underwent ultrasonography-guided percutaneous RF ablation as a first-line treatment. The patients were divided into two groups according to the presence or absence of contacting hepatic vessels that were 3 mm or larger in axial diameter: a group with perivascular HCC (n = 58) and a group with nonperivascular HCC (n = 183). Cumulative local tumor progression, disease-free and long-term survival rates, and prognostic factors were assessed by using Cox proportional hazard models with Bonferroni correction.

RESULTS

The overall median follow-up period was 58 months (range, 13-92 months). The cumulative local tumor progression rates were 10%, 16%, and 26% at 1, 3, and 5 years, respectively, in the perivascular group, and 6.7%, 15.5%, and 20.5% in the nonperivascular group; the differences were not significant (P = .323). The corresponding disease-free survival rates were 79%, 41%, and 29% in the perivascular group and 71.3%, 38.7%, and 26.0% in the nonperivascular group, with no significant difference (P = .689). The corresponding overall survival rates were 100%, 94%, and 82% in the perivascular group and 100%, 88.4%, and 73.9% in the nonperivascular group, also without significant difference (P = .267). There was no significant prognostic factor for local tumor progression, whereas extrahepatic and intrahepatic distant recurrences were significant prognostic factors for overall survival in multivariable analysis.

CONCLUSION

The long-term therapeutic outcomes of RF ablation as first-line treatment for small perivascular HCC were similar to those for nonperivascular HCC.

Utility of computed tomography fusion imaging for the evaluation of the ablative margin of radiofrequency ablation for hepatocellular carcinoma and the correlation to local tumor progression

AIM

To demonstrate the usefulness of the computed tomography (CT) fusion imaging for the evaluation of treatment effect of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC).

METHODS

Eighty-five patients with 94 HCC with complete ablation judged on conventional side-by-side interpretation of pre-RFA and post-RFA CT at the time of RFA were included in this retrospective study. CT data was retrospectively used to create fusion images of pre-RFA and post-RFA CT using automatic rigid registration and manual correction referring to intrahepatic structures and hepatic contours around a tumor. Clinical factors including a minimal ablative margin (MAM) measured on fusion images were examined to prove risk factors for local tumor progression (LTP).

RESULTS

LTP was observed in 13 (13.8%) tumors with a median follow up of 21.0 months (range, 2-75). The mean MAM on the fusion image was 1.4 ± 3.1 mm and 23 tumors (24.5%) were judged to be protruding from the ablation zone. Multivariate analysis revealed that protruding from the ablation zone was the only significant factor for LTP (hazard ratio, 7.09; 95% confidential interval, 2.26-22.3; P < 0.001).

CONCLUSION

Some HCC were assessed as incomplete ablation on the CT fusion images, although considered completely ablated on side-by-side images at the time of treatment, and incomplete ablation was revealed to be the only independent risk factor for LTP. The CT fusion imaging enables quantitative and accurate evaluation of treatment effect of RFA.

Small hepatocellular carcinoma: current and future approaches

Over 3 decades have passed since the first report of small hepatocellular carcinoma (SHCC), which has been confirmed as one of the most significant prognostic factors. Obviously, it is indeed very important to know when an early SHCC will become more aggressive and lead to worse clinical outcome once it grows beyond a critical size. However, so far, no consensus has been achieved on the size criterion for SHCC among different authors or different clinical practice guidelines that have been used worldwide, although there are currently numerous cutoff values for tumor size used to define SHCC, including 5, 3 and 2 cm in diameter, etc. Herein, based on our current understanding concerning the pathobiological features of SHCC, we briefly review the history of SHCC study, analyze the advantages and limitations of the above criteria for SHCC, and discuss the pathobiological characteristics as well as the clinical significance of SHCC.

Radiofrequency ablation combined with transcatheter arterial chemoembolization for the treatment of single hepatocellular carcinoma of 2 to 5 cm in diameter: comparison with surgical resection

OBJECTIVE

To compare the effectiveness of radiofrequency ablation (RFA) combined with transcatheter arterial chemoembolization (TACE) with surgical resection in patients with a single hepatocellular carcinoma (HCC) ranging from 2 to 5 cm.

MATERIALS AND METHODS

The study participants were enrolled over a period of 29 months and were comprised of 37 patients in a combined therapy group and 47 patients in a surgical resection group. RFA was performed the day after TACE, and surgical resection was performed by open laparotomy. The two groups were compared with respect to the length of hospital stay, rates of major complication, and rates of recurrence-free and overall survival.

RESULTS

Major complications occurred more frequently in the surgical resection group (14.9%) than in the combined therapy group (2.7%). However, there was no statistical significance (p = 0.059). The rates of recurrence-free survival at 1, 2, 3 and 4 years were similar between the combined therapy group (89.2%, 75.2%, 69.4% and 69.4%, respectively) and the surgical resection group (81.8%, 68.5%, 68.5% and 65%, respectively) (p = 0.7962, log-rank test). The overall survival rates at 1, 2, 3 and 4 years were also similar between groups (97.3%, 86.5%, 78.4% and 78.4%, respectively, in the combined therapy group, and 95.7%, 89.4%, 84.3% and 80.3%, respectively, in the surgical resection group) (p = 0.6321, log-rank test).

CONCLUSION

When compared with surgical resection for the treatment of a single HCC ranging from 2 to 5 cm, RFA combined with TACE shows similar results in terms of recurrence-free and overall survival rates.

Surgical resection versus local ablation for HCC on cirrhosis: results from a propensity case-matched study

BACKGROUND

Surgery for hepatocellular carcinoma (HCC) had great improvements in the last decades with low morbidity and mortality and good long-term results. Percutaneous local ablative therapies (LAT) such as radiofrequency ablation and ethanol injection (PEI) for HCC gained consent for their efficacy and safety. In retrospective studies, patients submitted to resection (LR) or LAT frequently have important selection bias. Propensity case-matched analysis proved to reduce selection bias of retrospective studies and allow comparison between different therapies.

AIM

The aim of this study was to evaluate survival comparing LR and LAT in two groups of cirrhotic patients with HCC matched with propensity score methods.

METHODS

Four hundred and seventy-eight cirrhotic patients with HCC treated with LR or LAT with curative intent between January 1995 and December 2009 were included in the study. One hundred and eighty-one patients underwent LR, and 297 patients were treated with LAT. Tumor stage and liver function were evaluated in all patients. To balance the covariates in the two groups, a one-to-one propensity case-matched analysis was used. A multivariable logistic model based on age, gender, etiology of cirrhosis, Child-Pugh class, number of nodules, maximum diameter of nodules, and serum alpha-fetoprotein level was used to estimate propensity score. One-to-one caliper matching of LR and LAT groups was performed, generating a matched sample of 176 patients with 88 patients in each group.

RESULTS

Median survival was 65.1 months (95% CI = 48.5-81.7) after LR and 37.3 months (95% CI = 29.3-45.3) after LAT (p = 0.008). For patients in Child-Pugh class A with single HCC and maximum diameter <5 cm, median survival was 65.0 months (95% CI = 58.4-71.6) for the LR group and 63.7 months (95% CI = 31.8-95.7) for the LAT group (p = 0.730). For patients in Child-Pugh class A with single HCC and diameter ≥5 cm, median survival was 79.9 months (95% CI = 40.1-119.8) for the LR group and 21.5 months (95% CI = 10.8-32.1) for the LAT group (p = 0.023). For patients in Child-Pugh class A with two to three nodules and maximum diameter ≤3 cm, mean survival was 69.3 months (95% CI 48.7-89.9) for the LR group and 45.7 months (95% CI = 22.8-68.7) for the LAT group (p = 0.168). For patients in Child-Pugh class A with two to three nodules and diameter >3 cm, median survival was 82.9 months (95% CI = 52.0-113.7) for the LR group and 18.9 months (95% CI = 6.3-31.4) for the LAT group (p = 0.001).

CONCLUSION

Our propensity case-matched study confirmed that survival is similar after LR and LAT for single HCC smaller than 5 cm and for oligofocal HCC (up to three nodules) smaller than 3 cm; instead, for HCC larger than 5 cm or oligofocal HCC (up to three nodules) larger than 3 cm, surgical resection improves significantly long-term survival.

Serum alpha-fetoprotein response can predict prognosis in hepatocellular carcinoma patients undergoing radiofrequency ablation therapy

AIMS

To evaluate the clinical inference of serum alpha-fetoprotein (AFP) response in hepatocellular carcinoma (HCC) patients undergoing percutaneous radiofrequency ablation (RFA).

MATERIALS AND METHODS

Three hundred and thirteen previously untreated HCC patients were enrolled in the study. The optimal AFP response was defined as >20% decrease from baseline after 1 month of RFA for those with a baseline AFP level of ≥100 ng/ml. The impact of AFP response on prognosis was analysed and prognostic factors were assessed.

RESULTS

After a median follow-up of 26.7 ± 19.1 months, 49 patients died and 264 patients were alive. The cumulative 5 year survival rates were 75.3 and 57.4% in patients with an initial AFP of <100 ng/ml and ≥100 ng/ml, respectively (p = 0.003). In the 58 patients with a baseline AFP of ≥100 ng/ml and initial completed tumour necrosis after RFA, the cumulative 5 year survival rates were 62.4 and 25.7% in optimal and non-optimal AFP responders, respectively (p = 0.001). By multivariate analysis, the prothrombin time international normalized ratio >1.1 (p = 0.009), non-optimal AFP response (p = 0.023), and creatinine >1.5 mg/dl (p = 0.021) were independent risk factors predictive of poor overall survival. Besides, the cumulative 5 year recurrence rates were 83.4 and 100% in optimal and non-optimal AFP responders, respectively (p < 0.001). Multivariate analysis demonstrated platelet count ≤10(5)/mm(3) (p = 0.048), tumour size >2 cm (p = 0.027), and non-optimal AFP response (p < 0.001) were independent risk factors associated with tumour recurrence after RFA.

CONCLUSIONS

Serum AFP response may be a useful marker for predicting prognosis in HCC patients undergoing RFA.

Magnetic navigation in ultrasound-guided interventional radiology procedures

AIM

To evaluate the usefulness of magnetic navigation in ultrasound (US)-guided interventional procedures.

MATERIALS AND METHODS

Thirty-seven patients who were scheduled for US-guided interventional procedures (20 liver cancer ablation procedures and 17 other procedures) were included. Magnetic navigation with three-dimensional (3D) computed tomography (CT), magnetic resonance imaging (MRI), 3D US, and position-marking magnetic navigation were used for guidance. The influence on clinical outcome was also evaluated.

RESULTS

Magnetic navigation facilitated applicator placement in 15 of 20 ablation procedures for liver cancer in which multiple ablations were performed; enhanced guidance in two small liver cancers invisible on conventional US but visible at CT or MRI; and depicted the residual viable tumour after transcatheter arterial chemoembolization for liver cancer in one procedure. In four of 17 other interventional procedures, position-marking magnetic navigation increased the visualization of the needle tip. Magnetic navigation was beneficial in 11 (55%) of 20 ablation procedures; increased confidence but did not change management in five (25%); added some information but did not change management in two (10%); and made no change in two (10%). In the other 17 interventional procedures, the corresponding numbers were 1 (5.9%), 2 (11.7%), 7 (41.2%), and 7 (41.2%), respectively (p=0.002).

CONCLUSION

Magnetic navigation in US-guided interventional procedure provides solutions in some difficult cases in which conventional US guidance is not suitable. It is especially useful in complicated interventional procedures such as ablation for liver cancer.

Radiofrequency ablation for recurrent hepatocellular carcinoma in postresectional patients: prognostic factors analysis

BACKGROUND

Percutaneous ablation therapies can be used for recurrent hepatocellular carcinoma (HCC) in postresectional patients not eligible for repeat surgery.

AIMS

To determine prognostic factors affecting the disease-free survival of postresectional patients after percutaneous ultrasound-guided radiofrequency ablation (RFA) for recurrent HCC.

METHODS

From August 2003 to December 2009, patients who had received previous hepatectomy because of HCC and suffered from tumor recurrence were included. Among them, 82 patients who received initial percutaneous ultrasound-guided RFA were included. Various host, treatment, and therapeutic-related factors were analyzed.

RESULTS

Eighty-two patients (64 men, mean age 64.27 years) were included. Sex (P=0.495), age (P=0.840), hepatitis marker (P=0.083), and Child-Pugh score (P=0.809) were not related to prognosis. Preresectional tumor number (P=0.502), recurrent tumor location (P=0.795), recurrent tumor number (P=0.533), pathology proved cirrhosis (P=0.889), and OKUDA stage of the primitive disease (P=0.865) were not related to prognosis, either. Survival rates were significantly related to the preresectional tumor size (P=0.008), microscopic portal vein invasion (P=0.001), recurrent tumor size (P<0.001), and preablation α-fetoprotein serum level (P=0.006). Ablation needle (P=0.373), ablation time (P=0.387), and postablation temperature (P=0.444) were not related to prognosis. Multivariate analysis revealed that microscopic portal vein invasion was the only factor that had a significant effect on patient survival.

CONCLUSION

In patients with postresectional HCC treated with percutaneous ultrasound-guided RFA for recurrent disease, those without microscopic portal vein invasion had a significantly higher probability of disease-free survival.