Outcomes of patients with hepatocellular carcinoma referred for percutaneous radiofrequency ablation at a tertiary center: analysis focused on the feasibility with the use of ultrasonography guidance

Hepatocellular carcinoma: Revising the surgical approach in light of the concept of multiparametric therapeutic hierarchy

The clinical management of hepatocellular carcinoma (HCC) is strongly influenced by several prognostic factors, mainly tumor stage, patient's health, liver function and specific characteristics of each intervention. The interplay between these factors should be carefully evaluated by a multidisciplinary tumor board. To support this, the novel "multiparametric therapeutic hierarchy" (MTH) concept has been recently proposed. This review will present the main features of available surgical treatments for HCC (liver transplantation, liver resection, ablation). Strengths and weaknesses are reported in the light of clinical decision making and of treatment allocation, with a special focus on the collocation of each treatment in the MTH framework and on how MTH may be useful in supporting clinical decision. Sequential treatments and their role to allow further surgical treatments will also be analyzed.

Occult liver nodules: their detection and characterization with CEUS

OBJECTIVES

Contrast enhanced ultrasound (CEUS) now joins the ranks of CT and MRI for noninvasive diagnosis of hepatocellular carcinoma (HCC). CEUS LI-RADS provides greater than 95% specificity for diagnosis within LR-5. Unlike CT/MRI, CEUS is nodule based. Currently, LI-RADS does not recommend CEUS of nodules occult or invisible on pre-contrast ultrasound except by experts. This study addresses our ability to find occult nodules using CEUS and to characterize them with CEUS LI-RADS.

METHODS

100 patients at risk for HCC, 81 with cirrhosis, with occult lesions were retrospectively identified from our archived patient logs. All patients had CEUS examination. Three specialized CEUS techniques (blindshot injection, portal venous (PVP) sweep of the liver, and on-top injection) are used to evaluate nodules.

RESULTS

There were 114 occult lesions in 100 patients. The origin of 78(68%) lesions was an MRI (n = 69) or CT scan (n = 9) with an observation of abnormal enhancement, generally arterial phase hyperenhancement (APHE). All these patients had blindshot CEUS injection looking for a correlate with APHE. The remainder of occult lesions (n = 36)(32%) were first detected during CEUS, generally as washout foci on PVP sweeps or incidental APHE or washout nearby other targets. All washout areas had subsequent on-top injection to assess for APHE. Application of CEUS LI-RADS algorithm categorized 26 LR-5, 34 LR-4, and 5 LR-M. CEUS upgraded LI-RADS category of 24/50(48%) occult lesions reported on CT/MRI. 29(25%) occult lesions were offered treatment and from categories LR-5 and LR-M, 5 had biopsy confirmation and 15 were treated. From both sources, MR/CT and CEUS, there were 12 occult lesions scanned for treatment response, categorized as 7 LR-TR viable, 1 LR-TR nonviable, and 4 LR-TR equivocal on CEUS.

CONCLUSION

Our study shows we can find and characterize occult nodules using CEUS techniques and CEUS LI-RADS algorithm, with positive impact on clinical management.

A Comparative Study of SonoVue and Sonazoid for Contrast-Enhanced Ultrasound CT/MRI Fusion Guidance During Radiofrequency Ablation of Poorly Visualized Hepatic Malignancies: A Prospective Intra-Individual Analysis

PURPOSE

This study aimed to evaluate the effectiveness of two contrast agents, SonoVue (SV) and Sonazoid (SZ), by comparing them intra-individually in contrast-enhanced ultrasound (CEUS)-CT/MRI fusion imaging (FI) to improve the visibility of inconspicuous liver malignancies on B-mode sonography for guiding percutaneous radiofrequency ablation (RFA). Additionally, the radiologists' preference between SonoVue- CT/MRI FI (SV-FI) and Sonazoid-CT/MRI FI (SZ-FI) was determined.

METHODS

This prospective study enrolled 23 patients with inconspicuous hepatic malignancies (≤ 3 cm) on B-mode US who underwent both SV-FI and SZ-FI for RFA guidance. The patients underwent real-time CEUS FI with CT/MRI on the same day, utilizing both SV and SZ with at least 15-min intervals. Tumor visibility and radiologists' preferences were assessed and graded using a 4-point scale during the dynamic phases of both SV-FI and SZ-FI and the Kupffer phase of SZ-FI.

RESULTS

The tumor visibility scores obtained from CEUS-CT/MRI FI were significantly better than those obtained from US-FI. Indeed, SV-FI and SZ-FI demonstrated comparable visibility scores when corresponding phases were compared (p > 0.05). However, the Kupffer phase images of SZ-FI displayed superior visibility scores (3.70 ± 0.56 vs. 2.96 ± 0.88; p = 0.002) than the late vascular phase images of SV-FI. The radiologists favored SZ-FI in many cases, exhibiting moderate inter-observer agreement (Kappa value = 0.587; 95% CI, 0.403-0.772).

CONCLUSION

Although CEUS-CT/MRI FI with either SV or SZ substantially improved the visibility of inconspicuous tumors on US-CT/MRI FI, radiologists preferred SZ to SV to guide the RFA procedure.

Benefits and drawbacks of radiofrequency ablation via percutaneous or minimally invasive surgery for treating hepatocellular carcinoma

The management of early stage hepatocellular carcinoma (HCC) presents significant challenges. While radiofrequency ablation (RFA) has shown safety and effectiveness in treating HCC, with lower mortality rates and shorter hospital stays, its high recurrence rate remains a significant impediment. Consequently, achieving improved survival solely through RFA is challenging, particularly in retrospective studies with inherent biases. Ultrasound is commonly used for guiding percutaneous RFA, but its low contrast can lead to missed tumors and the risk of HCC recurrence. To enhance the efficiency of ultrasound-guided percutaneous RFA, various techniques such as artificial ascites and contrast-enhanced ultrasound have been developed to facilitate complete tumor ablation. Minimally invasive surgery (MIS) offers advantages over open surgery and has gained traction in various surgical fields. Recent studies suggest that laparoscopic intraoperative RFA (IORFA) may be more effective than percutaneous RFA in terms of survival for HCC patients unsuitable for surgery, highlighting its significance. Therefore, combining MIS-IORFA with these enhanced percutaneous RFA techniques may hold greater significance for HCC treatment using the MIS-IORFA approach. This article reviews liver resection and RFA in HCC treatment, comparing their merits and proposing a trajectory involving their combination in future therapy.

Application of Cone-beam Computed Tomography in Interventional Therapies for Liver Malignancy: A Consensus Statement by the Chinese College of Interventionalists

Despite its crucial role in interventional therapies for liver malignancy, cone-beam computed tomography (CBCT) has not yet been fully integrated into clinical practice due to several complicating factors, including nonstandardized operations and limited recognition of CBCT among interventional radiologists. In response, the Chinese College of Interventionalists has released a consensus statement aimed at standardizing and promoting the application of CBCT in the interventional therapies for liver malignancy. This statement summarizes CBCT scanning techniques, and operational standards, and highlights its potential applications in clinical practice.

Chemoembolization versus Radiotherapy for Single Hepatocellular Carcinomas of ≤3 cm Unsuitable for Image-Guided Tumor Ablation

BACKGROUND/AIMS

Local ablation therapy (LAT) is primarily recommended for solitary inoperable hepatocellular carcinomas (HCCs) of ≤3 cm in diameter. However, only two-thirds of uninodular small HCCs are suitable for LAT, and the second-best treatment option for managing these nodules is unclear. We aimed to compare the therapeutic outcomes of chemoembolization and radiotherapy in small HCCs unsuitable for LAT.

METHODS

The study included 651 patients from a tertiary referral center who underwent planning sonography for LAT. These patients had 801 solitary HCCs of ≤3 cm in diameter and were treated with LAT, chemoembolization, or radiotherapy. Local tumor progression (LTP)-free survival and overall survival (OS) were measured according to the type of treatment of the index nodule.

RESULTS

LAT, chemoembolization, and radiotherapy were used to treat 561, 185, and 55 nodules in 467, 148, and 36 patients, respectively. LTP-free survival was significantly shorter in patients treated with chemoembolization than for those treated with LAT (multivariate hazard ratio [HR], 2.36; 95% confidence interval [CI], 1.61 to 3.47) but not for those treated with radiotherapy (HR, 0.83; 95% CI, 0.38 to 1.83). However, OS was not affected by treatment modality. Matching and weighting analyses confirmed that radiotherapy gave comparable results to chemoembolization in terms of OS despite better LTP-free survival (HR, 2.91; 95% CI, 1.13 to 7.47 and HR, 3.07; 95% CI, 1.11 to 8.48, respectively).

CONCLUSIONS

Our data suggest that chemoembolization and radiotherapy are equally effective options for single small HCCs found to be unsuitable for LAT after sonographic planning. Betterfit indications for each procedure should be established by specifically designed studies.

Laparoscopic Hepatic Resection Versus Laparoscopic Radiofrequency Ablation for Subcapsular Hepatocellular Carcinomas Smaller Than 3 cm: Analysis of Treatment Outcomes Using Propensity Score Matching

Objective

To compare the therapeutic outcomes of laparoscopic hepatic resection (LHR) and laparoscopic radiofrequency ablation (LRFA) for single subcapsular hepatocellular carcinoma (HCC).

Materials and Methods

We screened 244 consecutive patients who had received either LHR or LRFA between January 2014 and December 2016. The feasibility of LRFA in patients who underwent LHR was retrospectively assessed by two interventional radiologists. Finally, 60 LRFA-feasible patients who had received LHR and 29 patients who had received LRFA as the first treatment for a solitary subcapsular HCC between 1 cm and 3 cm were finally included. We compared the therapeutic outcomes, including local tumor progression (LTP), recurrence-free survival (RFS), and overall survival (OS) between the two groups before and after propensity score (PS) matching. Multivariable Cox proportional hazard regression was also used to evaluate the difference in OS and RFS between the two groups for all 89 patients.

Results

PS matching yielded 23 patients in each group. The cumulative LTP and OS rates were not significantly different between the LHR and LRFA groups after PS matching (p = 0.900 and 0.003, respectively). The 5-year LTP rates were 4.6% and 4.4%, respectively, and OS rates were 100% and 90.7%, respectively. The RFS rate was higher in LHR group without statistical significance (p = 0.070), with 5-year rates of 78.3% and 45.3%, respectively. OS was not significantly different between the LHR (reference) and LRFA groups in multivariable analyses, with a hazard ratio (HR) of 1.33 (95% confidence interval, 0.12–1.54) (p = 0.818). RFS was higher in LHR (reference) than in LRFA without statistical significance in multivariable analysis, with an HR of 2.01 (0.87–4.66) (p = 0.102).

Conclusion

There was no significant difference in therapeutic outcomes between LHR and LRFA for single subcapsular HCCs measuring 1–3 cm. The difference in RFS should be further evaluated in a larger study.

Operator Evaluation of Ultrasound Fusion Imaging Usefulness in the Percutaneous Ablation of Hepatic Malignancies: A Prospective Study

The purpose of the work described here was to evaluate the use of ultrasound fusion imaging (US-FI) in percutaneous ablation of hepatic malignancies with respect to its global usefulness, improvement of conspicuity, confidence increment, needle route changes, and time savings. Thirty-four hepatic tumors (28 hepatocellular carcinomas, 6 metastases) were prospectively ablated in 16 consecutive patients (64 ± 11 y, 75% males), first simulating B-mode-only planning and then synchronizing computed tomography/magnetic resonance images with US and proceeding to needle insertion and tumor ablation under US-FI guidance. Surveys were administered to the operators to evaluate their perception of US-FI advantages. First treatment and local recurrence were also compared. US-FI was judged useful in 91% of cases and more useful when the tumor was not conspicuous in B-mode (p < 0.001), in particular for ablation of local recurrences (p = 0.021). Forty-one percent of tumors were undetectable at B-mode evaluation, and 93% of them were completely ablated under US-FI guidance. The confidence of the operator was highly increased by US-FI in 68% of cases. In 71% of cases, the radiologist saved time using US-FI, especially in treatment of local recurrences (p = 0.024). In conclusion, US-FI significantly increases the detection of target tumors, improves the confidence of the operator and is a time-saving method, especially in the treatment of local recurrences.

Image-guided marking techniques in interventional radiology: A review of current evidence

Precise marking of lesions using image-guided techniques is essential, as imprecise targeting of a tumor can result in either insufficient excision/treatment with an increased risk of recurrence, or excessive removal of healthy tissue. Most frequent indications include localization of nonpalpable lesions before surgical resection (i.e., hook-wire localization of pulmonary nodules before video-assisted thoracoscopy) and definite marking of liver metastasis before neoadjuvant therapy. Other indications include marking of hepatocellular carcinomas that are not visible on ultrasound and unenhanced computed tomography before thermal ablation, of bone lesions before surgical excision, and of different visceral tumors before stereotactic radiotherapy. This review presents the different existing indications, assesses their usefulness, gives systematic details on the technique and lastly analyzes the current literature with emphasis on results and complications.

Assessing the value of volume navigation during ultrasound-guided radiofrequency- and microwave-ablations of liver lesions

Purpose

The goal of our study was to determine the influence of ultrasound (US)-coupled volume navigation on the use of computed tomography (CT) during minimally-invasive radiofrequency and microwave ablation procedures of liver lesions.

Method

Twenty-five patients with 40 liver lesions of different histological origin were retrospectively analysed. Lesions were ablated following standard protocol, using 1) conventional US-guidance, 2) manual registered volume navigation (mVNav), 3) automatic registered (aVNav) or 4) CT-guidance. In case of ultrasonographically inconspicuous lesions, conventional US-guidance was abandoned and mVNav was used. If mVNav was also unsuccessful, the procedure was either continued with aVNav or CT-guidance. The number, size and location of the lesions targeted using the different approaches were documented.

Results

Of the 40 lesions, sixteen (40.0 %) could be targeted with conventional US-guidance only, sixteen (40.0 %) with mVNav, three (7.5 %) with aVNav and five (12.5 %) only through the use of CT-guidance. Of the three alternatives (mVNav, aVNav and CT only) the mean size of the lesions targeted using mVNav (9.1 ± 4.6 mm) was significantly smaller from those targeted using US-guidance only (20.4 ± 9.4 mm; p < 0.001). The location of the lesions did not influence the selection of the modality used to guide the ablation.

Conclusions

In our cohort, mVNav allowed the ablation procedure to become less dependent on the use of CT. mVNav supported the ablation of lesions smaller than those that could be ablated with US only and doubled the application of minimally-invasive US-guided ablations.

Annular Fiber Probe for Interstitial Illumination in Photoacoustic Guidance of Radiofrequency Ablation

Unresectable liver tumors are commonly treated with percutaneous radiofrequency ablation (RFA). However, this technique is associated with high recurrence rates due to incomplete tumor ablation. Accurate image guidance of the RFA procedure contributes to successful ablation, but currently used imaging modalities have shortcomings in device guidance and treatment monitoring. We explore the potential of using photoacoustic (PA) imaging combined with conventional ultrasound (US) imaging for real-time RFA guidance. To overcome the low penetration depth of light in tissue, we have developed an annular fiber probe (AFP), which can be inserted into tissue enabling interstitial illumination of tissue. The AFP is a cannula with 72 optical fibers that allows an RFA device to slide through its lumen, thereby enabling PA imaging for RFA device guidance and ablation monitoring. We show that the PA signal from interstitial illumination is not affected by absorber-to-surface depth compared to extracorporeal illumination. We also demonstrate successful imaging of the RFA electrodes, a blood vessel mimic, a tumor-mimicking phantom, and ablated liver tissue boundaries in ex vivo chicken and bovine liver samples. PA-assisted needle guidance revealed clear needle tip visualization, a notable improvement to current US needle guidance. Our probe shows potential for RFA device guidance and ablation detection, which potentially aids in real-time monitoring.

Percutaneous radiofrequency ablation for hepatic metastasis of colorectal cancer: assessment of tumor visibility and the feasibility of the procedure with planning ultrasonography

Purpose

The aim of this study was to assess the incidence and causes of percutaneous radiofrequency ablation (RFA) infeasibility in cases of metastatic colorectal cancer and to evaluate factors affecting the invisibility of the tumor on planning ultrasonography (US).

Methods

This study screened 386 patients who underwent planning US using fusion imaging and/or contrast-enhanced US for percutaneous RFA for suspected metastatic colorectal cancer between January 2013 and December 2020, from whom 136 patients with a single hepatic metastasis from colorectal cancer measuring <3 cm were included. The factors related to the infeasibility of percutaneous RFA were investigated. Univariate and multivariate analyses were performed to assess the factors associated with tumor invisibility on planning US.

Results

Among the 136 patients, percutaneous RFA was considered infeasible in 24.3% (33/136) due to a high risk of the heat-sink effect caused by the abutment of a large vessel (n=12), an inconspicuous tumor on planning US (n=11), a high risk of collateral thermal damage to an adjacent organ (n=8), and the absence of a safe electrode path (n=2). In univariate and multivariate analyses, tumor size was a statistically significant factor affecting invisibility on planning US (P=0.003 and P=0.018, respectively).

Conclusion

Percutaneous RFA was infeasible in approximately one-fourth of patients with metastatic colorectal cancer. The reason for the infeasibility was mainly an unfavorable tumor location and invisibility on planning US. Small tumor size was the sole significant factor affecting the invisibility of hepatic metastases on planning US.

The semi-erect position for better visualization of subphrenic hepatocellular carcinoma during ultrasonography examinations

PURPOSE

This study investigated which body position is more useful for visualizing subphrenic hepatocellular carcinomas (HCCs) during ultrasonography (US) examinations.

METHODS

This prospective study was approved by the institutional review board and written informed consent was obtained from all patients. Twenty consecutive patients with a single subphrenic HCC (treatment-naïve, 1 to 3 cm) underwent a US examination for planning radiofrequency ablation. The examinations were done by one of three radiologists and the patients were examined in four different body positions-supine, right posterior oblique (RPO), left lateral decubitus (LLD), and semi-erect-by being positioned on a tilted table. The visibility of the index tumor was prospectively assessed using a 4-point scale. Needle insertion was considered to be technically feasible if the visibility score was lower than 2. The visibility score and technical feasibility were compared using the Wilcoxon signed rank test and the McNemar test, respectively, for pairwise comparisons between different body positions.

RESULTS

The visibility score was significantly lower in the semi-erect position (median, 2; interquartile range, 1 to 2.75) than in the supine (3, 2 to 4), RPO (3, 2 to 4), and LLD (4, 3.25 to 4) positions (P=0.007, P=0.005, and P=0.001, respectively). The technical feasibility of needle insertion was also significantly higher in the semi-erect position (75%, 15/20) than in the supine (45%, 9/45), RPO (35%, 7/20), and LLD (20%, 4/20) positions (P=0.031, P=0.021, and P=0.001, respectively).

CONCLUSION

The semi-erect position is more useful for the visualization of subphrenic HCCs than the supine, RPO, or LLD positions.

Laparoscopic radiofrequency ablation of subcapsular hepatocellular carcinomas: risk factors related to a technical failure

BACKGROUND

This study aimed to evaluate the risk factors related to a technical failure after laparoscopic radiofrequency ablation (RFA) for subcapsular hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

A total of 110 patients with 114 HCCs who underwent laparoscopic RFA for HCCs (new HCC [n = 85] and local tumor progression [LTP] [n = 29]) between January 2013 and December 2018 were included. We evaluated the incidence of technical failure on immediate post-RFA CT images. Risk factors for a technical failure after laparoscopic RFA were assessed using univariable logistic regression analyses. The cumulative LTP rate was estimated using the Kaplan-Meier method.

RESULTS

Technical failure was noted in 3.5% (4/114) of the tumors. All four tumors that showed a technical failure were cases of LTP from previous treatment and were invisible on laparoscopy. On univariate analysis, LTP lesion, invisibility of the index tumor on laparoscopy, and peri-hepatic vein location of the tumor were identified as risk factors for a technical failure. The cumulative LTP rates at 1, 3, and 5 years were estimated to be 2.8%, 4.8%, and 4.8%, respectively.

CONCLUSIONS

LTP lesion, invisibility of the index tumor on laparoscopy, and peri-hepatic vein location of the tumor were identified as the risk factors for a technical failure after laparoscopic RFA.

Virtual navigation-guided radiofrequency ablation for recurrent hepatocellular carcinoma invisible on ultrasound after hepatic resection

BACKGROUND

No reports are available on the technical efficiency and therapeutic response of virtual navigation (VN)-guided radiofrequency ablation (RFA) for patients with recurrent hepatocellular carcinoma (HCC) after hepatic resection. The aim of this study was to investigate the overall technical performance and outcome of VN-guided RFA in recurrent HCC patients. In addition, a nomogram model was developed to predict the factors influencing the overall survival (OS).

METHODS

This was a prospective study on 76 recurrent HCC patients who underwent VN-guided RFA between June 2015 and February 2018. The technical feasibility, success, and efficiency, OS, local tumor progression, and complications were evaluated. A multivariate Cox regression analysis was conducted to predict the significant factors, and a nomogram including independent predictive factors was subsequently plotted to predict OS.

RESULTS

The technical feasibility, success, and efficiency rates of VN-guided RFA were 86.4%, 94.7%, and 97.4%, respectively. The cumulative OS rates at 1-, 2-, and 3-year were 88.1%, 79.7%, and 71.0%, respectively. The cumulative local tumor progression rates at 1-, 2-, and 3-year were 5.5%, 8.7%, and 14.0%, respectively. In addition, the minor and major complication rates were 5.3% and 3.9%, respectively. No intervention-related deaths occurred during the follow-up period. The C-index of the OS nomogram in this study was 0.737.

CONCLUSIONS

VN-guided RFA is an effective therapeutic option in recurrent HCC patients and improves the long-term outcomes especially for the lesions that cannot be detected in the two-dimensional ultrasound. Besides, the nomogram may be a useful supporting tool in predicting OS to estimate the individual survival probability, optimize treatment options, and facilitate decision-making.

MR-guided microwave ablation in hepatic malignancies: clinical experiences from 50 procedures

Purpose: To investigate technical success, technique efficacy, safety and outcome of MR-guided microwave ablation (MWA) in hepatic malignancies.Material and methods: In this prospective IRB-approved study, patients scheduled for percutaneous treatment of hepatic malignancies underwent MR-guided MWA in a closed-bore 1.5 T MR system. Technical success was assessed on post-procedural MR control imaging. Technique efficacy was evaluated 4 weeks after the procedure on multi-parametric MRI. Assessment of safety followed the Society of Interventional Radiology grading system. Kaplan-Meier survival estimates were calculated to evaluate overall survival (OS), time to local tumor progression (TLTP), and time to non-target progression (TNTP).Results: Between 2015 and 2019, 47 patients (60.5 ± 12.2 years; 39 male) underwent 50 procedures for 58 hepatic tumors (21 hepatocellular carcinomas; 37 metastases). Mean target tumor size was 16 ± 7mm (range: 6-39 mm). Technical success and technique efficacy were 100% and 98%, respectively. Lesions were treated using 2.6 applicator positions (range: 1-6). Mean energy, ablation duration per tumor, and procedure duration were 43.2 ± 23.5 kJ, 26.7 ± 13.1 min and 211.2 ± 68.7 min, respectively. 10 minor (20%) and 3 major (6%) complications were observed. Median post-interventional hospital admission was 1 day (range: 1-19 days). Median OS was 41.6 (IQR: 26.4-) months. Local recurrence occurred after 4 procedures (8%) with TLTP ranging between 3.1 and 41.9 months. Non-target recurrence was observed in 64% of patients after a median TNTP of 13.8 (IQR 2.3-) months.Conclusion: MR-guided MWA allows for safe and successful treatment of hepatic malignancies with a high technique efficacy however with relatively long procedure durations.

SN, Kulkarni S, Shetty NS, Gupta A, Gupta S. Indian Society of Vascular and Interventional Radiology Expert Consensus Statements for Ablation in Hepatocellular Carcinoma: Part I

Locoregional therapies play an important role in the management of hepatocellular carcinoma (HCC). Percutaneous ablation is one of the most commonly employed nonsurgical methods for treating very early and early HCC. For small HCCs, ablation is potentially curative and competes with surgical resection. The widespread availability and the spectrum of ablative techniques mandate uniform approach among interventional radiologists. Thus, it is desirable to have a consensus regarding various aspects of liver ablation. This article represents a consensus document of the experts from the Indian Society of Vascular and Interventional Radiology involved in the care of patients with HCC. The statements are presented in two parts.

Stereotactic Image-Guided Microwave Ablation for Malignant Liver Tumors-A Multivariable Accuracy and Efficacy Analysis

Background: Therapeutic success of thermal ablation for liver tumors depends on precise placement of ablation probes and complete tumor destruction with a safety margin. We investigated factors influencing targeting accuracy and treatment efficacy of percutaneous stereotactic image-guided microwave ablation (SMWA) for malignant liver neoplasms. Materials and methods: All consecutive patients treated with SMWA for malignant liver tumors over a 3-year period were analyzed. A computed tomography-based navigation system was used for ablation probe trajectory planning, stereotactic probe positioning, and validation of probe positions and ablation zones. Factors potentially influencing targeting accuracy [target positioning error (TPE)] and treatment efficacy within 6 months [ablation site recurrence (ASR)] were analyzed in a multivariable regression model, including challenging lesion locations (liver segments I, VII, and VIII; subphrenic location). Results: Three hundred one lesions (174 hepatocellular carcinomas, 87 colorectal liver metastases, 17 neuroendocrine tumors, and 23 others) were targeted in 191 interventions in 153 patients. The median TPE per ablation probe was 2.9 ± 2.3 mm (n = 384). Correction of ablation probe positions by repositioning was necessary in 4 out of 301 lesions (1%). Factors significantly influencing targeting accuracy were cirrhosis (R 0.67, CI 0.22-1.12) and targeting trajectory length (R 0.21, CI 0.12-0.29). Factors significantly influencing early ASR were lesion size >30 mm (OR 5.22, CI 2.44-11.19) and TPE >5 mm (OR 2.48, CI 1.06-5.78). Challenging lesion locations had no significant influence on targeting accuracy or early ASR. Conclusions: SMWA allows precise and effective treatment of malignant liver tumors even for lesions in challenging locations, with treatment efficacy depending on targeting accuracy in our model. Allowing for many tumors to be safely reached, SMWA has the potential to broaden treatment eligibility for patients with otherwise difficult to target tumors.

Manual versus automated image fusion of real-time ultrasonography and MR/CT images for radiofrequency ablation of hepatic tumors: results of a randomized prospective trial (NCT02705118)

PURPOSE

This study compared the technical parameters and clinical outcomes of manual and automatic image fusion techniques of ultrasonography and magnetic resonance imaging/computed tomography for radiofrequency ablation (RFA) of hepatic tumors.

METHODS

Seventy consecutive patients (male:female=47:23, 67.1±10.9 years old) who underwent RFA for hepatic tumors were prospectively enrolled and randomly assigned to the manual or automatic registration group. Two operators performed RFA with one of two imaging fusion techniques. Technical parameters (the registration error, time required for image registration, number of point registrations) and clinical outcomes (technical success, technical effectiveness, local tumor progression [LTP]-free survival, and progression-free survival [PFS]) were compared.

RESULTS

The automatic group contained 35 patients with hepatocellular carcinoma, while the manual group included 34 hepatocellular carcinoma patients and a patient with colon cancer liver metastasis. The registration error, time required for registration, and number of point registrations were 5.7±4.3 mm, 147.8±78.2 seconds, and 3.26±1.20 in the automatic group, and 6.3±5.0 mm, 150.3±89.7 seconds, and 3.20±1.13 in the manual group, respectively. The technical success and effectiveness rates were both 97.1% in the automatic group and both 100.0% in the manual group. The above differences were not significant. The LTP-free survival and PFS (28.3 and 21.2 months in the automatic group, and 29.0 and 24.9 months in the manual group, respectively) showed no significant between-group differences during a median 20.1-month follow-up period.

CONCLUSION

The technical parameters and clinical outcomes of automatic image fusion were not significantly different from those of manual image fusion for RFA of hepatic tumors.

Multimodal Percutaneous Thermal Ablation of Small Hepatocellular Carcinoma: Predictive Factors of Recurrence and Survival in Western Patients

BACKGROUND

To identify the predictive factors of recurrence and survival in an unselected population of Western patients who underwent multimodal percutaneous thermal ablation (PTA) for small Hepatocellular Carcinomas (HCCs).

METHODS

January 2015-June 2019: data on multimodal PTA for <3 cm HCC were extracted from a prospective database. Local tumor progression (LTP), intrahepatic distant recurrence (IDR), time-to-LTP, time-to-IDR, recurrence-free (RFS) and overall (OS) survival were evaluated.

RESULTS

238 patients underwent 317 PTA sessions to treat 412 HCCs. During follow-up (median: 27.1 months), 47.1% patients had IDR and 18.5% died. LTP occurred after 13.3% of PTA. Tumor size (OR = 1.108, p < 0.001; hazard ratio (HR) = 1.075, p = 0.002) and ultrasound guidance (OR = 0.294, p = 0.017; HR = 0.429, p = 0.009) independently predicted LTP and time-to-LTP, respectively. Alpha fetoprotein (AFP) > 100 ng/mL (OR = 3.027, p = 0.037) and tumor size (OR = 1.06, p = 0.001) independently predicted IDR. Multinodular HCC (HR = 2.67, p < 0.001), treatment-naïve patient (HR = 0.507, p = 0.002) and AFP > 100 ng/mL (HR = 2.767, p = 0.014) independently predicted time-to-IDR. RFS was independently predicted by multinodular HCC (HR = 2.144, p = 0.001), treatment naivety (HR = 0.546, p = 0.004) and AFP > 100 ng/mL (HR = 2.437, p = 0.013). The American Society of Anesthesiologists (ASA) score > 2 (HR = 4.273, p = 0.011), AFP (HR = 1.002, p < 0.001), multinodular HCC (HR = 3.939, p = 0.003) and steatotic HCC (HR = 1.81 × 10-16, p < 0.001) independently predicted OS.

CONCLUSIONS

IDR was associated with tumor aggressiveness, suggesting a metastatic mechanism. Besides AFP association with LTP, IDR, RFS and OS, treatment-naïve patients had longer RFS, and multi-nodularity was associated with shorter RFS and OS. Steatotic HCC, identified on pre-treatment MRI, independently predicted longer OS, and needs to be further explored.

Locoregional treatments for hepatocellular carcinoma: Current evidence and future directions

Liver cancers are the second most frequent cause of global cancer-related mortality of which 90% are attributable to hepatocellular carcinoma (HCC). Despite the advent of screening programmes for patients with known risk factors, a substantial number of patients are ineligible for curative surgery at presentation with limited outcomes achievable with systemic chemotherapy/external radiotherapy. This has led to the advent of numerous minimally invasive options including but not limited to trans-arterial chemoembolization, radiofrequency/microwave ablation and more recently selective internal radiation therapy many of which are often the first-line treatment for select stages of HCC or serve as a conduit to liver transplant. The authors aim to provide a comprehensive overview of these various image guided minimally invasive therapies with a brief focus on the technical aspects accompanied by a critical analysis of the literature to assess the most up-to-date evidence from comparative systematic reviews and meta-analyses finishing with an assessment of novel combination regimens and future directions of travel.

Evaluation of Contrast-Enhanced Intraoperative Ultrasound in the Detection and Management of Liver Lesions in Patients with Hepatocellular Carcinoma

AIM

To evaluate the role of contrast-enhanced intraoperative ultrasound (CE-IOUS) during liver surgery in the detection and management of liver lesions in patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

From December 2016 to December 2017, 50 patients with HCC, who were candidates for liver resection, were evaluated with intraoperative ultrasound (IOUS). For all patients, MRI and/or CT were performed before surgery. During surgery, IOUS was performed after liver mobilization, and when nodules that had not been detected in the preoperative MRI and/or CT were observed, CE-IOUS scans were carried out with the dual purpose of better characterizing the unknown lesion and discovering new lesions.

RESULTS

In 12 patients, IOUS showed 14 nodules not detected by preoperative MRI and/or CT, before surgery. Out of the 12 lesions, five presented vascular features compatible with those of malignant HCC to the evaluation with CE-IOUS and four of these were simultaneously treated with intraoperative radiofrequency ablation (RFA). The fifth lesion was resected by the surgeon. The remaining nine lesions recognized by IOUS were evaluated as benign at CE-IOUS and considered regenerative nodules. The last diagnosis was confirmed during follow-up obtained by means of CT and/or MRI after 1, 3, 6, or 12 months.

CONCLUSION

In our experience, CE-IOUS is a useful diagnostic tool in both benign pathologies, such as regenerative nodules, and malignant liver lesions. The advantage of this approach is the possibility of intraoperatively characterizing, based on vascularization patterns, lesions that could not be diagnosed by preoperative imaging, resulting in modification of the surgical therapy decision and expansion of the resection or intraoperative ablation.

Thermal ablation with fusion imaging guidance of hepatocellular carcinoma without conspicuity on conventional or contrast-enhanced US: surrounding anatomical landmarks matter

AIM

Evaluating clinical and technical factors affecting thermal ablation of B-Mode/CEUS inconspicuous HCC nodules, relying only on fusion imaging (FI) performed under conscious sedation and using previously acquired CT or MR.

MATERIALS AND METHODS

Among 367 HCC nodules treated in the study period, data of 37 B-mode/CEUS undetectable HCC nodules treated with FI-guided ablation were extracted from our prospectively collected institutional database. Analyzed variables included patients' sex, age, cirrhosis etiology, Child-Pugh status, size of the lesion, liver segment, subcapsular or central liver site, type of imaging used for fusion (MR/CT), and the presence of surrounding anatomical landmarks (SAL) < 3 cm from the index lesion.

RESULTS

The primary efficacy was 59.4% (22/37 nodules); nine lesions (24.3%) were partially ablated (PA), six lesions (16.7%) were mistargeted (MA). Eight nodules were retreated with a CA obtained in all cases (100% CA, secondary efficacy in 30/37-81.1%). LTP was observed in 2/30 cases (6.7%). Two minor complications were registered (Clavien-Dindo, Grade1, CIRSE Classification Grade 2). SAL were related to a better ablation outcome (37.5% vs 84.6% p = 0.01). No differences were observed between CA group and PA-MA group in terms of lesion size (15.4 mm vs 14.9 mm p = 0.63), liver segment (p = 0.58), subcapsular or central liver site (8/22 36% vs 4/15 26.7% p = 0.84), and imaging (MR vs CT, p = 0.72).

CONCLUSION

Even in the presence of potentially critical conditions (completely B-Mode/CEUS inconspicuous nodules, spontaneous breathing, and previously acquired CT or MRI), FI-only guidance is safe and allows having good primary, secondary efficacy and LTP rates. The outcome of the procedure is heavily affected by the presence of SAL.

Laparoscopic Microwave Ablation of Hepatocellular Carcinoma at Liver Surface: Technique Effectiveness and Long-Term Outcomes

Background and Aims:

To evaluate long-term outcomes and prognostic factors of laparoscopic microwave ablation as a first-line treatment for hepatocellular carcinoma located at the liver surface not feasible for percutaneous ablation.

Methods:

51 consecutive patients receiving laparoscopic microwave ablation in our center between January 11, 2012, and July 31, 2014, were enrolled. Technique effectiveness (complete ablation or incomplete ablation) was evaluated 1 month postprocedure. Procedure-related complications were recorded. The influences of patients’ baseline characteristics on recurrence-free survival and overall survival were analyzed after a median follow-up of 34.0 (ranging 19.0-49.0) months.

Results:

Complete ablation was gained in 47 (92.2%) of the 51 patients. No patients died within 30 days of microwave ablation procedure. A total of 3 (5.9%) cases of complications were observed. Tumor progression/recurrence were observed in 40 patients (78.4%). The median recurrence-free survival and median overall survival of the total cohort was 11.0 months (95% confidence interval: 7.573-14.427) and 34.0 months (95% confidence interval: 27.244-40.756), respectively. Multivariate analysis identified alanine transaminase level and tumor number as independent significant prognosticators of recurrence-free survival whereas α-fetoprotein level as significant prognosticators of overall survival.

Conclusions:

As a first-line treatment, laparoscopic microwave ablation provides high technique effectiveness rate and is well tolerated in patients with hepatocellular carcinoma located at liver surface. Alanine transaminase and tumor number were significant predictors of recurrence-free survival, whereas α-fetoprotein level was significant predictor of overall survival. Laparoscopic microwave ablation might serve as a rational treatment option for patients with hepatocellular carcinoma with tumors at the liver surface, which merits validation in future perspective studies.

Treatment choice for early-stage hepatocellular carcinoma in real-world practice: impact of treatment stage migration to transarterial chemoembolization and treatment response on survival

OBJECTIVE

The objectives of our study were firstly to characterize the treatment stage migration phenomenon in early (Barcelona Clinic Liver Cancer [BCLC]-0/A) stage hepatocellular carcinoma (HCC) by comparing the efficacy of curative therapies with trans-arterial chemoembolization [TACE] and secondly, determining baseline and on-treatment predictors of survival.

METHODS

All patients within BCLC-0/A stage from six tertiary hospitals who received curative therapy with either resection, transplantation, or ablation or TACE as first-line treatment were included in the analyses. The primary endpoint was overall survival; secondary end-points were transplant-free survival and recurrence-free survival.

RESULTS

Between January 2000 and December 2013, we identified 253 BCLC-0/A HCC patients of whom 148 (58.5%) received curative therapy and 105 (41.5%) migrated to TACE. Patients undergoing TACE had lower median survival (2.7 vs. 6.7 years; p < .0001), transplant-free survival (2.6 vs. 4.8 years; p < .0001) and recurrence-free survival (1.3 vs. 2.7 years; p < .001). On multivariate analysis treatment allocation to TACE was an independent prognostic predictor for both lower overall survival (HR 1.70, p = .04) and for HCC recurrence (HR 2.25, p < .001). The main prognostic determinant for each target outcome was Child-Pugh score.

CONCLUSIONS

Our study confirms that curative treatments should always be preferred when applicable in early-stage HCC, but that in cases where this is not possible, TACE is a reasonable albeit inferior treatment option. In addition, it provides unique prognostic information on a significant proportion of patients with early-stage disease in whom curative therapy is not applicable.

Comparative Effectiveness of Computed Tomography- Versus Ultrasound-Guided Percutaneous Radiofrequency Ablation Among Medicare Patients 65 Years of Age or Older With Hepatocellular Carcinoma

BACKGROUND

For patients with hepatocellular carcinoma (HCC) not eligible for surgical resection, radiofrequency ablation (RFA) is a promising technique that reduces the risk of disease progression.

OBJECTIVES

To evaluate whether the trend of image guidance for RFA is moving toward the more expensive computed tomography (CT) technology and to determine the clinical benefits of CT guidance over the ultrasound (US) guidance.

METHODS

A cohort of 463 patients was identified from the Surveillance, Epidemiology, and End Results and Medicare-linked database. The temporal trends in use of image guidance were assessed using the Cochrane-Armitage test. The associations between modality of image guidance and survival, complications, and costs were assessed using the Cox regression model, the logistic regression model, and the generalized linear model, respectively.

RESULTS

The use of CT-guided RFA increased sharply, from 20.7% in 2002 to 75.9% in 2011. Compared with CT-guided RFA, those who received US-guided RFA had comparable risk of periprocedural and delayed postprocedural complications. Stratified analyses by tumor size also showed no statistically significant difference. In adjusted survival analysis, no statistically significant difference was observed in overall and cancer-specific survival. Nevertheless, the cost of CT-guided RFA ($2847) was higher than that of US-guided RFA ($1862).

CONCLUSIONS

Despite its rapid adoption over time, CT-guided RFA incurred higher procedural costs than US-guided RFA but did not significantly improve postprocedural complications and survival. Echoing the American Board of Internal Medicine's Choosing Wisely campaign and the American Society of Clinical Oncology's Value of Cancer Care initiative, findings from our study call for critical evaluation of whether CT-guided RFA provides high-value care for patients with HCC.

Real-Time 3D Virtual Target Fluoroscopic Display for Challenging Hepatocellular Carcinoma Ablations Using Cone Beam CT

Three-dimensional virtual target fluoroscopic display is a new guidance tool that can facilitate challenging percutaneous ablation. The purpose of this study was to assess the feasibility, local efficacy, and safety of liver ablation assisted by three-dimensional virtual target fluoroscopic display. Sixty-seven hepatocellular carcinomas (mean diameter: 31 mm, range: 9-90 mm, 24 ≥ 30 mm, 16 of an infiltrative form) in 53 consecutive patients were ablated using irreversible electroporation (n = 39), multibipolar radiofrequency (n = 25), or microwave (n = 3) under a combination of ultrasound and three-dimensional virtual target fluoroscopic display guidance because the procedures were considered to be unfeasible under ultrasound alone. This guidance technology consisted of real-time fluoroscopic three-dimensional visualization of the tumor previously segmented from cone beam computed tomography images acquired at the start of the procedure. The results were assessed by cross-sectional imaging performed at 1 month and then every 3 months in the event of complete ablation. Factors associated with overall local tumor progression (initial treatment failure and subsequent local tumor progression) were assessed using a logistic regression model. Sixty-one (91%) tumors were completely ablated after 1 (n = 53) or 2 (n = 8) procedures. After a median follow-up of 12.75 months (1-23.2) of the 61 tumors displaying imaging characteristics consistent with complete ablation at 1 month, local tumor progression was observed in 9, so the overall local tumor progression rate was 22.3% (15 of 67). Under multivariate analysis, dome locations and infiltrative forms were associated with local tumor progression. No major complications occurred. Three-dimensional virtual target fluoroscopic display is a feasible and efficient image guidance tool to facilitate challenging ablations that are generally considered as infeasible using ultrasound alone.

Comparison of Combined Therapy Using Conventional Chemoembolization and Radiofrequency Ablation Versus Conventional Chemoembolization for Ultrasound-Invisible Early-Stage Hepatocellular Carcinoma (Barcelona Clinic Liver Cancer Stage 0 or A)

Objective

To compare the therapeutic efficacy between conventional transarterial chemoembolization (cTACE) and combined therapy using cTACE and radiofrequency ablation (RFA) in ultrasound (US)-invisible early stage hepatocellular carcinoma (HCC).

Materials and Methods

From January 2008 to June 2016, 167 patients with US-invisible early stage HCCs were treated with cTACE alone (cTACE group; n = 85) or cTACE followed by immediate fluoroscopy-guided RFA targeting intratumoral iodized oil retention (combined group; n = 82). Procedure-related complications, local tumor progression (LTP), time to progression (TTP), and overall survival (OS) were compared between the two groups. Multivariate analyses were performed to identify prognostic factors.

Results

There was no major complication in either group. The cTACE group showed higher 1-, 3-, and 5-year LTP rates than the combined group; i.e., 12.5%, 31.7%, and 37.0%, respectively, in the cTACE group; compared to 7.3%, 16.5%, and 16.5%, respectively, in the combined group; p = 0.013. The median TTP was 18 months in the cTACE group and 24 months in the combined group (p = 0.037). Cumulative 1-, 3-, and 5-year OS rates were 100%, 93.2%, and 87.7%, respectively, in the cTACE group and 100%, 96.6%, and 87.4%, respectively, in the combined group (p = 0.686). Tumor diameter > 20 mm and cTACE monotherapy were independent risk factors for LTP and TTP.

Conclusion

Combined therapy using cTACE followed by fluoroscopy-guided RFA is a safe and effective treatment in US-invisible early stage HCCs. It provides less LTP and longer TTP than cTACE alone.

Optimized Echo Decorrelation Imaging Feedback for Bulk Ultrasound Ablation Control

Feasibility of controlling bulk ultrasound (US) thermal ablation using echo decorrelation imaging was investigated in ex vivo bovine liver. The first of two ablation and control procedures used a sequence of constant-intensity sonication cycles, ceased when the minimum echo decorrelation within a control region of interest (ROI) exceeded a predetermined threshold. The second procedure used a variable-intensity sonication sequence, with spatially averaged decorrelation as the stopping criterion. US exposures and echo decorrelation imaging were performed by a linear image-ablate array. Based on preliminary experiments, control ROIs and thresholds for the minimum-decorrelation and average-decorrelation criteria were specified. Controlled trials for the minimum-decorrelation and average-decorrelation criteria were compared with uncontrolled trials employing 9 or 18 cycles of matching sonication sequences. Lesion dimensions, treatment times, ablation rates, and areas under receiver operating characteristic curves were statistically compared. Successfully controlled trials using both criteria required significantly shorter treatment times than corresponding 18-cycle treatments, with better ablation prediction performance than uncontrolled 9-cycle and 18-cycle treatments. Either control approach resulted in greater ablation rate than corresponding 9-cycle or 18-cycle uncontrolled approaches. A post hoc analysis studied the effect of exchanging control criteria between the two series of controlled experiments. For either group, the average time needed to exceed the alternative decorrelation threshold approximately matched the average duration of successfully controlled experimental trials. These results indicate that either approach, using minimum-decorrelation or average-decorrelation criteria, is feasible for control of bulk US ablation. In addition, use of a variable-intensity sonication sequence for bulk US thermal ablation can result in larger ablated regions compared to constant-intensity sonication sequences.

Feasibility, efficacy, and safety of percutaneous MR-guided ablation of small (≤12 mm) hepatic malignancies

BACKGROUND

Percutaneous tumor ablation is commonly performed using computed tomography (CT) or ultrasound (US) guidance, although reliable visualization of the target tumor may be challenging. MRI guidance provides more reliable visualization of target tumors and allows for real-time imaging and multiplanar capabilities, making it the modality of choice, in particular if lesions are small.

PURPOSE

To investigate the feasibility, technical success, and safety of percutaneous MR-guided ablation (RFA n = 27 / MWA n = 16) of small (≤12 mm) hepatic malignancies.

STUDY TYPE

Retrospective case study.

POPULATION

In all, 45 patients (age: 61.1 ± 11.8) with hepatic malignancies and a lesion diameter of ≤12 mm scheduled for percutaneous MR-guided tumor ablation based on a tumor board decision were included.

FIELD STRENGTH

A 1.5T MR system was used for planning, targeting, and monitoring.

ASSESSMENT

Feasibility assessment included the detection of the target tumor, tumor delineation during MR-fluoroscopy guided targeting, and the number of attempts needed for precise applicator placement. Technical success was defined as successful performance of the procedure including a safety margin of 5 mm. Safety evaluation was based on procedure-related complications.

STATISTICAL TEST

Frequency.

RESULTS

Tumor ablation (mean diameter 9.0 ± 2.1 mm) was successfully completed in 43/45 patients. Planning imaging was conducted without a contrast agent in 79% (n = 37). In 64% (n = 30), the target tumors were visible with MR-fluoroscopy. In six patients (13%), planning imaging revealed new, unexpected small lesions, which were either treated in the same session (n = 4) or changed therapy management (n = 2) due to diffuse tumor progress. Postprocedural imaging revealed a technical success of 100% (43/43), with no major complications. During follow-up, no local tumor progression was observed (mean follow-up 24.7 ± 14.0 months) although 28% (12) patients developed new hepatic lesions distant to the ablation zone. No major complications were observed.

DATA CONCLUSION

MR-guided ablation is a feasible approach for an effective and safe treatment of small hepatic malignancies.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2019;49:374-381.

Percutaneous thermal ablation of hepatocellular carcinomas located in the hepatic dome using artificial carbon dioxide pneumothorax: retrospective evaluation of safety and efficacy

INTRODUCTION

The targeting of hepatocellular carcinomas (HCC) in the hepatic dome can be challenging during percutaneous thermal ablation (PTA). The aims of this study were (1) to evaluate the safety and efficacy of PTA of HCC in the hepatic dome that cannot be visualized under US, using artificial CO2 pneumothorax and CT-guidance and (2) to compare the results with US-visible HCC located in the liver dome treated under US-guidance.

MATERIALS

Over a 32-month period, 56 HCC located in the hepatic dome were extracted from a prospectively maintained database. Twenty-eight cases (US-guidance group) were treated under US-guidance, while the others (n = 28, CT-CO2 group) were treated under CT-guidance using artificial CO2 pneumothorax after lipiodol tagging of the tumor. The primary technical success and complications rates of this technique were retrospectively assessed. Local tumor progression (LTP), intrahepatic distant recurrence (IDR), local recurrence-free survival (LRFS) and overall survival (OS) were also compared between both groups.

RESULTS

Primary technical success was 100% in both groups. No major complications occurred. After a median follow-up of 13.8 months (range, 1-33.4 months), LTP occurred in 10.7% (3/28) in CT-CO2 vs. 25% (7/28) in the US-guidance group (p = NS). IDR occurred in 39.3% (11/28) in CT-CO2 vs. 28.6% (8/28) in the US-guidance group (p = NS). Death occurred in 17.9% (5/28) of patients in both groups. LRFS and OS did not significantly differ using Kaplan-Meier survival estimates.

CONCLUSION

CT-guided PTA after artificially induced CO2 pneumothorax is a safe and efficient technique to treat HCC located in the hepatic dome.

Percutaneous US/MRI Fusion-guided Radiofrequency Ablation for Recurrent Subcentimeter Hepatocellular Carcinoma: Technical Feasibility and Therapeutic Outcomes

Purpose To evaluate the technical feasibility and therapeutic outcomes of percutaneous US/MRI fusion-guided radiofrequency ablation (RFA) of recurrent subcentimeter-sized hepatocellular carcinomas (HCCs). Materials and Methods For this retrospective study, between January 2012 and December 2014 a total of 194 planning US examinations were performed in 186 patients (159 men and 27 women; mean age, 61.1 years ± 10.0 [standard deviation]) for newly developed subcentimeter recurrent HCCs. These recurrent HCCs were defined as hypervascular nodules (>5.5 mm and <10 mm) with typical MRI findings of HCC. The study assessed how often US/MRI fusion-guided percutaneous RFA was deemed technically feasible at planning US examination (the feasibility rate) and the therapeutic outcomes after RFA, including the rates of technical success, technique efficacy, local tumor progression (LTP), and major complications. Cumulative LTP rates were estimated with the Kaplan-Meier method. Results The feasibility rate of percutaneous RFA at planning US examination was 65.7% (138 of 210 HCCs). The most common reason for RFA infeasibility was that an index tumor was inconspicuous at US. Among 138 subcentimeter HCCs feasible for RFA, 125 lesions underwent percutaneous RFA. The rates of both technical success and technique efficacy were 98.4% (123 of 125). The cumulative LTP rates at 1, 2, and 3 years were 3.6%, 5.4%, and 7.4%, respectively. The major complication rate was 2.5% (three of 119). Conclusion Percutaneous US/MRI fusion-guided radiofrequency ablation (RFA) was feasible in approximately two-thirds of subcentimeter recurrent hepatocellular carcinomas (HCCs). Percutaneous US/MRI fusion-guided RFA is a safe and effective treatment modality for patients with subcentimeter recurrent HCCs.

Percutaneous Radiofrequency Ablation of Small (1-2 cm) Hepatocellular Carcinomas Inconspicuous on B-Mode Ultrasonographic Imaging: Usefulness of Combined Fusion Imaging with MRI and Contrast-Enhanced Ultrasonography

PURPOSE

To assess usefulness of adding contrast-enhanced ultrasonography (CEUS) to fusion imaging (FI) for percutaneous radiofrequency ablation (RFA) of hepatocellular carcinomas (HCCs) inconspicuous on FI alone. Therapeutic outcomes of RFA under CEUS-added FI guidance for HCCs inconspicuous on FI alone were also evaluated.

METHODS

This prospective study was approved by the institutional review board and informed consent was obtained from all patients. Planning US was performed with FI for 126 patients with a single HCC (1-2 cm) to evaluate the feasibility of RFA by grading lesion conspicuity score using a four-point scale. RFA was performed under CEUS-added FI guidance for HCCs inconspicuous on FI alone. We evaluated how many HCCs initially inconspicuous on FI became conspicuous after adding CEUS. After CEUS-added FI-guided RFA, therapeutic outcomes including rates of technical success, primary technique efficacy, major complications, and local tumor progression were assessed.

RESULTS

After adding CEUS, 90.5% (19/21) of all tumors initially inconspicuous on FI became conspicuous, thus enabling direct targeting for RFA. Technical success and primary technique efficacy rates were 94.7% (18/19) and 100% (19/19), respectively. No major complications were observed after RFA. Cumulative local tumor progression rates after RFA were estimated to be 5.3%, 10.8%, and 10.8% at 1, 2, and 3 years, respectively.

CONCLUSION

Adding CEUS to FI is useful for improving the conspicuity of HCCs inconspicuous on FI alone, thus enabling successful percutaneous RFA with excellent therapeutic outcomes.

Transarterial chemoembolization plus multi-imaging-guided radiofrequency ablation for elimination of hepatocellular carcinoma nodules measuring 3.1 to 5.0 cm: a single-center study

Objective This study was performed to determine whether transarterial chemoembolization (TACE) plus multi-imaging-guided radiofrequency ablation (MIG-RFA) can completely eliminate 3.1- to 5.0-cm hepatocellular carcinoma (HCC) nodules and identify factors that may influence the complete elimination rate (CER) of this therapy. Methods Patients who underwent TACE+MIG-RFA for initial treatment of HCC from January 2008 to January 2016 were retrospectively reviewed. In total, 162 patients with 216 HCC nodules (3.1-5.0 cm) were enrolled. TACE was performed first; MIG-RFA was performed 2 to 4 weeks later. Contrast-enhanced computed tomography was performed 1, 3, 6, and 12 months after TACE+MIG-RFA. If tumor enhancement was not detected by the end of the 12-month follow-up, the lesion was considered completely eliminated. Additional TACE+MIG-RFA was performed for residual lesions. The CER was calculated 12 months after the last therapy. Factors that may influence the CER were analyzed. Results In total, 207 (95.8%) nodules showed no residual lesions and were completely eliminated after one or more TACE+MIG-RFA sessions. Nine (4.2%) nodules were incompletely eliminated even with repeated TACE+MIG-RFA. Tumor location was the only significant prognostic factor influencing the CER. Conclusions TACE+MIG-RFA can eliminate 3.1- to 5.0-cm HCC nodules; the tumor location may affect the treatment outcome.

Clinical utility of real-time ultrasound-multimodality fusion guidance for percutaneous biopsy of focal liver lesions

OBJECTIVES

To prospectively evaluate the clinical value of real-time ultrasonography (US)-computed tomography (CT)/magnetic resonance imaging (MRI) fusion imaging for percutaneous needle biopsy of focal liver lesions (FLLs), and to compare its biopsy success rate with that of conventional US-guided biopsy in a propensity-score matched group.

METHODS

This study was approved by our Institutional Review Board and informed consent was obtained from all patients enrolled in the prospective study group. Ninety patients referred to the Department of Radiology for percutaneous biopsy of FLLs were enrolled in this study. Tumor visibility, attainment of a safe access route, and technical feasibility were assessed on conventional US first and later on real-time fusion imaging by one of four abdominal radiologists. Thereafter, differences in scores between real-time fusion imaging and conventional US were determined. In addition, overall diagnostic success rates of a real-time fusion imaging-guided biopsy group and a propensity-score matched, conventional US-guided biopsy group, consisting of 100 patients used as historical control, were compared.

RESULTS

With real-time fusion imaging, tumor visibility, attainment of a safe access route, and operator's technical feasibility were significantly improved compared with conventional US (P < .001). In addition, all invisible (n = 13) and not feasible (n = 10) FLLs on conventional US became visible and feasible for percutaneous US-guided biopsy after applying the fusion system. The diagnostic success rate of real-time fusion-guided biopsy was 94.4% (85/90), which was significantly better than that obtained with the conventional US-guided biopsy (94.4% vs. 83%, P < .03), with reduced biopsy procedure times (7.1 ± 3.5 vs. 9.7 ± 2.8, P < .02).

CONCLUSIONS

Real-time US-CT/MR fusion imaging guidance was able to provide clinical value for percutaneous needle biopsy of FLLs by improving the diagnostic success rate of biopsy and by reducing procedure time.

Surgical Resection vs. Ablative Therapies Through a Laparoscopic Approach for Hepatocellular Carcinoma: a Comparative Study

BACKGROUND

When compatible with the liver functional reserve, laparoscopic hepatic resection remains the treatment of choice for hepatocellular carcinoma while laparoscopic ablation therapies appear as a promising less invasive alternative. The aim of the study is to compare two homogeneous groups of patients submitted to either hepatic resection or thermoablation for the treatment of single hepatocellular carcinoma (≤ 3 cm).

METHODS

We enrolled 264 cirrhotic patients out of 905 cases consecutively evaluated for hepatocellular carcinoma. We performed 59 hepatic resections and 205 thermoablations through a laparoscopic approach, and they were then followed for similar follow-up (41.7 ± 31.5 months for laparoscopic hepatic resection vs. 38.7±32.3 for laparoscopic ablation therapy). Outcomes included short- and long-term morbidities, tumoral recurrence, and overall survival.

RESULTS

Short-term morbidity was significantly higher in the resection group (but the two groups had similar rates for severe complications) while, during follow-up, recurrence was more frequent in patients treated with thermoablation, with a clear disadvantage in terms of survival. At multivariate analysis, only the type of surgical treatment was an independent predictor of disease recurrence, while plasmatic alpha-fetoprotein and Hb values, model for end-stage liver disease score, time to recurrence, and the type of surgical treatment were independent predictors of overall survival.

CONCLUSION

Our data ultimately support some therapeutic advantages for hepatic resection in patients with a single nodule and preserved liver function. However, thermoablation is an adequate alternative in patients with nodules that would require complex surgical resections or imply a poor prognosis that might therefore better tolerate a less invasive procedure.

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.

Does intra-tumoural fat on MRI predict visibility of small (≤3 cm) hepatocellular carcinomas during ultrasound-guided tumour ablation?

AIM

To assess if intra-tumoural fat on magnetic resonance imaging (MRI) affects the ultrasonographic (US) visibility of small (≤3 cm) hepatocellular carcinomas (HCC) during radiofrequency ablation (RFA).

MATERIALS AND METHODS

Institutional review board approval was obtained. A retrospective review of all patients who underwent image-guided ablation between 1 January 2010 and 31 April 2015 was performed. Patients with HCC who underwent US RFA were included. Inclusion criteria included small tumours (≤3 cm), treatment-naive cases or new focus of HCC in a different and untreated segment, and pre-procedural MRI. The presence of intra-tumoural fat was determined retrospectively via in-and-out-of-phase MRI. Other factors that potentially affect ultrasonographic visibility, such as background fatty liver, presence of cirrhosis, tumour size, and distance from diaphragm, were recorded.

RESULTS

Ninety procedures performed on 74 patients (62 men and 12 women; mean age: 67.3 years; range: 39-88 years). Seventy-two tumours were visible on US (hypoechoic n=35, hyperechoic n=28, heterogeneous n=9). Intra-tumoural fat was seen in 23 tumours (25.6%, hyperechoic n=17, hypoechoic n=6). The presence of intra-tumoural fat (p=0.005) and distance from diaphragm (p=0.007) were found to be statistically significant factors affecting tumour visibility on planning US. The presence of background fatty liver (p=0.485), cirrhosis (p=0.48), and tumour size (p=0.15) were not found to be significant.

CONCLUSION

The present study shows that the presence of intra-tumoural fat in small HCCs on pre-procedural MRI can accurately predict their visibility on planning US during percutaneous tumour ablation.

Management consensus guideline for hepatocellular carcinoma: 2016 updated by the Taiwan Liver Cancer Association and the Gastroenterological Society of Taiwan

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortality in Taiwan. To help clinical physicians to manage patients with HCC, the Taiwan Liver Cancer Association and the Gastroenterological Society of Taiwan produced the management consensus guideline for HCC.

METHODS

The recommendations focus on nine important issues on management of HCC, including surveillance, diagnosis, staging, surgery, local ablation, transarterial chemoembolization/transarterial radioembolization/hepatic arterial infusion chemotherapy, systemic therapy, radiotherapy, and prevention.

RESULTS

The consensus statements were discussed, debated and got consensus in each expert team. And then the statements were sent to all of the experts for further discussion and refinement. Finally, all of the experts were invited to vote for the statements, including the level of evidence and recommendation.

CONCLUSION

With the development of the management consensus guideline, HCC patients could benefit from the optimal therapeutic modality.

Utility of T1-weighted MRI as a predictor of liver lesion visibility on ultrasound: A clinical tool to determine feasibility of ultrasound-guided percutaneous interventions

PURPOSE

To determine the utility of fat-suppressed T1-weighted gradient recalled echo (FS-T1W-GRE) MRI to predict visibility of focal liver lesions (FLL) on abdominal ultrasound (US).

MATERIALS AND METHODS

With IRB approval, between 2010 and 2013, 109 patients (28.4% females, age 66.9±10.9years) with 177 FLL (hepatocellular carcinoma=132, metastases=44, other=1) underwent MRI and prospective, radiologist-performed treatment-planning US (to determine eligibility for US-guided ablation). MRI examinations were reviewed by a blinded radiologist who assessed: a) size and location of FLL, b) presence of hepatic steatosis on dual-echo T1W-GRE, and c) quantitative signal intensity of FLL relative to liver on FS-T1W-GRE. Associations between MR imaging findings and visibility on US were assessed using independent t-tests and the chi-squares test.

RESULTS

69.5% (123/177) FLL were identified with US and 30.5% (54/177) were not visible. Size of FLL on MRI was associated with visibility on US (p<0.0001) with no association between FLL visibility on US and segmental or subcapsular location (p=0.29 and p=0.25, respectively). 20.2% (22/109) patients had hepatic steatosis on MRI, which was not associated with non-visibility of FLL on US (p=0.67). 38.4% (68/177) FLL were isointense to liver on FS-T1W-GRE which was associated with non-visibility on US (p=0.036) particularly in non-steatotic livers (p=0.014).

CONCLUSION

FLL size and isointensity of FLL to liver parenchyma on FS-T1W-GRE MRI are associated with non-visibility on US, particularly in non-steatotic livers. These results have implications when planning US-guided percutaneous interventions of FLL detected with MRI.

Transarterial chemoembolization for early stage hepatocellular carcinoma decrease local tumor control and overall survival compared to radiofrequency ablation

BACKGROUND & AIMS

To compare treatment failure and survival associated with ultrasound-guided radiofrequency ablation (RFA) and trans-arterial chemoembolization (TACE) for early-stage HCC in Child-Pugh A cirrhosis patients.

METHODS

122 cirrhotic patients (RFA: 61; TACE: 61) were well matched according to cirrhosis severity; tumor size and serum alpha-fetoprotein. TACE was performed in case of inconspicuous nodule on US or nodule with "at risk location". Treatment failure was defined as local tumor progression (LTP) and primary treatment failure (failing to obtain complete response after two treatment session). Treatment failure and overall survival (OS) were compared after coarsened exact matching. Cox proportional model to assess independent predictive factors was performed.

RESULTS

No significant difference was seen for baseline characteristics between the two groups. Mean tumor size was 3cm in both group with 41% HCC>3cm. Treatment failure rates after TACE was 42.6% (14 primary treatment failures and 12 LTP) and 9.8% after RFA (no primary treatment failure and 6 LTP) P < 0.001. TACE was the only predictive factor of treatment failure (Hazard ratio: 5.573). The 4-years OS after RFA and TACE were 54.1% and 31.5% (P = 0.042), respectively.

CONCLUSION

For Child-Pugh A patients with early-stage HCC, alternative treatment as supra-selective TACE to RFA regarded as too challenging using common US guidance decrease significantly the local tumor control and overall survival. Efforts to improve feasibility of RFA especially for inconspicuous target have to be made.

Comparison Between CT and MR Images as More Favorable Reference Data Sets for Fusion Imaging-Guided Radiofrequency Ablation or Biopsy of Hepatic Lesions: A Prospective Study with Focus on Patient's Respiration

PURPOSE

To identify the more accurate reference data sets for fusion imaging-guided radiofrequency ablation or biopsy of hepatic lesions between computed tomography (CT) and magnetic resonance (MR) images.

MATERIALS AND METHODS

This study was approved by the institutional review board, and written informed consent was received from all patients. Twelve consecutive patients who were referred to assess the feasibility of radiofrequency ablation or biopsy were enrolled. Automatic registration using CT and MR images was performed in each patient. Registration errors during optimal and opposite respiratory phases, time required for image fusion and number of point locks used were compared using the Wilcoxon signed-rank test.

RESULTS

The registration errors during optimal respiratory phase were not significantly different between image fusion using CT and MR images as reference data sets (p = 0.969). During opposite respiratory phase, the registration error was smaller with MR images than CT (p = 0.028). The time and the number of points locks needed for complete image fusion were not significantly different between CT and MR images (p = 0.328 and p = 0.317, respectively).

CONCLUSION

MR images would be more suitable as the reference data set for fusion imaging-guided procedures of focal hepatic lesions than CT images.

Real-time US-CT/MR fusion imaging for percutaneous radiofrequency ablation of hepatocellular carcinoma

BACKGROUND & AIMS

Although ultrasonography (US) guided radiofrequency ablation (RFA) is a commonly used treatment option for early hepatocellular carcinoma (HCC), inconspicuous tumors on US limits its feasibility. Thus, we prospectively determined whether real-time US-CT/MR fusion imaging can improve the technical feasibility of RFA compared with B-mode US, and help predict local tumor progression after RFA in patients with HCC.

METHODS

A total of 216 patients with 243 HCCs ⩽5cm referred for RFA were prospectively enrolled. Prior to RFA, the operators scored the visibility of tumors, and technical feasibility on a 4-point scale at both B-mode US and fusion imaging. RFA was performed with a switching monopolar system using a separable cluster electrode under fusion imaging guidance. Technique effectiveness, local tumor progression and intrahepatic remote recurrences were evaluated.

RESULTS

Tumor visibility and technical feasibility were significantly improved with fusion imaging compared with B-mode US (p<0.001). Under fusion imaging guidance, the technique effectiveness of RFA for invisible tumors on B-mode US was similar to those for visible tumors (96.1% vs. 97.6%, p=0.295). Estimated cumulative incidence of local tumor progression at 24months was 4.7%, and previous treatment for other hepatic tumors (p=0.01), higher expected number of electrode insertions needed and lower technical feasibility scores (p<0.01) on fusion imaging were significant negative predictive factors for local tumor progression.

CONCLUSION

Real-time fusion imaging guidance significantly improved the tumor visibility and technical feasibility of RFA in patients with HCCs compared with B-mode US, and low feasibility scores on fusion imaging was a significant negative predictive factor for local tumor progression.

LAY SUMMARY

US/CT-MR fusion imaging guidance improved the tumor visibility and technical feasibility of RFA in patients with HCCs. In addition, fusion imaging guided RFA using multiple electrodes demonstrated a high technique effectiveness rate and a low local tumor progression rate during mid-term follow-up. Clinical trial number: ClinicalTrials.gov number, NCT02687113.

Comparable Outcomes of Ultrasound versus Computed Tomography in the Guidance of Radiofrequency Ablation for Hepatocellular Carcinoma

Objectives

To compare the efficacy and safety of ultrasound (US) and computed tomography (CT) in the guidance of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC).

Materials and Methods

We retrospectively analyzed consecutive treatment-naïve patients who received curative RFA for HCC from January 2008 to July 2013. Patients were divided into the US group or the CT group according to their RFA guidance instruments. Patients who were only suitable for US- or CT-guided RFA were excluded. Cumulative incidences of and hazard ratios for HCC recurrence were analyzed after adjusting for competing mortality risk.

Results

We recruited a total of 101 patients in the US group and 51 patients in the CT group. The baseline demographic characteristics were not significantly different in both groups. Initial response rates were similar between the two groups (US vs. CT: 89.1% vs. 92.2%, p = 0.54), and complete tumor ablation was finally achieved for all patients. However, more ablations per session were performed in US group (median 2.0 [1.0–3.0] vs. 1.0 [1.0–2.0]; p<0.01). The 1-, 2- and 3-year local tumor recurrence rates (US vs. CT: 13.0%, 20.9%, and 29.2% vs. 11.2%, 29.8% and 29.8%, respectively) and overall mortality rates (US vs. CT: 5.2%, 9.6% and 16.5% vs. 0%, 3.1% and 23.8%, respectively) were not significantly different. In multivariate analysis, tumor characteristics and underlying liver function, but not US or CT guidance, were independent prognostic factors. The complication rates were similar between the two groups (US vs. CT: 10.9% vs. 9.8%; p = 0.71), and there was no procedure-related mortality.

Conclusions

With comparable major outcomes, either US or CT can be used in the guidance of RFA in experience hands.

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

BACKGROUND

Laparoscopic thermal ablation is a common alternative to surgical resection in treating hepatic tumors, particularly in those located in difficult-to-reach locations.

OBJECTIVE

The aim of this study was to compare the safety and long-term efficacy of laparoscopic radiofrequency ablation (RFA) and microwave ablation (MWA) in treating hepatocellular carcinoma (HCC).

METHOD

From February 2009 to May 2015, data from patients with HCC nodules who had undergone either laparoscopic MWA or laparoscopic RFA were examined. Complications, complete ablation rates, local tumor progression (LTP) rates, and disease-free and cumulative survival rates were compared between the two treatment groups.

RESULTS

A total of 154 patients with HCC (60 MWA and 94 RFA) were treated via the laparoscopic approach. Major complication rates were identified as 1 and 2 % in the RFA and MWA groups, respectively (p = 0.747). Complete ablation rates were 95 % for both treatment groups (p = 0.931), and LTP rates were 21.2 % for RFA and 8.3 % for MWA (p = 0.034). Disease-free survival rates at 5 years were 19 % in the RFA group and 12 % in the MWA group (p = 0.434), while cumulative survival rates at 5 years were 50 % in the RFA group and 37 % in the MWA group (p = 0.185).

CONCLUSION

Laparoscopic RFA and MWA appear to be safe in the treatment of early-stage HCC. The LTP rates were lower in the laparoscopic MWA group compared with the laparoscopic RFA group, but their respective overall and disease-free survival rates remained similar.