Subcapsular liver tumors treated with percutaneous radiofrequency ablation: a prospective comparison with nonsubcapsular liver tumors for safety and effectiveness

Radiofrequency ablation with or without conventional transarterial chemoembolization for subcapsular versus nonsubcapsular hepatocellular carcinoma within Milan criteria: a propensity score-matched study

OBJECTIVE

Our study was to compare the therapeutic outcomes of radiofrequency ablation (RFA) with or without conventional transarterial chemoembolization (cTACE) for hepatocellular carcinoma (HCC) within Milan criteria in subcapsular versus nonsubcapsular locations by using propensity score matching.

MATERIALS AND METHODS

This retrospective study included 171 consecutive HCC patients meeting Milan criteria who initially received RFA with or without cTACE at a tertiary academic center between January 2017 to December 2022. Technical success rate, progression-free survival (PFS) were recorded. Factors predicting PFS after RFA with or without cTACE were investigated through a Cox proportional hazard model.

RESULTS

The cumulative 1-, 3-, and 5-year PFS were 73.9%%, 27.7%%, and 7.7%, respectively. The cumulative PFS rates were 76.1% and 17.3% at 1 and 3 years, respectively, in the subcapsular group and 71.8% and 37.2% in the nonsubcapsular group (p = 0.034). Matching yielded 49 matched pairs of patients. In the matched group, corresponding cumulative PFS rates were 75.6% and 14.6% at 1 and 3 years, respectively, in the subcapsular group and 69.6% and 30.2% in the nonsubcapsular group (p = 0.156). Multivariate analysis confirmed that subcapsular tumor location was not an independent risk factor for PFS. Additionally, differences in technical success rate were not significant between groups.

CONCLUSION

The differences in PFS rates and technical success rate in HCC patients within the Milan criteria who received RFA with or without cTACE were not significant between the subcapsular and non-subcapsular groups. Future larger prospective multicenter trials are needed to validate these findings.

Microwave ablation for colorectal liver metastases with ultrasound fusion imaging assistance: a stratified analysis study based on tumor size and location

PURPOSE

To investigate the efficacy of ultrasound fusion imaging-assisted microwave ablation (MWA) for patients with colorectal liver metastases (CRLM) based on stratified analysis of tumor size and location.

METHODS

Patients with CRLM who underwent ultrasound fusion imaging-assisted MWA in our hospital between February 2020 and February 2023 were enrolled into this retrospective study. Ultrasound fusion imaging was used for detection, guidance, monitoring and immediate evaluation throughout the MWA procedures. Technical success, technique efficacy, local tumor progression (LTP), intrahepatic progression and overall survival (OS) were recorded and analyzed. The subgroup analysis of intrahepatic progression of MWA for CRLM was performed according to tumor size and location.

RESULTS

A total of 51 patients with 122 nodules were enrolled. Both technical success and technique efficacy were acquired in all nodules. In a median follow-up period of 19 months, 2.5% of the nodules (3/122) were observed LTP. The 1-year and 2-year cumulative intrahepatic progression rates were 38.7% and 52.1% respectively. Patients were divided into subgroups according to tumor size (≥ 30 mm, n = 13; < 30 mm, n = 38) and tumor location (perivascular, n = 20; non-perivascular, n = 31 and subcapsular, n = 36; non-subcapsular, n = 15). The cumulative intrahepatic progression rates were similar between the subgroups regarding tumor size and perivascular location, while significantly higher in the subcapsular group than in the non-subcapsular group (p = 0.021).

CONCLUSION

Ultrasound fusion imaging-assisted MWA exhibited satisfactory local efficacy for CRLM, especially for non-subcapsular tumors.

Imaging Classification of Exophytic HCC and Our Experience with Microwave Ablation of Type 2 Lesions

Purpose  The purpose of this article is to classify hepatocellular carcinoma (HCC) based on imaging and to evaluate the role of ultrasound-guided microwave ablation (MWA) in the management of type 2 exophytic HCC. Materials and Methods  A retrospective study was performed at our institution after approval by the Institutional Review Board. The study was undertaken from January 2017 to May 2022. Based on the location, HCC was classified and categorized on cross-sectional imaging into four types. All MWA procedures were performed using ultrasound guidance. Patients were followed up every 3 months with cross-sectional imaging. Results  During the study period, 225 lesions were reviewed. MWA was performed in 13 type 2 exophytic HCC patients. Segment 3 (38%) was the most common site when categorized as per Couinaud classification and segment 6 was the next common site. Technical success of complete ablation, evaluated by postprocedure contrast-enhanced computed tomography scan, was 100%. The median follow-up period was 24 months (range: 9-24 months). One patient presented with a residual lesion on the first follow-up at 30 days. Two other patients followed up to 9 months were free of HCC. Ten patients followed up at 1 year showed no recurrence, while 7 of them were followed up for 24 months, and 1 of whom showed multicentric recurrence which was treated by selective intra-arterial radiation therapy. Conclusion  A classification system for exophytic lesions can allow for better patient selection, planning, and reporting of ablative outcomes. MWA has performed well when ablating these technically challenging lesions with a certain degree of planning.

Temporal trends and long-term outcomes of radiofrequency ablation for hepatocellular carcinoma within the Milan criteria

No study has analysed the temporal trends of the long-term results and clinical characteristics of patients with hepatocellular carcinoma (HCC) treated using radiofrequency ablation (RFA). Therefore, we examined temporal trends of characteristics of patients and treatment-naïve HCCs within the Milan criteria treated by RFA over 20 years. We retrospectively analysed 1099 patients with HCC within the Milan criteria treated with percutaneous RFA from January 2000 to December 2019. The overall survival (OS), recurrence-free survival (RFS), and factors affecting survival and local tumor progression were analysed using the Kaplan‒Meier method and Cox proportional hazards model. A trend test was performed to analyse the changing trends in participants and treatment outcomes. The overall and RFS of patients improved during the later period. In addition, viral hepatitis-related HCC incidence decreased, whereas that of alcohol- or non-alcoholic fatty liver disease-related HCC increased from the earlier to the later period (P for trend < 0.001). HBV antiviral therapy was increased and improved OS and RFS in patients treated using RFA. The outcomes after RFA over a 20-year period improved due to changes over time in target tumors and patients. The results could be useful for selecting patients who will benefit from RFA.

Radiofrequency ablation of subcapsular versus nonsubcapsular hepatocellular carcinomas ≤ 3 cm: analysis of long-term outcomes from two large-volume liver centers

OBJECTIVES

To compare the safety and efficacy of RFA for single HCCs ≤ 3 cm in subcapsular versus nonsubcapsular locations using a propensity score matched analysis.

MATERIALS AND METHODS

This retrospective study included patients with solitary HCCs ≤ 3 cm in size who underwent percutaneous RFA from 2005 to 2015 as initial treatment at two large-volume liver centers. Patients were divided into two groups, consisting of those with subcapsular and nonsubcapsular tumor locations. Complications, local tumor progression (LTP), and overall survival (OS) were compared in these two groups before and after propensity score matching (PSM).

RESULTS

The study population consisted of 964 patients (712 men [74%]) of mean age 58.3 years. Of these 964 patients, 561 (58%) had nonsubcapsular and 403 (42%) had subcapsular HCCs. PSM generated 402 pairs of patients. Major complication rate was low, but significantly higher in the subcapscular group (p = 0.047). Rates of technical effectiveness in these two groups were 99% and 98%, respectively (p = 0.315). However, during follow-up, cumulative 1-, 3-, 5-, and 10-year LTP and OS rates did significantly differ in both entire and PSM cohorts, resulting in the latter 8%, 15%, 20%, and 26% in the nonsubcapsular group vs. 13%, 24%, 30%, and 31% in the subcapsular group (p = 0.015), and 99%, 91%, 80%, and 59% vs. 98%, 85%, 73%, and 50% in the two groups (p = 0.004), respectively.

CONCLUSION

Rates of major complications, LTP, and OS differed significantly following first-line RFA treatment of single HCCs ≤ 3 cm in favor of the nonsubcapsular locations.

CLINICAL RELEVANCE STATEMENT

This large-scale study provides evidence that radiofrequency ablation for small (≤ 3 cm) hepatocellular carcinomas is safer and more effective in nonsubcapsular location than in subcapsular location.

KEY POINTS

• There exist conflicting outcomes on the effectiveness of RFA for early HCC depending on tumor location. • Rate of local tumor progression was significantly higher in the subcapsular hepatocellular carcinomas. • Overall survival rate was significantly poorer in the subcapsular hepatocellular carcinomas.

Risk factors for the recurrence of early hepatocellular carcinoma treated by percutaneous radiofrequency ablation with a multiple-electrode switching system: a multicenter prospective study

PURPOSE

To investigate the long-term efficacy of radiofrequency ablation (RFA) with a multiple-electrode switching system (MESS) in the treatment of early hepatocellular carcinoma (HCC) and evaluate the patterns and risk factors of intrahepatic recurrence of HCC after RFA.

METHODS

In total, 139 patients with early HCC who underwent RFA with MESS as primary treatment at multiple centers were prospectively enrolled according to the inclusion criteria. We evaluated the local tumor progression (LTP), intrahepatic distant recurrence (IDR), the incidence of cumulative disease-free survival (DFS), LTP-free survival, IDR-free survival, and overall survival. We also analyzed the associated risk factors.

RESULTS

A total of 139 patients were included in the study and the median follow-up time was 64 months, ranging from 11 to 72 months. The complete ablation rate was 98.56%. Sixty-nine (49.64%) were found to have intrahepatic recurrence (LTP, n = 15; IDR, n = 55) during follow-up. The 1-year, 3-year and 5-year cumulative DFS, LTP-free survival, and IDR-free survival rates were 74.82, 94.46 and 78.75%; 54.68, 88.03 and 61.79%; and 51.80, 85.67 and 60.17%, respectively. In the multivariable analysis, tumor size > 4 cm was the only important risk factor for LTP. The alkaline phosphatase (ALP) level and the number of tumors were independent risk factors for IDR; α-fetoprotein (AFP) level > 400 µg/L and recurrence interval were risk factors for the overall survival period.

CONCLUSIONS

The MESS-RFA is an effective method for local control of tumors in early HCC. Early HCC with multiple high-ALP tumors has a higher rate of recurrence, which mainly occurs in an IDR pattern. Early HCC with high AFP levels and a shorter initial recurrence interval resulted in a poorer prognosis. Thus, treatments such as liver transplantation or surgical resection may be a good strategy in those cases.

CLINICALTRIALS.GOV ID

NCT02046356.

Contemporary evidence on colorectal liver metastases ablation: toward a paradigm shift in locoregional treatment

Image-guided percutaneous ablation techniques represent an attractive local therapy for the treatment of colorectal liver metastases (CLM) given its low risk of severe complications, which allows for early initiation of adjuvant therapies and spare functional liver parenchyma, allowing repeated treatments at the time of recurrence. However, ablation does not consistently achieve similar oncological outcomes to surgery, with the latter being currently considered the first-line local treatment modality in international guidelines. Recent application of computer-assisted ablation planning, guidance, and intra-procedural response assessment has improved percutaneous ablation outcomes. In addition, the evolving understanding of tumor molecular profiling has brought to light several biological factors associated with oncological outcomes following local therapies. The standardization of ablation procedures, the understanding of previously unknown biological factors affecting ablation outcomes, and the evidence by ongoing prospective clinical trials are poised to change the current perspective and indications on the use of ablation for CLM.

Hepatocellular carcinoma: metastatic pathways and extra-hepatic findings

Although a small portion of patients with hepatocellular carcinoma (HCC) have radiologically evident extrahepatic disease at the initial presentation, a larger number of them develop metastatic disease later during the course of treatment or after definitive treatment. Furthermore, early metastatic disease could be overlooked by imaging due to small size and non-specificity of findings. Extrahepatic spread of HCC occurs via different pathways and is directly fueled by tumor biology and its molecular characteristics. Early and accurate detection of extrahepatic disease in patients with HCC has significant impact on management and selection of treatment options. Additionally, precise staging of disease will allow for better prediction of survival and outcome. Different pathways of regional and systemic spread of HCC with their proposed mechanisms and relevant underlying molecular derangement will be discussed in this article. Potential roles in management of patients with HCC will be discussed and reviewed in this article.

Radiofrequency ablation of surface v/s intraparenchymal hepatocellular carcinoma in cirrhotic patients

Objective

To retrospectively evaluate the safety and technical efficacy of percutaneous radiofrequency ablation (RFA) of surface hepatocellular carcinoma (HCC) in comparison to intraparenchymal HCC in cirrhotic patients.

Materials and Methods

Surface lesions were defined as tumours located or reaching within 1cm of liver capsule including exophytic lesions. Seventy-four surface HCC including 21 exophytic in 58 patients (surface group) and 60 intraparenchymal HCC in 54 patients (intraparenchymal group) measuring up to 4 cm in maximum extent underwent percutaneous [ultrasound (US) or computed tomography-guided (CT-guided)] RFA. The response to the treatment was assessed by contrast enhanced CT/magnetic resonance imaging (MRI) done at 1, 3, 6, 9, and 12 months of RFA and thereafter every 4-6 months. In case of features suggesting residual disease, a repeat RFA was performed. The technical success after single-session RFA, complications and disease recurrence rates were calculated and compared between two groups.

Results

Technical success achieved after first session of RFA in surface HCC was 95% (70/74) and intraparenchymal HCC was 97% (58/60). Hundred percent secondary success rate was achieved in both groups after second repeat RFA in residual lesion. No major difference in complication and local recurrence rate in both group on follow-up in surface HCC and intraparenchymal HCC. No case of needle track, peritoneal seeding, and treatment mortality was found.

Conclusions

The complication rate and efficacy of RFA for surface and exophytic HCC's were comparable to that of intraparenchymal HCC. Hence surface and exophytic lesions should not be considered a contraindication for RFA in cirrhotic patients.

Periprocedural risk factors for incomplete radiofrequency ablation of liver metastases from colorectal cancer: a single-center retrospective analysis

OBJECTIVE

To explore independent risk factors for incomplete radiofrequency ablation (iRFA) of colorectal cancer liver metastases (CRLM) and evaluate adverse outcomes following iRFA.

MATERIALS AND METHODS

Magnetic resonance imaging data of CRLM patients who received percutaneous RFA were randomized into training (70%) and validation set 1 (30%) data sets. An independent validation set 2 was derived from computed tomography scans. Uni- and multivariate analyses identified independent risk factors for iRFA. Area under the curve (AUC) values were used to evaluate the predictive model performance. Risk points were assigned to independent predictors, and iRFA was predicted according to the total risk score. Kaplan-Meier curves were used to assess new intrahepatic metastases (NIHM), unablated tumor progression, and overall survival (OS).

RESULTS

Multivariate regression determined as independent iRFA risk factors perivascular tumor location, subcapsular tumor location, tumor size ≥20 mm, and minimal ablative margin ≤5 mm. The AUC values of the model in the training set, validation set 1, and validation set 2 were 0.867, 0.772, and 0.820, respectively. The respective AUC values of the total risk score were 0.864, 0.768, and 0.817. During the 6-year follow-up, the cumulative OS was significantly shorter in the iRFA than in the complete RFA group, and NIHM (hazard ratio [HR] = 2.79; 95% confidence interval [CI]: 1.725, 4.513) and unablated tumor progression (HR = 3.473; 95% CI: 1.506, 8.007) were more severe.

CONCLUSIONS

Perivascular tumor location, subcapsular tumor location, tumor size ≥20 mm, and minimal ablative margin ≤5 mm were independent risk factors for iRFA. iRFA may be a potential predictor of NIHM, unablated tumor progression, and OS.

Comparison of Percutaneous Radiofrequency Ablation for Subcapsular and Non-Subcapsular Colorectal Cancer Liver Metastases

Purpose

To evaluate the efficacy and safety of percutaneous radiofrequency ablation (RFA) for subcapsular colorectal cancer liver metastases (CLMs).

Materials and Methods

With the approval of the Institutional Review Board, the clinical data of CLM patients who underwent percutaneous RFA for the first time from August 2010 to August 2020 were continuously collected. All CLMs were divided into subcapsular and non-capsular groups. Baseline characteristic data, technical effectiveness, minimal ablative margin, complications, local tumor progression (LTP), and overall survival (OS) between the two groups were analyzed using the t-test or chi-square test. A Cox regression model was used to evaluate the prognostic factors of LTP.

Results

One hundred and ninety-nine patients (124 males; mean age, 60.2 years) with 402 CLMs (221 subcapsular; mean size, 16.0 mm) were enrolled in the study. Technical effectiveness was achieved in 93.5% (376/402) of CLMs, with a major complication rate of 5.5%. Compared with non-subcapsular tumors, the minimal ablative margin achieved in subcapsular CLM was smaller (χ² = -8.047, P < 0.001). With a median follow-up time of 23 months (range, 3−96 months), 37.1% of the tumors had LTP. The estimated cumulative OS at 1, 3, and 5 years was 96.1%, 66.0%, and 44.2%, respectively. There were no statistically significant differences between the two groups in terms of technical effectiveness (χ² = 0.484, P = 0.487), major complications (χ² = 0.082, P = 0.775), local tumor progression-free survival (LTPFS) (χ² = 0.881, P = 0.348), and OS (χ² = 2.874, P = 0.090). Minimal ablative margin, tumor size (≥20 mm), and technical effectiveness were predictors of LTP (all P < 0.05).

Conclusion

RFA is a safe and effective technique for local tumor control of subcapsular CLMs.

A new predictor of bleeding based on ultrasonographic features in percutaneous liver mass biopsy

Background/aim

An ultrasound-guided liver mass biopsy is a method frequently used in determining the diagnosis and treatment plan.The aim of this study was to evaluate the potential new predictors of bleedingbased on ultrasonographic features in liver mass biopsies, which are frequently applied in routine clinical practice.

Materials and methods

The images and data of patients aged over 18years,who underwent an imaging-guided percutaneous liver mass biopsy between January 2018 and December 2019 with various indications, were retrospectively reviewed. Liver size, liver steatosis status, parenchyma appearance, and mass vascularity on Doppler ultrasonography before the procedure, and hemoglobin (Hb) values before and after the procedure were recorded.

Results

A total of 176 patients were included in the study. Ninety-six patients were male (54.5%) and 80 were female (45.5%). The mean age of the patients was 64 ± 12.3 years. The mean hemoglobin values of the patients were 11.5 ± 1.9 gr/dL before the procedure and 11.4 ± 1.5 gr/dL after the procedure. While 144 of the patients had less than 10% hemoglobin decrease (81.8%), 32 had more than 10% decrease (8.2%). In 56 patients, a heterogeneous and coarse granular pattern was observed in the liver parenchyma (31.8%). The decrease in the Hb rate was significantly higher in patients with heterogeneous and coarse granular liver parenchyma (8.7%) than in patients with normal parenchyma (6.6%) (P = 0.036).

Conclusion

In our study, it was shown for the first time in the literature that the ultrasonographic appearance of the liver (heterogeneous and coarse granular parenchyma) may also be one of the parameters that can help to predict the risk of bleeding.

Percutaneous cryoablation of subcapsular hepatocellular carcinoma: a retrospective study of 57 cases

PURPOSE This study aims to evaluate the safety and effectiveness of the percutaneous cryoablation for subcapsular hepatocellular carcinoma (HCC). METHODS A total of 57 patients with subcapsular (<1 cm form the liver edge) HCCs (68 lesions), who were treated with CT-guided percutaneous cryoablation in the Department of Interventional Radiology of our hospital between July 1, 2016 and September 1, 2018, were retrospectively included. Complete ablation rate, local tumor progression (LTP) and treatment-related complications were evaluated. Furthermore, the degree of intraoperative and postoperative pain was measured with the visual analog scale (VAS), and laboratory findings were compared before and after the procedure. RESULTS All patients successfully completed the treatment. The mean follow-up period was 12.8 months (range, 3-27 months), and the complete ablation rate was 97% (66/68). Local tumor progression occurred in 11 lesions (16.2%), and the 6-, 12- and 18-month cumulative LTP rates were 4.0%, 8.2% and 20.5%, respectively. Two patients (3.5%, 2/57) developed major complications, and 12 patients had minor complications (22.8%, 12/57). The mean VAS score during the operation was 1.65 points (range, 1-3 points). Postoperative pain worsened in 3 patients, and the VAS scores reached 4-5. Transient changes in biochemical and hematologic markers were observed. CONCLUSION Percutaneous cryoablation for subcapsular HCC is safe and effective, the procedure is simple and the patients suffer less pain.

Ten-Year Outcomes of Percutaneous Radiofrequency Ablation for Colorectal Cancer Liver Metastases in Perivascular vs. Non-Perivascular Locations: A Propensity-Score Matched Study

Purpose

To compare long-term outcomes of percutaneous radiofrequency ablation for colorectal liver metastases in perivascular versus non-perivascular locations.

Methods

This retrospective study included 388 consecutive patients with colorectal liver metastases (246 men, 142 women; age range 27–86 years) who underwent percutaneous radiofrequency ablation between January 2006 and December 2018. Propensity-score matching was performed for groups with perivascular and non-perivascular colorectal liver metastases. Rates of accumulative local tumor progression, overall survival, intra/extrahepatic recurrence, and complications were compared between the two groups.

Results

We successfully matched 104 patients each in the perivascular and non-perivascular groups (mean age: 60.1 ± 11.5 and 60.1 ± 11.3 years, respectively). Cumulative local tumor progression rates at 6 months, 1 years, 3 years, and 5 years, respectively, were 8.8%,14.8%, 18.9%, and 18.9% in the perivascular group and 8.8%, 13.1%, 15.5%, and 15.5% in the non-perivascular group. The 1-, 3-, 5-, and 10-year overall survival rates, respectively, were 91.3%, 45.6%, 23.9%, and 18.7% in the perivascular group and 88.0%, 47.2%, 27.2%, and 22.6% in the non-perivascular group. No significant between-group differences were detected in cumulative local tumor progression (p=0.567, hazard ratio: 1.224) or overall survival (p = 0.801, hazard ratio: 1.047). The major complication rate was 1.0% (1/104, p > 0.999) in both groups. Tumor size was the only independent prognostic factor for local tumor progression (hazard ratio: 2.314; p = 0.002). On multivariate analysis for overall colorectal liver metastases, tumor diameter >3 cm, tumor location in the right colon, multiple tumors, and extrahepatic metastases before radiofrequency ablation (hazard ratios: 2.046, 1.920, 1.706, and 1.892, respectively; all p < 0.001) and intrahepatic recurrence (hazard ratio: 1.564; p = 0.002) were associated with poor overall survival.

Conclusion

Cumulative local tumor progression, overall survival, and major complications rates did not differ significantly between perivascular and non-perivascular colorectal liver metastases after percutaneous radiofrequency ablation. For perivascular colorectal liver metastases, percutaneous radiofrequency ablation is a safe and effective treatment option.

Percutaneous thermal ablation of subcapsular hepatocellular carcinomas: influence of tumor-surface contact and protrusion on therapeutic efficacy and safety

PURPOSE

To evaluate therapeutic efficacy and complication of percutaneous thermal ablation of subcapsular hepatocellular carcinomas (HCCs), and how these may be influenced by the degree of tumor to liver surface contact and tumor protrusion from liver surface.

MATERIALS AND METHODS

Our retrospective study was approved by the Institutional Review Board. Between January 2006 and December 2013, 290 patients (82 women, 208 men; mean age, 64.5 years; range, 33-89 years) with 474 subcapsular (within 1 cm to the liver surface) HCCs (mean size, 23.7 mm; range, 6-71 mm) underwent percutaneous thermal ablation. The HCCs were divided into surface contact group (n = 243) and non-surface contact group (n = 231). The former was further subdivided into exophytic and non-exophytic HCCs. Technical success, primary technique efficacy, local tumor progression (LTP), and secondary technique efficacy rates were analyzed and compared by the chi-square test or Fisher exact test. Prognostic factors for LTP and secondary technique efficacy were assessed using the Cox regression model. Major complications were also assessed.

RESULTS

With median follow-up of 15 months (range, 1-87 months), technical success and primary technique efficacy were 98.7% and 95.7% % in the non-surface contact group; 96.4% and 94.0% in the non-exophytic group; and 100% and 94.7% in the exophytic group (p > 0.05). Tumor size > 3 cm was a significant predictor for LTP, but not for secondary efficacy. Overall major complication rate was 3.8% (24/624) and was not different among the three groups.

CONCLUSION

Subcapsular HCCs can be effectively treated with thermal ablation techniques. Degree of tumor-surface contact including moderate protrusion does not appear to limit feasibility or procedure effectiveness.

KEY POINTS

• Subcapsular HCCs can be effectively treated with thermal therapy when proper image-guided technique and assistive techniques are applied. • Degree of tumor surface contact including moderate protrusion does not appear to limit feasibility or procedure effectiveness. • Major complications after percutaneous thermal ablation of subcapsular HCCs such as tumor seeding can be minimized by avoiding breach of the tumor capsule exposed to the peritoneal surface and use of tract ablation.

No-Touch Multi-bipolar Radiofrequency Ablation for the Treatment of Subcapsular Hepatocellular Carcinoma ≤ 5 cm Not Puncturable via the Non-tumorous Liver Parenchyma

PURPOSE

The percutaneous ablation of subcapsular hepatocellular carcinoma (S-HCC) may involve a risk of complications such as hemorrhage and tumor seeding, mainly linked to the direct tumor puncture often inevitable with mono-applicator ablation devices. The purpose of this study was to assess the efficacy and safety of no-touch multi-bipolar radiofrequency ablation (NTMBP-RFA) for the treatment of S-HCC ≤ 5 cm not puncturable via the non-tumorous liver parenchyma.

MATERIALS AND METHODS

Between September 2007 and December 2014, 58 consecutive patients (median age: 63 years [46-86], nine females) with 59 S-HCC ≤ 5 cm (median diameter: 25 mm [10-50 mm]), not puncturable via the non-tumorous liver parenchyma, were treated with NTMBP-RFA. Response and follow-up were assessed by CT or MRI. Complications were graded using the Cardiovascular and Interventional Radiological Society of Europe classification. Overall local tumor progression (OLTP)-free survival was assessed using the Kaplan-Meier method. A Cox proportional model evaluated the factors associated with OLTP. Signs of peritoneal or parietal tumor seeding were noted during follow-up imaging studies.

RESULTS

A complete ablation was achieved in 57/58 patients (98.3%) after one (n = 51) or two (n = 6) procedures. Three patients (5.2%) experienced complications (sepsis, cirrhosis decompensation; CIRSE grade 2 or 3). After a median follow-up period of 30.5 months [1-97], no patients had tumor seeding. The 1, 2 and 3-year OLTP-free survival rates were 98%, 94% and 91%, respectively. No factors were associated with OLTP.

CONCLUSION

NTMBP-RFA is a safe and effective treatment for S-HCC not puncturable via the non-tumorous liver parenchyma.

Percutaneous microwave ablation of exophytic tumours in hepatocellular carcinoma patients: Safe or not?

BACKGROUND & AIMS

To explore the long-term outcomes and safety of ultrasound-guided percutaneous microwave ablation (MWA) of exophytic tumours in hepatocellular carcinoma (HCC) patients.

METHODS

One hundred and thirty-two patients with subcapsular HCC were enrolled in this retrospective study. These patients were divided into the exophytic group (n=71) and non-exophytic group (n=61) according to the location of the tumour(s). A special technology of puncture and ablation was performed to treat the exophytic tumours. The local tumour progression (LTP), progression free survival (PFS) and overall survival (OS) were analysed using Kaplan-Meier and Log-rank tests.

RESULTS

Sixty-nine of 71 exophytic tumours and 60 of 61 subcapsular tumours were completely ablated. The complete ablation rates were 97.2% and 98.4% respectively. The follow-up periods ranged from 6 to 62 months with a median of 31 months in the exophytic group, and ranged from 5 to 61 months, with a median of 27 months in the non-exophytic group. The 1-, 3- and 5-year cumulative LTP rates were 2.4%, 12.3%, 18.4% and 5.1%, 12.0%, 17.8% in the exophytic and non-exophytic groups respectively (P=.733). The 1-, 3- and 5-year OS rates were 100%, 75.7%, 52.9% and 95.0%, 73.8%, 61.5% in the exophytic group and non-exophytic group respectively (P=.980). There was no procedure-related mortality or major complication.

CONCLUSION

Ultrasound-guided percutaneous MWA is safe and effective for exophytic tumours in HCC patients. Treated by MWA, the HCC patients with exophytic tumours can get the similar local response and long-term outcome to those with non-exophytic subcapsular tumours.

Early outcomes of radiofrequency ablation in unresectable metastatic colorectal cancer from a tertiary cancer hospital in India

AIMS

The study was carried out to evaluate the early outcomes using Radiofrequency Ablation (RFA) for unresectable liver metastases in the management of metastatic colorectal cancer (mCRC) from an area of low endemicity.

MATERIAL AND METHODS

60 Patients with unresectable colorectal liver metastases had undergone 88 sessions of RFA from January 2007 till December 2013. The results were retrospectively analysed to evaluate the outcomes in terms of efficacy and survival rates.

RESULTS

The median follow up of patients in our series was 24.8months. 35/52 (67.3%) patients had complete response at 3 months while 8 patients were lost to follow up. Of the 17 patients who had recurrence, 4 (23.5%) were at the ablated site while 13 patients (76.4%) progressed elsewhere. Abdominal pain was commonest post procedural symptom (20%). There was no procedure related mortality or any major complications. Mean disease free interval and Progression free survival was 6.7 and 13.1 months. Estimated median survival in patients with liver limited disease and those with small lesion (<3cm) was 3.79 years and 3.45 years respectively. Median survival in patients with lesion size 3-5 cms was 1.5 years. Annual survival rates would be 94.5%, 55.2% and 26.2% for 1, 3 and 5 years.

CONCLUSION

Radiofrequency ablation of unresectable liver metastases is effective in treatment of mCRC. Estimated survival rates and Annual survival rates at our institute from the low endemic region also follow the global trend. Size of the lesion was an important predictor of efficacy of RFA. Presence of extrahepatic disease and lesion size >3 cm was associated with decreased survival.

Laser ablation of liver tumors: An ancillary technique, or an alternative to radiofrequency and microwave?

Radiofrequency ablation (RFA) is currently the most popular and used ablation modality for the treatment of non surgical patients with primary and secondary liver tumors, but in the last years microwave ablation (MWA) is being technically improved and widely rediscovered for clinical use. Laser thermal ablation (LTA) is by far less investigated and used than RFA and MWA, but the available data on its effectiveness and safety are quite good and comparable to those of RFA and MWA. All the three hyperthermia-based ablative techniques, when performed by skilled operators, can successfully treat all liver tumors eligible for thermal ablation, and to date in most centers of interventional oncology or interventional radiology the choice of the technique usually depends on the physician’s preference and experience, or technical availability. However, RFA, MWA, and LTA have peculiar advantages and limitations that can make each of them more suitable than the other ones to treat patients and tumors with different characteristics. When all the three thermal ablation techniques are available, the choice among RFA, MWA, and LTA should be guided by their advantages and disadvantages, number, size, and location of the liver nodules, and cost-saving considerations, in order to give patients the best treatment option.

Embolization for Bleeding after Hepatic Radiofrequency Ablation

PURPOSE

To evaluate safety and clinical efficacy of embolization for management of bleeding after hepatic radiofrequency (RF) ablation.

MATERIALS AND METHODS

From January 2000 to December 2014, 5,196 patients with 9,743 tumors underwent 8,303 RF ablation sessions. Of these patients, 62 experienced bleeding after hepatic RF ablation; 15 patients (12 men and 3 women; mean age 62 y; range, 49-76 y) underwent embolization and composed the final study cohort. Tumors were hepatocellular carcinomas in 13 (87%) patients and metastatic adenocarcinomas from colorectal cancer in 2 (13%) patients. Mean number of tumors was 1.5 (22 nodules; range, 1-3). Tumor locations were segment I (n = 1), segment II (n = 2), segment III (n = 1), segment IV (n = 1), segment V (n = 3), segment VI (n = 5), segment VII (n = 1), and segment VIII (n = 9). Mean tumor size was 2.3 cm (range, 0.9-5 cm).

RESULTS

Median time interval between presentation and angiography was 22 hours (mean 38.4 h; range, 3-168 h). On angiography, contrast extravasation with or without pseudoaneurysm was seen in all 15 patients; 14 patients underwent transarterial embolization, and 1 patient underwent percutaneous transhepatic portal vein embolization. Successful hemostasis was achieved in all patients. There was no rebleeding within 30 days after embolization. No embolization-related major complications were observed.

CONCLUSIONS

Embolization is safe and effective for controlling bleeding related to hepatic RF ablation without the need for surgery.

Angled Cool-Tip Electrode for Radiofrequency Ablation of Small Superficial Subcapsular Tumors in the Liver: A Feasibility Study

Objective

To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin.

Materials and Methods

In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25–35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10–26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications.

Results

Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3–12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21–1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients.

Conclusion

Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate.

Cryoablation of Hepatocellular Carcinoma with High-Risk for Percutaneous Ablation: Safety and Efficacy

PURPOSE

The aim of this study was to evaluate the safety and effectiveness of cryoablation in the treatment of subcapsular hepatocellular carcinoma (HCC) adjacent to various organs.

MATERIALS AND METHODS

Twenty-eight patients with subcapsular HCC were treated with cryoablation in our institution. The degree of peri-procedural pain was measured using the visual analog scale (VAS). Technical success, local tumor progression, and overall disease progression rates were calculated. Procedure-related complications were identified by reviewing electronic medical records. Biochemical data, including serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin levels before and after the procedure were collected.

RESULTS

Subcapsular HCC tumors were located near the gallbladder, colon, stomach, kidney, diaphragm, or abdominal wall. The technical success rate of cryoablation was 96.4 % (27/28). Local recurrence- and progression-free survival rates were 96 and 84 % at 6 months, and 82 and 43 % at 1 year, respectively. All patients survived during the follow-up period. The VAS pain score ranged from 0 to 3 (mean, 1.57). A major complication occurred in one patient (3.6 %) and minor complications occurred at a rate of 17.9 %. Transient elevations of serum AST, ALT, and bilirubin levels were observed.

CONCLUSION

Cryoablation is a safe and an effective procedure for the treatment of subcapsular HCC adjacent to various major organs.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Long-term Therapeutic Outcomes of Radiofrequency Ablation for Subcapsular versus Nonsubcapsular Hepatocellular Carcinoma: A Propensity Score Matched Study

Purpose To compare the long-term therapeutic outcomes of radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) in subcapsular versus nonsubcapsular locations by using propensity score matching. Materials and Methods RF ablation for subcapsular HCC is controversial because of a high risk of incomplete ablation or major complications. This retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. Between April 2006 and December 2011, 508 consecutive patients (396 men, 112 women; age range, 30-80 years) with a single HCC (Barcelona Clinic Liver Cancer stage 0 or A) underwent ultrasonography-guided percutaneous RF ablation as a first-line treatment. The patients were divided into two groups according to tumor location: subcapsular (n = 227) and nonsubcapsular (n = 281). Subcapsular HCC was defined as an index tumor located within 0.1 cm of the liver capsule. The association of subcapsular location and therapeutic outcomes of RF ablation was evaluated, including (a) local tumor progression (LTP) by using a competing risk regression model and (b) overall survival (OS) by using a Cox proportional hazards model according to propensity score matched data. The major complication rates from both overall data and matched data were assessed. Results Matching yielded 163 matched pairs of patients. In the two matched groups, cumulative LTP rates were 18.8% and 20.9% at 3 and 5 years, respectively, in the subcapsular group and 13.2% and 16.0% in the nonsubcapsular group. Corresponding OS rates were 90.7% for 3 years and 83.2% for 5 years in the subcapsular group and 91.4% and 79.1%, respectively, in the nonsubcapsular group. Hazard ratios (HRs) for LTP (HR = 1.37, P = .244) and OS (HR = 0.86, P = .604) were not significantly different between the two matched groups. Additionally, differences in major complication rates were not significant between groups for the two sets of data (P > .05). Conclusion The differences in LTP, OS, and major complication rates of RF ablation for HCC were not significant between subcapsular and nonsubcapsular groups. (©) RSNA, 2016.

Application of the Barcelona Clinic Liver Cancer therapeutic strategy and impact on survival

BACKGROUND

The Barcelona Clinic Liver Cancer (BCLC) classification of hepatocellular carcinoma (HCC) has proved useful in the management of HCC patients. However, BCLC-recommended first-line treatment is not always applicable in clinical practice.

OBJECTIVE

We performed a multicentre retrospective analysis of reasons for deviation from first-line treatment in 2008-2012.

METHODS

One to three-year survival data were analysed using Kaplan-Meier method.

RESULTS

A total of 407 consecutive HCC patients (66.6 ± 3 years, 83% male) with cirrhosis were included. Tumours were detected during surveillance in 53% of patients, grouped as Child-Pugh A (67%), B (25%) and C (8%); and BCLC A (including stage 0, 44%), B (26%), C (15%) and D (15%). In 31% of patients, first-line treatment was not feasible (51% in early stages) due to: technical reasons (74%); patient non-conformity (20%); medical decision (3%); and disease progression (3%). One to three-year survival of patients not receiving the recommended first-line treatment was similar to that of patients treated according to BCLC recommendations (log-rank, p = 0.229).

CONCLUSION

In real-life practice one-third of HCC patients could not receive first-line BCLC treatment. In our cohort of patients, similar short and medium-term survival was observed. Long-term prospective studies are required to determine the best alternative treatment option when BCLC first-line treatment is not feasible.

Complications after percutaneous ablation of liver tumors: a systematic review

BACKGROUND

Although ablation therapy has been accepted as a promising and safe technique for treatment of unrespectable hepatic tumors, investigation of its complications has been limited. A physician who performs ablation treatment of hepatic malignancies should be aware of the broad spectrum of complications. Proper management is possible only if the physician Performing ablation understands the broad spectrum of complications encountered after ablation.

OBJECTIVES

TO SYSTEMATICALLY REVIEW THE COMPLICATIONS AFTER DIFFERENT ABLATION MODALITIES: Radiofrequency ablation (RFA), microwave ablation (MWA) and Nano knife for the treatment of liver tumors and analyze possible risk factors that precipitate these complications.

SEARCH METHODS

WE PERFORMED ELECTRONIC SEARCHES IN THE FOLLOWING DATABASES: MEDLINE, EMBASE and COCHARNE. Current trials were identified through the Internet (from January 1, 2000 to January 1, 2014). We included only studies who specific mentioned complications after liver ablation therapy (RFA/MWA/Nano knife).

MAIN RESULTS

A total of 2,588 publications were identified, after detailed examination only 32 publications were included in the review. The included studies involved 15,744 participants. According to the type of technique, 13,044 and 2,700 patients were included for RFA and MWA. Analysis showed a pooled mortality of 0.15% for RFA, and 0.23% for MWA.

CONCLUSIONS

This systematic review gathers information from controlled clinical trials and observational studies which are vulnerable to different types of bias, never the less RFA and MWA can be considered safe techniques for the treatment of liver tumors.

Various complications of percutaneous radiofrequency ablation for hepatic tumors: radiologic findings and technical tips

Radiofrequency ablation is a safe and effective treatment for primary and secondary liver malignancies and has a low complication rate; however, there are various radiofrequency ablation-related complications which can occur from the thorax to the pelvis. Although most of these complications are usually minor and self-limited, they may become fatal if diagnosis and treatment are delayed. It is important for radiologists performing radiofrequency ablation to have a perspective regarding the possible radiofrequency ablation-related complications and their risk factors as well as the radiologic findings for their timely detection and increase of the treatment efficacy, and thereby encouraging the use of the radiofrequency ablation technique. This article illustrates the various imaging features of common and rare radiofrequency ablation-related complications as well as offers technical tips in order to avoid these complications.

Radiofrequency ablation of liver tumors

Radiofrequency ablation (RFA) is an alternative therapy for hepatocellular carcinoma and liver metastases when resection cannot be performed or, in the case of hepatocellular carcinoma, when transplant cannot be performed in a timely enough manner to avoid the risk of dropping off the transplant list. RFA has the advantage of being a relatively low-risk minimally invasive procedure used in the treatment of focal liver tumors. This review article discusses the current evidence supporting RFA of liver tumors, as well as the indications, complications, and follow-up algorithms used after RFA.

Ablative margin states by magnetic resonance imaging with ferucarbotran in radiofrequency ablation for hepatocellular carcinoma can predict local tumor progression

BACKGROUND

Our aim was to determine how well ablative margin (AM) grading assessed by magnetic resonance imaging (MRI) with ferucarbotran administered prior to radiofrequency ablation (RFA) predicts local tumor progression in comparison with enhanced computed tomography (CT).

METHODS

101 hepatocellular carcinomas were treated by RFA after ferucarbotran administration. We performed T2*-weighted MRI after 1 week and enhanced CT after 1 month. The assessment was categorized in three grades: AM(+): high-intensity area with continuous low-intensity rim; AM zero: high-intensity area with discontinuous low-intensity rim; and AM(-): high-intensity area extending beyond the low-intensity rim.

RESULTS

AM(+), AM zero, AM(-) and indeterminable were found in 47, 36, 8 and 10 nodules, respectively. The overall agreement rate between MRI and enhanced CT for the diagnosis of AM was 71.3%. The κ coefficient was 0.523 (p < 0.001), indicating moderate agreement. Multivariate logistic regression showed that a significant factor for the achievement of AM(+) on MRI was only segment location (odds ratio 5.9, non-segment 4 + 8 vs. segment 4 + 8). The cumulative local tumor progression rates (4.4, 7.6, and 7.6% in 1, 2, and 3 years) in 47 AM(+) nodules were significantly lower than those (13.9, 33.4, and 41.8% in 1, 2, and 3 years) in 36 AM zero nodules. A multivariate Cox proportional hazards model identified contiguous vessels (odds ratio 12.0) and AM(+) on MRI (odds ratio 0.19) as independent factors for local tumor progression.

CONCLUSION

AM assessment by MRI using ferucarbotran can predict local tumor progression after RFA and enable early and less invasive diagnosis.

Diaphragmatic perforation with colonic herniation due to hepatic radiofrequency ablation: A case report and review of the literature

Radiofrequency ablation (RFA) has been widely accepted as an alternative treatment for unresectable primary and metastatic hepatic tumors, with satisfactory rates of local response and significant improvements in rates of overall survival. Numerous large series studies have shown that RFA is safe and effective, with a low mortality rate and a low major complication rate. Major complications, including diaphragmatic perforation and hernia, have rarely been previously reported. The current case report presents a case of diaphragmatic hernia with perforation of the incarcerated colon in the thoracic cavity 12 months following hepatic RFA, and reviews nine previously reported cases of diaphragmatic hernia. Comprehensive analysis of the nine cases demonstrated possibilities leading to diaphragmatic hernia following diaphragmatic thermal injury as a consequence of hepatic RFA. Clinicians and radiologists must consider diaphragmatic thermal damage following hepatic RFA for liver tumors adjacent to the diaphragm, particularly for patients with symptoms of ileus, dyspnea, chest pain, pleural effusion and right shoulder pain.

First-line radiofrequency ablation with or without artificial ascites for hepatocellular carcinomas in a subcapsular location: local control rate and risk of peritoneal seeding at long-term follow-up

AIM

To compare the long-term local control of hepatocellular carcinoma (HCC) and risk of peritoneal seeding via percutaneous radiofrequency ablation (RFA) using artificial ascites with those of RFA without artificial ascites.

MATERIALS AND METHODS

The Institutional Review Board approved this retrospective study. From April 2005 to February 2008, 160 patients (121 men, 39 women; age range 36-79 years) with a single subcapsular HCC (mean size 2.19 cm) were treated with ultrasonography-guided percutaneous RFA as a first-line therapy. Forty-four patients were treated with RFA using artificial ascites, whereas the other 116 patients were treated without artificial ascites. The cumulative local tumour progression (LTP) and peritoneal seeding were compared in both groups using follow-up computed tomography (CT). Cumulative LTP rates were analysed using the Kaplan-Meier method and the log-rank test. Risk of peritoneal seeding was investigated by means of multivariate analysis.

RESULTS

The overall median follow-up period was 52.5 months (range 13-76 months). The 1, 2, 4, and 6 year cumulative LTP rates were 17.1, 27.6, 35.2, and 35.2%, respectively, in the group with artificial ascites, and 8, 15.2, 26.6, and 34.4% in the group without artificial ascites, without significant difference (p = 0.332). The rates of peritoneal seeding were 6.8% (3/44) in the group with artificial ascites and 2.6% (3/116) in the group without artificial ascites, a non-significant difference (p = 0.347). The biopsy prior to RFA was the independent risk factor of peritoneal seeding regardless of the use of artificial ascites.

CONCLUSION

Long-term local tumour control and risk of peritoneal seeding were comparable for RFA with or without artificial ascites when used as a first-line therapy for subcapsular HCC.

Effectiveness, safety, and local progression after percutaneous laser ablation for hepatocellular carcinoma nodules up to 4 cm are not affected by tumor location

OBJECTIVE

A high-risk location--defined as the tumor margin being less than 5 mm from large vessels or vital structures--represents a well-known limitation and contraindication for radiofrequency ablation of hepatocellular carcinoma (HCC) nodules. The aim of this study was to verify whether HCC nodule location negatively affected the outcome of percutaneous laser ablation in terms of its primary effectiveness, safety, and ability to prevent local tumor progression.

MATERIALS AND METHODS

The medical records and radiologic examinations of 164 cirrhotic patients (90 men, 74 women; mean age ± SD, 68.6 ± 8.3 years) with 182 HCC nodules 4 cm or smaller (mean diameter ± SD, 2.7 ± 0.78 cm) that had been treated by laser ablation between 1996 and 2008 were retrospectively analyzed. One hundred six patients had 116 nodules in high-risk sites (high-risk group), whereas 58 patients had 66 tumors located elsewhere (standard-risk group).

RESULTS

The overall median follow-up was 81 months (range, 6-144 months). The initial complete ablation rate per nodule did not significantly differ between the high-risk group and the standard-risk group (92.2% vs 95.5%, respectively; p = 0.2711). Rates of major complications (high-risk group vs standard-risk group, 1.9% [including one death] vs 0%) and minor complications (5.6% vs 1.0%) were not statistically different between the two groups. Only side effects were recorded significantly more often in high-risk patients than in standard-risk patients (31.5% vs 19.8%; p = 0.049). There was no significant difference in either cumulative incidence of local tumor progression (p = 0.499) or local tumor progression-free survival (p = 0.499, log rank test) between the high-risk group and the standard-risk group.

CONCLUSION

When laser ablation is used to treat small HCC nodules, tumor location does not have a significant negative impact on the technique's primary effectiveness or safety or on its ability to achieve local control of disease.

Percutaneous radiofrequency ablation using internally cooled wet electrodes for the treatment of hepatocellular carcinoma

OBJECTIVE

The objective of our study was to evaluate the efficacy and safety of percutaneous radiofrequency ablation (RFA) using internally cooled wet electrodes in patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

From March 2008 to October 2010, 122 patients with 129 HCCs (mean size, 2.2 ± 0.6 [SD] cm; range, 0.7-4 cm) were treated with RFA using internally cooled wet electrodes. Primary technical effectiveness, the frequency of major complications, and local tumor progression rates were evaluated.

RESULTS

Two patients (2%) had major complications (liver abscess, significant pleural effusion) after RFA. When evaluated 1 month after RFA, the primary technical effectiveness rate was 99%. The 1- and 2-year local tumor progression rates were 8% and 12%, respectively. Additionally, there was no difference in effectiveness and complication rates between patients with subcapsular HCC and those with nonsubcapsular HCC.

CONCLUSION

Percutaneous RFA using internally cooled wet electrodes is safe and provides successful local tumor control in patients with HCC. The safety and effectiveness of RFA using internally cooled wet electrodes are comparable to those reported in the literature using conventional RFA electrodes and are similar for nonsubcapsular and subcapsular tumors.

Percutaneous radiofrequency ablation using internally cooled wet electrodes for treatment of colorectal liver metastases

AIM

To evaluate the efficacy and safety of internally cooled wet (ICW) electrodes, which provide interstitial infusion of saline and intra-electrode cooling simultaneously, in the percutaneous radiofrequency ablation (RFA) of liver metastases from colorectal cancer.

MATERIALS AND METHODS

From February 2008 to October 2010, 27 patients with 35 hepatic metastatic lesions (mean size 1.99cm; range 0.7-3.8cm) underwent RFA using ICW electrodes. Of these 35 tumours, 32 had diameters ≤3cm, and three had diameters of 3-4cm. Moreover, 18 tumours were non-subcapsular and 17 were subcapsular.

RESULTS

No patients (0%) had major complications after RFA. During follow-up (median 27 months; range 4.5-36 months), 14 of the 35 treated lesions (40%) showed local tumour progression. The local tumour progression-free survival rates at 1 and 3 years were 73 and 56%, respectively. The local tumour progression-free survival period was significantly longer in patients with tumours ≤2cm than >2cm (p<0.001), but did not differ significantly between patients with non-subcapsular and subcapsular tumours (p=0.454). The overall 1 and 3 year survival rates after RFA were 100 and 77%, respectively.

CONCLUSIONS

Percutaneous RFA using ICW electrodes is safe and technically feasible for the treatment of liver metastases from colorectal cancer. It provides effective local tumour control with low complication rates and reduced number of needle placements.

Mortality and complication rates of percutaneous ablative techniques for the treatment of liver tumors: a systematic review

OBJECTIVES

Reported rates of major complications and mortality of radiofrequency ablation (RFA), microwave ablation (MWA) and percutaneous ethanol injection (PEI) for the treatment of liver tumours were substantially heterogeneous among studies. The aim was to analyse the mortality and major complication rates of percutaneous RFA, PEI and MWA.

METHODS

MEDLINE and EMBASE search from January 1982 to August 2010. Randomised clinical trials and observational studies, age >18, more than 50 patients for each technique analysed, studies reporting mortality and major complications were included. Random effects model was performed, with assessment for heterogeneity and publication bias.

RESULTS

Thirty-four studies including 9531, 1185, and 1442 patients for RFA, MWA, and PEI, respectively were included. For all ablative techniques pooled proportion mortality rate was 0.16% (95% confidence interval [CI], 0.10-0.24). Pooled mortality rate associated with RFA, PEI and MWA was 0.15% (0.08-0.23), 0.59% (0.14-1.3) and 0.23% (0.0-0.58) respectively. Pooled proportion of major complications was 3.29% (2.43-4.28). Major complication rates associated with RFA, MWA, and PEI was 4.1% (3.3-5.1), 4.6% (0.7-11.8) and 2.7% (0.28-7.4) respectively.

CONCLUSIONS

Percutaneous RFA, PEI and MWA can be considered safe techniques for the treatment of liver tumours.

Percutaneous radiofrequency ablation for liver tumors: Is it safer and more effective in low-risk areas than in high-risk areas?

AIM

  To evaluate the feasibility and safety of ultrasound-guided radiofrequency ablation (RFA) of hepatic tumors in high-risk areas (in caudate lobe, adjacent to the hilum, capsular surface, gallbladder or diaphragm) in comparison with those in low-risk areas.

METHODS

  A total of 526 patients with hepatic tumor treated with ultrasound-guided cool-tip RFA between October 2001 and October 2008 were included. The patients were divided into two groups according to the tumor location: group I (high-risk areas, 163 patients); group II (low-risk areas, 363 patients). The two groups had similar baseline characteristics. Repeated RFA was adopted if complete ablation (CA) was not achieved.

RESULTS

  In group I, 20 cases had tumors close to the hilum, 11 in the caudate, 79 adjacent to the capsule, 24 near the gallbladder and 29 cases against the diaphragm. The percentage of patients with primary hepatic tumors in group I was higher than that in group 2 (80.4% vs 56.2%, P < 0.01). More patients in group I felt pain (61.3%, 100/163) than in group II (33.1%, 120/363) (P < 0.01). There was no mortality or major complications in either group. No significant differences were found in the CA rate and the minor complications between the two groups.

CONCLUSION

  RESULTS for RFA using cool-tip electrodes for liver tumors in high-risk areas are comparable to those in low-risk areas in the aspects of CA, complications and mortality.