Microwave ablation of hepatic tumors abutting the diaphragm is safe and effective. AJR Am J Roentgenol. 2015;204:197-203. [PMID: 25539257 DOI: 10.2214/ajr.14.12879]

Comparison of Effectiveness and Safety of Microwave Ablation of Colorectal Liver Metastases Adjacent versus Nonadjacent to the Diaphragm

PURPOSE

To compare the effectiveness and safety of percutaneous microwave ablation (MWA) for colorectal liver metastasis (CLM) adjacent versus nonadjacent to the diaphragm.

MATERIALS AND METHODS

This was a retrospective analysis of a prospectively created MWA database, from 2 prospective clinical trials for patients with CLM treated in a single tertiary center from 2012 to 2023. CLM adjacent to the diaphragm was defined as a tumor located <1 cm from the diaphragm. Minimal ablation margin (MM) was calculated with 3-dimensional software using postablation contrast-enhanced computed tomography (CT). Adverse events were assessed with Common Terminology Criteria for Adverse Events (CTCAE) v5.0 classification for 6 months.

RESULTS

Two hundred nine CLMs underwent 191 MWA sessions in 143 patients. Mean tumor diameter was 1.52 cm (SD ± 0.53). Eighty-three of 209 (39.7%) CLMs were adjacent to the diaphragm. There was no difference in local tumor progression-free survival (LTPFS) between CLMs adjacent and nonadjacent to the diaphragm (hazard ratio [HR], 0.65; 95% CI, 0.37-1.16; P = .15). MMs of 5-10 mm and >10 mm were documented in 49.3% versus 46.8% (P = .83) and 21.6% versus 12.6% (P = .16) for CLMs adjacent versus nonadjacent to the diaphragm, respectively. Twelve-month LTPFS was similar between groups (HR, 0.65; 95% CI, 0.37-1.16; P = .15) without local tumor progression for MM of >10 mm. There were 3 Grade IV adverse events: 1 diaphragmatic perforation, 1 liver abscess, and 1 biloma. Pneumothorax was associated with location adjacent to the diaphragm (P < .001) and transpulmonary approach (P < .001). Median length of hospital stay was 2 days (interquartile range [IQR], 1-3 days) for patients who needed thoracostomy (n = 20, 9.6%) compared with 1 day (IQR, 1-8 days) for those who did not, without long-term sequelae.

CONCLUSIONS

MWA of CLM adjacent to the diaphragm is effective and safe, without difference in success and 12-month LTPFS. Pneumothorax was associated with location adjacent to the diaphragm and thoracostomy that resulted in longer hospitalization without long-term sequelae.

A retrospective study of irreversible electroporation for tumors adjacent to perihepatic important structure

Background

Irreversible electroporation has been proved as a feasible and safe method against tumor in liver. However, few studies focused on tumors adjacent to perihepatic important structure like vessels, biliary system and gall bladder. These structures limit the effectiveness of conventional treatments. The aim of this article is to analyze the clinical outcomes of patients with hepatic tumors at the special sites who received IRE treatment and provide reliable evidence for broadening the scope of IRE's clinical application.

Methods

The clinical information of patients who underwent IRE ablation for tumors adjacent to perihepatic important structure between February 2017 and December 2021 was collected and retrospectively analyzed. All patients underwent contrast-enhanced CT or MRI for further evaluation at the 1-month follow-up and every 3 months thereafter. Post-ablation complications, recurrence, progression-free survival and overall survival were evaluated to analyze the prognosis of IRE ablation adjacent to perihepatic important structure. Categorical variables are presented as numbers followed by percentages. Continuous data are presented as the mean ± deviation. The tumor size and IRE ablation size were evaluated by the maximum diameters.

Results

Thirty-two patients who underwent IRE ablation for tumor adjacent to perihepatic important structure were studied in this research. There were 39 lesions in 32 patients treated with IRE ablation. Fourteen of them (35.9%) were located adjacent to the porta hepatis, and 8 of them (20.5%) were located adjacent to the hepatocaval confluence. Subcapsular lesions accounted for 15.4% (6 of 39 lesions). The other 11 lesions were in the para gallbladder (5 of 39 lesions, 12.8%), the caudate lobe (5 of 39 lesions, 12.8%) and the colonic hepatic flexure (1 of 39 lesions, 2.6%). According to the Clavien-Dindo classification system for complications, all relative patients with cancer experienced complications below class III except one patient who developed postoperative hemorrhagic shock and improved after timely treatment. Recurrence in situ was observed in 5 of 32 (15.6%) patients. The median PFS of the patients who received IRE ablation was 384 days, and the median OS was 571 days.

Conclusion

IRE ablation is a feasible and safe treatment strategy for tumors adjacent to perihepatic important structure. With improved equipment, optimized therapeutic parameters and long-term clinical trials, IRE will play an increasingly important role in the treatment of tumors in liver.

Effectiveness and safety of sequential transarterial chemoembolization and microwave ablation for subphrenic hepatocellular carcinoma: A comprehensive evaluation

BACKGROUND

Subphrenic carcinoma has been identified as a significant risk factor for the thermal ablation of intrahepatic tumors, resulting in a high rate of residual tumor recurrence. Some studies have proposed that combination treatment with transarterial chemoembolization (TACE) followed by radiofrequency ablation is both feasible and safe for tumors in the subphrenic region. However, research specifically examining the therapeutic outcomes of combination therapy using TACE and microwave ablation (TACE-MWA) in subphrenic tumors is lacking.

AIM

To evaluate the efficacy and safety of TACE-MWA in patients with subphrenic hepatocellular carcinoma (HCC).

METHODS

Between December 2017 and December 2021, 49 patients diagnosed with HCC ≤ 6 cm, who received TACE-MWA, were included in this retrospective cohort study. These patients were classified into subphrenic and non-subphrenic groups based on the distance between the diaphragm and the tumor margin. The rates of local tumor progression (LTP), progression-free survival (PFS), and overall survival (OS) were compared between the two groups. Complications were evaluated by using a grading system developed by the Society of Interventional Radiology.

RESULTS

After a median follow-up time of 38 mo, there were no significant differences in LTP between the subphrenic and non-subphrenic groups (27.3% and 22.2% at 5 years, respectively; P = 0.66), PFS (55.5% at 5 years in both groups; P = 0.91), and OS (85.0% and 90.9% in the subphrenic and non-subphrenic groups at 5 years; P = 0.57). However, a significantly higher rate of LTP was observed in subphrenic HCC > 3 cm compared to those ≤ 3 cm (P = 0.085). The dosage of iodized oil [hazard ratio (HR): 1.52; 95% confidence interval (CI): 1.11-2.08; P = 0.009] and multiple tumors (HR: 13.22; 95%CI: 1.62-107.51; P = 0.016) were independent prognostic factors for LTP. There were no significant differences in complication rates between the two groups (P = 0.549).

CONCLUSION

Combined TACE and MWA was practical and safe for managing subphrenic HCC. The efficacy and safety levels did not vary significantly when tumors outside the subphrenic region were treated.

Effective and Safe Treatment of Risky Localized Liver Tumors Using Microwave Ablation in Patients with Comorbid Lung Diseases Unfit for Deep Anesthesia

Objective

To assess the safety and efficacy of percutaneous microwave ablation (MWA) in treating high-risk localized liver tumors in patients unable to undergo deep anesthesia because of comorbid lung diseases.

Methods

Between January 2019 and January 2022, percutaneous MWA procedures were performed for 50 liver tumors. These lesions were situated in close proximity to anatomically essential structures, with a maximum distance to surrounding structures being 10 mm. Because of comorbid lung diseases, patients could not undergo deep anesthesia. Regular follow-ups were performed using blood tests and dynamic contrast-enhanced computed tomography or magnetic resonance imaging.

Results

The patient cohort consisted of 30 (68%) men and 14 (32%) women, with a mean age of 64.36±11.65 years (range: 40-80 years). The lesions were challenging to access and were located in proximity to critical structures such as the diaphragm (32, 64%), gallbladder (8, 16%), major vessels (5, 10%), and heart (5, 10%). During the follow-up period, 10 patients (23%) had local tumor recurrence and 14 (32%) had new primary foci in a different location and metastasis [liver (10) and non-liver organs (4)]. No major complications developed, and 21 of 44 patients experienced minor complications, which were treated with local medications during follow-up.

Conclusions

Percutaneous MWA results in very low mortality and morbidity, coupled with high complete ablation rates for liver cancer. Most liver tumors can be treated safely and effectively with percutaneous MWA, even in cases of high-risk localization, without the need for deep anesthesia.

Different power modes of microwave ablation for hepatocellular carcinoma: Evaluation of recurrence rate and factors related to recurrence

PURPOSE

To evaluate the safety and efficacy of different power modes(constant power and variable power) percutaneous microwave ablation (MWA) for treating hepatocellular carcinoma (HCC) and to predict the risk factors of recurrence after MWA.

MATERIALS AND METHODS

In this retrospective study, a total of 112 patients with solitary HCC were included from January 2015 to January 2021. All patients received MWA through a percutaneous approach that was guided by ultrasound, 45 patients received variable power MWA, and the remaining 67 were treated with constant power MWA. The complete ablation rates, local recurrence rates, complications, and short-term survival were analyzed. Possible risk factors for tumor recurrence were analyzed.

RESULTS

The complete ablation rates were 95.9% for the first ablation and 100% for the second ablation for ≤3 cm lesions. The complete ablation rates were 84.2%(95.9% versus 84.2%, p = 0.039) for the first ablation and 94.7% (100% versus 94.7%, p = 0.113) for the second ablation for 3-5 cm lesions. Local and distant recurrence rates were 18.7%(21/112) and 14.3%(16/112). The 1-, 2-year survival rates were 86.3 and 66.3%, respectively. Subgroup analysis showed that 1-, 2-year survival rates were 91.1% and 78.5% in ≤3 cm group, and were 74.4% and 40.9% in 3-5 cm group, respectively. Univariate analysis revealed that a positive correlation existed between the HBV DNA replication(p = 0.007), AFP level of pre-MWA(p = 0.001) and post-MWA(p<0.001), tumor diameter(p<0.001), irregular shape(p = 0.014), proximity to the risk location(p = 0.008), poor differentiation(p = 0.003), constant power(p = 0.028), length(p<0.001) and width of ablation zone(p = 0.001), and present complication(p<0.001), and early recurrence. Multivariate analysis identified HBV DNA replication(OR = 0.266, p = 0.036), AFP level of pre-MWA (OR = 4.001, p = 0.036), tumor diameter (OR = 2.153, p = 0.042), tumor location (OR = 0.910, p = 0.046), and width of ablation zone(OR = 2.530, p = 0.044) were independent prognosis factors causing postoperative HCC recurrence.

CONCLUSION

Variable power MWA of HCC appears to be a safe and effective treatment. HBV DNA, AFP level of pre-MWA, tumor diameter, tumor location, and width of ablation range appear to be independent predictors of tumor recurrence.

3.0-T closed MR-guided microwave ablation for HCC located under the hepatic dome: a single-center experience

PURPOSE

To analyze the clinical safety and efficacy of 3.0-T closed MR-guided microwave ablation (MWA) for the treatment of HCC located under the hepatic dome.

METHODS

From May 2018 to October 2020, 49 patients with 74 HCCs located under the hepatic dome underwent MWA using 3.0-T closed MR guidance. The technical success rate, operative time, complete ablation (CA) rate, complications, local tumor progression (LTP), tumor-free survival (TFS) and overall survival (OS) were examined. Routine blood analysis, liver/kidney function and alpha fetoprotein (AFP) and protein induced by vitamin k absent or antagonist (PIVKA) levels were compared before and 2 months after MWA.

RESULTS

All patients underwent MWA successfully, including 10 patients who underwent general anesthesia. The technical success rate was 100% without major complications. The CA rate was 95.9% (71/74) at the 2-month evaluation. The LTP rate was 2.7% during the median follow-up of 17.8 months (range: 4-43 months); the 6-, 12-, 18-month TFS rates were 97.8, 90.6, 68.1%, respectively, and the 6-, 12-, 18-month OS rates were 100, 97.6, 92.1%, respectively. There were no significant changes in routine blood tests and liver/kidney function (p > 0.05), while the AFP and PIVKA level decreased significantly at 2 months (p < 0.05).

CONCLUSION

3.0-T MR-guided MWA is safe and feasible for HCC lesions located under the hepatic dome.

A prospective randomized trial comparing microwave and radiofrequency ablation for the treatment of liver metastases using a dual ablation system ─ The Mira study

PURPOSE

The aim of this study was to prospectively compare the therapy response and safety of microwave (MWA) and radiofrequency ablation (RFA) for the treatment of liver metastases using a dual ablation system.

METHODS

Fifty patients with liver metastases (23 men, mean age: 62.8 ± 11.8 years) were randomly assigned to MWA or RFA for thermal ablation using a one generator dual ablation system. Magnetic resonance imaging (MRI) was acquired before treatment and 24 h post ablation. The morphologic responses to treatment regarding size, volume, necrotic areas, and diffusion characteristics were evaluated by MRI. Imaging follow-up was obtained for one year in three months intervals, whereas clinical follow-up was obtained for two years in all patients.

RESULTS

Twenty-six patients received MWA and 24 patients received RFA (mean diameter: 1.6 cm, MWA: 1.7 cm, RFA: 1.5 cm). The mean volume 24 h after ablation was 37.0 cm3 (MWA: 50.5 cm3, RFA: 22.9 cm3, P < 0.01). The local recurrence rate was 0% (0/26) in the MWA-group and 8.3% (2/24) in the RFA-group (P = 0.09). The rate of newly developed malignant formations was 38.0% (19/50) for both groups (MWA: 38.4%, RFA: 37.5%, P = 0.07). The overall survival rate was 70.0% (35/50) after two years (MWA: 76.9%, RFA: 62.5%, P = 0.60). No major complications were reported.

CONCLUSION

In conclusion, MWA and RFA are both safe and effective methods for the treatment of liver metastases with MWA generating greater volumes of ablation. No significant differences were found for overall survival, rate of neoplasm, or major complications between both groups.

Long-term outcome for colorectal liver metastases: combining hepatectomy with intraoperative ultrasound guided open microwave ablation versus hepatectomy alone

OBJECTIVE

To compare the long-term outcome of combining hepatectomy with intraoperative ultrasound (IOUS)-guided open microwave ablation (MWA) versus hepatectomy alone in patients with colorectal cancer liver metastases (CRLM).

METHOD

A retrospective analysis of patients with CRLM who underwent hepatectomy alone (HT group; 380 patients) or hepatectomy combined with IOUS-guided open MWA (HT + MWA group; 57 patients) from April 2002 to September 2018 was conducted at our center. A propensity score-matched (PSM) analysis was used to reduce data bias between the two groups.

RESULTS

The overall survival (OS) and disease-free survival (DFS) were not significantly different between the two groups after matching. Although intrahepatic recurrence was more frequent in the HT + MWA group in both the whole and matched cohort, the two groups exhibited similar rates of extrahepatic recurrence as well as concomitant intra- and extrahepatic recurrence. A higher number of CRLM (>3), larger maximum-size and absence of response to induction chemotherapy were independent risk factors for OS.

CONCLUSION

The oncological outcomes of hepatectomy combined with intraoperative open ablation was not significantly different to hepatectomy alone and should be considered as a safe and fair option for patients with difficultly resectable CRLM.

Advanced Techniques in the Percutaneous Ablation of Liver Tumours

Percutaneous ablation is an accepted treatment modality for primary hepatocellular carcinoma (HCC) and liver metastases. The goal of curative ablation is to cause the necrosis of all tumour cells with an adequate margin, akin to surgical resection, while minimising local damage to non-target tissue. Aside from the ablative modality, the proceduralist must decide the most appropriate imaging modality for visualising the tumour and monitoring the ablation zone. The proceduralist may also employ protective measures to minimise injury to non-target organs. This review article discusses the important considerations an interventionalist needs to consider when performing the percutaneous ablation of liver tumours. It covers the different ablative modalities, image guidance, and protective techniques, with an emphasis on new and advanced ablative modalities and adjunctive techniques to optimise results and achieve satisfactory ablation margins.

Percutaneous microwave ablation applications for liver tumors: recommendations for COVID-19 patients

Microwave ablation (MWA) is an alternative locoregional therapy to surgical resection of solid tumors in the treatment of malignancies, and is widely used for hepatic tumors. It has a slightly higher overall survival (OS) rate compared to external beam radiation therapy (EBRT), and proton beam therapy (PBT), and better long-term recurrence-free OS rate compared to radiofrequency ablation (RFA). In this paper, current commercial devices, most recent noncommercial designs, and the principles behind them alongside the recently reported developments and issues of MWA are reviewed. The paper also provides microscopic insights on effects of microwave irradiation in the body. Our review shows that MWA is a safe and effective, minimally invasive method with high ablation completion rates. However, for large tumors, the completion rates slightly decrease, and recurrences increase. Thus, for large tumors we suggest using a cooled shaft antenna or multiple antenna placements. Comparisons of the two common ablation frequencies 915 MHz and 2.45 GHz have shown inconsistent results due to non-identical conditions. This review suggests that 915 MHz devices are more effective for ablating large tumors and the theory behind MWA effects corroborates this proposition. However, for small tumors or tumors adjacent to vital organs, 2.45 GHz is suggested due to its more localized ablation zone. Among the antenna designs, the double-slot antenna with a metallic choke seems to be more effective by localizing the radiation around the tip of the antenna, while also preventing backward radiation towards the skin. The review also pertains to the use of MWA in COVID-19 patients and risk factors associated with the disease. MWA should be considered for COVID-19 patients with hepatic tumors as a fast treatment with a short recovery time. As liver injury is also a risk due to COVID-19, it is recommended to apply liver function tests to monitor abnormal levels in alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, and other liver function indicators.

Feasibility and safety of fine positioning needle-mediated breathing control in CT-guided percutaneous puncture of small lung/liver nodules adjacent to diaphragm

To assess the efficacy, safety, and feasibility of a separate inserted positioning fine needle-mediated breathing-control technique applied to computed tomography (CT)-guided percutaneous puncture for biopsy or microwave ablation (MWA) of small lung/liver nodules near diaphragm. Total 46 patients with pulmonary/liver small nodules (≤ 3 cm in size) near diaphragm(nodule within 1 cm distance to the diaphragm)were undergone percutaneous biopsy ( n = 15) or MWA (n = 31) under the guidance of CT, and a separate positioning fine needle-mediated breathing-control technique was applied for the precise punctures. CT plain scan was performed to monitor the complications after the procedure. The patient baseline data, operation details, successful rate, major complications as well as radiation dose during the procedure were recorded and analyzed. With the assistance of a fine positioning needle insertion for controlling the breathing, the puncture success rate for biopsy or MWA reached 91.30% (42/46). For biopsy, the mean nodule diameter, nodule distance to the diaphragm, puncture time and radiation dose during CT scan were 2.27 cm ± 0.74, 0.61 cm ± 0.24, 18.67 min ± 6.23, 28.84 mSv ± 6.99, respectively; For MWA, the mean nodule diameter, nodule distance to the diaphragm, puncture time and CT radiation dose were 2.35 cm ± 0.64, 0.69 cm ± 0.23, 38.71 min ± 13.65, 33.02 mSv ± 8.77, respectively. Totally, there were three and four cases found minimal puncture-related hemoptysis and pneumothorax needed no additional treatments, respectively. We recently developed and verified a feasible, safe and highly effective puncture technique with reasonable radiation dose for CT-guided biopsy or MWA for small nodules abutting diaphragm, therefore worthy of extensive application to similar clinical situations.

Efficacy and safety of percutaneous microwave ablation for hepatocellular carcinomas <4 cm in difficult location

OBJECTIVE

Tumor location is a critical factor for determining technical success and local recurrence following percutaneous ablation of hepatocellular carcinomas (HCC). The purpose of this retrospective study was to evaluate the safety and outcome measures of percutaneous microwave ablation (pMWA) for HCCs <4 cm in difficult locations.

METHODS

Retrospective review included 81 patients who underwent pMWA for HCCs <4 cm. Fourty-three patients (30 males and 13 females; mean age, 61 years) with 53 HCCs located near the diaphragm, heart, gallbladder, kidney, gastrointestinal tract, large vessel and exophytic location were included under difficult location group. Thirty-eight patients (29 males and nine females; mean age, 60 years) with 48 HCCs in other locations were included under control group. Baseline demographics were recorded. Technical efficacy, local tumor progression (LTP), and complication rates were evaluated.

RESULTS

Mean follow-up period was 3.4 months (range 1-7). There was no major complication in both the groups; two patients had a mild perihepatic hemorrhage in the difficult location group which was managed conservatively. There was no difference between the groups in the overall technical efficacy rate (84.9% vs 91.7%, p = 0.294), LTP rate (4.4% vs 2.2%. p = 0.57) or complication rate (4.6% vs 0%, p = 0.177).

CONCLUSION

Our data suggest that there is no significant difference in technical efficacy, LTP or complication rates for MWA in both difficult and normal locations.

ADVANCES IN KNOWLEDGE

With proper patient selection, pre-procedural planning and appropriate technique, pMWA is feasible, safe, and effective for small HCCs in difficult location with an acceptable range of complications.

Liver tumor ablation in difficult locations: Microwave ablation of perivascular and subdiaphragmatic hepatocellular carcinoma

AIM

To assess the safety and efficacy of CT-guided microwave ablation (MWA) of hepatocellular carcinoma (HCC) near large blood vessels and the diaphragm by analyzing procedural complications and local tumor progression (LTP).

METHODS

From October 2013 through January 2019, 80 patients (54 males and 26 females) with 136 tumors who underwent CT-guided MWA of HCC were included in this retrospective analysis. MWA was performed on 43 perivascular HCC (≤5 mm from a vessel measuring ≥5 mm in diameter), 38 subdiaphragmatic HCC (≤5 mm from diaphragm), and 64 control HCC. Risk factors for local tumor progression (LTP), overall survival, and complications were analyzed using the Chi-square and Cox proportional hazards model methods.

RESULTS

The technical success rate of MWA was 100%. Complication incidence was not significantly different between perivascular and control tumors (20.9% vs 10.9%; p = 0.155) or between subdiaphragmatic and control tumors (21.1% vs 10.9%; p = 0.163). The effect of lesion location on LTP disappeared while controlling for age and lesion size. There was no significant difference in median survival time between patients who had only control tumors (38.8 months) compared to patients with at least one perivascular or subdiaphragmatic tumor (42.5 months; p = 0.098).

CONCLUSION

CT-guided percutaneous MWA of perivascular and subdiaphragmatic HCC tumors is safe and effective. The local tumor recurrence and survival was not significantly different compared to control tumors.

Adjunctive hydrodissection of the bare area of liver during percutaneous thermal ablation of sub-cardiac hepatic tumours

OBJECTIVE

To report the technique of hydrodissection of the sub-diaphragmatic bare area of the liver, in order to protect the diaphragm/heart during percutaneous thermal ablation (PTA) of sub-cardiac hepatic tumours.

MATERIALS AND METHODS

Between January 2016 and December 2018, five patients (four female, one male; mean age 56.2 years) with five sub-cardiac liver tumours (two hepatocellular carcinoma, three metastases; mean size 39 mm) abutting the bare area (segments II/IVA) with expected ablation zones ≤ 5 mm from the myocardium were treated with PTA and adjunctive hydrodissection. Time to perform hydrodissection, distance between superior hepatic and diaphragmatic/pericardial surfaces before and after hydrodissection, ablation efficacy, complications, and local tumour progression (LTP) at last imaging follow-up were recorded.

RESULTS

Technical feasibility was 100%, with mean hydrodissection-volume of 126 ml (range 80-200 ml) and median hydrodissection-time of 9 min (range 8-45 min). Liver-diaphragmatic and liver-pericardial distance increased, respectively, from 2.4 mm (range 0-8 mm) to 10.8 mm (range 6-19 mm) and from 4 mm (range 1-10 mm) to 12.6 mm (range 8-20 mm) post-hydrodissection. All procedures were performed at full-power with complete tumour ablation and without complications (including peri-procedural haemodynamic/electrocardiographic disturbances, pericardial effusion and diaphragmatic hernia) or evidence of LTP at mean 12.2-month (range 1-26 month) follow-up.

CONCLUSION

Hydrodissection of the sub-diaphragmatic bare area of the liver is technically feasible and may potentially optimize safety PTA of sub-cardiac hepatic tumours.

Value of MRI/CT Image Fusion for Targeting "invisible" Lesions in Stereotactic Microwave Ablation (SMWA) of Malignant Liver Lesions: A Retrospective Analysis

PURPOSE

To assess the technical feasibility of MRI/CT image fusion and completeness of ablation treatment for primary or metastatic liver lesions invisible on contrast-enhanced CT planning scans and outcome in patients treated with stereotactic microwave ablation (SMWA).

MATERIALS AND METHODS

The study was approved by the local ethics committee. Patients who underwent SMWA between January 2015 and December 2018 were retrospectively analyzed. All liver lesions for which MRI/CT fusion was performed due to invisibility on pre-interventional CT planning scans were included and reassessed. The outcome measurement was successful ablation of the lesion at first follow-up imaging.

RESULTS

During the study period, 236 patients underwent 312 SMWAs with ablation of 496 lesions. Twenty-four lesions in 15 patients (mean age, 62 years; range, 43-80 years) were included. Following MRI/CT image fusion, all 24 lesions could be sufficiently localized to perform SMWA. The first follow-up imaging showed complete ablation of 22 lesions. Two initially incompletely ablated lesions were hepatocellular carcinomas and were successfully re-ablated afterwards.

CONCLUSION

SMWA with MRI/CT image fusion is an accurate and safe treatment option for patients with liver lesions not detectable on contrast-enhanced CT planning scans. MRI/CT image fusion may allow more patients with malignant liver lesions to benefit from local ablation treatment even if their lesions are not visible on CT planning examinations.

Efficacy and Safety of Percutaneous Argon-Helium Cryoablation for Hepatocellular Carcinoma Abutting the Diaphragm

PURPOSE

To evaluate the efficacy and safety of percutaneous argon-helium cryoablation (CA) for hepatocellular carcinoma (HCC) abutting the diaphragm (<5 mm).

MATERIALS AND METHODS

A total of 61 consecutive patients (50 men, 11 women; mean age, 56.3 ± 12.1 years old; range, 32-83 years) with 74 HCC tumors (mean size, 3.3 ± 1.7 cm; range, 0.8-7 cm) who were treated with percutaneous argon-helium CA were enrolled in this retrospective study. Adverse events were evaluated according to Common Terminology Criteria for Adverse Events, version 5.0. Local tumor progression (LTP) and overall survival (OS) were analyzed using the Kaplan-Meier method and the log-rank test. The risk factors associated with OS and LTP were evaluated using univariate and multivariate Cox regression analysis.

RESULTS

No periprocedural (30-day) deaths occurred. A total of 29 intrathoracic adverse events occurred in 24 of the 61 patients. Major adverse events were reported in 5 patients (pleural effusion requiring catheter drainage in 4 patients and pneumothorax requiring catheter placement in 1 patient). Median follow-up was 18.7 months (range, 2.3-60.0 months). Median time to LTP after CA was 20.9 months (interquartile range [IQR], 14.1-30.6 months). Median times of OS after CA and diagnosis were 27.3 months (IQR, 15.1-45.1 months) and 40.9 months (interquartile range, 24.8-68.6 months), respectively. Independent prognostic factors for OS included tumor location (left lobe vs right lobe; hazard ratio [HR], 2.031; 95% confidence interval [CI], 1.062-3.885; P = .032) and number of intrahepatic tumors (solitary vs multifocal; HR, 2.684; 95% CI, 1.322-5.447; P = .006). Independent prognostic factors for LTP included age (HR, 0.931; 95% CI, 0.900-0.963; P  < .001), guidance modality (ultrasound vs computed tomography and US; HR, 6.156 95% CI, 1.862-20.348; P  =   .003) and origin of liver disease.

CONCLUSIONS

Percutaneous argon-helium CA is safe for the treatment of HCC abutting the diaphragm, with acceptable LTP and OS.

Hepatic Microwave Ablation in Challenging Locations

In recent years, there has been increased utilization of microwave ablation (MWA) in the treatment of soft tissue tumors. MWA has several theoretical advantages over radiofrequency ablation (RFA) by achieving a more rapid and sustained heating of tissues, increased efficacy in tissues with poor thermal conductivity, and less susceptibility to heat sink effect. While its greater power output has led to appropriate caution when applying this energy to soft tissue tumors, many commonly held beliefs regarding contraindications to MWA are unsupported by data and have been passed along based on experience with RFA. The goal of this article is to review the use of MWA in challenging clinical situations along with the existing evidence for its use.

Image-Guided Percutaneous ‎Microwave Ablation Versus Cryoablation For Hepatocellular Carcinoma In High-Risk Locations: Intermediate-Term Results

Objective

The aims of this study were to compare the clinical outcomes between image-guided percutaneous microwave ablation (MWA) and cryoablation (CRA) in patients with hepatocellular carcinoma (HCC) in high-risk locations and to identify the prognostic factors associated with the two treatment methods.

Methods

This retrospective study was institutional review board approved. A total of 120 patients (88 men and 32 women) with one hundred and thirty-four HCC lesions in high-risk locations from April 2014 to March 2018 were reviewed. Sixty-four patients underwent MWA and 56 patients underwent CRA. Survival, recurrence and complications were compared between the two groups. Effect of changes in key outcomes (i.e., overall survival (OS), recurrence-free survival (RFS) and local tumor progression (LTP)) was statistically analyzed with the log rank test. Univariate and multivariate analysis were performed on clinicopathological variables to identify factors affecting intermediate-term outcomes.

Results

The OS and RFS after MWA were comparable to those of CRA (P =0.141, and P=0.469, respectively). The LTP and major complication in MWA group was higher than those in CRA group (P=0.003, and P=0.039). Univariate analysis showed that age (P=0.007), tumor size (P=0.001), and Child-Turcotte-Pugh (CTP) grade (P=0.003) were risk factors for OS, and multivariate analysis results showed that older age (≥65 years) (P=0.002, HR:3.338, 95% CI:1.928–5.281), 3.0–5.0 cm in size (P<0.001, HR: 3.312, 95% CI: 1.872–4.489) and CTP grade B (P=0.001, HR:3.382, 95% CI: 1.882–5.902) were independently associated with poor OS.

Conclusion

CRA had comparable oncologic outcomes with MWA and could be a safe and effective treatment for HCC in high-risk locations.

Cu2ZnSnS4 nanocrystals for microwave thermal and microwave dynamic combination tumor therapy

Cu2ZnSnS4 nanocrystals (CZTS NCs) have been demonstrated to be effective in tumor therapy as a novel susceptible agent for microwave thermal and microwave dynamic therapy. CZTS NCs intensify the heating effect of microwaves with a significant temperature increase of about 15 °C compared to the control group and showed remarkable anti-tumor performance after 5 min of microwave irradiation. For the first time, we report the microwave absorption performance and singlet oxygen production of CZTS NCs used in microwave therapy, which reveals new opportunities for novel combined mechanisms of microwave thermal and microwave dynamic tumor therapies.

MRI-Guided Cryoablation of Hepatic Dome Hepatocellular Carcinomas Using 1-T Open High-Field-Strength Scanner

OBJECTIVE. The objective of our study was to prospectively evaluate the feasibility, safety, and effectiveness of 1-T open MRI-guided percutaneous cryoablation of hepatic dome hepatocellular carcinomas (HCCs). SUBJECTS AND METHODS. Thirty-seven patients with 37 hepatic dome HCCs underwent MRI-guided percutaneous cryoablations. MR fluoroscopy with a freehand technique was applied in the procedure. All lesions ranged in size from 8 to 38 mm. Patients were followed for at least 12 months after cryoablation or until death. Survival period, local tumor control, and complications were recorded. RESULTS. MRI-guided percutaneous cryoablation procedures were successfully performed on all 37 lesions. The technical success rate was 100%. The median follow-up time was 21.0 months (range, 10-26 months). Two patients with local tumor progression at the 4th and 11th month after the procedure were treated with a supplementary cryoablation. One patient died of upper gastrointestinal hemorrhage at the 10th month after cryoablation. Local tumor progression and overall survival rates were 2.7% (1/37) and 100% (37/37) at 6 months and 5.4% (2/37) and 97.3% (36/37) at 1 year, respectively. Postoperative hydrothorax that required chest tube drainage occurred in two patients; no other severe complications occurred. CONCLUSION. Cryoablation of hepatic dome HCCs with 1-T open MRI guidance is a feasible, safe, and effective therapy method.

Percutaneous Microwave Ablation Under CT Guidance for Hepatocellular Carcinoma: a Single Institutional Experience

BACKGROUND

Microwave ablation (MWA) is an emerging treatment for treatment of patients with hepatocellular carcinoma (HCC) not amenable of surgical resection.

PATIENTS AND METHODS

We searched for patients diagnosed as having small-, medium-, and large HCCs treated with MWA under CT guidance between 2010 and 2014. The main outcomes of interest were rates of complete ablation, complications, and overall survival. Rates of complete ablation were compared with Chi-square test, and estimated survival rates were calculated by means of Kaplan-Meier method.

RESULTS

Thirty-two patients with 45 HCC nodules received MWA. Seventeen (37.8%) nodules were <3 cm (small), 15 (33.3%) between 3 and 5 cm (medium), and 13 (28.9%) > 5 cm (large). Complete ablation was obtained in 94.1% of small tumors, 80% of medium tumors, and 53.8% of large tumors (p = 0.03). Two patients had HCC located in risk area (paracardiac position). Minor complications occurred after seven procedures (15.5%). Estimated median survival was 37 months (95% confidence interval 11.97-62.02). One-year OS was 82.7%, 2-year survival 68.9%, and 3-year survival 55.2%.

CONCLUSION

MWA is a versatile ablative method that can be applied in HCC at various stages, and also in lesions located in risk areas.

Imaging guided percutaneous interventions in hepatic dome lesions: Tips and tricks

Percutaneous hepatic interventions are generally safe given the fact that liver closely abuts the abdominal wall and hence it is easily accessible. However, the superior portion of liver, adjacent to the diaphragm, commonly referred as the "hepatic dome", presents unique challenges for interventionists. Percutaneous access to the hepatic dome may be restricted by anatomical factors and special considerations may be required to avoid injury to the surrounding organs. The purpose of this review article is to discuss certain specific maneuvers and techniques that can enhance the success and safety of interventions in the hepatic dome.

The clinical utility and outcomes of microwave ablation for colorectal cancer liver metastases

In recent years, the microwave ablation (MWA) has been reported to play an important role in the treatment of patients with colorectal liver metastases (CRLM). In this work, 62 cases of patients who received MWA for liver metastases from colon or rectal cancer between Jan 2012 and Jan 2014 were enrolled in this trial. 28 underwent MWA, and 34 were treated with liver resection as control. Perioperative and 60 months of follow-up data were collected to analyze potential adverse effects, concurrent conditions and survival status. Here, we found there were no significant differences between both groups in the baseline level, including gender, size, number and pathological type (all p>0.05). In those patients, the mean hospitalization duration of patients with MWA is 5.9±0.9d, which is significantly different from control (11.8±6.9 d) (p<0.001). Little severe complication was observed in MWA group, while 26.5% (9/34) of patients developed severe complications (p=0.003). Besides, the mean hospitalization cost of patients with MWA was significantly less than that of control (p<0.000). Additionally, we found no statistically significant differences in disease-free survival (DFS) (p=0.156) or overall survival (OS) (p=0.580). In conclusion, MWA may be a safe, economical and competent way to treat inoperable CRLM patients, which has more advantages than liver resection in some degree.

Combination therapy of three-dimensional (3D) visualisation operative treatment planning system and US-guided percutaneous microwave ablation in larger renal cell carcinomas (D ≥ 4 cm): preliminary results

PURPOSE

To analyse the clinical outcomes of combination therapy of three-dimensional (3D) visualisation operative treatment planning system and US-guided percutaneous microwave ablation (PMWA) in larger renal cell carcinomas (RCCs) (D ≥ 4 cm).

MATERIALS AND METHODS

The results from 20 patients with 20 larger RCCs treated with a 3D visualisation operative treatment planning system and US-guided PMWA were reviewed retrospectively. The patients were followed up by contrast-enhanced images at 1, 3, and 6 months and every 6 months thereafter. The outcomes of overall survival and local tumour progression rate were statistically analysed.

RESULTS

The median follow-up period was 26 months. The mean time of ablation for one tumour was 1.1 ± 0.3 sessions. The average number of ablation points of one tumour was 4.5 ± 0.9. The mean output power of ablation was 50.50 ± 2.2 W. The mean time of ablation for one tumour was 1374.4 ± 391.1 s. Artificial ascites was used in 12 (60%) tumours adjacent to the intestinal tract, and thermal monitoring system was used in all tumours (100%). Technical effectiveness and metastasis-free status were achieved in all tumours. The 1- and 2-year local tumour progression rates were both 5%. The cancer-specific survival rate and 2-year overall survival rates were both 100%. No severe major complications occurred. There was no significant difference in creatinine or urea nitrogen before or 3 days after ablation.

CONCLUSIONS

Combination therapy of 3D visualisation operative treatment planning system and US-guided PMWA appeared to be a safe and effective technique for the management of larger RCCs, which could improve clinical efficacy.

Stereotactic CT-Guided Percutaneous Microwave Ablation of Liver Tumors With the Use of High-Frequency Jet Ventilation: An Accuracy and Procedural Safety Study

OBJECTIVE

The purpose of the present study is to evaluate the accuracy and safety of antenna placement performed with the use of a CT-guided stereotactic navigation system for percutaneous ablation of liver tumors and to assess the safety of high-frequency jet ventilation for target motion control.

MATERIALS AND METHODS

Twenty consecutive patients with malignant liver lesions for which surgical resection was contraindicated or that were not readily visible on ultrasound or not accessible by ultrasound guidance were included in the study. Patients were treated with percutaneous microwave ablation performed using a CT-guided stereotactic navigation system. High-frequency jet ventilation was used to reduce liver motion during all interventions. The accuracy of antenna placement, the number of needle readjustments required, overall safety, and the radiation doses were assessed.

RESULTS

Microwave ablation was completed for 20 patients (28 lesions). Performance data could be evaluated for 17 patients with 25 lesions (mean [± SD] lesion diameter, 14.9 ± 5.9 mm; mean lesion location depth, 87.5 ± 27.3 mm). The antennae were placed with a mean lateral error of 4.0 ± 2.5 mm, a depth error of 3.4 ± 3.2 mm, and a total error of 5.8 ± 3.2 mm in relation to the intended target. The median number of antenna readjustments required was zero (range, 0-1 adjustment). No major complications were related to either the procedure or the use of high-frequency jet ventilation. The mean total patient radiation dose was 957.5 ± 556.5 mGy × cm, but medical personnel were not exposed to irradiation.

CONCLUSION

Percutaneous microwave ablation performed with CT-guided stereotactic navigation provides sufficient accuracy and requires almost no repositioning of the needle. Therefore, it is technically feasible and applicable for safe treatments.

CT-Guided Percutaneous Microwave Ablation of Tumors in the Hepatic Dome: Assessment of Efficacy and Safety

PURPOSE

To evaluate the technique, efficacy, safety, and clinical outcomes of CT-guided microwave ablation of tumors in the hepatic dome.

MATERIALS AND METHODS

Retrospective review was conducted of 46 consecutive patients (31 men and 15 women; mean age, 64 y) treated with CT-guided microwave ablation for hepatic-dome tumors between June 2011 and December 2014. Baseline demographics of sex, tumor diagnosis, tumor location, tumor size, and technical details were recorded. Technical success was evaluated. Treatment response was assessed per European Association for the Study of the Liver criteria. Overall success and overall survival were calculated, and complications were recorded.

RESULTS

Forty-eight tumors were treated. Tumor locations included segments VIII (n = 32), VII (n = 10), and VIa (n = 6). Mean tumor size was 2.4 cm (range, 0.9-5.2 cm). Thirty-four tumors (70%) were treated following creation of artificial ascites with 0.9% normal saline solution (mean volume, 1,237 mL; range, 300-3,000 mL). The technical success rate was 100%, and the complete response rate was 94%. Overall survival rate was 73.9% over 24.7 months of follow-up. There were no major complications. Two patients experienced small, asymptomatic pneumothoraces that were aspirated at the time of the procedure and required no further treatment.

CONCLUSIONS

CT-guided microwave ablation of tumors in the hepatic dome is associated with a high technical success rate, high complete response rate, and low complication rate.

Liver Ablation: Best Practice

Tumor ablation in the liver has evolved to become a well-accepted tool in the management of increasing complex oncologic patients. At present, percutaneous ablation is considered first-line therapy for very early and early hepatocellular carcinoma and second-line therapy for colorectal carcinoma liver metastasis. Because thermal ablation is a treatment option for other primary and secondary liver tumors, an understanding of the underlying tumor biology is important when weighing the potential benefits of ablation. This article reviews ablation modalities, indications, patient selection, and imaging surveillance, and emphasizes technique-specific considerations for the performance of percutaneous ablation.