Efficacy and safety of artificial ascites in assisting percutaneous microwave ablation of hepatic tumours adjacent to the gastrointestinal tract

Microwave ablation versus liver resection for primary intrahepatic cholangiocarcinoma within Milan criteria: a long-term multicenter cohort study

Background

Ablation has been recommended by worldwide guidelines as first-line treatment for hepatocellular carcinoma (HCC), while evidence regarding its efficacy for primary intrahepatic cholangiocarcinoma (iCCA) is lacking. We aimed to study the efficacy of ablation in treating iCCA by comparing its prognosis with surgery.

Methods

In this real-world multicenter cohort study from January 2009 to June 2022, 10,441 iCCA patients from ten tertiary hospitals were identified. Patients who underwent curative-intent microwave ablation (MWA) or liver resection (LR) for tumors within Milan criteria were included. One-to-many propensity score matching (PSM) at variable ratios (1:n ≤4) was used to balance baseline characteristics. Mediation analysis was applied to identify potential mediators of the survival difference.

Findings

944 patients were finally enrolled in this study, with 221 undergoing MWA and 723 undergoing LR. After PSM, 203 patients in the MWA group were matched with 588 patients in the LR group. The median follow-up time was 4.7 years. Compared with LR, MWA demonstrated similar overall survival (5-year 44.8% versus 40.4%; HR 0.96, 95% CI 0.71-1.29, P = .761). There was an improvement in the 5-year disease-free survival rate for MWA from 17.1% during the period of 2009-2016 to 37.3% during 2017-2022, becoming comparable to the 40.8% of LR (P = .129). The proportion of ablative margins ≥5 mm increased from 25% to 61% over the two periods, while this proportion of surgical margins was 62% and 77%, respectively. 34.5% of DFS disparity can be explained by the mediation effect of margins (P < .0001). Similar DFS was observed when both ablative and surgical margins exceeded 5 mm (HR 0.83, 95% CI 0.52-1.32, P = .41).

Interpretation

MWA may be considered as a viable alternative to LR for iCCA within Milan criteria when an adequate margin can be obtained.

Funding

National Natural Science Foundation of China.

Study of ultrasound-guided percutaneous microwave ablation combined with portal vein embolization for rapid future liver remnant increase of planned hepatectomy

Purpose

To evaluate the efficacy of ultrasound-guided percutaneous microwave ablation (PMA) combined with portal vein embolization (PVE) for planned hepatectomy.

Methods

We retrospectively reviewed data of 18 patients with multiple right liver tumors or hilar tumor of liver invades the surrounding tissue and insufficient future liver remnant (FLR) for hepatectomy from July 2015 to March 2017. Ultrasound-guided PMA was performed by using PMCT cold circulation microwave treatment apparatus. PVE was performed after PMA. The increase of FLR was evaluated by computed tomography (CT) 6-22 days after PVE. The proportion of FLR, increase in the amplitude of FLR, procedure-related complications, perioperative morbidity and mortality, and overall survival (OS) rates, the median survival time were analyzed.

Results

The median volume of FLR before PMA and PVE was 369.7 ml (range: 239.4-493.1 ml). After a median waiting period of 11.5 days (range: 6-22 days), the median volume of FLR was increased to 523.4 ml (range: 355.4-833.3 ml). The changes in FLR before and after PMA and PVE were statistically significant (p<0.001). No serious perioperative complications or mortality were found. After a median follow-up time of 51.0 months (range: 2-54 months), the 6-month, 1-year, 2-year, 3-year and 4-year survival rates were 88.9%, 72.2%, 44.4%, 33.3%, 22.2%, respectively, and the median survival time was 15.0 ± 7.1 months.

Conclusion

PMA combined with PVE increases FLR rapidly, avoids touching malignant tumors, and produces fewer procedure-related complications. It appears safe and efficacious for planned hepatectomy.

Long-term efficacy and safety of microwave ablation for hepatocellular carcinoma adjacent to the gallbladder with a diameter ≤ 5 cm: a multicenter, propensity score matching study

OBJECTIVE

To compare the long-term efficacy and safety of microwave ablation (MWA) as first-line therapy for hepatocellular carcinoma (HCC) adjacent versus nonadjacent to the gallbladder.

MATERIALS AND METHODS

From 2006 to 2018, 657 patients with ≤5 cm HCC who underwent percutaneous ultrasound-guided MWA as first-line therapy from 5 hospitals were enrolled in this retrospective study. Patients were grouped into the adjacent group (n = 49) and the nonadjacent group (n = 608) according to whether the tumor was adjacent to the gallbladder. Propensity score matching (PSM) was used to balance baseline variables between the two groups.

RESULTS

Forty-eight patient pairs were matched after PSM. For the PSM cohort, during a median follow-up time of 60 months, there were no differences in PFS (hazard ratio [HR], 1.011; 95% confidence interval [CI], 0.647-1.578; p = 0.963) or OS (HR 0.925; 95% CI 0.522-1.639; p = 0.789) between the adjacent and nonadjacent groups. Univariate and multivariate analyses revealed that the tumor adjacent to the gallbladder was not an independent risk factor for PFS or OS (all p > 0.05). Subgroup analysis showed comparable PFS and OS between the two groups in the <3 cm subgroup and the 3-5 cm subgroups (all p > 0.05). In addition to more use of assistive technology (p < 0.05), the adjacent group shared comparable local tumor progression, complications, technical success rate, and hospital stay (all p > 0.05) to the nonadjacent group.

CONCLUSION

There were comparable long-term efficacy and complications between patients with HCC adjacent and nonadjacent to the gallbladder treated with MWA.

Predictive Value of Ablative Margin Assessment After Microwave Ablation for Local Tumor Progression in Medium and Large Hepatocellular Carcinoma: Computed Tomography-Computed Tomography Image Fusion Method Versus Side-by-Side Method

OBJECTIVE

This study aimed to explore the feasibility and predictive value for local tumor progression (LTP) of the computed tomography (CT)-CT image fusion method versus side-by-side method to assess ablative margin (AM) in hepatocellular carcinoma ≥3 cm in diameter.

MATERIALS AND METHODS

We selected patients with hepatocellular carcinoma ≥3 cm in diameter who underwent microwave ablation and had complete tumor ablation. We used the CT-CT image fusion method and side-by-side method to assess AM separately and divided the lesions into 3 groups: group I, minimum ablative margin (min-AM) <0 mm (the ablation zone did not fully cover the tumor); group II, 0 mm ≤ min-AM <5 mm; and group III, min-AM ≥5 mm.

RESULTS

A total of 71 patients involving 71 lesions were included. The κ coefficient for the agreement between the CT-CT image fusion method and the side-by-side method in assessing min-AM was 0.14 (P = 0.028). Cumulative LTP rate was significantly different between groups by min-AM from the CT-CT image fusion method (P < 0.05) but not by min-AM from the side-by-side method (P = 0.807). Seventeen of the 20 LTP lesions were located at min-AM on fused CT images, with consistency rate of 85%.

CONCLUSIONS

Compared with the side-by-side method, the CT-CT image fusion method is more accurate in assessing the AM of eccentrically ablated lesions and shows better predictive value for LTP. The min-AM based on CT-CT image fusion assessment is an important influencing factor for LTP.

Perithyroidal hemorrhage caused by hydrodissection during radiofrequency ablation for benign thyroid nodules: Two case reports

BACKGROUND

Hydrodissection is a widely used technique during radiofrequency ablation (RFA) for benign thyroid nodules. Although it could effectively avoid thermal injury to the surrounding critical structures and achieve complete treatment, routine operation of the remaining needle could cause perithyroidal hemorrhage. In this report, we present 2 cases of perithyroidal hemorrhage during RFA caused by a hydrodissection needle, which have not been reported before.

CASE SUMMARY

A 21-year-old female and a 45-year-old male were admitted for RFA for benign thyroid nodules. Considering that their nodules were adjacent to the recurrent laryngeal nerve, the needle used for hydrodissection was placed and remained between the dorsal capsule of the lateral lobe and the recurrent laryngeal nerve. During the procedure, active bleeding near the needle appeared on ultrasonography (US). Although moderate pressure was quickly applied to the neck for several minutes, contrast-enhanced US (CEUS) still showed an active hemorrhage. A radiofrequency electrode was placed at the bleeding point under the guidance of CEUS to stop the bleeding, and the procedure was finally confirmed to be successful by CEUS, without other complications.

CONCLUSION

Hydrodissection during RFA of benign thyroid nodules was associated with a risk of perithyroidal hemorrhage. The timely recognition of this acute hemorrhage could help in the timely control of the bleeding, and CEUS-guided ablation of the bleeding point could be useful.

Indian College of Radiology and Imaging Guidelines on Interventions in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies and a significant cause of cancer-related death. Treatment of HCC depends on the stage of the tumor. As many patients with HCC are not deemed fit for surgical resection or liver transplantation, locoregional therapies play an essential role in the management. Image-guided locoregional treatments include percutaneous ablative therapies and endovascular therapies. The choice of an individual or a combination of therapies is guided by the tumor and patient characteristics. As the outcomes of image-guided locoregional treatments depend on the ability to achieve necrosis of the entire tumor along with a safety margin around it, it is mandatory to follow standard guidelines. In this manuscript, we discuss in detail the various aspects of image-guided locoregional therapies to guide interventional radiologists involved in the care of patients with HCC.

One-Step Method in Creation of Artificial Ascites

Background

The study aims to improve the success rate and the rapidity in creating artificial ascites before starting the treatment for subcapsular hepatocellular carcinomas.

Methods

Two hundred and forty-six consecutive hepatocellular carcinoma patients who required the instillation of artificial ascites for better visualization or prevention from organ injury were recruited between November 2011 and September 2017. Initially, 95 patients were using the Seldinger technique, while the remaining 151 patients were using the one-step method. The proportions of patients who had undergone surgery, transarterial chemoembolization, or radiofrequency ablation therapy before performing artificial ascites infusion were 11.6% (11/95), 3% (3/95), and 37% (35/95) in the Seldinger group, and 15.9% (24/151), 15.2% (23/151), and 52.3% (79/151), respectively, in the one-step group.

Results

The complete success rate, partial success rate, and failure rate in creating artificial ascites using the Seldinger technique and the one-step method were 76.8% (73/95), 11.6% (11/95), 11.6% (11/95) and 88.1% (133/151), 7.9% (12/151), 4% (6/151), respectively. The complete success rate was significantly higher in the one-step method group (P < 0.05) than that of the Seldinger group. The mean time required from starting the procedure to successful intraperitoneal instillation of glucose water was 145.79 ± 133.37 s in the one-step method, which was statistically shorter than that of 238.68 ± 95.58 s in the Seldinger group (P < 0.05).

Conclusion

The one-step method has a higher success rate than the Seldinger method in creating artificial ascites and is faster, especially in treatment-experienced patients.

Period-Dependent Survival Benefit of Percutaneous Microwave Ablation for Hepatocellular Carcinoma: A 12-Year Real-World, Multicentric Experience

INTRODUCTION

Although microwave ablation (MWA) is a promising technique for hepatocellular carcinoma (HCC) treatment, its 10-year efficacy is unknown.

OBJECTIVE

The objective of the study was to assess whether the advances in MWA for HCC translated into a real-world survival benefit.

METHODS

This retrospective study included 2,354 patients with Barcelona Clinic Liver Cancer (BCLC) stage 0 to B from 5 hospitals, with at least 2 years of follow-up for all the patients. Recurrence and survival were analyzed using the Kaplan-Meier method with time-period stratification.

RESULTS

A total of 5,326 HCCs (mean diameter, 2.9 cm ± 1.2) underwent 4,051 sessions of MWA with a median follow-up of 61.3 (0.6-169.5 range) months during 3 periods (2007-2010, 2011-2014, and 2015-2018). Technical success was achieved in 5,194 (97.5%) tumors with significant improvement over time, especially for >3.0-cm HCC (p < 0.001). Local tumor progression (LTP) showed no period-dependent advance, with >3.0-cm HCC and perivascular location being the risk factors for LTP. The median intrahepatic metastasis time was 27.6 (95% confidence interval [CI]: 25.2-28.8) months, with 5- and 10-year occurrence rates of 68.8% and 79.4%, respectively. The 5- and 10-year overall survivals were 63.9% and 41.1%, respectively, and BCLC stage 0, A, and all B patients showed an observable survival improvement over time (p < 0.001). The median disease-free survival time increased from 19.4 (95% CI: 16.5-22.6) months in 2007-2010 to 28.1 (95% CI: 25.9-32.3) months in 2015-2018. The improved survival for early recurrent (≤2 years) patients was period-dependent, as verified by Cox regression analyses. The major complications rate per procedure was 3.0% (122/4,051).

CONCLUSIONS

These real-world data show that MWA provided an upward trend in survival for HCC patients with BCLC stage 0-B over a 12-year follow-up period. An encouraging clear survival benefit in early recurrent patients was also observed.

Cause Analysis and Diagnosis and Treatment of Intestinal Fistulas After Ultrasound-Guided Microwave Ablation of Abdominopelvic Lesions

Objective: To determine the cause and high-risk factors for the development of intestinal fistulas (IFs) after ultrasound-guided microwave ablation (MA) of abdominopelvic lesions, and to identify effective prophylactic and therapeutic actions. Methods: Clinical data were collected from patients with an IF after ultrasound-guided MA of abdominopelvic lesions in our hospital from January 1, 2010 to December 31, 2018. The cause, diagnosis, and treatment of IFs in these patients were analyzed. Results: Among 8,969 patients who underwent ultrasound-guided MA of abdominopelvic lesions, eight patients developed IF after MA, Seven patients were discharged after being cured and one died. Conclusion: Abdominopelvic lesions are close to the intestines, so histories of surgery, radiotherapy, and abdominopelvic infection are high-risk factors for IF development after MA of these lesions. Surgical treatment should be provided as soon as an IF is identified.

Percutaneous thermal ablation of hepatic tumors: local control efficacy and risk factors for artificial ascites failure

OBJECTIVE

To investigate the risk factors affecting the technical failure of artificial ascites (AA) formation and to evaluate the local control efficacy of percutaneous thermal ablation assisted by the AA for hepatic tumors.

METHODS

A total of 341 patients with 362 hepatic tumors who underwent thermal ablation assisted by AA were reviewed retrospectively. The technical success of AA, the volume of liquid, and local efficacy after ablation were assessed. Predictive factors for the technical failure of AA formation and local tumor progression (LTP) were analyzed using univariate and multivariate analysis.

RESULTS

The technical success rate of AA formation was 81.8% (296/362). The amount of fluid was higher when the tumor was located in the left lobe of the liver than when it was located in the right lobe (median 950 ml versus 700 ml, p < 0.001). Previous hepatic resection (OR: 12.63, 95% CI: 2.93-54.45, p < 0.001), ablation (OR: 6.48, 95% CI: 1.36-30.92, p = 0.019) and upper-abdomen surgery (OR: 11.34, 95% CI: 1.96-65.67, p = 0.007) were the independent risk factors of AA failure. In the AA success group, the complete ablation rate was higher and the LTP rate was lower than that in the AA failure group (98.7 versus 92.4%, p = 0.012; 8.8 versus 21.2%, p = 0.004). Multivariate analysis identified AA failure (p = 0.004), tumor size (>3.0 cm) (p = 0.002) and metastatic liver tumor (p = 0.008) as independent risk factors for LTP.

CONCLUSION

History of hepatic resection, ablation and upper abdomen surgery were significant predictive factors affecting the technical failure of AA formation. Successful introduction of AA before thermal ablation can achieve better local tumor control efficacy.

Evaluation of the efficacy and postoperative outcomes of hydrodissection-assisted microwave ablation for subcapsular hepatocellular carcinoma and colorectal liver metastases

PURPOSE

To explore the effect of hydrodissection assisted percutaneous microwave ablation (MWA) on the primary technique efficacy (PTE) and local tumor progression (LTP) of subcapsular hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM).

METHODS

A retrospective review of 135 patients with 181 hepatic subcapsular HCC and CRLM that underwent MWA with (hydrodissection group) and without the use of hydrodissection (control group). The PTE, cumulative LTP rate, and postoperative complications were compared between the two groups.

RESULTS

Amongst the 135 patients with 181 tumors, 60 patients with 72 tumors were in the hydrodissection group and 75 patients with 109 tumors were in the control group. The PTEs were 97.2% and 85.3% in hydrodissection and control groups, respectively (P = 0.019). Multivariate analysis showed that hydrodissection significantly improved the PTE of MWA [odds ratio (OR) 0.147; 95% confidence interval (CI) 0.031-0.703; P = 0.016). Among the tumors which achieved complete response at the first (1 month) follow-up, the overall LTP rates were 8.6% (6/70) and 11.8% (11/93) in the hydrodissection and control groups, respectively. The 1- and 2-year cumulative LTP rates were 3.0% and 5.0% for the hydrodissection group and 6.8% and 13.5% in the control group, respectively (P = 0.391). No significant differences were observed in major postoperative complications between the two groups.

CONCLUSION

Hydrodissection-assisted MWA had a significantly higher PTE than MWA alone in hepatic subcapsular HCC and CRLM. Hydrodissection did not significantly impact the cumulative LTP rate or the incidence of postoperative complications.

The effect of tumor location on long-term results of microwave ablation for early-stage hepatocellular carcinoma

BACKGROUND

To analyze the influence of tumor location, including tumor adjacency and located segments on long-term survival outcomes for patients with solitary hepatocellular carcinoma (HCC) after microwave ablation (MWA).

METHODS

This retrospective study evaluated 850 patients. The hepatic segments where the tumor is located, tumor adjacency (important tissues adjacent to tumor) and other clinical characteristics were collected. Overall survival (OS), local tumor progression (LTP) and disease-free survival (DFS) were compared and analyzed. Influence of tumor location was evaluated by multi-models and the effect of adjacency for OS, LTP, and DFS in different segments was analyzed by stratification analysis.

RESULTS

The OS, LTP, and DFS rates were similar in different hepatic segments, so were in high risk and safe locations. In multi-models, HCC in segment 8 showed lower death rate of 43% than that in segment 2 (HR 0.57; P = 0.01) and tumors in segment 6 seemed to have lower LTP rate. Tumors in high-risk locations were risk factors for OS, LTP, and DFS compared with tumors in safe locations, but all differences were not significant in different models. The effects of tumor adjacency on survival outcomes among subgroups of segments were limited.

CONCLUSION

The tumor adjacency was not a prognostic factor of survival outcomes for patients with solitary tumors after MWA, but tumors in segment 8 seemed to better OS rate than tumors in other segments.

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

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

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

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

Value of artificial ascites to assist thermal ablation of liver cancer adjacent to the gastrointestinal tract in patients with previous abdominal surgery

Background

To evaluate the feasibility and effectiveness of artificial ascites to assist thermal ablation of liver cancer adjacent to the gastrointestinal tract in patients with previous abdominal surgery.

Methods

Thirty-nine patients with a total of 40 liver malignant tumors were enrolled between January 2016 and June 2019. All had histories of hepatectomy, splenectomy, cholecystectomy, and intestinal surgery. The distance between the tumor and the gastrointestinal tract was < 5 mm. Normal saline was used as artificial ascites to protect the gastrointestinal tract during thermal ablation. The success rate of the procedure, incidence of major complications, and the technical efficacy of ablation were recorded. Patients were followed for local tumor progression (LTP), and overall survival (OS).

Results

The use of artificial ascites was successful in 38 of the 40 procedures (95%). Major complications occurred in two of the 39 patients (5.1%) following the procedure. One was an intestinal fistula that occurred in a failed case and was associated with an infection. The other was a liver abscess that occurred in a successful case. The technical efficacy of ablation was 100% (40/40 procedures). The median follow-up was 16 months. The 1-, 2-, and 3-year LTP rates were 2.9, 5.7 and 5.7%. The 1-, 2-, and 3-year OS rates were 97.1, 86.8 and 69.5%.

Conclusion

In patients with previous abdominal surgery, artificial ascites is feasible and effective for assisting thermal ablation of liver cancer adjacent to the gastrointestinal tract.

Complications from percutaneous microwave ablation of liver tumours: a pictorial review

Percutaneous microwave ablation of liver tumours is a well-established technique that has been proven to be effective in the curative and palliative treatment of small volume primary and secondary liver tumours. Microwave ablation is designed to achieve larger areas of necrosis compared to radiofrequency ablation and has a good safety profile among liver tumour treatments. Mortality is unreported and major complications are rare. Knowledge of potential complications is essential for interventional radiologists performing liver ablation in order to reduce patient morbidity. The aim of this review is to illustrate major complications post microwave ablation in a pictorial format as well as a discussion on how best to avoid these complications.

Safety and Efficacy of Percutaneous Cryoablation for Small Hepatocellular Carcinomas Adjacent to the Heart

PURPOSE

This study evaluated the safety and efficacy of percutaneous cryoablation for treatment of the left subdiaphragmatic small hepatocellular carcinomas (HCCs) adjacent to the heart.

MATERIALS AND METHODS

Between September 2013 and March 2018, 189 consecutive patients underwent cryoablation for small HCCs (≤3 cm); 70 patients (mean: 61.3 ± 10.6 years of age; range: 40-82 years) with left hepatic tumors (22 juxtacardiac and 48 nonjuxtacardiac tumors) were retrospectively analyzed. Patients were divided into juxtacardiac and nonjuxtacardiac tumor groups (tumor margins: ≤10 mm and >10 mm, respectively, from the heart border). The rates of technical success, complete ablation, complications, and local tumor recurrence (LTR) were evaluated.

RESULTS

No significant intergroup differences were observed in the mean diameter of the tumor (17.9 ± 5.5 mm vs. 17.5 mm ± 5.2, respectively; P = 0.781) and of the ablation zone (41.3 ± 4.2 mm vs. 43.5 ± 5.8 mm, respectively; P = 0.115). Technical success was achieved in all patients. No procedure-related major complications occurred in either group. The median follow-up period was 15 months (range: 3.1-49.6 months). No statistically significant intergroup differences were observed in the rates of complete ablation (90.9% vs. 93.8%, respectively; P = 0.646) and LTR (20% vs. 15.6%, respectively; P = 0.725).

CONCLUSIONS

Cryoablation is a safe treatment modality for patients with juxtacardiac small HCCs, without an increased risk of cardiac complications compared to treatment of HCCs that are nonjuxtacardiac, and with comparable efficacy.

Clinical Application of Artificial Ascites in assisting CT-guided Percutaneous Cryoablation of Hepatic Tumors Adjacent to the Gastrointestinal Tract

This study was to assess the safety and efficacy of artificial ascitetes in assisting CT-guided cryoablation of hepatic tumors adjacent to the gastrointestinal (GI) tract. A total of 84 patients with peripheral hepatic tumors adjacent to the GI tract, who were treated cryoablation, were included in this retrospective study. Of these 84 patients, cryoablation had been performed in 39 patients with 41 peripheral hepatic tumors. These were assisted by induction artificial ascites while 40 patients with 43 peripheral hepatic tumors underwent cryoablation without induction of ascites. The artificial ascites separation success rate, the cryoablation technique effectiveness, local tumor progression and complications were all evaluated. The results showed that the artificial ascites separation success rate for 41 hepatic tumors adjacent to the GI tract was 95% (39/41). Technique effectiveness of group I was achieved in 35 of 43 tumors (81.3%) after follow-up imaging three months after cryoablation. In group II, technique effectiveness was achieved in 39 of 41 tumors after follow-up imaging three months following cryoablation. No major complications were encountered in either of the two groups. Artificial ascites assisting in CT-guided percutaneous cryoablation is a reliable and effective method for the treatment of hepatic tumors adjacent to the GI tract, and it can achieve a fine local control of such tumors.

Percutaneous Ablation for Hepatocellular Carcinoma and Peritoneal Dialysis

Hepatocellular carcinoma (HCC) is the second leading cause of death by cancer worldwide. Resection and liver transplantation are the gold standards, but only a minority of people are eligible. Percutaneous ablation therapies, such as microwave ablation (MWA), have consequently been developed. There is a lack of guidelines regarding the treatment of HCCs in end-stage renal disease (ESRD) patients. Here, we report the case of a 67-year-old patient who was undergoing peritoneal dialysis (PD) for chronic congestive heart failure and who presented with an HCC while undergoing PD. The tumor size was 48 mm. Due to the patient's comorbidities, MWA was chosen as a first-line treatment. Peritoneal dialysis was stopped 1 day before the MWA, which was performed by an interventional radiology department. There were no complications from the procedure. The treated area completely covered the tumoral lesion. Peritoneal dialysis was resumed 3 weeks after the MWA without any complications. The computed tomography (CT) scan performed 3 months later showed that the tumor mass had completely regressed; a year and a half after the MWA, no recurrence has been observed. This report shows that an MWA of an HCC in PD patients is a feasible and safe procedure.

Ultrasound-guided hydrodissection for assisting percutaneous microwave ablation of renal cell carcinomas adjacent to intestinal tracts: a preliminary clinical study

PURPOSE

To evaluate the safety and efficacy of the clinical application of hydrodissection under ultrasound (US) guidance for assisting percutaneous microwave ablation (MWA) for the treatment of renal cell carcinomas (RCCs) adjacent to the intestinal tract.

MATERIALS AND METHODS

From April 2014 to December 2016, clinical data from 24 patients with 25 RCCs were retrospectively analysed. Percutaneous MWA under the assistance of US-guided hydrodissection were performed to treat RCCs with a mean maximal diameter of 3.80 ± 1.60 cm because the distance between the index tumour and the adjacent intestinal tracts were less than 0.5 cm on imaging. The separation success rate of the hydrodissection, technique efficacy rate of the MWA, local tumour progression (LTP), complications, and renal function including serum creatinine (Cr) and blood urea nitrogen (BUN) were assessed.

RESULTS

In total, 28 sessions of hydrodissection and MWA procedures were performed (one procedure in 22 patients and two procedures in 3 patients), and the separation success rate was 100% (28/28). The technique efficacy rate was 100% (25/25), and no LTP occurred. One patient exhibited a major complication (4.2%). Minor complications in 5 patients (20.8%) and side effects in 12 patients (50.0%) occurred. Compared with the pre-MWA levels, there were no significant differences in serum Cr and BUN 1-day post-MWA and at the last follow-up.

CONCLUSIONS

US-guided hydrodissection assistance for percutaneous MWA could be a safe and effective alternative for selected patients with RCCs adjacent to the intestinal tracts and can achieve good local tumour control and renal function preservation.

Effect of a poloxamer 407-based thermosensitive gel on minimization of thermal injury to diaphragm during microwave ablation of the liver

AIM

To assess the insulating effect of a poloxamer 407 (P407)-based gel during microwave ablation of liver adjacent to the diaphragm.

METHODS

We prepared serial dilutions of P407, and 22.5% (w/w) concentration was identified as suitable for ablation procedures. Subsequently, microwave ablations were performed on the livers of 24 rabbits (gel, saline, control groups, n = 8 in each). The P407 solution and 0.9% normal saline were injected into the potential space between the diaphragm and liver in experimental groups. No barriers were applied to the controls. After microwave ablations, the frequency, size and degree of thermal injury were compared histologically among the three groups. Subsequently, another 8 rabbits were injected with the P407 solution and microwave ablation was performed. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN) and creatinine (Cr) in serum were tested at 1 d before microwave ablation and 3 and 7 d after operation.

RESULTS

In vivo ablation thermal injury to the adjacent diaphragm was evaluated in the control, saline and 22.5% P407 gel groups (P = 0.001-0.040). However, there was no significant difference in the volume of ablation zone among the three groups (P > 0.05). Moreover, there were no statistical differences among the preoperative and postoperative gel groups according to the levels of

ALT, AST, BUN and Cr in serum (all P > 0.05).

CONCLUSION

Twenty-two point five percent P407 gel could be a more effective choice during microwave ablation of hepatic tumors adjacent to the diaphragm. Further studies for clinical translation are warranted.

Microwave ablation for hepatocellular carcinoma associated with Budd-Chiari syndrome after transarterial chemoembolization: an analysis of ten cases

PURPOSE

To evaluate the feasibility, efficacy, and safety of microwave ablation (MWA) in the treatment of hepatocellular carcinoma associated with Budd-Chiari syndrome (BCS) after transarterial chemoembolization (TACE).

METHODS

A total of 10 patients (mean 50.0 ± 7.5 years) with 15 BCS-associated HCC lesions were retrospectively evaluated. All patients received MWA treatment for residual tumors after 1 to 3 sessions of TACE. The diagnosis of residual tumors was confirmed by at least two types of enhanced imaging. CEUS images were performed to confirm the residual lesions and guide the placement of antenna before MWA. Thermal monitoring and artificial pleural effusion or ascites were used to guarantee ablative accuracy and safety for patients with tumors adjacent to vital structures. Technical success, technique efficacy, local tumor progression, survival rate, and the incidence of complications were comprehensively analyzed.

RESULTS

Technical success and technique effectiveness were achieved in all patients. Thirteen lesions achieved complete ablation for the first time, and 2 lesions needed two sessions. Thermal monitoring was used in 2 patients, artificial pleural effusion was used in 1 patient, and artificial ascites in 2 patients. In a median follow-up of 34.5 months (range 21-52 months), no LTP was founded in all patients. Intrahepatic recurrence was found in 5 patients. 1-, 2-, 3-, and 4-year survival rates were 100%, 100%, 74.1%, and 37.0%, respectively. No major or minor complications were observed.

CONCLUSION

Microwave ablation is a feasible and effective way to treat residual tumors after TACE treatment in patients with BCS-associated HCC.

Status and advancement of microwave ablation in China

Tumour ablation is defined as the direct application of chemical or thermal therapy to eradicate or substantially destroy a tumour. Currently, minimally invasive ablation techniques are available for the local destruction of focal tumours in multiple organ sites. Microwave ablation (MWA) is premised on the biological response of solid tumours to tissue hyperthermia, and it is a relatively low-risk procedure. Due to several advantages of MWA, including higher thermal efficiency, higher capability for coagulating blood vessels, faster ablation time and the simultaneous application of multiple antennae, MWA could be a promising minimally invasive ablation technique for the treatment of solid tumours. Therefore, the use of MWA has developed rapidly in China during the last decade. Many successful studies have been performed, and widespread use has been achieved for multiple types of tumours in China, especially for liver cancer. This review will describe the state-of-the-art of MWA in China, including the development of MWA equipment and its application in the treatment of multiple types of tumours.

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.

Microwave ablation in primary and secondary liver tumours: technical and clinical approaches

Thermal ablation is increasingly being utilised in the treatment of primary and metastatic liver tumours, both as curative therapy and as a bridge to transplantation. Recent advances in high-powered microwave ablation systems have allowed physicians to realise the theoretical heating advantages of microwave energy compared to other ablation modalities. As a result there is a growing body of literature detailing the effects of microwave energy on tissue heating, as well as its effect on clinical outcomes. This article will discuss the relevant physics, review current clinical outcomes and then describe the current techniques used to optimise patient care when using microwave ablation systems.

Ultrasound-Guided Percutaneous Microwave Ablation for Hepatocellular Carcinoma in the Caudate Lobe

Treatment for liver tumors in the caudate lobe is challenging because of their location and complex anatomy. This study was intended to evaluate the feasibility, efficacy and tolerability of ultrasound-guided percutaneous microwave (MW) ablation for treating hepatocellular carcinoma (HCC) in the caudate lobe. From December 2011 to May 2015, a total of 20 patients (mean age: 62 ± 11 y) with HCC in the caudate lobe were enrolled in this study. Patient characteristics and tumor features were analyzed. The epigastric approach, intercostal approach and the combination were used in 4, 14 and 2 patients, respectively. Contrast-enhanced ultrasound (CEUS) guidance and temperature monitoring were applied as ancillary techniques. Ethanol injection was performed for tumors adjacent to the inferior vena cava or hepatic hilum. Contrast images were performed to evaluate treatment response after ablation. Technical success, technique efficacy, local tumor progression and complications were documented. Technique efficacy was achieved in 18 patients (18/20, 90%). Two patients received (125)I brachytherapy as palliative therapy for residual tumors that could not be ablated technically after the first ablation. Technical success was achieved in 16 patients (16/20, 80%). In 2 patients, ablation was completed after two sessions. CEUS was applied in 5 patients and temperature monitoring in 2 patients. Eight patients received an ethanol injection during ablation. Eleven patients achieved a minimum 5-mm safety margins. Local tumor progression was detected in 3 patients (16.7%, 3/18) during a median follow-up of 18.4 mo (range: 3-45 mo). Tumors in these 3 patients were all larger than 2.0 cm. No major or minor complications were observed. In conclusion, ultrasound-guided percutaneous microwave ablation combined with CEUS, temperature monitoring, and ethanol injection is a tolerable and relatively effective treatment for HCC in the caudate lobe.

Comparison of real-time contrast-enhanced ultrasonography and standard ultrasonography in liver cancer microwave ablation

Primary liver cancer has a high incidence and high mortality rates, and currently the only viable option is surgery, although there are a number of difficulties related to this method. The aim of the present study was to investigate the potential advantages of the real-time contrast-enhanced ultrasonography (CEUS) for microwave ablation of primary liver cancer. One hundred patients with primary liver cancer were included in the study. The patients were divided into the ordinary ultrasonography and the CEUS groups. For the ordinary ultrasonography group, the ordinary ultrasonography-guided microwave ablation method was used, while microwave ablation under the guidance of CEUS was conducted for the CEUS group. The size of lesions and clearness of the tumor boundary prior to surgery in the two groups were compared. Additionally, postoperative complications and the survival rate were monitored. Lesion boundary areas measured by CEUS were significantly larger than those measured with ordinary ultrasonography. The incidence rate of postoperative pain, fever, intra-abdominal hemorrhage and infection and other complications in the ordinary ultrasonography group were significantly higher than that in the CEUS group. The tumor recurrence rate in the CEUS group was significantly lower than that in the ordinary ultrasonography group. Seventy-two percent of patients in the CEUS group showed no progress, compared to 48% of in the ordinary ultrasonography group. The progress-free survival rate in the CEUS group after 6 months was significantly higher than that in the ordinary ultrasonography group. Disease-free survival time in the CEUS group was considerably longer than the control group. In conclusion, the guidance of real-time CEUS on the primary liver cancer microwave ablation treatment can achieve good intra-operative results. It offers a real-time guidance effect, improves survival time and reduces the incidence of complications.

Microwave ablation for liver tumors

Surveillance programs and widespread use of medical imaging have increased the detection of hepatic tumors. When feasible, surgical resection is widely accepted as the curative treatment of choice, but surgical morbidity and mortality has spurred the development of minimally invasive ablative technologies over the last 2 decades. Microwave ablation has emerged as a promising thermal ablation modality with improving oncologic efficacy due to technical improvements and image guidance strategies. This article provides an overview of microwave application in liver tumors, and we discuss currently available equipment, clinical efficacy, and safety and provide comparisons with other commonly used therapies. This article also introduces advanced ablative techniques and combination therapies that may help achieve precise ablation and further enhance the efficacy of microwave ablation.

Percutaneous microwave ablation for liver tumours adjacent to the marginal angle

PURPOSE

This study was designed to describe the technical essentials of microwave ablation (MWA) for tumours adjacent to the liver marginal angle (LMA) and to determine the feasibility, safety and efficacy of this approach.

MATERIALS AND METHODS

A total of 22 patients with primary or metastatic liver tumours adjacent to the LMA were enrolled. There were 19 small tumours (≤3 cm) and three larger tumours (>3 cm) with maximum diameters ranging from 0.7-2.7 cm (mean 1.7 ± 0.6 cm) and 4.7-6.6 cm (mean 5.4 ± 1.0 cm), respectively. For small tumours the entire acute angle was segmentally blocked utilising MWA. For larger tumours, the feeding arteries were initially blocked with ethanol before conformal ablation. Artificial ascites, real-time monitoring, small ethanol doses, colour Doppler flow imaging or contrast enhanced ultrasound guidance was used as an additional technique to assist with ablation. Contrast imaging was performed to evaluate the ablative efficacy. Treatment responses, local tumour progression (LTP) and complications were recorded.

RESULTS

All patients achieved a complete response. LTP was identified in two cases (9.1%) during the 4.5 month median follow-up period (range 2-29 months). A total of five additional sessions were performed, and secondary effectiveness was achieved in patients with LTP. No major complications were observed.

CONCLUSIONS

Percutaneous MWA is a new promising technique for tumours adjacent to the LMA, especially in cases with small tumours. Technical improvements to this procedure are expected to improve the results for large tumours abutting the LMA.

Microwave ablation of malignant hepatic tumours: intraperitoneal fluid instillation prevents collateral damage and allows more aggressive case selection

PURPOSE

Theaim of this peper was to retrospectively review our experience utilising protective fluid instillation techniques during percutaneous microwave ablation of liver tumours to determine if fluid instillation prevents non-target injuries and allows a more aggressive case selection.

MATERIALS AND METHODS

This institute review board-approved, U.S. Health Insurance Portability and Accountability Act-compliant, retrospective study reviewed percutaneous microwave ablation of 151 malignant hepatic tumours in 87 patients, comparing cases in which protective fluid instillation was performed with those where no fluid was utilised. In cases utilising hydrodisplacement for bowel protection, a consensus panel evaluated eligibility for potential ablation without hydrodisplacement. Patient age, tumour size, local tumour progression rate, length of follow-up, complications, displacement distance/artificial ascites thickness, and treatment power/time were compared.

RESULTS

Fluid administration was utilised during treatment in 29/151 of cases: 10/29 for protection of bowel (8/10 cases not possible without fluid displacement), and 19/29 for body wall/diaphragm protection. Local tumour progression was higher when hydrodisplacement was used to protect bowel tissue; this may be due to lower applied power due to operator caution. Local tumour progression was not increased for artificial ascites. There was no difference in complications between the fluid group and controls.

CONCLUSION

Intraperitoneal fluid administration is a safe and effective method of protecting non-target structures during percutaneous hepatic microwave ablation. While hydrodisplacement for bowel protection allows more aggressive case selection, these cases were associated with higher rates of local tumour progression.

Safety assessment and therapeutic efficacy of percutaneous microwave ablation therapy combined with percutaneous ethanol injection for hepatocellular carcinoma adjacent to the gallbladder

OBJECTIVE

This study sought to evaluate the safety and efficacy of ultrasound-guided (US-guided) percutaneous microwave (MW) ablation combined with percutaneous ethanol injection (PEI) to treat liver tumours adjacent to the gallbladder.

MATERIALS AND METHODS

A total of 136 patients with hepatocellular carcinoma (HCC) adjacent to the gallbladder, who underwent ultra-sonographically-guided percutaneous MW ablation, which was combined with PEI in 132 patients, were retrospectively assessed. The patient population characteristics, tumour features, local tumour progression and treatment were compared and analysed. The safety and efficacy of the therapy were assessed by clinical data and imaging in follow-up examinations.

RESULTS

All patients were completely treated with two sessions; 120 patients underwent one session, 16 patients underwent two sessions. The primary technique was effective in 95.6% of the cases, according to the computed tomography (CT) or magnetic resonance imaging (MRI) in the one-month follow-up (132 of 138 sessions). PEI and other therapies were performed in the patients who had been incompletely treated (all six patients underwent PEI, and some underwent other therapies, including one transcatheter arterial chemoembolisation (TACE), one liver transplantation and two liver resections). There was a median follow-up period of 30.1 months and a range of 4 to 68 months. None of the patients had major complications. There were no treatment-related deaths. Twenty-six patients died of primary disease progression that was not directly attributable to MW ablation (19.1%, 26/136). Local tumour progression was noted in five patients (3.7%, 5/136), who had completely ablated tumours at follow-up. The patients with locally progressing tumours underwent additional therapy (three patients underwent PEI, one patient TACE, and one liver resection).

CONCLUSION

Ultrasound-guided percutaneous MW ablation, in combination with percutaneous ethanol injection and thermal monitoring, is a safe and effective treatment for HCC adjacent to the gallbladder.