Early Outcomes with Single-antenna High-powered Percutaneous Microwave Ablation for Primary and Secondary Hepatic Malignancies: Safety, Effectiveness, and Predictors of Ablative Failure

Anatomic sub-segmentectomy with single-session combined transcatheter arterial embolization/microwave ablation for the treatment of hepatocellular carcinoma: preliminary results

PURPOSE

This retrospective study aimed to confirm the safety and long-term efficacy of a single-session combined treatment approach with transcatheter arterial embolization (TAE) and microwave ablation (MWA) for inoperable small-to intermediate-sized hepatocellular carcinomas (HCC), focusing on their combined benefits for improving local control.

MATERIALS AND METHODS

All consecutive patients with up to 2 small-to-intermediate HCC lesions (≤ 5 cm) treated with a combined single-session MWA-TAE approach were enrolled between April 2020 and October 2023. All procedures were performed in two stages: TAE and MWA. Clinical and radiological follow-up was performed 3, 6, and 12 months after treatment.

RESULTS

In the 21 enrolled patients (15 males, mean age 75.9 years), post-procedural contrast-enhanced CT scans confirmed a satisfactory ablation zone in all patients (100%), with minor peri-procedural complications reported in three patients (14%). At the last 12-month follow-up, one patient (8%) displayed local tumor progression, previously classified as LR-TR equivocal at the 6-month follow-up, and half of the patients (6 patients, 50%) exhibited distant tumor progression, predominantly in the form of intra-hepatic recurrence.

CONCLUSION

The combined approach of TAE and MWA is a promising method to enhance the percutaneous treatment of small to intermediate-sized HCCs with a resulting anatomic ablation area resembling a surgical sub-segmentectomy. This technique can potentially reduce the gap between percutaneous treatment and liver resection outcomes, allowing for a safe and effective option for oncological control in patients with > 3 cm lesions.

Radioactive seed localization is a safe and effective tool for breast cancer surgery: an evaluation of over 25,000 cases

Radioactive seed localization (RSL) provides a precise and efficient method for removing non-palpable breast lesions. It has proven to be a valuable addition to breast surgery, improving perioperative logistics and patient satisfaction. This retrospective review examines the lessons learned from a high-volume cancer center's RSL program after 10 years of practice and over 25 000 cases. We provide an updated model for assessing the patient's radiation dose from RSL seed implantation and demonstrate the safety of RSL to staff members. Additionally, we emphasize the importance of various aspects of presurgical evaluation, surgical techniques, post-surgical management, and regulatory compliance for a successful RSL program. Notably, the program has reduced radiation exposure for patients and medical staff.

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

Objectives

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

Material and Methods

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

Results

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

Conclusion

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

Current perspectives on microwave ablation of liver lesions in difficult locations

Microwave ablation (MWA) is becoming the standard of care in treating liver lesions smaller than 3 cm benefiting from a plethora of radiofrequency ablation (RFA) data in the literature. Some of the advantages of MWA compared to RFA are as follows: Faster ablations, more reproducible and predictable heating, better thermal conductivity in different liver tissue environments, and less susceptibility to heat-sink effect. Despite its many advantages, there are still concerns regarding MWA use in high-risk locations such as near portal veins, near the bile ducts, and near the heart. Some centers have historically considered these tumor locations as a contraindication to percutaneous thermal ablation. In this review, we summarize the current data on the safety of MWA of liver tumors in challenging locations. We also discuss several technical tips with examples provided.

Percutaneous Thermal Segmentectomy: Proof of Concept

AIM

To report the multicenter retrospective experience on combination of balloon-occluded MWA(b-MWA) followed by balloon-occluded TACE(b-TACE) in patients with liver malignancies > 3 cm, focusing on appearance and volume of necrotic area, safety profile and oncological results.

MATERIALS AND METHODS

Twenty-three patients with liver primary malignancies (hepatocellular carcinoma,HCC = 18; intrahepatic cholangiocarcinoma,iCC = 2) and metastasis (colorectal cancer metastasis = 1;sarcoma metastasis = 1;breast metastasis = 1) were treated. Maximum mean diameter of lesions was 4.4 cm (± 1 cm). Treatments were performed using a single-step approach:b-MWA was performed after balloon-microcatheter inflation, followed by b-TACE (with epirubicin or irinotecan). Necrotic area shape and discrepancy with the expected volume of necrosis suggested by vendor's ablation chart were assessed at post-procedural CT. Complications were categorized according to CIRSE classification. Oncological results at 1 and 3-6 months were evaluated using m-RECIST(HCC) and RECISTv1.1(metastasis/iCC).

RESULTS

Mean volume of necrotic area was 75 cm³ (± 36). Discrepancy with vendor chart consisted in a medium percentage of volumetric incrementation of necrotic area of 103.2% (± 99.8). Non-spherical shape was observed in 22/23 patients (95.7%). No complications occurred; Post-embolization syndrome occurred in 12/23patients. Complete response and partial response were, respectively, 91, 3% (21/23) and 8.7% (2/23) at 1 month, 85.7% (18/21) and 9.5% (2/21) at 3-6 months. Progression of disease was 4.7% (1/21) at 3-6 months for extra-hepatic progression. Among partial responders, average percentage of tumor volume debulking was 78.8% (± 9.8%).

CONCLUSION

b-MWA followed by b-TACE in a single-step procedure led to larger necrotic areas than the proposed by vendors ablation chart, non-spherical in shape and corresponded to the vascular segment occluded during ablation. This permitted to safely achieve promising oncological results in patients with > 3 cm tumors.

On Efficacy of Microwave Ablation in the Thermal Treatment of an Early-Stage Hepatocellular Carcinoma

Microwave ablation at 2.45 GHz is gaining popularity as an alternative therapy to hepatic resection with a higher overall survival rate than external beam radiation therapy and proton beam therapy. It also offers better long-term recurrence-free overall survival when compared with radiofrequency ablation. To improve the design and optimization of microwave ablation procedures, numerical models can provide crucial information. A three-dimensional model of the antenna and targeted tissue without homogeneity assumptions are the most realistic representation of the physical problem. Due to complexity and computational resources consumption, most of the existing numerical studies are based on using two-dimensional axisymmetric models to emulate actual three-dimensional cancers and surrounding tissue, which is often far from reality. The main goal of this study is to develop a fully three-dimensional model of a multislot microwave antenna immersed into liver tissue affected by early-stage hepatocellular carcinoma. The geometry of the tumor is taken from the 3D-IRCADb-01 liver tumors database. Simulations were performed involving the temperature dependence of the blood perfusion, dielectric and thermal properties of both healthy and tumoral liver tissues. The water content changes during the ablation process are also included. The optimal values of the input power and the ablation time are determined to ensure complete treatment of the tumor with minimal damage to the healthy tissue. It was found that a multislot antenna is designed to create predictable, large, spherical zones of the ablation that are not influenced by varying tissue environments. The obtained results may be useful for determining optimal conditions necessary for microwave ablation to be as effective as possible for treating early-stage hepatocellular carcinoma, with minimized invasiveness and collateral damages.

Comparing the Safety and Efficacy of Microwave Ablation Using ThermosphereTM Technology versus Radiofrequency Ablation for Hepatocellular Carcinoma: A Propensity Score-Matched Analysis

Simple Summary

Microwave ablation using Thermosphere^TM technology is a novel locoregional treatment for hepatocellular carcinoma. This study compared the safety and efficacy outcomes of this microwave ablation strategy versus radiofrequency ablation using propensity score-matched analysis. Microwave ablation led to a high rate of curative ablation (94.7%) and a low rate of local recurrence (3.3%), with an overall survival rate of 99.3% at 1 year (recurrence-free survival: 81.1%) and 88.4% at 2 years (recurrence-free survival: 60.5%). There were no significant differences in survival outcomes after microwave and radiofrequency ablation. However, microwave ablation required significantly fewer insertions (1.22 ± 0.49 vs. 1.59 ± 0.94; p < 0.0001). Based on the similar survival outcomes, we recommend microwave ablation using Thermosphere^TM technology for hepatocellular carcinoma with a diameter of >2 cm because of the lower number of insertions.

Abstract

There is limited information regarding the oncological benefits of microwave ablation using Thermosphere^TM technology for hepatocellular carcinoma. This study compared the overall survival and recurrence-free survival outcomes among patients with hepatocellular carcinoma after microwave ablation using Thermosphere^TM technology and after radiofrequency ablation. Between December 2017 and August 2020, 410 patients with hepatocellular carcinoma (a single lesion that was ≤5 cm or ≤3 lesions that were ≤3 cm) underwent ablation at our institution. Propensity score matching identified 150 matched pairs of patients with well-balanced characteristics. The microwave ablation and radiofrequency ablation groups had similar overall survival rates at 1 year (99.3% vs. 98.2%) and at 2 years (88.4% vs. 87.5%) (p = 0.728), as well as similar recurrence-free survival rates at 1 year (81.1% vs. 76.2%) and at 2 years (60.5% vs. 62.1%) (p = 0.492). However, the microwave ablation group had a significantly lower mean number of total insertions (1.22 ± 0.49 vs. 1.59 ± 0.94; p < 0.0001). This retrospective study revealed no significant differences in the overall survival and recurrence-free survival outcomes after microwave ablation or radiofrequency ablation. However, we recommend microwave ablation for hepatocellular carcinoma tumors with a diameter of >2 cm based on the lower number of insertions.