Percutaneous microwave ablation vs radiofrequency ablation in the treatment of hepatocellular carcinoma

Microwave ablation for benign thyroid nodules with cosmetic problems and related factors for post-ablative complete relief: a two-center retrospective study

PURPOSE

To investigate the efficacy of ultrasound (US)-guided percutaneous MWA for benign thyroid nodules with cosmetic problems and identify related factors contributing to post-ablative complete relief (CR).

METHODS

This retrospective study reviewed the efficacy of MWA in treating thyroid nodules in patients with cosmetic problems who underwent MWA from January 2021 to May 2023. Patients were followed up at 1, 3, and 6 months after MWA. Pre-treatment clinical characteristics, conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS) features were analyzed to explore their correlation with cosmetic improvement, defined as a cosmetic score of 1 or 2 at the 6-month follow-up. Univariable and multivariable regression analyses were carried out to identify variables associated with CR, and the related nomogram was established. Calibration curve and decision curve analysis were used to evaluate the nomogram performance.

RESULTS

118 patients with 118 nodules were included in the study. During the 1-, 3- and 6-month follow-up, the mean volume reduction ratios (VRR) were 2%, 36% and 73%, respectively. 22.0% (26/118), 57.6% (68/118), and 89.8% (106/118) patients achieved CR of cosmetic problems at 1, 3, and 6 months after MWA. In multivariable analysis, three variables (i.e., non-hashimoto's thyroiditis [HT] [OR: 90.036, P = 0.001], nodule location not close to danger triangle area [OR: 66.812, P = 0.003], early hyperenhancement on CEUS [OR: 0.035, P = 0.024]) were found to be closely associated with CR of cosmetic problems at 6 months after MWA. A nomogram model was constructed, and its accuracy was well validated (i.e., C-index = 0.914).

CONCLUSION

MWA was effective and safe for treating benign thyroid nodules with cosmetic problems. Non-HT, nodule location not close to danger triangle area, and early hyperenhancement on CEUS were associated with CR of cosmetic problems after MWA.

Embolic and Ablative Therapy for Hepatocellular Carcinoma

Embolic and ablative locoregional therapies (LRTs) for hepatocellular carcinoma are widely used to cure, bridge, or downstage patients for more definitive therapies. Common ablative therapies include microwave ablation and radiofrequency ablation, while embolic options include transarterial chemoembolization and 90Y transarterial radioembolization. While these therapies can be highly effective for the appropriate stage of disease, LRTs can suffer from a high rate of posttreatment recurrences. Considerations for administration of specific therapies include disease burden and underlying liver function. Recent data on concomitant or adjuvant systemic therapy, with LRT, have the potential to improve disease control and improve outcomes in this high-risk patient population.

Comparative efficacy and safety of radiofrequency ablation and microwave ablation in benign thyroid nodule treatment: a systematic review and meta-analysis

OBJECTIVE

Ultrasound-guided thermal ablation, including radiofrequency ablation (RFA) and microwave ablation (MWA), has become one of the main options for treating benign thyroid nodules (BTNs). To assess the efficacy of thermal ablation of BTNs, we performed a systematic review and meta-analysis of relevant studies.

MATERIALS AND METHODS

A comprehensive search of MEDLINE, EMBASE, and COCHRANE databases was performed up to September 25, 2023, to identify studies directly comparing RFA and MWA for pathologically proven BTNs and reporting clinical outcomes and complications. Data extraction and quality assessment were independently performed by two radiologists according to PRISMA guidelines. The analysis yielded the serial volume reduction ratios (VRRs) of ablated nodules for up to 12 months, symptom and cosmetic scores, and complications.

RESULTS

This analysis included nine studies with 1305 BTNs treated by RFA and 1276 by MWA. VRRs at 1 month, 3 months, and 6 months were similar between RFA and MWA, but RFA showed a significantly higher VRR (83.3%) than MWA (76.9%) at 12 months (p = 0.02). Complication rates showed no significant difference between the two methods. Symptom and cosmetic scores significantly decreased after ablation, without a significant difference between the methods. Subgroup analysis indicated a significantly higher VRR at 12 months for RFA than for MWA for less experienced investigators (≤ 10 years), but no significant difference for more experienced investigators (> 10 years).

CONCLUSION

RFA and MWA are both effective and safe methods for treating BTNs. RFA showed a higher VRR at 12 months and seems more suitable for less experienced investigators.

CLINICAL RELEVANCE STATEMENT

RFA and MWA are both effective and safe treatments for BTNs, with RFA showing a higher VRR at 12 months. Both methods offer minimally invasive and reliable treatment for thyroid nodules.

KEY POINTS

The most effective thermal ablation technique for BTNs remains undetermined. RFA showed a higher VRR at 12 months than MWA. Both techniques are effective for treating thyroid nodules; RFA offers greater benefits, particularly for less experienced investigators.

Minimally Invasive Image-Guided Percutaneous Irreversible Electroporation of Adrenal Metastases

PURPOSE

A single-center retrospective study was performed to evaluate the safety and efficacy of minimally invasive irreversible electroporation (IRE) to treat metastatic adrenal tumors.

MATERIALS AND METHODS

This single-center study, approved by the Institutional Review Board, retrospectively analyzed six patients who underwent image-guided percutaneous IRE for adrenal metastases. Pre-procedural imaging included CT, MRI and/or 18F-FDG PET-CT scans. Primary outcomes measures included technical success, efficacy and safety, while secondary outcome measures were local progression-free survival (LPFS), distant progression-free survival (DPFS) and overall survival (OS). Follow-up scans were scheduled post-procedure, and data analysis employed Excel, SPSS and R.

RESULTS

Patients had diverse primary tumor origins including renal cell carcinoma (2/6), colorectal carcinoma (1/6), non-small cell lung carcinoma (1/6), leiomyosarcoma (1/6) and urothelial carcinoma (1/6). Adverse events were minimal, with only one grade 1 complication reported. Tumor characteristics revealed tumors close to critical structures, with a median pre-ablation size of 23 mm. Technical success was achieved in all procedures. At first follow-up, one patient had complete response, one patient had partial response of the right adrenal gland and complete response of the left adrenal gland, two patients had partial response and two patients had stable disease. Local tumor progression occurred in two out of seven tumors with a median LPFS of 10.9 months, and distant progression was observed in four out of six patients.

CONCLUSION

Percutaneous, minimally invasive IRE shows promise as a safe treatment option for unresectable metastatic adrenal tumors, demonstrating potential effectiveness. However, further studies with larger patient cohorts are needed to confirm its safety and efficacy.

Development and management of iatrogenic biloma post microwave ablation of solitary metastatic breast cancer lesion in the liver

Thermal ablation is used to treat liver metastasis including those from breast cancer. The ablation is associated with pain, hemorrhage, and biliary structure damage leading to bilomas. Biloma is a collection of bile that can occur inside or outside the biliary system, which could happen as a rare complication of surgery (from procedures like abdominal surgery or diagnostic procedures), trauma, or spontaneously. We report a case of biloma development after microwave ablation (MWA) of a metastatic lesion in the liver. We present a 66-year-old female diagnosed with stage 4 intraductal carcinoma of the right breast with metastasis to the liver. She developed biloma and infarction of the left lobe of the liver following MWA, which was treated with percutaneous internal/external biliary drain placement. Her symptoms and liver function tests were completely resolved after 3 months, and her left hepatic lobe completely atrophied in the same period. Biloma is a rare but concerning complication of MWA, therefore high suspicion should be maintained in patients presenting with cholestatic symptoms and fever postprocedure. When identified, drainage with antibiotic therapy can effectively treat biloma and resolve the symptoms.

The Efficacy and Safety of a Microwave Ablation System with a Dipole Antenna Design Featuring Floating Sleeves and Anti-Phase Technology in Stereotactic Percutaneous Liver Tumor Ablation: Results from a Prospective Study

Purpose: To evaluate the efficacy and safety of the Surgnova Dophi™ M150E microwave ablation system in a prospective single-center observational study. Methods: A cohort of 50 patients with 77 primary or secondary liver tumors underwent CT-navigated stereotactic percutaneous microwave ablation with curative intention using the Surgnova Dophi™ M150E system. The endpoints were primary technique efficacy (PTE), number of complications, ablation defect dimensions, and sphericity index compared to previously reported findings. Results: The PTE was 97.4%, with complete ablation in 75 out of 77 tumors. Complications occurred in 10% of patients, with 4% classified as major. A comparison with previous in vivo data confirmed the reliability of the system in achieving reproducible and predictable ablation results. Conclusions: Stereotactic percutaneous microwave ablation with the Surgnova Dophi™ M150E system is safe and effective for liver tumor treatment.

Percutaneous microwave ablation of HCC: comparison between 100 and 150 W technology systems

PURPOSE

To evaluate the differences in efficacy and safety between the 100 and 150 W percutaneous microwave ablation (MWA) systems in the treatment of hepatocellular carcinoma (HCC).

METHODS

We retrospectively reviewed all patients who underwent percutaneous MWA (Emprint™ HP Ablation System, Medtronic) between January 2021 and May 2023. We divided the cohort into two groups: Group 1, treated with MWA at 100 W power system, and Group 2, treated with 150 W one. Effectiveness was defined as the absence of residual disease at 1-month CT follow-up; safety was defined as the absence of grade II-VI complications.

RESULTS

A total of 135 HCC nodules were treated with MWA in 87 patients with a median age of 66 ± 10 years: 76 procedures in 42 patients were carried out in group 1, while 59 procedures in 45 patients in group 2. Cases treated with 150 W had a shorter ablation time (p: 0.002; mean 227.37 ± 92.5 vs 180.51 ± 75.6 s (100 vs 150 W)) and a larger ablation volume (p 0.008; mean 13,920.0 ± 10,723.2 vs 21,241.4 ± 18,374.7 mm3 (100 vs 150 W)), and a major effectiveness at 1-month CT follow-up (p: 0.013). A higher rate of complications (grade II and III) was observed in Group 2 (p < 0.001).

CONCLUSIONS

In conclusion, these preliminary results showed a good correlation between intended-to-treat area and ablation volume and intended-to-treat area and ablation time for both Groups. A minor ablation time, and major ablation volume, but also a higher incidence of complications was observed in 150 W Group.

Transarterial chemoembolization combined with microwave ablation versus repeated resection for recurrent small hepatocellular carcinoma after resection: What is the better treatment?

PURPOSE

This study aimed to compare the effectiveness of transcatheter arterial chemoembolization combined with microwave ablation (TACE-MWA) versus repeated hepatic resection (RHR) in patients with recurrent small hepatocellular carcinoma (sHCC) following primary resection.

MATERIALS AND METHODS

A total of 59 patients diagnosed with recurrent sHCC (≤3 cm) and treated with either TACE-MWA or RHR were recruited from two centers between June 2015 and October 2021. Patients were matched using propensity scores at a 1:1 ratio. Disease-free survival (DFS), overall survival (OS), and complications were assessed and compared between the two treatment groups.

RESULTS

After propensity score matching, 38 patients were included, with 19 in each group. Prior to matching, the 1-, 3-, and 5-year DFS rates for the TACE-MWA group were 68.1%, 46.6%, and 23.3%, respectively, and for the RHR group, they were 84.6%, 47.3%, and 47.3%, respectively. The corresponding 1-, 3-, and 5-year OS rates for TACE-MWA were 100.0%, 83.7%, and 47.8%, while for RHR, they were 100.0%, 95.0%, and 45.2%. After matching, the 1-, 3-, and 5-year DFS rates were 78.0%, 48.3%, and 24.1% for TACE-MWA, and 77.5%, 38.7%, and 38.7% for RHR. The 1-, 3-, and 5-year OS rates for TACE-MWA were 100.0%, 88.9%, and 54.9%, and for RHR, they were 100.0%, 93.3%, and 44.4%. Statistical analysis showed no significant differences in DFS rates (P=0.834 before matching, P=0.490 after matching) or OS rates (P=0.825 before matching, P=0.625 after matching) between the two groups.

CONCLUSIONS

TACE-MWA demonstrates comparable effectiveness to RHR in managing recurrent sHCC.

Comparative Efficacy of Microwave versus Radiofrequency Ablation in Hepatocellular Carcinoma: Systematic Review and Meta-Analysis of Randomized-Controlled Trials

Introduction: Hepatocellular carcinoma (HCC) is a leading global cause of cancer-related deaths. Thermal ablation techniques, especially radiofrequency ablation (RFA) and microwave ablation (MWA), have become pivotal treatments for HCC. This systematic review and meta-analysis aim to compare these modalities, highlighting their efficacy, strengths, and limitations in treating HCC. Methods: A comprehensive literature search was conducted across major databases (PubMed, MEDLINE, Springer, ProQuest, EBSCOhost, Cochrane, and EMBASE) targeting studies on hepatocellular carcinoma with RFA and MWA. Heterogeneity analyses and pooled outcomes using random-effect models with were evaluated to compare both thermal ablation methods. Results: Nine studies, which consists of 368 patients underwent RFA and 387 patients underwent MWA, were included in review. The findings showed no significant differences in pooled analysis of volume of ablation, complete ablation rate, local tumor progression, survival rates, major complications, and adverse events. Subgroup analysis showed significantly higher risk of local tumor progression in RFA in African populations. Conclusion: No statistically significant difference was seen between outcomes across studies. MWA may offer a potential for longer therapeutic response with comparable risk of complications and adverse outcomes.

Tissue Radiologic and Pathologic Response to Biphasic Pulsed Electric Field Technology in a Porcine Model

PURPOSE

To evaluate the radiologic, pathologic, and safety characteristics of a commercially available pulsed electric field (PEF) ablation system in a porcine model.

MATERIALS AND METHODS

Monopolar biphasic PEF ablation was delivered to the liver, kidney, and longissimus dorsi muscle through a single needle via a percutaneous or open approach with the Aliya System (Galvanize Therapeutics, Redwood City, California). Six animals were ablated and evaluated in 2 cohorts (Day 3 and Day 28). Muscle, kidney, and liver were ablated in each animal. Intraprocedural cone-beam computed tomography (CT), follow-up weekly CT, blood serology, gross pathology, and histopathology were performed to characterize the radiographic evolution and tissue response.

RESULTS

There were no adverse events and no findings of electrocardiographic abnormalities, and serologic values returned to baseline by Day 28. Ablation zones were visible on unenhanced CT images during follow-up. Most identified zones became radiographically smaller over time, with some fully resolved by Day 28. The relative decrease in gross ablation zone diameter in the liver and skeletal muscle was 20% and 26%, respectively, whereas kidney sites grew in diameter by 22%. Ablation sites were focal and contained within the intended target tissue without extension to nontarget tissues or collateral structures.

CONCLUSIONS

The biphasic PEF system evaluated here resulted in a safe and predictable ablation response, with preservation of structural tissues in an animal model, offering an alternative to thermal ablative modalities, particularly near critical structures.

Comparison of Microwave and Radiofrequency Ablation for the Treatment of Small- and Medium-Sized Hepatocellular Carcinomas in a Prospective Randomized Trial

Purpose To compare the therapeutic response and clinical outcome of CT-guided percutaneous microwave (MWA) and radiofrequency ablation (RFA) for the treatment of small- and medium-sized HCC.

Materials and Methods In this prospective trial, 50 patients with HCC were randomly assigned to MWA or RFA treatment. MRI was performed 24 h before and after ablation and subsequently in 3-month intervals. Ablation volumes, ablation durations, adverse events (AE), technique efficacy, technical success, local tumor progression (LTP), disease-free survival (DFS), intrahepatic distant recurrence (IDR), and overall survival (OS) rates were evaluated.

Results The mean ablation volume was 66.5 cm³ for MWA and 29.2  cm³ for RFA (p < 0.01). The mean ablation durations for MWA and RFA were 11.2 ± 4.0 min and 16.3 ± 4.7 min, respectively (p < 0.01). Six mild AEs were documented (p > 0.05). All treatments had a technical success rate and a technique efficacy rate of 100 % (50/50, p = 1.00). LTP within 2 years occurred in 1/25 (4 %) in the MWA group and in 4/25 (16 %) in the RFA group (p = 0.06). IDR within 2 years was 8/25 (32 %) for MWA and 14/25 (56 %) for RFA (p < 0.05). The median DFS was 24.5 months and 13.4 months for MWA and RFA, respectively (p = 0.02). The 1-, 2-, 3-year OS rates were 100 %, 80 %, 72 % in the MWA group and 72 %, 64 %, 60 % in the RFA group, respectively (p ≥ 0.14).

Conclusion The clinical outcome after MWA or RFA for HCC treatment was very similar with no significant differences in LTP or OS. However, MWA shows a trend toward better DFS with fewer IDRs than RFA.

Key Points 

Safety of local thermal ablation in hepatocellular carcinoma patients with cirrhosis and severe thrombocytopenia

Generally, invasive treatment is contraindication for patients with severe thrombocytopenia, because it may increase risk of bleeding. However, many early hepatocellular carcinoma (HCC) patients with cirrhosis have platelet counts (PC) less than 50 × 109/L due to hypersplenism. These patients are often accompanied by hepatic insufficiency, which makes hepatectomy impossible, and local thermal ablation (LTA) has become a major treatment. The aim of our study is to investigate the correlation between severe thrombocytopenia and bleeding after LTA in HCC patients with cirrhosis, and evaluate risk factors of bleeding. 473 patients with cirrhosis who underwent LTA for HCC from 2016 to 2020 were enrolled, and 709 ablations were performed in total. Based on preoperative PC, cases were divided into three groups, namely, group A (PC > 50 × 109/L), group B (30 × 109/L < PC ≤ 50 × 109/L) and group C (PC ≤ 30 × 109/L). The incidence of bleeding after LTA was compared among the three groups. Logistic regression was used to explore the risk factors for bleeding after ablation. The overall incidence of bleeding complications was 4.4%, and no significant difference was observed between group A, B, and C (3.9% vs. 6.4% vs. 3.3%, P = 0.410). In multivariate analysis, tumor diameter (OR = 2.657 per 1 cm, P < 0.001), and multiple lesions (≥ 3) (OR = 3.723, P = 0.006) were found to be independent predictors of bleeding after LTA. In small HCC patients with cirrhosis and hypersplenism, the PC range 30-50 × 109/L will not increase the risk of bleeding after LTA. Tumor diameter and number of lesions are independent predictors for bleeding after LTA in HCC patients.

Immunotherapy Responses in Viral Hepatitis-Induced HCC: A Systematic Review and Meta-Analysis

Background: Hepatocellular carcinoma (HCC) is a prevalent liver cancer with poor prognosis, often linked to hepatitis B (HBV) and C (HCV) infections. This meta-analysis evaluates the efficacy of immunotherapy in HCC, particularly in cases arising from viral hepatitis. Methods: In adherence to PRISMA Statement 2020 guidelines, the immunotherapeutic outcomes comprised objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Data were analyzed from randomized controlled trials up to April 2024 using the fixed-effects models in R (V.4.3.3.) and RevMan (Cochrane). Results: This study included 9 trials with 5316 patients. The ORR was slightly higher in the viral group at 27.93% compared to 24.07% in the non-viral group, though this difference was not significant (p = 0.15). Viral HCC patients exhibited a median PFS of 7.3 months (IQR: 6.2-8.4) compared to 5.8 months (IQR: 5.48-6.13) in non-viral patients, a significant improvement (p = 0.005). Similarly, median OS was longer in the viral group at 16.8 months (IQR: 12.99-20.61) versus 15.2 months (IQR: 13.25-17.15) for non-viral HCC, which was also significant (p < 0.0001). The median OS for viral HCC was 16.8 months (IQR: 14.11-19.49 months), with HBV patients experiencing slightly higher survival at 17.15 months (IQR: 14.3-20 months) compared to 16.8 months (IQR: 12.99-20.61 months) for HCV patients; this difference was not statistically significant (p = 0.89). Conclusions: Immunotherapy shows potential in treating HCC, with significantly better outcomes in viral HCC, particularly HBV-associated cases. The heterogeneity highlights the need for personalized treatment approaches based on the viral background of HCC patients. Further research should aim to optimize these therapies to improve survival rates.

Locoregional Therapies for Hepatocellular Carcinoma in Patients with Nonalcoholic Fatty Liver Disease

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death worldwide with an average five-year survival rate in the US of 19.6%. With the advent of HBV and HCV treatment and prevention, along with the rising rates of obesity, nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome are set to overtake infectious causes as the most common cause of HCC. While surgical resection and transplantation can be curative when amenable, the disease is most commonly unresectable on presentation, and other treatment approaches are the mainstay of therapy. In these patients, locoregional therapies have evolved as a vital tool in both palliation for advanced disease and as a bridge to surgical resection and transplantation. In this review, we will be exploring the primary locoregional therapies for HCC in patients with NAFLD, including transarterial chemoembolization (TACE), bland transarterial embolization (TAE), transarterial radioembolization (TARE), and percutaneous ablation.

Analysis of technical failure after 1,613 surgical microwave ablations: A propensity score-matched analysis

BACKGROUND

Microwave ablation is becoming increasingly common for the treatment of liver tumors. Despite numerous studies aimed at identifying risk factors for local recurrence after microwave ablation, a consensus on modifiable risk factors for failure remains elusive, partly because of the limited statistical power of these studies. This study investigated the incidence of technical failure after microwave ablation, encompassing both incomplete ablation and local recurrence, and aimed to identify modifiable factors that reduce technical failure.

METHODS

This retrospective review included patients who underwent surgical microwave ablation at a high-volume institution between October 2006 and March 2023. Univariate analysis, multivariate analysis, and propensity score matching were performed to identify risk factors for technical failure.

RESULTS

A total of 1,613 surgical microwave ablations were performed on 3,035 tumors, with 226 instances (14% per procedure, 7.4% per tumor) of technical failure. Incomplete ablation occurred at a rate of 1.7% per tumor, whereas local recurrence was identified in 6.5% of ablations in per-tumor analysis. Body mass index >25 was significant for failure (odds ratio, 1.50; 95% confidence interval, 1.07-2.11; P < .05), suggesting that more difficult targeting may lead to increased technical failure rates. African American race (odds ratio, 1.62; 95% confidence interval, 1.16-2.27; P < .05), pre-microwave ablation transarterial chemoembolization (odds ratio, 1.54; 95% confidence interval, 1.08-2.21; P < .05), and previous ablation (odds ratio, 1.58; 95% confidence interval, 1.09-2.29; P < .05) were found to be statistically significant.

CONCLUSION

On the basis of the largest microwave ablation database available to date, this study identified novel modifiable and nonmodifiable risk factors of microwave ablation failure. These results can lead to decreasing technical failure rates after microwave ablation.

Non-Operating Room Anesthesia (NORA) for Ultrasound-Guided Liver Radiofrequency Ablation

INTRODUCTION

Percutaneous ultrasound-guided radiofrequency ablation (RFA) is a well-studied treatment option for locally non-advanced hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLMs). Sedation is of crucial interest as it enables safe and pain-free procedures. Whether the type of sedation has an impact on procedural outcome is still not well investigated.

METHODS

We retrospectively collected data on patients undergoing liver RFA for various oncological conditions. Procedures were conducted in a non-operating room anesthesia (NORA) setting. Procedural-related complications and short-term oncological outcomes were analyzed.

RESULTS

Thirty-five patients (mean age 71.5 y, 80% male) were treated for HCC (26), CRLM (6) and gastric cancer metastases (3). Mean lesion size was 21 mm (SD ± 10.1 mm), and the most common tumor localization was the right hepatic lobe. RFA was performed in a step-up sedation approach, with subcutaneous lidocaine injection prior to needle placement and subsequent deep sedation during ablation. No anesthesia-related early or late complications occurred. One patient presented with pleural effusion due to a large ablation zone and was treated conservatively. Local tumor-free survival after 1 and 6 months was 100% in all cases where a curative RFA approach was intended.

CONCLUSIONS

NORA for liver RFA comes with high patient acceptance and tolerance, and optimal postoperative outcomes and oncologic results.

Effect of high blood flow on heat distribution and ablation zone during microwave ablation-numerical approach

Microwave ablation has become a viable alternative for cancer treatment for patients who cannot undergo surgery. During this procedure, a single-slot coaxial antenna is employed to effectively deliver microwave energy to the targeted tissue. The success of the treatment was measured by the amount of ablation zone created during the ablation procedure. The significantly large blood vessel placed near the antenna causes heat dissipation by convection around the blood vessel. The heat sink effect could result in insufficient ablation, raising the risk of local tumor recurrence. In this study, we investigated the heat loss due to large blood vessels and the relationship between blood velocity and temperature distribution. The hepatic artery, with a diameter of 4 mm and a height of 50 mm and two branches, is considered in the computational domain. The temperature profile, localized tissue contraction, and ablation zones were simulated for initial blood velocities 0.05, 0.1, and 0.16 m/s using the 3D Pennes bio-heat equation, temperature-time dependent model, and cell death model, respectively. Temperature-dependent blood velocity is modeled using the Navier-Stokes equation, and the fluid-solid interaction boundary is treated as a convective boundary. For discretization, we utilized H curl Ω elements for the wave propagation model,H 1 Ω elements for the Pennes bio-heat model, andH 1 Ω 3 × L 0 2 Ω elements for the Navier-Stokes equation, where Ω represents the computational domain. The simulated results show that blood vessels and blood velocity have a significant impact on temperature distribution, tissue contraction, and the volume of the ablation zone.

Tissue Ablation: Applications and Perspectives

Tissue ablation techniques have emerged as a critical component of modern medical practice and biomedical research, offering versatile solutions for treating various diseases and disorders. Percutaneous ablation is minimally invasive and offers numerous advantages over traditional surgery, such as shorter recovery times, reduced hospital stays, and decreased healthcare costs. Intra-procedural imaging during ablation also allows precise visualization of the treated tissue while minimizing injury to the surrounding normal tissues, reducing the risk of complications. Here, the mechanisms of tissue ablation and innovative energy delivery systems are explored, highlighting recent advancements that have reshaped the landscape of clinical practice. Current clinical challenges related to tissue ablation are also discussed, underlining unmet clinical needs for more advanced material-based approaches to improve the delivery of energy and pharmacology-based therapeutics.

Comparison of Radiofrequency Ablation and Microwave Ablation for the Management of Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Hepatocellular carcinoma (HCC) is a common critical type of hepatic cancer worldwide. Recent guidelines have considered ablative therapeutic approaches as the primary option for managing early-stage surgically untreatable HCC. Among these therapies, radiofrequency ablation (RFA) and microwave ablation (MWA) have attained a significant role due to their efficacy and theoretical advantages. This review aims to compare and analyze the efficacy and safety of two common modalities, i.e., MWA and RFA, in the management of HCC. The literature search included PubMed, Cochrane Central Register of Controlled Trials, Medline, and Ovid for articles published until 2024. The outcomes included the local tumor progression (LTP), complete ablation (CA), the overall survival (OS) rate, or major complications. A meta-analysis was performed using Review Manager 5.3. The systematic review included six randomized controlled trials, including 826 patients. The findings revealed that MWA resulted in lower LTP and higher CA rates compared to RFA. However, the effect of complications was higher in the MWA therapy group. Despite that, the differences between all parameters were not significant. Statistical significance was not evident in the OS rates between the two modalities. Three studies found comparable survival rates between the two modalities, while one study reported similar local tumor recurrence-free survival rates between the two approaches. Both techniques appear to be effective and safe for the management of liver tumors, providing clinicians with valuable options for personalized patient care. Further high-quality research is needed to confirm these findings and guide clinical decision-making.

Meta-analysis of transarterial chemoembolization combined with cryoablation vs transarterial chemoembolization alone for ≥ 5 cm hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) ranks sixth globally in cancer incidence and third in mortality rates. Unfortunately, over 70% of HCC patients forego the opportunity for curative surgery or liver transplantation due to inadequate physical examinations, poor physical condition, and limited organ availability upon diagnosis. Clinical guidelines endorse transarterial chemoembolization (TACE) as the frontline treatment for intermediate to advanced-stage HCC. Cryoablation (CRA) is an emerging local ablative therapy increasingly used in HCC management. Recent studies suggest that combining CRA with TACE offers complementary and synergistic effects, potentially improving long-term survival rates. However, the superiority of combined TACE + CRA therapy over TACE alone for HCC lesions equal to or exceeding 5 cm requires further investigation.

AIM

To compare the efficacy and safety of TACE combined with CRA vs TACE alone in the treatment of HCC with a diameter of ≥ 5 cm.

METHODS

PubMed, EMBASE, Cochrane Library, CNKI, Wanfang, and VIP databases were searched to retrieve all relevant studies on TACE and CRA up to July 2022. Meta-analysis was performed using RevMan 5.3 software.

RESULTS

After screening according to the inclusion and exclusion criteria, 6 articles were included, including 2 randomized controlled trials and 4 nonrandomized controlled trials, with a total of 575 patients included in the meta-analysis. The results showed that the objective response rate [odds ratio (OR) = 2.56, 95% confidence interval (CI):1.66-3.96, P < 0.0001), disease control rate (OR = 3.03, 95%CI: 1.88-4.89, P < 0.00001), 1-year survival rate (OR = 3.79, 95%CI: 2.50-5.76, P < 0.00001), 2-year survival rate (OR = 2.34, 95%CI: 1.43-3.85, P = 0.0008), and 3-year survival rate (OR = 3.34, 95%CI: 1.61-6.94, P = 0.001) were all superior to those of the control group; the postoperative decrease in alpha-fetoprotein value (OR = 295.53, 95%CI: 250.22-340.85, P < 0.0001), the postoperative increase in CD4 value (OR = 10.59, 95%CI: 8.78-12.40, P < 0.00001), and the postoperative decrease in CD8 value (OR = 6.47, 95%CI: 4.44-8.50, P < 0.00001) were also significantly higher than those in the TACE-alone treatment group.

CONCLUSION

Compared with TACE-alone treatment, TACE + CRA combined treatment not only improves the immune function of HCC patients with a diameter of ≥ 5 cm, but also enhances the therapeutic efficacy and long-term survival rate, without increasing the risk of complications. Therefore, TACE + CRA combined treatment may be a more recommended treatment for patients with HCC with a diameter of ≥ 5 cm.

Adjuvant holmium-166 radioembolization after radiofrequency ablation in early-stage hepatocellular carcinoma patients: a dose-finding study (HORA EST HCC trial)

PURPOSE

The aim of this study was to investigate the biodistribution of (super-)selective trans-arterial radioembolization (TARE) with holmium-166 microspheres (166Ho-MS), when administered as adjuvant therapy after RFA of HCC 2-5 cm. The objective was to establish a treatment volume absorbed dose that results in an absorbed dose of ≥ 120 Gy on the hyperemic zone around the ablation necrosis (i.e., target volume).

METHODS

In this multicenter, prospective dose-escalation study in BCLC early stage HCC patients with lesions 2-5 cm, RFA was followed by (super-)selective infusion of 166Ho-MS on day 5-10 after RFA. Dose distribution within the treatment volume was based on SPECT-CT. Cohorts of up to 10 patients were treated with an incremental dose (60 Gy, 90 Gy, 120 Gy) of 166Ho-MS to the treatment volume. The primary endpoint was to obtain a target volume dose of ≥ 120 Gy in 9/10 patients within a cohort.

RESULTS

Twelve patients were treated (male 10; median age, 66.5 years (IQR, [64.3-71.7])) with a median tumor diameter of 2.7 cm (IQR, [2.1-4.0]). At a treatment volume absorbed dose of 90 Gy, the primary endpoint was met with a median absorbed target volume dose of 138 Gy (IQR, [127-145]). No local recurrences were found within 1-year follow-up.

CONCLUSION

Adjuvant (super-)selective infusion of 166Ho-MS after RFA for the treatment of HCC can be administered safely at a dose of 90 Gy to the treatment volume while reaching a dose of ≥ 120 Gy to the target volume and may be a favorable adjuvant therapy for HCC lesions 2-5 cm.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03437382 . (registered: 19-02-2018).

Long-term results of liver thermal ablation in patients with hepatocellular carcinoma and colorectal cancer liver metastasis regarding spatial features and tumor-specific variables

PURPOSE

Colorectal cancer liver metastasis (CRLM) and hepatocellular carcinoma (HCC) are widely treated using microwave and radiofrequency ablation. Local tumor progression (LTP) may develop depending on the shortest vascular distance and large lesion diameter. This study aims to explore the effect of these spatial features and to investigate the correlation between tumor-specific variables and LTP.

METHODS

This is a retrospective study covering the period between January 2007 and January 2019. One hundred twenty-five patients (CRLM: HCC: 64:61) with 262 lesions (CRLM: HCC: 142:120) were enrolled. The correlation between LTP and the variables was analyzed using the chi-square test, Fischer's exact test, or the Fisher-Freeman-Halton test where applicable. The local progression-free survival (Loc-PFS) was analyzed using the Kaplan-Meier method. Univariable and multivariable Cox regression analyses were performed to identify prognostic factors.

RESULTS

Significant correlations were observed for LTP in both CRLM and HCC at a lesion diameter of 30-50 mm (P = 0.019 and P < 0.001, respectively) and SVD of ≤3 mm (P < 0.001 for both). No correlation was found between the ablation type and LTP (CRLM: P = 0.141; HCC: P = 0.771). There was no relationship between residue and the ablation type, but a strong correlation with tumor size was observed (P = 0.127 and P < 0.001, respectively). In CRLM, LTP was associated with mutant K-ras and concomitant lung metastasis (P < 0.001 and P = 0.003, respectively). In HCC, a similar correlation was found for Child-Pugh B, serum alpha-fetoprotein (AFP) level of >10 ng/mL, predisposing factors, and moderate histopathological differentiation (P < 0.001, P = 0.008, P = 0.027, and P < 0.001, respectively). In CRLM, SVD of ≤3 mm proved to be the variable with the greatest negative effect on Loc-PFS (P = 0.007), followed by concomitant lung metastasis (P = 0.027). In HCC, a serum AFP level of >10 ng/mL proved to be the variable with the greatest negative effect on Loc-PFS (P = 0.045).

CONCLUSION

In addition to the lesions' spatial features, tumor-specific variables may also have an impact on LTP.

Comparison of Microwave and Radiofrequency Ablation for the Treatment of Small- and Medium-Sized Hepatocellular Carcinomas in a Prospective Randomized Trial

PURPOSE

To compare the therapeutic response and clinical outcome of CT-guided percutaneous microwave (MWA) and radiofrequency ablation (RFA) for the treatment of small- and medium-sized HCC.

MATERIALS AND METHODS

In this prospective trial, 50 patients with HCC were randomly assigned to MWA or RFA treatment. MRI was performed 24 h before and after ablation and subsequently in 3-month intervals. Ablation volumes, ablation durations, adverse events (AE), technique efficacy, technical success, local tumor progression (LTP), disease-free survival (DFS), intrahepatic distant recurrence (IDR), and overall survival (OS) rates were evaluated.

RESULTS

The mean ablation volume was 66.5 cm³ for MWA and 29.2  cm³ for RFA (p < 0.01). The mean ablation durations for MWA and RFA were 11.2 ± 4.0 min and 16.3 ± 4.7 min, respectively (p < 0.01). Six mild AEs were documented (p > 0.05). All treatments had a technical success rate and a technique efficacy rate of 100 % (50/50, p = 1.00). LTP within 2 years occurred in 1/25 (4 %) in the MWA group and in 4/25 (16 %) in the RFA group (p = 0.06). IDR within 2 years was 8/25 (32 %) for MWA and 14/25 (56 %) for RFA (p < 0.05). The median DFS was 24.5 months and 13.4 months for MWA and RFA, respectively (p = 0.02). The 1-, 2-, 3-year OS rates were 100 %, 80 %, 72 % in the MWA group and 72 %, 64 %, 60 % in the RFA group, respectively (p ≥ 0.14).

CONCLUSION

The clinical outcome after MWA or RFA for HCC treatment was very similar with no significant differences in LTP or OS. However, MWA shows a trend toward better DFS with fewer IDRs than RFA.

KEY POINTS

· MWA allows for larger ablation volumes and a shorter treatment duration compared to RFA in patients with HCC.. · MWA shows a trend toward better disease-free survival and fewer intrahepatic distant recurrences compared to RFA.. · The three-year survival rates show no significant difference between the two methods..

Liver-Directed Locoregional Therapies for Neuroendocrine Liver Metastases: Recent Advances and Management

Neuroendocrine tumors (NETs) are a heterogeneous class of cancers, predominately occurring in the gastroenteropancreatic system, which pose a growing health concern with a significant rise in incidence over the past four decades. Emerging from neuroendocrine cells, these tumors often elicit paraneoplastic syndromes such as carcinoid syndrome, which can manifest as a constellation of symptoms significantly impacting patients' quality of life. The prognosis of NETs is influenced by their tendency for metastasis, especially in cases involving the liver, where the estimated 5-year survival is between 20 and 40%. Although surgical resection remains the preferred curative option, challenges emerge in cases of neuroendocrine tumors with liver metastasis (NELM) with multifocal lobar involvement, and many patients may not meet the criteria for surgery. Thus, minimally invasive and non-surgical treatments, such as locoregional therapies, have surfaced. Overall, these approaches aim to prioritize symptom relief and aid in overall tumor control. This review examines locoregional therapies, encompassing catheter-driven procedures, ablative techniques, and radioembolization therapies. These interventions play a pivotal role in enhancing progression-free survival and managing hormonal symptoms, contributing to the dynamic landscape of evolving NELM treatment. This review meticulously explores each modality, presenting the current state of the literature on their utilization and efficacy in addressing NELM.

Imaging Considerations before and after Liver-Directed Locoregional Treatments for Metastatic Colorectal Cancer

Colorectal cancer is a leading cause of cancer-related death. Liver metastases will develop in over one-third of patients with colorectal cancer and are a major cause of morbidity and mortality. Even though surgical resection has been considered the mainstay of treatment, only approximately 20% of the patients are surgical candidates. Liver-directed locoregional therapies such as thermal ablation, Yttrium-90 transarterial radioembolization, and stereotactic body radiation therapy are pivotal in managing colorectal liver metastatic disease. Comprehensive pre- and post-intervention imaging, encompassing both anatomic and metabolic assessments, is invaluable for precise treatment planning, staging, treatment response assessment, and the prompt identification of local or distant tumor progression. This review outlines the value of imaging for colorectal liver metastatic disease and offers insights into imaging follow-up after locoregional liver-directed therapy.

Complication Rates and Risk of Recurrence After Percutaneous Radiofrequency Ablation and Microwave Ablation for the Treatment of Liver Tumors: a Meta-analysis

RATIONALE AND OBJECTIVES

The rate of complications and risk of local recurrence following percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) for liver tumors varies significantly between investigations. This meta-analysis aimed to assess complication rates and risk of local recurrence after percutaneous RFA and MWA.

MATERIALS AND METHODS

PubMed, Medline, Web of Science, the Cochrane Library, Embase, Google Scholar, and CINAHL were systematically searched from database inception until August 2022 to retrieve articles reporting the complication rates and risk of recurrence after percutaneous RFA and MWA for the treatment of liver tumors. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated and displayed by forest plots. To measure heterogeneity, Cochran Q and I2 statistics were also applied. Egger's test and funnel plots were also performed to assess any potential publication bias. Additionally, subgroup analysis was done to investigate the source of heterogeneity.

RESULTS

26 studies including 2026 and 1974 patients for RFA and MWA, respectively, were included. The rate of minor complications was significantly higher after MWA compared to RFA, yielding an overall OR of 0.688 (95% CI: 0.549-0.862, P = 0.001). Similarly, the rate of major complications was significantly higher after MWA than RFA (P = 0.012), yielding an overall OR of 0.639 (95% CI: 0.450-0.907). No significant difference was found between RFA and MWA in terms of local recurrence after ablation (P > 0.05). In addition, there was no statistical evidence of publication bias.

CONCLUSION

When most factors are considered equally, percutaneous RFA and MWA can be considered safe modalities for the treatment of liver tumors, with RFA superior in terms of the incidence of minor and major complications.

Usefulness of Body Position Change during Local Ablation Therapies for the High-Risk Location Hepatocellular Carcinoma

Local ablation therapies are important treatment options for early-stage hepatocellular carcinoma (HCC). Various techniques have been used to perform these therapies efficiently and safely. However, few reports have discussed the usefulness of body position change (BPC). This study aimed to investigate the usefulness of BPC during local ablation therapies in patients with HCC. We evaluated 283 HCC nodules that underwent local ablation therapy. These nodules were categorized into high- or low-risk locations on the basis of their proximity to large vessels, adjacent extrahepatic organs, or poor visibility under ultrasound (US) guidance. The technical success rates, procedure time, and prognosis were evaluated. In this study, 176 (62%) nodules were classified in the high-risk location group. The high-risk location group was treated with techniques such as BPC, artificial pleural fluid, artificial ascites, fusion imaging, and contrast-enhanced US more frequently than the low-risk location group. The technical success rates were 96% and 95% for the high- and low-risk location groups, respectively. Within the high-risk location group, those without BPC had a lower success rate than those with BPC (91% vs. 99%, p = 0.015). Notably, BPC emerged as the sole contributing factor to the technical success rate in the high-risk location group (OR = 10, 95% CI 1.2-86, p = 0.034). In contrast, no differences were found in the procedure time, local tumor progression rates, intrahepatic distant recurrence rates, and overall survival between the groups with and without BPC in the high-risk location group. In conclusion, BPC during local ablation therapy in patients with HCC in high-risk locations was safe and efficient. The body position should be adjusted for HCC in high-risk locations to maintain good US visibility and ensure a safe puncture route in patients undergoing local ablation therapies.

Computed tomography-guided percutaneous cryoablation and microwave ablation in the treatment of perivascular hepatocellular carcinoma: A comparative study with propensity score matching

OBJECTIVE

To evaluate the safety and efficacy of cryoablation (CYA) and microwave ablation (MWA) in the treatment of patients with perivascular hepatocellular carcinoma (HCC).

METHODS

Patients with perivascular HCC who underwent computed tomography (CT)-guided percutaneous CYA or MVA treatment in our hospital from August 2009 to March 2019 were included. Propensity score matching (PSM) was performed to adjust for potential baseline differences in the two groups. The technical success rate (TS), complications, and visual analog scale (VAS) were analyzed. The overall survival (OS) was evaluated using Kaplan-Meier curves and Cox proportional hazards models.

RESULTS

After PSM, 32 patients from each group were selected. The technical success rate was 94 % for CYA and 91 % for MWA, and 13 patients developed recurrence (CYA, n = 5, 2 local, 3 distant; MWA, n = 8, 6 local, 2 distant). There were no significant differences in OS (36-months OS: CYA 53.1 % vs, MWA 40.6 %; P = 0.191). No intraoperative deaths or complication-related deaths were observed, and 19 patients (CYA, n = 8; MWA, n = 11) experienced complications (P = 0.435). The VAS in the MWA group (5.38 ± 1.21) was significantly higher than that in the CYA group (2.22 ± 0.87; P < 0.001).

CONCLUSIONS

While CYA has equal safety and high primary efficacy as MWA in the treatment of perivascular HCC, it is associated with less periprocedural pain.

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.

Evidence Supporting Diagnostic Value of Liver Imaging Reporting and Data System for CT- and MR Imaging-based Diagnosis of Hepatocellular Carcinoma: A Systematic Review and Meta-analysis

Background

Based on the Liver Imaging Data and Reporting System (LI-RADS) guidelines, Hepatocellular Carcinoma (HCC) can be diagnosed using imaging criteria in patients at risk of HCC.

Objective

This study aimed to assess the diagnostic value of LI-RADS in high-risk patients with HCC.

Material and Methods

This systematic review is conducted on international databases, including Google Scholar, Web of Science, PubMed, Embase, PROQUEST, and Cochrane Library, with appropriate keywords. Using the binomial distribution formula, the variance of each study was calculated, and all the data were analyzed using STATA version 16. The pooled sensitivity and specificity were determined using a random-effects meta-analysis approach. Also, we used the chi-squared test and I2 index to calculate heterogeneity among studies, and Funnel plots and Egger tests were used for evaluating publication bias.

Results

The pooled sensitivity was estimated at 0.80 (95% CI 0.76-0.84). According to different types of Liver Imaging Reporting and Data Systems (LI-RADS), the highest pooled sensitivity was in version 2018 (0.83 (95% CI 0.79-0.87) (I2: 80.6%, P of chi 2 test for heterogeneity <0.001 and T2: 0.001). The pooled specificity was estimated as 0.89 (95% CI 0.87-0.92). According to different types of LI-RADS, the highest pooled specificity was in version 2014 (93.0 (95% CI 89.0-96.0) (I2: 81.7%, P of chi 2 test for heterogeneity <0.001 and T2: 0.001).

Conclusion

LI-RADS can assist radiologists in achieving the required sensitivity and specificity in high-risk patients suspected to have HCC. Therefore, this strategy can serve as an appropriate tool for identifying HCC.

Downstaging Techniques for Hepatocellular Carcinoma in Candidates Awaiting Liver Transplantation

During the last decade, downstaging for hepatocellular carcinoma has expanded the pool of patients eligible for liver transplantation. The literature is rife with attempts to elucidate best treatment strategies with novel locoregional and systemic therapies continuing to emerge. Several trials have confirmed the large-scale success of downstaging protocols, with equitable long-term survival and recurrence rates after liver transplant. We review the currently available techniques used for downstaging, including their indications, complications, and efficacies. New frontiers have focused on the potential role of immunotherapy in the neoadjuvant setting, although more research is needed to delineate its role in current treatment paradigms.

Comparison of laparoscopic radiofrequency ablation with percutaneous radiofrequency ablation in the treatment of chronic hepatitis B-related hepatocellular carcinoma involving specific sites: A retrospective cohort study

BACKGROUND

This study compared the effectiveness and safety of laparoscopic radiofrequency ablation (LRFA) and percutaneous radiofrequency ablation (PRFA) in the treatment of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) involving specific sites.

METHODS

This retrospective cohort study included patients with HBV-related HCC involving specific sites treated with LRFA or PRFA between January 2012 and December 2020. The overall survival (OS), disease-free survival (DFS), and complications were compared between the LRFA and PRFA groups. The Cox proportional-hazards regression model was used to determine the factors affecting prognosis.

RESULTS

This study included 109 patients: 69 in the LRFA group and 40 cases in the PRFA group. No significant differences were found in the 3-year OS rate between the two groups (73.7% vs. 70.0%, P = 0.514), but the LRFA group showed a higher 3-year DFS rate than the PRFA group (58.2% vs. 42.5%, P = 0.018). The RFA method was not associated with OS but was independently associated with DFS (LRPA vs. PRFA, HR = 2.078, P = 0.012). The common complications were ascites, pleural effusion, and fever in the two groups. The occurrence of complications in patients treated with LRFA or PRFA was similar (15.9% vs. 12.5%, P = 0.785).

CONCLUSION

LRFA was associated with a better DFS in patients with HBV-related HCC involving specific sites. Thus, LRFA might have more advantages in treating liver cancer involving specific sites.

Simulation of Image-Guided Microwave Ablation Therapy Using a Digital Twin Computational Model

Emerging computational tools such as healthcare digital twin modeling are enabling the creation of patient-specific surgical planning, including microwave ablation to treat primary and secondary liver cancers. Healthcare digital twins (DTs) are anatomically one-to-one biophysical models constructed from structural, functional, and biomarker-based imaging data to simulate patient-specific therapies and guide clinical decision-making. In microwave ablation (MWA), tissue-specific factors including tissue perfusion, hepatic steatosis, and fibrosis affect therapeutic extent, but current thermal dosing guidelines do not account for these parameters. This study establishes an MR imaging framework to construct three-dimensional biophysical digital twins to predict ablation delivery in livers with 5 levels of fat content in the presence of a tumor. Four microwave antenna placement strategies were considered, and simulated microwave ablations were then performed using 915 MHz and 2450 MHz antennae in Tumor Naïve DTs (control), and Tumor Informed DTs at five grades of steatosis. Across the range of fatty liver steatosis grades, fat content was found to significantly increase ablation volumes by approximately 29-l42% in the Tumor Naïve and 55-60% in the Tumor Informed DTs in 915 MHz and 2450 MHz antenna simulations. The presence of tumor did not significantly affect ablation volumes within the same steatosis grade in 915 MHz simulations, but did significantly increase ablation volumes within mild-, moderate-, and high-fat steatosis grades in 2450 MHz simulations. An analysis of signed distance to agreement for placement strategies suggests that accounting for patient-specific tumor tissue properties significantly impacts ablation forecasting for the preoperative evaluation of ablation zone coverage.

Technical and Clinical Outcomes of Laparoscopic-Laparotomic Hepatocellular Carcinoma Thermal Ablation with Microwave Technology: Case Series and Review of Literature

PURPOSE

To evaluate technical and clinical outcomes of intraoperative (laparoscopic/laparotomic) microwave ablation on HCC.

MATERIALS AND METHODS

This is a retrospective single-center study evaluating consecutive patients treated for very early/early-stage HCC with intraoperative microwave ablation from 1 July 2017 to 30 June 2023. In these patients, a percutaneous US-guided approach was excluded due to the nodule's suboptimal visibility or harmful location and liver resection for a deep position or adherences. Data about the clinical stage, surgical approach, liver pathology and nodules characteristics, technical success, complications, and follow-up were collected. Technical success was intended as the absence of locoregional persistence at follow-up CT/MRI controls.

RESULTS

A total of 36 cirrhotic patients (M:F = 30:6, median age 67 years) were enrolled; 18/36 (50%) had a single nodule, 13/36 (36%) had two, 4/36 had three (11%), and 1/36 had four (3%). Among the patients, 24 (67%) were treated with laparoscopy, and 12/36 (33%) with a laparotomic approach. Sixty HCCs of 16.5 mm (6-50 mm) were treated for 7 min (2-30 min) with 100 W of power. A total of 55 nodules (92%) were treated successfully and showed no residual enhancement at the first postoperative follow-up; the other 5/60 (8%) underwent chemo/radioembolization. There was one complication (3%): a biliary fistula treated with percutaneous drainage and glue embolization. The average hospital stay was 3.5 days (1-51 days), and patients were followed up on average for 238 days (13-1792 days). During follow-up, 5/36 patients (14%) underwent liver transplantation, 1/36 (2%) died during hospitalization and 1 after discharge.

CONCLUSIONS

Laparoscopic/laparotomic intraoperative HCC MW ablation is feasible in patients unsuitable for percutaneous approach or hepatic resection, with rare complications and with good technical and clinical outcomes.

Tumor size and survival in intrahepatic cholangiocarcinoma treated with surgical resection or ablation

OBJECTIVES

We performed a retrospective analysis within a national cancer registry on outcomes following resection or ablation for intrahepatic cholangiocarcinoma (iCCA).

METHODS

The National Cancer Database was queried for patients with clinical stage I-III iCCA diagnosed during 2010-2018, who underwent resection or ablation. Overall survival (OS) was compared with Kaplan-Meier and multivariable Cox proportional hazards methods.

RESULTS

Of 2140 patients, 1877 (87.7%) underwent resection and 263 (12.3%) underwent ablation, with median tumor sizes of 5.5 and 3 cm, respectively. Overall, resection was associated with greater median OS (41.2 months (95% confidence interval [95% CI]: 37.6-46.2) vs. 28 months (95% CI: 15.9-28.6) on univariable analysis (p < 0.0001). There was no significant difference on multivariable analysis (p = 0.42); however, there was a significant interaction between tumor size and management. On subgroup analysis of patients with tumors <3 cm, there was no difference in OS between resection versus ablation. However, ablation was associated with increased mortality for tumors ≥3 cm.

CONCLUSION

Although resection is associated with improved OS for tumors ≥3 cm, we observed no difference in survival between management strategies for tumors < 3 cm. Ablation may be an alternative therapeutic strategy for small iCCA, particularly in patients at risk for high surgical morbidity.

Chronic Liver Disease in the Older Patient-Evaluation and Management

PURPOSE OF REVIEW

As our population ages, the number of elderly patients with advanced chronic liver disease (ACLD) will increase. In this review we explore risk factors for liver injury, noninvasive assessment of liver disease, complications of cirrhosis, and management of frailty and sarcopenia in the older patient with ACLD.

RECENT FINDINGS

Multiple guidelines regarding ACLD have been updated over the past few years. New cutoffs for FIB-4 and NAFLD (MASLD - Metabolic Dysfunction Associated Steatotic Liver Disease) fibrosis scores for elderly patients are being validated. Older patients with MASLD benefit from caloric restriction, exercise programs, and GLP-1 agonists. Patients with ACLD need to be screened for alcohol use disorder with modified scoring systems, and if positive, benefit from referral to chemical dependency programs. Carvedilol and diuretics may safely be used in the elderly for portal hypertension and ascites, respectively, with careful monitoring. Malnutrition, frailty, sarcopenia, and bone mineral disease are common in older patients with ACLD, and early intervention may improve outcomes. Early identification of ACLD in elderly patients allows us to manage risk factors for liver injury, screen for complications, and implement lifestyle and pharmacological therapy to reduce decompensation and death. Future studies may clarify the role of noninvasive imaging in assessing liver fibrosis in the elderly and optimal interventions for nutrition, frailty, sarcopenia, bone health in addition to reevaluation of antibiotic prophylaxis for liver conditions with rising antibiotic resistance.

A Comparison of Microwave Ablation and Cryoablation for the Treatment of Renal Cell Carcinoma: A Systematic Literature Review and Meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis comparing microwave ablation (MWA) and cryoablation for renal cell carcinoma (RCC).

METHODS

The systematic search was performed in MEDLINE, Embase, and Cochrane databases. Studies published in English from January 2006 to February 2022 that assessed adults with primary RCC who received MWA or cryoablation were included. Study arms from RCTs, comparative observational, and single-arm studies were eligible. The outcomes included local tumor recurrence (LTR), overall survival, disease-free survival, overall/major complications, procedure/ablation time, 1- to 3-month primary technique efficacy, and technical success. Single-arm meta-analyses were performed using the random effects model. Sensitivity analyses excluding low-quality studies assessed using the MINORs scale were performed. Univariable and multivariable examined the effects of prognostic factors.

RESULTS

Baseline characteristics were similar between groups and mean tumor size for MWA and cryoablation were 2.74 and 2.69 cm. Single-arm meta-analyses were similar for LTR and secondary outcomes between cryoablation and MWA. Ablation time was significantly shorter with MWA than with cryoablation (meta-regression weighted mean difference 24.55 minutes, 95% confidence interval -31.71, -17.38, P < .0001). One-year LTR was significantly lower with MWA than cryoablation (odds ratio 0.33, 95% confidence interval 0.10-0.93, P = .04). There were no significant differences for other outcomes.

CONCLUSION

MWA provides significantly improved 1-year LTR and ablation time compared with cryoablation for patients with RCC. Other outcomes appeared similar or favorable for MWA; however, results were not statistically significant. MWA of primary RCC is as safe and effective as cryoablation, which should be confirmed with future comparative studies.

Comparative Study of Ablation Zone of EMPRINT HP Microwave Device with Contemporary 2.4 GHz Microwave Devices in an Ex Vivo Porcine Liver Model

(1) Background: Percutaneous microwave ablation (MWA) is an accepted treatment of non-operative liver cancer. This study compares the ablation zones of four commercially available 2.45 GHz MWA systems (Emprint, Eco, Neuwave, and Solero) in an ex vivo porcine liver model. (2) Methods: Ex vivo porcine livers (n = 85) were obtained. Two ablation time setting protocols were evaluated, the manufacturer's recommended maximum time and a 3 min time, performed at the manufacturer-recommended maximum power setting. A total of 236 ablation samples were created with 32 (13.6%) samples rejected. A total of 204 samples were included in the statistical analysis. (3) Results: For single-probe protocols, Emprint achieved ablation zones with the largest SAD. Significant differences were found in all comparisons for the 3 min time setting and for all comparisons at the 10 min time setting except versus Neuwave LK15 and Eco. Emprint produced ablation zones that were also significantly more spherical (highest SI) than the single-probe ablations from all other manufacturers. No statistical differences were found for ablation shape or SAD between the single-probe protocols for Emprint and the three-probe protocols for Neuwave. (4) Conclusions: The new Emprint HP system achieved large and spherical ablation zones relative to other 2.45 GHz MWA systems.

Optimal treatment for small HCC (<3 cm): Resection, liver transplantation, or locoregional therapy?

Hepatocellular carcinoma (HCC) remains the most common form of liver cancer, accounting for 90% of all primary liver cancers. Up to 30% of HCC cases could be small (2-3 cm in diameter) at the time of diagnosis with advances in imaging techniques and surveillance programmes. Treating patients with early-stage HCC can be complex and often requires interdisciplinary care, owing to the wide and increasing variety of treatment options, which include liver resection, liver transplantation, and various locoregional therapies offered by interventional radiology and radiation oncology. Decisions regarding the optimal management strategy for a patient involve many considerations, including patient- and tumour-specific characteristics, as well as socioeconomic factors. In this review, we aim to comprehensively summarise the commonly used therapies for single, small HCC (<3 cm), with a focus on the impact of tumour size (<2 cm vs. 2-3 cm), as well as a brief discussion on the cost-effectiveness of the different treatment options.

3D modeling of vector/edge finite element method for multi-ablation technique for large tumor-computational approach

Microwave ablation (MWA) is a cancer thermal ablation treatment that uses electromagnetic waves to generate heat within the tissue. The goal of this treatment is to eliminate tumor cells while leaving healthy cells unharmed. During MWA, excess heat generation can kill healthy cells. Hence, mathematical models and numerical techniques are required to analyze the heat distribution in the tissue before the treatment. The aim of this research is to explain the implementation of the 3D vector finite element method in a wave propagation model that simulates the specific absorption rate in the liver. The 3D Nedelec elements from H(curl; Ω) space are used to discretize the wave propagation model, and this implementation is helpful in solving many real-world problems that involve electromagnetic propagation with perfect conducting and absorbing boundary conditions. One of the difficulties in ablation treatment is creating a large ablation zone for a large tumor (diameter greater than 3 cm) in a short period of time with minimum damage to the surrounding tissue. This article addresses the aforementioned issue by introducing four antennas into the different places of the tumor sequentially and producing heat uniformly over the tumor. The results demonstrated that 95.5% of the tumor cells were killed with minimal damage to the healthy cells when the heating time was increased to 4 minutes at each position. Subsequently, we studied the temperature distribution and localised tissue contraction in the tissue using the three-dimensional bio-heat equation and temperature-time dependent model, respectively. The local tissue contraction is measured at arbitrary points in the domain and is more noticeable at temperatures higher than 102°C. The thermal damage in the liver during MWA treatment is investigated using the three-state cell death model. The system of partial differential equations is solved numerically due to the complex geometry of the domain, and the results are compared with experimental data to validate the models and parameters.

Recent Advances in Image-Guided Locoregional Therapies for Primary Liver Tumors

Primary liver cancer is the leading cause of cancer-related deaths worldwide. with incidences predicted to rise over the next several decades. Locoregional therapies, such as radiofrequency or microwave ablation, are described as image-guided percutaneous procedures, which offer either a curative intent for early-stage hepatocellular carcinoma or bridging/downstaging for surgical resection or transplantation. Catheter-driven locoregional therapies, such as transarterial chemoembolization and radioembolization, induce tumor hypoxia, can be palliative, and improve survival for early-to-intermediate hepatocellular carcinoma and unresectable intrahepatic cholangiocarcinoma. Herein, we provide a comprehensive overview of the antineoplastic mechanisms underpinning locoregional therapies, different treatment approaches, and the current state of the literature for the efficacy of locoregional therapies for primary liver cancer. We also discuss emerging advancements, such as the adjuvant use of immunotherapies and molecular targeting agents with locoregional therapy, for the treatment of primary liver cancer.

Analysis of the metastatic mechanism and progress in the treatment of breast cancer liver metastasis: a narrative review

Background and Objective

Breast cancer is the most common malignancy in women, and metastasis to other target organs is one of the main causes of death. Breast cancer liver metastasis (BCLM) has long been a research focus. Enhancing therapeutic effects, optimizing treatment plans and improving the prognosis of patients are major clinical challenges at present.

Methods

We performed a comprehensive, nonsystematic review of the latest literature to define the current metastatic mechanism and related treatment advances of BCLM.

Key Content and Findings

Due to the lack of research on the mechanism of BCLM, present treatment programs still have limited benefits, and the prognosis of patients is generally poor. New research directions and treatment ideas for BCLM are urgently needed. In this article, we indicated the specific procedures of the BCLM mechanism from the microenvironment to metastasis formation and progress in treatment, including drug therapies such as targeted therapy, surgery, intervention therapy and radiotherapy. Research on the molecular mechanism plays a crucial role in the development of BCLM-related therapies. Based on the metastasis process, we are able to propel new findings and further progression of antineoplastic drugs.

Conclusions

The process of BCLM is multistep, and various factors are involved in it, which provides a powerful theoretical basis for the development of therapeutic methods for treatment of this disease. Further understanding of the mechanism of BCLM is essential to guide clinical management.

Comparison of Ablation Volume Between Emprint® and Mimapro® Systems for Hepatocellular Carcinoma -A Preliminary Study

Background

Microwave ablation (MWA) is a standard percutaneous local therapy for hepatocellular carcinoma (HCC). Next-generation MWA is reported to create a more spherical ablation zone than radiofrequency ablation (RFA). We compared the ablation zone and aspect ratio of two 2.45 GHz MWA ablation probes; Emprint^® (13G) and Mimapro^® (17G). We compared the ablation zone to the applied energy after MWA in patients with hepatocellular carcinoma (HCC). Furthermore, we investigated local recurrence.

Materials and Methods

We included 20 patients with HCC, with an average tumour diameter of 33.2 ± 12.2 mm, who underwent MWA using Emprint^®, and 9 patients who underwent MWA using Mimapro^® with an average tumour diameter of 31.1 ± 10.5 mm. Both groups underwent the same ablation protocol using the same power settings. The images obtained after MWA showed the treatment ablation zone and aspect ratio, which were measured and compared using three-dimensional image analysis software.

Results

The aspect ratios in the Emprint^® and Mimapro^® groups were 0.786 ± 0.105 and 0.808 ± 0.122, respectively, with no significant difference (p = 0.604). The ablation time was significantly shorter in the Mimapro^® group than in the Emprint^® group, and there was no significant difference in the frequency of popping or the ablation volume. There were no significant differences in local recurrence between the two groups.

Conclusion

There was no significant difference in the aspect ratios of the ablation diameter, and the ablation zone was almost spherical in both cases. Mimapro^® at 17G was less invasive than Emprint^® at 13G.

Stereotactic body radiation therapy and thermal ablation for treatment of NSCLC: A systematic literature review and meta-analysis

RATIONALE

Stereotactic body radiation therapy (SBRT) is the standard of care for inoperable early stage non-small cell lung cancer (NSCLC). Use of image guided thermal ablation (IGTA; including microwave ablation [MWA] and radiofrequency ablation [RFA]) has increased in NSCLC, however there are no studies comparing all three.

OBJECTIVE

To compare the efficacy of IGTA (including MWA and RFA) and SBRT for the treatment of NSCLC.

METHODS

Published literature databases were systematically searched for studies assessing MWA, RFA, or SBRT. Local tumor progression (LTP), disease-free survival (DFS), and overall survival (OS) were assessed with single-arm pooled analyses and meta-regressions in NSCLC patients and a stage IA subgroup. Study quality was assessed with a modified methodological index for non-randomized studies (MINORS) tool.

RESULTS

Forty IGTA study-arms (2,691 patients) and 215 SBRT study-arms (54,789 patients) were identified. LTP was lowest after SBRT at one and two years in single-arm pooled analyses (4% and 9% vs. 11% and 18%) and at one year in meta-regressions when compared to IGTA (OR = 0.2, 95%CI = 0.07-0.63). MWA patients had the highest DFS of all treatments in single-arm pooled analyses. In meta-regressions at two and three-years, DFS was significantly lower for RFA compared to MWA (OR = 0.26, 95%CI = 0.12-0.58; OR = 0.33, 95%CI = 0.16-0.66, respectively). OS was similar across modalities, timepoints, and analyses. Older age, male patients, larger tumors, retrospective studies, and non-Asian study region were also predictors of worse clinical outcomes. In high-quality studies (MINORS score ≥ 7), MWA patients had better clinical outcomes than the overall analysis. Stage IA MWA patients had lower LTP, higher OS, and generally lower DFS, compared to the main analysis of all NSCLC patients.

CONCLUSIONS

NSCLC patients had comparable outcomes after SBRT and MWA, which were better than those with RFA.

Ablative strategies for recurrent hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and is the fifth leading cause of cancer death worldwide and the third leading cause of all diseases worldwide. Liver transplantation, surgical resection and ablation are the three main curative treatments for HCC. Liver transplantation is the optimal treatment option for HCC, but its usage is limited by the shortage of liver sources. Surgical resection is considered the first choice for early-stage HCC, but it does not apply to patients with poor liver function. Therefore, more and more doctors choose ablation for HCC. However, intrahepatic recurrence occurs in up to 70% patients within 5 years after initial treatment. For patients with oligo recurrence after primary treatment, repeated resection and local ablation are both alternative. Only 20% patients with recurrent HCC (rHCC) indicate repeated surgical resection because of limitations in liver function, tumor location and intraperitoneal adhesions. Local ablation has become an option for the waiting period when liver transplantation is unavailable. For patients with intrahepatic recurrence after liver transplantation, local ablation can reduce the tumor burden and prepare them for liver transplantation. This review systematically describes the various ablation treatments for rHCC, including radiofrequency ablation, microwave ablation, laser ablation, high-intensity focused ultrasound ablation, cryablation, irreversible electroporation, percutaneous ethanol injection, and the combination of ablation and other treatment modalities.

Comparison of local ablative therapies, including radiofrequency ablation, microwave ablation, stereotactic ablative radiotherapy, and particle radiotherapy, for inoperable hepatocellular carcinoma: a systematic review and meta-analysis

Surgical intervention is the first-line treatment in well-selected hepatocellular carcinoma (HCC) patients. However, only a few patients are suitable to receive radical surgery. We conducted a systematic review and meta-analysis to evaluate local control among four local ablative therapies in inoperable HCC patients, including radiofrequency ablation therapy (RFA), microwave ablation therapy (MWA), stereotactic ablative radiotherapy (SABR), and particle radiotherapy. The primary outcome was the local control rate and the secondary were regional and distant progression rates, overall survival rate, and adverse events. We included twenty-six studies from PubMed, EMBASE, and Cochrane Library databases. MWA (p < 0.001) and particle radiotherapy (p < 0.001) showed better performance of local control compared to RFA, while SABR (p = 0.276) showed a non-significant trend. However, SABR (p = 0.002) and particle radiotherapy (p < 0.001) showed better performance than RFA in HCCs of ≥ 30 mm in size. MWA showed a similar result to RFA while SABR and particle radiotherapy showed a lower survival rate in the 2-, 3-, and 4-year overall survival rates. Our results indicate that MWA, SABR and particle radiotherapy were safe and no inferior to RFA in local control rate. Besides, the local control rates of SABR and particle radiotherapy are better than RFA in HCC of ≥ 30 mm in size. As a result, we suggested that MWA, SABR and particle radiotherapy to be effective alternatives to RFA for inoperable HCC. Moreover, the tumor size should be taken into consideration for optimal treatment selection between local ablative therapies.

Novel tumor localization model and prediction of ablation zone using an intertwined helical antenna for the treatment of hepatocellular carcinoma

Hepatocellular carcinoma has been the leading cause of death in recent centuries and with the advent of newer technologies, several thermal and cryo-ablation techniques have been introduced in the recent past. In this regard, microwave ablation has developed into a promising method for thermal ablation technique. However, due to clinical obligations, in-vivo analysis is not feasible and ex-vivo analysis is inaccurate due to changes in the electrical and thermal properties of the tissue. Therefore, in this study, temperature-dependent permittivity, electrical conductivity, and thermal conductivity along with phase change effect due to temperature reaching above 100°C are incorporated using finite element method model. Further, using an intertwined normal mode helical antenna ablation probe, a change in resonant frequency (Δf) and reflection coefficient (ΔS₁₁ ) from the actual value (antenna parameter in the air at 5 GHz) is modeled using second-order polynomial curve fitting to predict the surrounding permittivity in the range of 30-70. A maximum deviation of 0.8 value in permittivity from the actual value is observed. However, to obtain a generalized methodology, XG Boost and CAT Boost algorithms are used. Further, since ablation diameter plays a crucial role in achieving optimal tumor ablation, an artificial neural network (ANN) algorithm with three different optimizers is incorporated to predict ablation diameter using five critical parameters. Such an ANN algorithm which can predict the transversal and axial ablation zone may provide optimal ablation outcomes.

Nonsurgical Therapy for Early-Stage Lung Cancer

Treatment options for medically inoperable, early-stage non-small cell lung cancer (NSCLC) include stereotactic ablative radiotherapy (SABR) and percutaneous image guided thermal ablation. SABR is delivered over 1-5 sessions of highly conformal ablative radiation with excellent tumor control. Toxicity is depending on tumor location and anatomy but is typically mild. Studies evaluating SABR in operable NSCLC are ongoing. Thermal ablation can be delivered via radiofrequency, microwave, or cryoablation, with promising results and modest toxicity. We review the data and outcomes for these approaches and discuss ongoing studies.