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

Development and validation of a prognostic nomogram for early hepatocellular carcinoma treated with microwave ablation

Objective

An effective model for risk stratification and prognostic assessment of early hepatocellular carcinoma (HCC) patients following microwave ablation (MWA) is lacking in clinical practice. The aim of this study is to develop and validate a prognostic model specifically for these patients.

Methods

Between January 2008 and December 2018, 345 treatment-naïve patients with HCC conforming to the Milan criteria who underwent MWA were enrolled and randomly assigned to the training (n=209) and validation (n=136) cohorts. The nomogram model was constructed based on the predictors assessed by the multivariate Cox proportional hazards model and validated. Predictive accuracy and discriminative ability were further evaluated and compared with other prognostic models.

Results

After a median follow-up of 59.0 months, 52.5% (187/356) of the patients had died. Prognostic factors for overall survival (OS) were α-fetoprotein (AFP), albumin-bilirubin (ALBI) score, platelets, and ablation margins, which generated the nomograms. The nomogram model consistently achieved good calibration and discriminatory ability with a concordance index of 0.64 (95% confidence interval (CI): 0.59-0.69) and 0.69 (95% CI: 0.63-0.75) in both the training and validation cohorts. The performance of the nomogram model also outperformed other prognostic models. By using the nomogram model, the patient population could be correctly divided into low- and high-risk strata presenting significantly different median OS of 105.0 (95% CI: 84.1-125.9) months, and 45.0 (95% CI: 28.0-62.0) months, respectively.

Conclusion

The nomogram model based on AFP, PLT, ablation margins, and ALBI score was a simple visualization model that could stratify patients with early-stage HCC after MWA and predict individualized long-term survival with favorable performance.

Anti-CTLA-4 antibody self-presented dendritic cell nanovesicles boost the immunotherapy of hepatocellular carcinoma after microwave ablation

Microwave ablation (MWA) is a frequently adopted regional therapy for treating hepatocellular carcinoma (HCC) in clinic. However, incomplete microwave ablation (IMWA) is often inevitable due to the restraint of ablating large tumors or tumors in special locations, resulting in a high recurrence rate of HCC. Moreover, the most promising immune checkpoint blockade (ICB)-based immunotherapy is raising hindered by the toxicity and insufficient immune response. To overcome these barriers, we conjugate small nanovesicle (smDV)-derived from matured dendritic cells (mDCs) with anti-CTLA-4 antibody (smDV-aCTLA-4) using a metabolic tagging technology, which could trigger the infiltration of cytotoxic T cells (CTLs) and adopted tumor-infiltrating lymphocytes (TILs) in residual HCC after IMWA. In HCC microenvironment, the administration of smDV-aCTLA-4 could promote antigen presentation and immune checkpoint suppression to activate CTLs and improve the safety of anti-CTLA-4 antibody. Moreover, the anti-tumor efficacy of CTLs elicited by smDV-aCTLA-4 could also be further enhanced by anti-programmed death 1 (aPD-1) antibody. In addition, compared to the adoptive TILs therapy, the treatment using smDV-aCTLA-4-bonded TILs (smDV-aCTLA-4@TILs) could promote the proliferation and infiltration of cytotoxic TILs in residual HCC after IMWA. Our results clearly evidenced the potency of a new type of engineered DC nanovesicles in reducing HCC recurrence after IMWA.

Long-term survival analysis of ultrasound-guided percutaneous microwave ablation for hepatocellular carcinoma conforming to the Milan criteria: primary versus recurrent HCC

BACKGROUND

This study compared long-term outcomes between patients with initial hepatocellular carcinoma (IHCC) and those with recurrent HCC (RHCC) treated with microwave ablation (MWA).

METHODS

This retrospective study included 425 patients with HCCs (294 IHCCs and 131 RHCCs) within the Milan criteria who were treated with ultrasound-guided percutaneous MWA between January 2008 and November 2021. All patients with RHCC had previously undergone MWA for initial HCC. Overall survival (OS) and recurrence-free survival (RFS) rates were compared between the IHCC and RHCC groups before and after propensity score matching (PSM).

RESULTS

Before matching, the 1-, 3-, 5-, and 10-year OS rates in the IHCC group were 95.9%, 78.5%, 60.2%, and 42.5%, respectively, which were significantly higher than those in the RHCC group (93.8%, 70.0%, 42.0%, and 6.6%, respectively). This difference remained significant after PSM. However, subgroup analyses suggested that there were no significant differences in OS rates between IHCC and RHCC in patients with solitary HCC ≤3.0 cm, AFP ≤200 ng/mL, ablative margins ≥0.5 cm, or Albumin-Bilirubin (ALBI) grade 1. RFS was significantly higher in IHCC than in RHCC before and after PSM, as well as in subgroup analyses. ALBI grade (hazard ratio (HR), 2.38; 95% CI: 1.46-3.86; p < 0.001), serum AFP level (HR, 2.07; 95% CI: 1.19-3.62; p = 0.010) and ablative margins (HR, 0.18; 95% CI: 0.06-0.59; p = 0.005) were independent prognostic factors for OS of RHCC. Serum AFP(HR, 1.29; 95% CI: 1.02-1.63, p = 0.036) level was the only factor associated with RFS in RHCC.

CONCLUSIONS

MWA yielded comparable OS in IHCC and RHCC patients with solitary HCC ≤3.0 cm, AFP ≤200 ng/mL, ablative margins ≥0.5 cm, or ALBI grade 1.

MRI non-rigid registration with tumor contraction correction for ablative margin assessment after microwave ablation of hepatocellular carcinomas

Objective. This study aims to develop and assess a tumor contraction model, enhancing the precision of ablative margin (AM) evaluation after microwave ablation (MWA) treatment for hepatocellular carcinomas (HCCs).Approach. We utilize a probabilistic method called the coherent point drift algorithm to align pre-and post-ablation MRI images. Subsequently, a nonlinear regression method quantifies local tumor contraction induced by MWA, utilizing data from 47 HCC with viable ablated tumors in post-ablation MRI. After automatic non-rigid registration, correction for tumor contraction involves contracting the 3D contour of the warped tumor towards its center in all orientations.Main results. We evaluate the performance of our proposed method on 30 HCC patients who underwent MWA. The Dice similarity coefficient between the post-ablation liver and the warped pre-ablation livers is found to be 0.95 ± 0.01, with a mean corresponding distance between the corresponding landmarks measured at 3.25 ± 0.62 mm. Additionally, we conduct a comparative analysis of clinical outcomes assessed through MRI over a 3 month follow-up period, noting that the AM, as evaluated by our proposed method, accurately detects residual tumor after MWA.Significance. Our proposed method showcases a high level of accuracy in MRI liver registration and AM assessment following ablation treatment. It introduces a potentially approach for predicting incomplete ablations and gauging treatment success.

Tips for Preparing and Practicing Thermal Ablation Therapy of Hepatocellular Carcinoma

Thermal ablation therapy, including radiofrequency ablation (RFA) and microwave ablation (MWA), is considered the optimal locoregional treatment for unresectable early-stage hepatocellular carcinomas (HCCs). Percutaneous image-guided ablation is a minimally invasive treatment that is being increasingly performed because it achieves good clinical outcomes with a lower risk of complications. However, the physics and principles of RFA and MWA markedly differ. Although percutaneous thermal ablation under image guidance may be challenging in HCC cases with limited access or a risk of thermal injury, a number of ablative techniques, each of which may be advantageous and disadvantageous for individual cases, are available. Furthermore, even when a HCC is eligible for ablation based on tumor selection and technical factors, additional patient factors may have an impact on whether it is the appropriate treatment choice. Therefore, a basic understanding of the advantages and limitations of each ablation device and imaging guidance technique, respectively, is important. We herein provide an overview of the basic principles of tissue heating in thermal ablation, clinical and laboratory parameters for ablation therapy, preprocedural management, imaging assessments of responses, and early adverse events. We also discuss associated challenges and how they may be overcome using optimized imaging techniques.

Initial experience of the treatment of large glioma with microwave ablation-assisted surgical resection

Aim

This study aimed to investigate the preliminary clinical outcomes of microwave ablation (MWA)-assisted surgical treatment for large glioma.

Materials and Methods

In total, six cases of large glioma (diameter >4 cm) were described. All cases were treated with MWA-assisted surgical resection, which was performed using ultrasound to guide the accurate placement of the antenna in the central region of the tumor. The MWA power was 40-45 W, and 6 min was applied. Changes in the ablation area were observed using intraoperative Doppler ultrasound and contrast-enhanced ultrasound (CEUS). Ten patients treated with surgical resection alone were included in the control group. Data on surgical times (i.e., the time from the incision of the dura to the removal of the tumor), intraoperative blood loss, and complications were recorded.

Results

The median patient age was 45 years (range: 36.5-60.3 years). The median lesion diameter was 4.9 cm (range: 4.3-5.8). The microwave power was 40-45 W, and the median ablation time was 240 s (range: 208-297 s). The intra-tumoral vascular flow was significantly reduced after MWA. The median surgical time was shorter (38.5 min [range: 34.3-42.8 min]) and the median intraoperative blood loss was less (400 mL, [range: 400-450 mL]) in the combination treatment group than in the surgery-alone group. During the ablation process, no obvious additional neurological deficits were detected; however, a tube-shaped carbonide was found after the operation.

Conclusion

MWA may be a useful complement to conventional techniques for the surgical resection of large glioma.

Recent therapeutics in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a malignant tumor of hepatocytes. It is a common malignant tumor of the digestive system that often has initially hidden presentation followed by rapid progression. There are no obvious symptoms in the early stage of HCC. When diagnosed, most patients have locally advanced tumor or distant metastasis; therefore, HCC is difficult to treat and only supportive and symptomatic treatment is adopted. The prognosis is poor and survival time is short. How to effectively treat HCC is important clinically. In recent years, advances in medical technology have resulted in comprehensive treatment methods based on surgery.

Efficacy and safety of single- and multiple-antenna microwave ablation for the treatment of hepatocellular carcinoma and liver metastases: A systematic review and network meta-analysis

BACKGROUND

There is a myriad of microwave ablation (MWA) systems used in clinical settings worldwide for the management of liver cancer that offer a variety of features and capabilities. However, an analysis on which features and capabilities result in the most favorable efficacy and safety results has never been completed due to a lack of head-to-head comparisons. The aim of this study is to compare single-antenna and multiple-antenna MWA using radiofrequency ablation (RFA) as a common comparator in the treatment of very-early, early hepatocellular carcinoma (HCC) and ≤5 cm liver metastases.

METHODS

This network meta-analysis was performed according to PRISMA guidelines. PubMed, Cochrane, and Web of Science databases were searched for comparative studies. Complete ablation (CA) rate, local tumor progression-free (LTPF) rate, overall survival (OS), and major complication rate were assessed. Subgroup analyses were further performed based on synchronous or asynchronous MWA generators and tumor size (<2 cm or ≥2 cm).

RESULTS

Twenty-one studies (3424 patients), including 3 randomized controlled trials (RCTs) and 18 observational studies, met eligibility criteria. For CA, LTPF and major complications, as compared to single-antenna MWA, multiple-antenna MWA had relative risks (RRs) of 1.051 (95% CI: 0.987-1.138), 1.099 (95% CI: 0.991-1.246), and 0.605 (95% CI: 0.193-1.628), respectively. For 1-year and 3-year OS, as compared to single-antenna MWA, multiple-antenna MWA had odds ratios (ORs) of 0.9803 (95% CI: 0.6772-1.449) and 1.046 (95% CI: 0.615-1.851), respectively. Subgroup analysis found synchronized multi-antenna MWA was associated with significantly better LTPF by 22% (RR: 1.22, 95% CI 1.068, 1.421), and 21.4% (RR: 1.214, 95% CI 1.035, 1.449) compared with single-antenna MWA, and asynchronous multiple-antenna MWA, respectively, with more evident differences in larger tumors (≥2 cm).

CONCLUSION

Multi-antenna and single-antenna MWA showed similar effectiveness for local treatment of liver tumors, but synchronous multi-antenna MWA exhibited better LTPF compared to other MWA approaches, particularly for larger liver tumors (≥2 cm). Large-scale RCTs should be further conducted.

An Analysis of Microwave Ablation Parameters for Treatment of Liver Tumors from the 3D-IRCADb-01 Database

Simulation techniques are powerful tools for determining the optimal conditions necessary for microwave ablation to be efficient and safe for treating liver tumors. Owing to the complexity and computational resource consumption, most of the existing numerical models are two-dimensional axisymmetric models that emulate actual three-dimensional cancers and the surrounding tissue, which is often far from reality. Different tumor shapes and sizes require different input powers and ablation times to ensure the preservation of healthy tissues that can be determined only by the full three-dimensional simulations. This study aimed to tailor microwave ablation therapeutic conditions for complete tumor ablation with an adequate safety margin, while avoiding injury to the surrounding healthy tissue. Three-dimensional simulations were performed for a multi-slot microwave antenna immersed in two tumors obtained from the 3D-IRCADb-01 liver tumors database. The temperature dependence of the dielectric and thermal properties of healthy and tumoral liver tissues, blood perfusion, and water content are crucial for calculating the correct ablation time and, thereby, the correct ablation process. The developed three-dimensional simulation model may help practitioners in planning patient-individual procedures by determining the optimal input power and duration of the ablation process for the actual shape of the tumor. With proper input power, necrotic tissue is placed mainly in the tumor, and only a small amount of surrounding tissue is damaged.

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.