Microwave ablation provides better survival than liver resection for hepatocellular carcinoma in patients with borderline liver function: application of ALBI score to patient selection

Efficacy of microwave ablation vs laparoscopic hepatectomy for primary small liver cancer: A comparative study

BACKGROUND

In-depth comparative investigations in terms of clinical efficacies of liver tumor microwave ablation (MWA) and laparoscopic hepatectomy (LH), which are both important treatment modalities for liver neoplasms, have been limited in patients diagnosed with primary small liver cancer (PSLC).

AIM

To compare and analyze the clinical efficacy of liver tumor MWA and LH for PSLC.

METHODS

This study retrospectively analyzed the medical records of 123 patients with PSLC admitted to Xuzhou Central Hospital from January 2015 to November 2022 and categorized them based on treatment modalities into the LH and MWA groups. The LH group, consisting of 61 cases, received LH, and the MWA group, which included 62 cases, underwent liver tumor MWA. Basic data and various perioperative indicators were compared between the two groups, including changes in liver function indicators [alanine aminotransferase (ALT), glutamic aminotransferase (AST), and total bilirubin (TBIL)] pre- and post-treatment, and efficacy and postoperative complications were analyzed.

RESULTS

No statistically significant difference was observed between the two groups in terms of age, gender, tumor diameter, liver function Child-Pugh classification and number of tumors, body mass index, and educational status (P > 0.05). The overall effective rate was higher in the MWA group than in the LH group (98.39% vs 88.52%) (χ 2 = 4.918, P = 0.027). The MWA group exhibited less operation time, intraoperative bleeding, defecation time, and hospital stay than the LH group (P < 0.05). No difference was found in liver function indicators between the two groups pre-treatment (P > 0.05), and ALT, AST, and TBIL levels decreased in both groups post-treatment, with the MWA group demonstrating lower levels (P < 0.05). The MWA and LH groups exhibited postoperative complication rates of 4.84% and 19.67%, respectively, with statistically significant differences between the two groups (P = 0.012, χ 2 = 6.318).

CONCLUSION

MWA is more effective in treating PSLC, and it promotes faster postoperative recovery for patients, and more security improves liver function and reduces postoperative complications compared to LH.

Temperature Simulation of an Ablation Needle for the Prediction of Tissue Necrosis during Liver Ablation

Background/Objectives: Microwave ablation (MWA) is the leading therapy method for treating patients with liver cancer. MWA simulation is used to further improve the therapy and to help develop new devices. Methods: A water-cooled ablation needle was reconstructed. MWA simulations of a polyacrylamide phantom were carried out and compared with a representative clinical example (tumor diameter: 8.75 mm). The Arrhenius damage model and a critical temperature approach of 60 °C were applied to assess the necrosis zones. Finally, the simulation results were compared to the corresponding MR measurements. Results: Most of the heating in the simulation took place at a distance of 5 mm along the transverse axis and 20 mm along the longitudinal axis above the needle tip. The calculated Dice scores for the Arrhenius model were 0.77/0.53 for the phantom/clinical case. For the critical temperature approach, Dice scores of 0.60/0.66 for the phantom/clinical case were achieved. Conclusions: The comparison between simulated and measured temperature increases showed an excellent agreement. However, differences in the predicted necrosis volume might be caused by omitting consideration of the heat sink effect, especially in the clinical case. Nevertheless, this workflow enables short MWA simulation times (approximately 3 min) and demonstrates a step towards possible integration into daily clinical use.

Short-term efficacy of microwave ablation in the treatment of liver cancer and its effect on immune function

BACKGROUND

Hepatectomy is the first choice for treating liver cancer. However, inflammatory factors, released in response to pain stimulation, may suppress perioperative immune function and affect the prognosis of patients undergoing hepatectomies.

AIM

To determine the short-term efficacy of microwave ablation in the treatment of liver cancer and its effect on immune function.

METHODS

Clinical data from patients with liver cancer admitted to Suzhou Ninth People's Hospital from January 2020 to December 2023 were retrospectively analyzed. Thirty-five patients underwent laparoscopic hepatectomy for liver cancer (liver cancer resection group) and 35 patients underwent medical image-guided microwave ablation (liver cancer ablation group). The short-term efficacy, complications, liver function, and immune function indices before and after treatment were compared between the two groups.

RESULTS

One month after treatment, 19 patients experienced complete remission (CR), 8 patients experienced partial remission (PR), 6 patients experienced stable disease (SD), and 2 patients experienced disease progression (PD) in the liver cancer resection group. In the liver cancer ablation group, 21 patients experienced CR, 9 patients experienced PR, 3 patients experienced SD, and 2 patients experienced PD. No significant differences in efficacy and complications were detected between the liver cancer ablation and liver cancer resection groups (P > 0.05). After treatment, total bilirubin (41.24 ± 7.35 vs 49.18 ± 8.64 μmol/L, P < 0.001), alanine aminotransferase (30.85 ± 6.23 vs 42.32 ± 7.56 U/L, P < 0.001), CD4+ (43.95 ± 5.72 vs 35.27 ± 5.56, P < 0.001), CD8+ (20.38 ± 3.91 vs 22.75 ± 4.62, P < 0.001), and CD4+/CD8+ (2.16 ± 0.39 vs 1.55 ± 0.32, P < 0.001) were significantly different between the liver cancer ablation and liver cancer resection groups.

CONCLUSION

The short-term efficacy and safety of microwave ablation and laparoscopic surgery for the treatment of liver cancer are similar, but liver function recovers quickly after microwave ablation, and microwave ablation may enhance immune function.

Multidisciplinary Treatment of Hepatocellular Carcinoma in 2023: Italian practice Treatment Guidelines of the Italian Association for the Study of the Liver (AISF), Italian Association of Medical Oncology (AIOM), Italian Association of Hepato-Bilio-Pancreatic Surgery (AICEP), Italian Association of Hospital Gastroenterologists (AIGO), Italian Association of Radiology and Clinical Oncology (AIRO), Italian Society of Pathological Anatomy and Diagnostic Cytology (SIAPeC-IAP), Italian Society of Surgery (SIC), Italian Society of Gastroenterology (SIGE), Italian Society of Medical and Interventional Radiology (SIRM), Italian Organ Transplant Society (SITO), and Association of Patients with Hepatitis and Liver Disease (EpaC) - Part I - Surgical treatments

Worldwide, hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death. The remarkable improvements in treating HCC achieved in the last years have increased the complexity of HCC management. Following the need to have updated guidelines on the multidisciplinary treatment management of HCC, the Italian Scientific Societies involved in the management of this cancer have promoted the drafting of a new dedicated document. This document was drawn up according to the GRADE methodology needed to produce guidelines based on evidence. Here is presented the first part of guidelines, focused on the multidisciplinary tumor board of experts and surgical treatments of HCC.

Evaluation of liver function using Gd-EOB-DTPA-enhanced MRI with T1 mapping

PURPOSE

To evaluate the value of MRI T1 mapping with Gd-EOB-DTPA for assessing liver function.

METHODS

Seventy-two patients who underwent Gd-EOB-DTPA-enhanced MRI for focal liver lesions at Beijing Friendship Hospital from August 2020 to March 2022 were prospectively enrolled, and variable-flip-angle T1 mapping was performed before and 20 min after enhancement. The Child-Pugh (C-P) score and albumin-bilirubin (ALBI) grade of liver function were assessed using the clinical data of the patients. Correlation analysis was used to evaluate the correlation between T1 mapping parameters and liver function grading and laboratory tests. Nonparametric tests were used to compare the differences among different liver function groups. The liver function classification efficiency of each image index was evaluated with receiver operating characteristic (ROC) curves.

RESULTS

T1post was positively correlated with the C-P grade and the ALBI grade (r = 0.717 and r = 0.652). ΔT1 was negatively correlated with the C-P grade and the ALBI grade (r = -0.790 and r = -0.658). T1post and ΔT1 significantly differed among different liver function grades (p < 0.05). For the C-P grade, T1post and ΔT1 were significantly different between each pair of groups (p < 0.05), and ΔT1 had a better diagnostic efficiency than T1post. For the ALBI grade, ΔT1 and T1post were significantly different between the NLF and ALBI1 groups (p < 0.05), and ΔT1 had a better diagnostic efficacy than T1post. T1post significantly differed between the ALBI1 and ALBI2 + 3 groups (p < 0.05), while ΔT1 had a weak ability to differentiate between these two groups.

CONCLUSION

T1post and ΔT1 were strongly correlated with the two liver function grades and can be noninvasive imaging indexes for evaluating liver function.

Clinical Results, Risk Factors, and Future Directions of Ultrasound-Guided Percutaneous Microwave Ablation for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide, with a relatively poor prognosis, especially for advanced HCC. With the availability of a variety of treatment options, the treatment strategies for HCC have become more and more diversified. Microwave ablation (MWA) has gradually been considered as a viable alternative to surgical resection (SR) owing to its comparable long-term survival, reduced complications, and greater preservation of hepatic parenchyma. However, clinical outcomes, tumor progression, and recurrence of HCC after MWA remain major concerns. Here, after reviewing the current therapeutic options for HCC, we focus on MWA, describing the advantages and challenges of MWA and the clinical results after treatment. We then focused on prognostic factors that influence post-ablation clinical outcomes and briefly presented the strategy of MWA for future clinical treatment.

Patient Selection and Outcomes of Laparoscopic Microwave Ablation of Hepatocellular Carcinoma

Background: Laparoscopic microwave ablation (MWA) of hepatocellular carcinoma is underutilized and predictors of survival in this setting are not well characterized. Methods: The prognostic value of clinicopathologic variables was evaluated on progression-free survival (PFS) and overall survival (OS) by univariate and multivariate analyses. The aim of this study was to evaluate a preferred laparoscopic MWA approach in HCC patients that are not candidates for percutaneous ablation and further classify clinicopathologic factors that may predict survival outcomes following operative MWA in the setting of primary HCC. Results: 184 patients with HCC (median age 66, (33–86), 70% male) underwent laparoscopic MWA (N = 162, 88% laparoscopic) compared to 12% undergoing open MWA (N = 22). Median PFS was 29.3 months (0.2–170) and OS was 44.2 months (2.8–170). Ablation success was confirmed in 100% of patients. Ablation recurrence occurred in 3% (6/184), and local/hepatic recurrence occurred in 34%, at a median time of 19 months (9–18). Distant progression was noted in 8%. Median follow up was 34.1 months (6.4–170). Procedure-related complications were recorded in six (9%) patients with one 90-day mortality. Further, >1 lesion, AFP levels ≥ 80 ng/mL, and an “invader” on pre-operative radiology were associated with increased risk of progression (>1 lesion HR 2.92, 95% CI 1.06 –7.99, p = 0.04, AFP ≥ 80 ng/mL HR 4.16, 95% CI 1.71–10.15, p = 0.002, Invader HR 3.16, 95% CI 1.91–9.15, p = 0.002 ) and mortality (>1 lesion HR 3.62, 95% CI 1.21–10.81, p = 0.02], AFP ≥ 80 ng/mL HR 2.87, 95% CI 1.12–7.35, p = 0.01, Invader HR 3.32, 95% CI 1.21–9.81, p = 0.02). Conclusions: Preoperative lesion number, AFP ≥ 80 ng/mL, and an aggressive imaging characteristic (Invader) independently predict PFS and OS following laparoscopic operative MWA.

Microwave ablation versus surgical resection for subcapsular hepatocellular carcinoma: a propensity score-matched study of long-term therapeutic outcomes

OBJECTIVES

The therapeutic efficacy of microwave ablation (MWA) for subcapsular hepatocellular carcinoma (HCC) has not been well characterized. We aimed to compare the long-term outcomes of MWA and surgical resection (SR) in patients with subcapsular HCC.

METHODS

This retrospective study comprised 321 patients with subcapsular HCC meeting the Milan criteria who received MWA (n = 99) or SR (n = 222). Local tumor progression (LTP), overall survival (OS), and disease-free survival (DFS) were analyzed using propensity score matching (PSM) to compare the therapeutic efficacy.

RESULTS

In the total cohort, there were no significant differences in 5-year LTP rates (14.0% vs. 8.9%, p = 0.12), OS rates (70.7% vs. 73.2%, p = 0.63), and DFS rates (38.3% vs. 41.2%, p = 0.22) between the MWA and SR groups. After PSM, the cumulative LTP rates at 1, 3, and 5 years were 9.7%, 14.0%, and 16.4% in the MWA group (n = 84) and 7.2%, 8.6%, and 10.6% in the SR group (n = 84), respectively, with no significant difference (p = 0.31). Neither corresponding OS rates (96.4%, 84.8%, and 73.0% vs. 95.2%, 85.5%, and 72.1%, p = 0.89) nor DFS rates (76.0%, 52.6%, and 38.1% vs. 76.2%, 44.7%, and 32.3%, p = 0.43) were significantly different between the MWA and SR groups. Whereas MWA obtained fewer complications for both cohorts (both p < 0.05).

CONCLUSION

MWA showed comparable long-term therapeutic outcomes to SR, and it might be an alternative curative option for subcapsular HCC within the Milan criteria.

KEY POINTS

• Microwave ablation showed comparable local tumor progression, overall survival, and disease-free survival to surgical resection for subcapsular hepatocellular carcinoma meeting the Milan criteria. • Microwave ablation obtained fewer complications and shorter postoperative hospital stay.

Liver resection versus microwave ablation for hepatocellular carcinoma in ideal candidates for ablation per Barcelona Clinic Liver Cancer staging: a propensity score matching and inverse probability of treatment weighting analysis

BACKGROUND

Liver resection (LRE) and microwave ablation (MWA) for hepatocellular carcinoma (HCC) have been widely compared.

AIMS

To compare the therapeutic outcomes of percutaneous MWA and LRE for HCC in ideal candidates for ablation according to Barcelona Clinic Liver Cancer (BCLC) staging METHODS: Between August 2013 and November 2020, 483 consecutive patients meeting criteria for "ideal candidates for ablation" per the BCLC staging initially treated with MWA (n = 168) or LRE (n = 315) were included. Patients were further divided into BCLC-0 (n = 116) and BCLC-A (n = 367) groups. Overall survival (OS), recurrence-free survival (RFS) and post-procedure-related complication rates were compared before and after propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) in the overall population and subgroups. Multivariate Cox regression analysis was performed to determine whether the treatment modality was an independent prognostic factor.

RESULTS

LRE had a better RFS and similar OS and post-procedure-related complication rates compared to MWA in the overall population and in the BCLC-A subgroup both before and after PSM and IPTW. However, the OS, RFS and post-procedure-related complication rates were equivalent between the two groups before and after PSM and IPTW in patients with BCLC-0 disease. The multivariate Cox regression analysis showed that LRE was associated with better RFS over MWA in overall population (p = 0.003; HR = 0.67; 95% CI: 0.51-0.87) and BCLC-A disease (p = 0.046; HR = 0.74; 95% CI: 0.56-0.99), while it did not differ in OS.

CONCLUSION

An 'ideal candidate for ablation' according to the BCLC staging system may not be an ideal candidate for MWA. However, patients with BCLC-0 may be the optimal population for MWA.

Hepatic resection versus microwave ablation for the treatment of early hepatocellular carcinoma: a comparative analysis of treatment outcomes and survival predictors

Introduction

Liver resection and local ablation are the two primary curative treatments for early-stage hepatocellular carcinoma (HCC). Microwave ablation (MWA) shows promising performance in terms of early tumor response, recurrence, and survival. This study aims to determine whether MWA would be comparable to liver resection in treating early-stage HCC.

Methods

This study included patients with hepatitis C-related HCC attending the multidisciplinary HCC clinic, Kasr Al-Ainy Hospital (March 2018 to September 2020). We included adults with early-stage HCC (BCLC stages 0-A). We studied patients and tumor characteristics, HCC treatment response, recurrence, and overall survival.

Results

Thirty-one patients were treated with liver resection and 41 patients were treated with MWA, including 4 patients who received intraoperative MWA. By the end of the study, 21 patients (28.77%) died. Patients who underwent MWA were younger compared to the hepatectomy group with lower baseline AFP (21 (6.7–54) versus 77 (31.3–136.0), respectively, (P value 0.024) and tumor size (2.78 (0.87) cm versus 3.77 (0.97) cm, respectively, (P value < 0.001). We found no differences between the studied groups in terms of treatment response, post-treatment decompensation, recurrence, or overall survival. One-year survival probability in the MWA and resection groups was 75.5% and 76.3% respectively. Post-procedure hepatic decompensation was the only independent predictor of lower survival by multivariate logistic regression analysis (OR 37.74, 95%CI 6.251–227.87, P value < 0.001) after adjusting for age, AFP, and tumor size.

Conclusion

Liver resection and MWA showed similar satisfactory results in the treatment of early-stage HCC, in terms of treatment response, recurrence, and overall survival.

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.

Percutaneous Thermal Ablation Therapy of Hepatocellular Carcinoma (HCC): Microwave Ablation (MWA) versus Laser-Induced Thermotherapy (LITT)

The purpose of this study is to compare the efficacy and safety of microwave ablation (MWA) versus laser-induced thermotherapy (LITT) as a local treatment for hepatocellular carcinoma (HCC,) with regard to therapy response, survival rates, and complication rates as measurable outcomes. This retrospective study included 250 patients (52 females and 198 males; mean age: 66 ± 10 years) with 435 tumors that were treated by MWA and 53 patients (12 females and 41 males; mean age: 67.5 ± 8 years) with 75 tumors that were treated by LITT. Tumor response was evaluated using CEMRI (contrast-enhanced magnetic resonance imaging). Overall, 445 MWA sessions and 76 LITT sessions were performed. The rate of local tumor progression (LTP) and the rate of intrahepatic distant recurrence (IDR) were 6% (15/250) and 46% (115/250) in the MWA-group and 3.8% (2/53) and 64.2% (34/53) in the LITT-group, respectively. The 1-, 3-, and 5-year overall survival (OS) rates calculated from the date of diagnosis were 94.3%, 65.4%, and 49.1% in the MWA-group and 96.2%, 54.7%, and 30.2% in the LITT-group, respectively (p-value: 0.002). The 1-, 2-, and 3-year disease-free survival (DFS) rates were 45.9%, 30.6%, and 24.8% in the MWA-group and 54.7%, 30.2%, and 17% in the LITT-group, respectively (p-value: 0.719). Initial complete ablation rate was 97.7% (425/435) in the MWA-group and 98.7% (74/75) in the LITT-group (p-value > 0.99). The overall complication rate was 2.9% (13/445) in the MWA-group and 7.9% (6/76) in the LITT-group (p-value: 0.045). Based on the results, MWA and LITT thermal ablation techniques are well-tolerated, effective, and safe for the local treatment of HCC. However, MWA is recommended over LITT for the treatment of HCC, since the patients in the MWA-group had higher survival rates.

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.

Recent Advances in Local Thermal Ablation Therapy for Hepatocellular Carcinoma

Image-guided local thermal ablation (LTA) plays an important role in the treatment of hepatocellular carcinoma (HCC), especially in patients with HCC who are not suitable for hepatectomy. Radiofrequency ablation (RFA) and microwave ablation (MWA) are the most widely used LTA clinically. Radiofrequency ablation can achieve the best result; that is, a similar therapeutic effect as hepatectomy if the tumor ≤3 cm, while MWA can effectively ablate tumors ≤5 cm. Local thermal ablation has an advantage over liver resection in terms of minimally invasive surgery and can achieve a comparable prognosis and efficacy to liver resection. For borderline liver function, selecting LTA as the first-line therapy may bring more benefits to patients with cirrhosis background. In addition, a combination of multiple therapies for HCC is a good choice, such as LTA combined with transcatheter arterial chemoembolization (TACE), which can achieve a better prognosis than single therapy for larger tumors. For patients who are awaiting liver transplantation, LTA is a good choice. The main problem of LTA needed to be solved is to prevent the local tumor recurrence after ablation in patients with HCC.

Recent Advances in Local Thermal Ablation Therapy for Hepatocellular Carcinoma

Image-guided local thermal ablation (LTA) plays an important role in the treatment of hepatocellular carcinoma (HCC), especially in patients with HCC who are not suitable for hepatectomy. Radiofrequency ablation (RFA) and microwave ablation (MWA) are the most widely used LTA clinically. Radiofrequency ablation can achieve the best result; that is, a similar therapeutic effect as hepatectomy if the tumor ≤3 cm, while MWA can effectively ablate tumors ≤5 cm. Local thermal ablation has an advantage over liver resection in terms of minimally invasive surgery and can achieve a comparable prognosis and efficacy to liver resection. For borderline liver function, selecting LTA as the first-line therapy may bring more benefits to patients with cirrhosis background. In addition, a combination of multiple therapies for HCC is a good choice, such as LTA combined with transcatheter arterial chemoembolization (TACE), which can achieve a better prognosis than single therapy for larger tumors. For patients who are awaiting liver transplantation, LTA is a good choice. The main problem of LTA needed to be solved is to prevent the local tumor recurrence after ablation in patients with HCC.

Effect of Severity of Liver Cirrhosis on Surgical Outcomes of Hepatocellular Carcinoma After Liver Resection and Microwave Coagulation

BACKGROUND

Liver resection (LR) and percutaneous microwave coagulation therapy (PMCT) are both considered as radical treatments for small hepatocellular carcinoma (HCC). However, it is still unclear whether to select LR or PMCT in HCC patients with different degrees of liver cirrhosis. The purpose of this study was to compare the efficacy of LR and PMCT in the treatment of solitary and small HCC accompanied with different degrees of liver cirrhosis.

METHODS

In this study, 230 patients with solitary HCC lesions ≤ 3 cm and Child-Pugh A liver function were retrospectively reviewed. Among these patients, 122 patients underwent LR, and 108 received PMCT. The short- and long-term outcomes were compared between these two procedures. Severity of liver cirrhosis was evaluated by using clinical scoring system (CSS) as previously published. Subgroup analysis based on CSS was performed to evaluate the effect of severity of liver cirrhosis on surgical outcomes after LR and PMCT.

RESULTS

There was no mortality within 90 days in both groups. Major complications were significantly more frequent in the LR group than in the PMCT group (18.8% vs. 4.6%, p<0.001). However, LR provided better surgical outcomes than PMCT. The 5-year overall survival (OS) rates for the LR and PMCT groups were 65.2% and 42%, respectively (p=0.006), and the corresponding disease-free survival (DFS) rates were 51.7% and 31.5%, respectively (p=0.004). Nevertheless, subgroup analysis showed that PMCT provided long-term outcomes that were similar to LR and lower surgical complications in HCC patients with CSS score≥4.

CONCLUSIONS

LR may provide better OS and DFS rates than PMCT for patients with solitary HCC lesions ≤ 3 cm and Child-Pugh A liver function irrespective of liver cirrhosis. PMCT should be viewed as the optimal treatment for solitary and small HCC with severe cirrhosis.

Comparison of Survival Outcomes in Transarterial Ethanol Ablation and Liver Resection for Solitary Hepatocellular Carcinoma ≤ 5 cm in Patients Stratified by Liver Function

PURPOSE

To compare the survival outcomes of patients treated with transarterial ethanol ablation (TEA) with those treated with liver resection (LR) for solitary HCC less than 5 cm in diameter, in patients stratified according to liver function using ALBI grade.

MATERIALS AND METHODS

This retrospective study approved by the Institutional Committee included all treatment-naïve patients with solitary HCC (≤ 5 cm) and Child-Pugh score 5, and who had received TEA (33 patients) or LR (192 patients) between 2004 and 2012. Treatment outcomes were compared between patients treated with TEA and LR after a period of at least 7 years of follow-up. Comparison was repeated for those patients with ALBI grade 2 or 3.

RESULTS

Both overall survival (OS, months) and recurrence-free survival (RFS months) were significantly longer in the LR group (OS: LR 129.7[119.5, 140], TEA 69.1[55.9, 82.3], P < 0.0001; RFS: LR 91.3[43.5, 139.1], TEA 13.8 [11, 16.5], P < 0.0001). In patients with ALBI grade 2 or 3, there was no significant difference between the groups in OS or RFS (OS: LR 43.1[0, 91.2], TEA 55.4 [43.7, 67.2], P = 0.65; RFS: LR 17.8 [11.4, 24.2], TEA 11.9 [6.7, 17.1], P = 0.132). Transient epigastric discomfort and low-grade fever without consequence occurred in 8 patients (8/33 or 24.2%) in the TEA group.

CONCLUSION

The overall survival after LR for HCCs ≤ 5 cm was superior to that after TEA but similar when compared in patients with ALBI grade 2 or 3, the ALBI grade is useful for patient selection for TEA or LR for HCCs ≤ 5 cm.

Therapeutic efficacy of microwave coagulation versus liver resection for hepatocellular carcinoma within the Milan criteria: A propensity score matching analysis

INTRODUCTION

This study aimed to compare the therapeutic efficacy of resection (RES) and microwave ablation (MWA) for hepatocellular carcinoma (HCC) within the Milan criteria.

MATERIALS AND METHODS

Between 2011 and 2019, 426 HCC patients within the Milan criteria were treated at our institution (RES: n = 291; MWA: n = 135). We compared overall survival (OS), disease-free survival (DFS), complications, and hospital stay in these patients using propensity score matching (PSM) and determined the prognostic factors using multivariate Cox analysis.

RESULTS

Following 1:1 matching using PSM, 121 patients were matched in each group. The 1-, 3-, and 5-year OS rates were 98.3%, 84.7%, and 69.6% for the MWA group and 96.5%, 81.8%, and 78.1% for the RES group (p = 0.667). The corresponding DFS rates for the MWA and RES groups were 81.8%, 54.4%, and 42.3% and 85.4%, 67.8%, and 57.9%, respectively (p = 0.174). The MWA group had less blood loss and shorter hospital stays (both p < 0.001) than the RES group.

CONCLUSION

MWA resulted in survival outcomes that were similar to those of RES for HCC within the Milan criteria. However, it had more favorable hospital stay and blood loss outcomes than RES.

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

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

Laparoscopic left hemihepatectomy in small dogs: an easy and effective new technique

The present report describes a novel approach to and presents the surgical results for laparoscopic hepatectomy of the left lobes in small dogs. A purely laparoscopic four-port approach was used in seven beagles. The left triangular ligament was cut first, then the base of the left medial lobe (LMB) was ligated with silk thread using a needle, and the liver parenchyma of the LMB approximately 0.5 cm above the ligation site was removed with LigaSure. The left lateral lobe (LLB) was removed in the same manner. Blood was collected on postoperative days 1, 3, 7, and 14 for laboratory testing. Left hepatic lobe resection was successfully completed in all dogs, with an average operation time of 102.53 ± 9.07 min and an average blood loss of 32.10 ± 6.43 ml. Serious postoperative complications were not observed. The white blood cell (WBC) count and alkaline phosphatase (ALP) level were significantly increased in experimental dogs 1 day after surgery (P< 0.05); aspartate transferase (AST) and alanine transaminase (ALT) were significantly different before and after surgery (P< 0.01); and all the indicators were basically normal seven days after the operation. Exploratory laparoscopy at 28 days revealed adhesion of the surface of the liver section to the omentum or the gastric wall, but there were no other abnormal findings. The combined application of liver pedicle ligation and LigaSure for liver lobectomy provides a simple and effective method for generating liver lobectomy models for research on liver disease and regeneration and a feasible laparoscopic liver lobectomy operation scheme for small dogs (10–15 kg).

Direct-acting antivirals improve survival and recurrence rates after treatment of hepatocellular carcinoma within the Milan criteria

BACKGROUND

The effects of direct-acting antivirals (DAAs) on survival and recurrence rates after curative hepatocellular carcinoma (HCC) treatment in patients with hepatitis C virus (HCV) infection remain controversial.

METHODS

This retrospective, multicenter study involved Child-Pugh class A patients within the Milan criteria who had a first diagnosis of HCC and survived 6 months or longer after undergoing hepatectomy or radiofrequency ablation (RFA). The DAA-treated group (DAA group) included 56 patients, and the DAA-untreated group (untreated group) included 261 patients. The study was conducted using the propensity score-matched (1:2) DAA group and untreated group, 56 and 112 patients, respectively.

RESULTS

The survival rate at 48 months in the DAA group and the untreated group was 91.0% and 68.7%, respectively, showing significantly better survival in the DAA group (HR: 0.33; 95% CI 0.13-0.84; p = 0.021). The recurrence rate at 48 months was 36.7% and 66.7%, respectively, showing a significantly lower recurrence rate in the DAA group (HR, 0.46; 95% CI 0.27-0.77; p = 0.003). The median albumin-bilirubin (ALBI) score at 3 years post-HCC treatment was - 2.84 in the DAA group and - 2.34 in the untreated group. The ALBI score showed a significant improvement from baseline to 3 years post-HCC treatment (p = 0.001), whereas that in the untreated group showed a significant decline (p = 0.040).

CONCLUSIONS

DAAs after HCC treatment prevents deterioration of hepatic functional reserve and significantly improves both recurrence and survival rates.

Treatment Options for Early-Stage Hepatocellular Carcinoma

Patients with early stage hepatocellular carcinoma have good prognosis and are treated with curative intent. Although this cohort of patients is generally defined by limited tumor burden, good liver function, and preserved functional status, there remains utility in further stratification to optimize overall survival and limit post-operative morbidity and mortality. Transplant, resection, ablation, transarterial radioembolization, and transarterial chemoembolization, either as monotherapy or in combination, may play a crucial role in treating this cohort of patients depending on a multitude of factors. In this section, we review each treatment modality and provide general guidelines for patient selection.

Neutrophil to lymphocyte ratio and albumin bilirubin grade in hepatocellular carcinoma: A systematic review

BACKGROUND

Hepatocellular carcinoma (HCC) is a frequent cause of cancer related death globally. Neutrophil to lymphocyte ratio (NLR) and albumin bilirubin (ALBI) grade are emerging prognostic indicators in HCC.

AIM

To study published literature of NLR and ALBI over the last five years, and to validate NLR and ALBI locally in our centre as indicators of HCC survival.

METHODS

A systematic review of the published literature on PubMed of NLR and ALBI in HCC over the last five years. The search followed the guidelines of the preferred reporting items for systematic reviews and meta-analyses. Additionally, we also investigated HCC cases between December 2013 and December 2018 in our centre.

RESULTS

There were 54 studies describing the relation between HCC and NLR and 95 studies describing the relation between HCC and ALBI grade over the last five years. Our local cohort of patients showed NLR to have a significant negative relationship to survival (P = 0.011). There was also significant inverse relationship between the size of the largest HCC nodule and survival (P = 0.009). Median survival with alpha fetoprotein (AFP) < 10 KU/L was 20 mo and with AFP > 10 KU/L was 5 mo. We found that AFP was inversely related to survival, this relationship was not statically significant (P = 0.132). Mean survival for ALBI grade 1 was 37.7 mo, ALBI grade 2 was 13.4 months and ALBI grade 3 was 4.5 mo. ALBI grades performed better than Child Turcotte Pugh score in detecting death from HCC.

CONCLUSION

NLR and ALBI grade in HCC predict survival better than the conventional alpha fetoprotein. ALBI grade performs better than Child Turcotte Pugh score. These markers are done as part of routine clinical care and in cases of normal alpha fetoprotein, these markers could give a better understanding of the patient disease progression. NLR and ALBI grade could have a role in modified easier to learn staging and prognostic systems for HCC.

Analysis of the clinical efficacy of liver resection combined with adjuvant microwave coagulation for patients with hepatocellular carcinoma

Background

Liver resection has been widely applied as a curative measure in the treatment of hepatocellular carcinoma (HCC) patients. However, the high rate of postoperative recurrence observed following liver resection proposes a problem, the solution for which is yet to be well established. Microwave coagulation is a therapy that was recently proposed as an adjuvant tool. In this study, we intended to evaluate the effectiveness of microwave coagulation as an auxiliary therapeutic method for patients undergoing liver resection.

Methods

A total of 236 consecutive patients classified as Barcelona Clinic Liver Cancer (BCLC) stage A who had only one tumor were enrolled in this retrospective study, regardless of tumor size. Survival analyses were performed using the Kaplan-Meier method, and the statistical differences between patients who underwent liver resection with and without adjuvant microwave coagulation were examined by the log-rank test. To investigate the prognostic factors for OS, we carried out univariate and multivariate Cox regression analyses.

Results

Based on the Kaplan-Meier curves, patients who underwent surgical resection with intraoperative adjuvant microwave coagulator had prolonged recurrence-free survival time and showed better overall survival (OS) than those who underwent surgical resection alone, with OS at 1, 3, and 5 years of 77.8%, 33.2%, 12.6% vs. 58.2%, 15.5%, 9.7%, respectively (log-rank P<0.001). The univariate and multivariate analyses demonstrated that tumor size, albumin, bilirubin, Child-Pugh score, and treatment method had significant prognostic power for both PFS and OS. According to the subgroup analyses based on the tumor size, there were significant differences in PFS and OS among overall subsets between the liver resection with adjuvant microwave coagulator and liver resection only groups.

Conclusions

Liver resection combined with intraoperative adjuvant microwave coagulation had a better prognostic performance than treatment with liver resection alone. Adjuvant microwave coagulation should be suggested as an alternative treatment modality for BCLC stage A patients with a single tumor, regardless of its size.

Microwave ablation of liver cancer: An updated review

The treatment methods for early liver cancer include surgical resection, liver transplantation, and local ablation. Among them, microwave ablation (MWA) is widely used in clinical practice because of its outstanding advantages, such as minimal invasiveness, radical curative effect, short treatment time, few complications, and no heat-sink effect, especially for the treatment of tumors adjacent to major vessels and hepatic metastases. However, MWA also has limitations such as unpredictable size and shape of the ablation area. This review systematically illustrates the effectiveness and safety of MWA in the treatment of liver cancer. Meanwhile, the relative superiority of the new generation of MWA is discussed, with an aim to provide reference for MWA of liver cancer.

N-acetylcysteine alleviates liver injury by suppressing macrophage-mediated inflammatory response post microwave ablation

OBJECT

To investigate N-acetyl-cysteine (NAC) would able to alleviate liver injury and systemic inflammatory response caused by microwave ablation (MWA) in rats.

MATERIALS AND METHODS

Male Sprague-Dawley rats weighing 150-200 g were randomly divided into sham group (only anesthesia and laparotomy except MWA but with intraperitoneal PBS or NAC solution injection according to different situations), control group (intraperitoneal PBS injection for comparation 2 h prior to MWA), and NAC-treated group (intraperitoneal N-acetyl-cysteine (300 mg/kg) injection 2 h prior to MWA). Experimental rats were sacrificed at 4 h following operation in line with the liver injury severity curve. Liver tissue and serum samples were collected for determination of pathology, apoptosis, macrophages contents and protein expression.

RESULTS

The elevated serum level of liver enzymes, Myeloperoxidase (MPO) and inflammatory factors (TNF-α and CXCL1) in MWA-treated rats revealed injurious and pro- inflammatory effect of MVA. Macrophages aggregation was detected in MWA exposure rats similarly. and NAC pre-conditioning mitigate liver damage and hepatocyte apoptosis, besides macrophages accumulation and following inflammatory response in liver tissue.

CONCLUSION

Our results demonstrated that N-acetyl-cysteine application alleviate macrophages aggregation and inflammatory response in liver suffering microwave ablation, and mitigating liver injury and cell apoptosis.

Computed Tomography-Guided Percutaneous Cryoablation for ‎ Subcardiac Hepatocellular Carcinoma: Safety, Efficacy, Therapeutic Results and Risk Factors for Survival Outcomes

Objective

To investigate the clinical safety, efficacy, therapeutic outcomes and risk factors of computed tomography-guided percutaneous cryoablation (CT-PCRA) for subcardiac hepatocellular carcinoma (HCC).

Patients and Methods

In this study, patients with single HCC nodules located on the left lobe who subsequently underwent CT-PCRA were reviewed from July 2012 to August 2016. According to the definition of subcardiac HCC, the patients were grouped into the subcardiac HCC group (n=33) and the non-subcardiac HCC group (n=40). The technical success rates, tumour response rates, oncological outcomes including overall survival (OS) and recurrence-free survival (RFS) and complications were compared. Multivariate analysis was performed on clinicopathological variables to identify factors affecting long-term outcomes.

Results

Seventy-three patients with subcardiac HCC were included in this study. After a median follow-up time of 37.8 months, 27.4% (20/73) of the patients died. The technical success and complete response rates were not significantly different between the two groups (p = 1.000; p = 0.590). The cumulative OS and RFS of the subcardiac HCC group were comparable to those of the non-subcardiac HCC group (p =0.820, p =0.922). Two major complications, intra-abdominal bleeding and right pleural effusion, were found at 2.2 and 3.1 months in the subcardiac HCC group, which were comparable with those in the non-subcardiac HCC group (p = 0.683). The multivariate analysis results showed that older age (hazard ratio [HR]: 2.382, 95% confidence interval [CI]: 1.884–7.823; p = 0.038) and ALBI grade 2–3 (HR: 3.398, 95% CI: 1.950–6.058; p = 0.021) may be predictors of poor OS and that tumour size ≥3 cm in diameter (HR: 3.302, 95% CI: 2.232–8.293; p = 0.012) may be a predictor of poor RFS.

Conclusion

CT-PCRA for subcardiac HCC can be performed safely and efficiently and contribute to improving survival prognosis.

The efficacy of microwave ablation versus liver resection in the treatment of hepatocellular carcinoma and liver metastases: A systematic review and meta-analysis

BACKGROUND

Microwave ablation (MWA) is an important method in the treatment of liver cancer. This systematic review compared MWA with liver resection (LR) for liver cancer treatment. In recent years, the MWA has been also reported to play an important role. Studies comparing MWA and LR are lacking. This study aims to compare the efficacy of MWA and LR in the treatment of hepatocellular carcinoma (HCC).

METHODS

A systematic search of PubMed, Embase, Cochrane Library and Web of Science up to April 1, 2019 was conducted for relevant studies that compared the efficacy of MWA and LR in the treatment of HCC. The primary outcomes were local tumor recurrence (LTR) and overall survival (OS) of patients. The secondary outcomes included disease free survival (DFS), extrahepatic metastasis, intrahepatic de novo lesions, length of stay, complications, intraoperative blood loss and operative time.

RESULTS

A total of 16 studies including 2622 patients were identified. Incidence of LTR was significantly higher in patients with MWA than LR, with a pooled OR of 2.69 (95% CI 1.33-5.41; P = 0.006). No significant difference in 1-year OS was found. However, patients with MWA experienced higher 3- and 5-year OS, with pooled ORs of 1.40 (95% CI 1.07-1.84; P = 0.01) and 1.41 (95% CI 1.10-1.80; P = 0.007) respectively. In secondary measures, the 1- and 3-year DFS were significantly higher in patients with MWA. However, no significant difference of 5-year DFS was observed. In addition, lower incidence of complications, less intraoperative blood loss and shorter operative time and shorter length of stay were observed in MWA.

CONCLUSIONS

Though MWA may lead to higher incidence of recurrence, it may be an effective and safe alternative in patients with HCC or liver metastases. MWA may have benefits in patients' survival and safety. Randomized studies should be performed to determine the target population that benefits most from MWA in the future.

A review of conventional and newer generation microwave ablation systems for hepatocellular carcinoma

Although microwave ablation (MWA) exhibits a high thermal efficiency, the major limitation of conventional MWA systems is the lack of predictability of the ablation zone size and shape. Therefore, a specific newer generation MWA system, The Emprint™ Ablation System with Thermosphere™ Technology, was designed to create predictable large spherical zones of ablation that are not impacted by varying tissue environments. The time required for ablation with MWA systems is short, and the shape of the necrosis is elliptical with the older systems and spherical with the new system. In addition, because MWA has no heat-sink effect, it can be used to ablate tumors adjacent to major vessels. Although these factors yield a large ablation volume and result in good local control, excessive ablation of liver tissue and unexpected ablation of surrounding organs are possible. Therefore, MWA should be carefully performed. This review highlights the efficacy and complications of MWA performed with conventional systems and the newer generation system in patients with hepatocellular carcinoma (HCC). MWA with the newer generation system seems to be a promising treatment option for large HCCs and secondary hepatic malignancies, with several advantages over other available ablation techniques, including conventional MWA. However, further randomized controlled trials are necessary to fully clarify the benefits and pitfalls of this new system.

Newly Proposed ALBI Grade and ALBI-T Score as Tools for Assessment of Hepatic Function and Prognosis in Hepatocellular Carcinoma Patients

BACKGROUND

Because of the rapid progression of antiviral treatment options and the increasing frequency of nonviral-related hepatocellular carcinoma (HCC) due to the aging of society, the number of HCC patients with good hepatic function has been increasing and a more detailed method of assessment of hepatic function is needed. The Child-Pugh classification (CP) is used worldwide as an assessment tool for hepatic reserve function, even though it has some weaknesses. Recently, the albumin-bilirubin (ALBI) grade, calculated based on only albumin and total bilirubin, was proposed, and recent investigations have suggested that ALBI grade instead of CP can be used as an assessment tool for hepatic function as part of therapeutic strategies such as Barcelona Clinic Liver Cancer staging and a practical guideline presented by the Japan Society of Hepatology as well for total staging scoring systems. There has been an increasing number of reports showing that it has better capability than CP for HCC patients who undergo not only curative but also palliative treatments. Transcatheter arterial chemoembolization (TACE) is a major palliative treatment used for unresectable HCC, and the idea of TACE-refractory status has been proposed to indicate the possibility of switching to a tyrosine kinase inhibitor (TKI). However, TKI administration requires a maintained hepatic reserve function, thus the importance of assessment of hepatic function in patients undergoing TACE treatments has increased. We consider that ALBI grade might also play a significant role as part of a detailed assessment of relative changes in hepatic function during treatment. In this review, we evaluate the practical usefulness of ALBI grade for assessing hepatic function and HCC prognosis.

KEY MESSAGE

A detailed assessment of hepatic function is required for recent HCC therapeutic strategies. ALBI grade may be a powerful tool to improve treatment options for affected patients.

Microwave ablation versus resection for hepatocellular carcinoma within the Milan criteria: a propensity-score analysis

Background:

Whether the efficient heat-generating mechanism of microwave ablation (MWA) is comparable with resection (RES) in treating hepatocellular carcinoma (HCC) remains unclear.

Methods:

This retrospective cohort study comprised 126 and 1183 patients with HCC meeting the Milan criteria who received MWA or RES between 2002 and 2017. We compared 5-year overall survival (OS) and recurrence-free survival (RFS) using both propensity-score matching (PSM) and inverse-probability-of-treatment-weighting (IPW) analysis and investigated the prognostic factors with multivariate Cox analysis.

Results:

After PSM (1:2), although MWA (n = 116) offered decreased 5-year RFS (30.6% versus 57.5%, p < 0.001) compared with RES (n = 212), both treatments provided similar 5-year OS (82.2% versus 80.5%, p = 0.360) because most patients with intrahepatic recurrence remained eligible for repeat treatments; similar results were found in the IPW analysis. Additionally, the comparable efficacy of MWA and RES was consistent across all subgroups: those with solitary HCC ⩽ 3.0 cm or >3.0 cm, or multifocal HCCs within the Milan criteria, patients with liver function of albumin–bilirubin grade 1 or 2, and older (⩾60 years) or younger (<60 years) patients. Multivariate Cox analysis confirmed that no difference was seen between MWA and RES in OS (hazard ratio = 0.85; p = 0.581) in the overall population; similar results were obtained in the propensity-score-matched and IPW cohorts.

Conclusions:

Compared with RES, MWA offered worse RFS for HCC within the Milan criteria; however, both treatments provided equivalent long-term OS because most patients with intrahepatic recurrence remained eligible for repeat treatments.

Microwave ablation compared with hepatic resection for the treatment of hepatocellular carcinoma and liver metastases: a systematic review and meta-analysis

Background

Hepatic resection (HR) is the gold standard liver cancer treatment, but few patients are eligible due to comorbidities or tumor location. Microwave ablation (MWA) is an important complementary liver cancer treatment to HR. This systematic review compared MWA with HR for liver cancer treatment.

Methods

A systematic search of MEDLINE, EMBASE, and CENTRAL was conducted for randomized and observational studies published from 2006 onwards. The primary outcome was local tumor recurrence (LTR), and a random effects model was used for meta-analyses.

Results

Of the 1845 studies identified, 1 randomized and 15 observational studies met the inclusion criteria. LTR was significantly increased with MWA versus HR (risk ratio (RR) = 2.49; P = 0.016). In secondary measures, HR provided significantly higher 3- and 5-year overall survival (RR = 0.94; P = 0.03 and RR = 0.88; P = 0.01, respectively) and 3-year disease-free survival (RR = 0.78; P = 0.009). MWA exhibited significantly shorter length of stay (weighted mean difference (WMD) = − 6.16 days; P < 0.001) and operative time (WMD = − 58.69 min; P < 0.001), less intraoperative blood loss (WMD = − 189.09 mL; P = 0.006), and fewer complications than HR (RR = 0.31; P < 0.001). When MWA was combined with HR and compared with either modality alone, complications and blood loss were significantly lower with the combination treatment; however, there were no differences in other outcomes. Subgroup and sensitivity analyses were generally aligned with the main results.

Conclusions

MWA can be an effective and safe alternative to HR in patients/tumors that are not amenable to resection. More randomized and economic studies should be performed that compare the two treatments, especially to determine the target population that benefits most from MWA.

Electronic supplementary material

The online version of this article (10.1186/s12957-019-1632-6) contains supplementary material, which is available to authorized users.

Effects of a Thermal Accelerant Gel on Microwave Ablation Zone Volumes in Lung: A Porcine Study

Background Thermal ablation of cancers may be associated with high rates of local tumor progression. A thermal accelerant gel has been developed to improve the transmission of microwave energy in biologic tissues with the aim of enlarging the thermal ablation zone. Purpose To determine the effects of a thermal accelerant gel on microwave ablation zone volumes in porcine lung and to compare percutaneous and endobronchial delivery methods. Materials and Methods Thirty-two consecutive microwave lung ablations were performed in nine 12-week-old domestic male swine under general anesthesia by using fluoroscopic guidance between September 2017 and April 2018. Experimental ablations were performed following percutaneous injection of thermal accelerant into the lung (n = 16) or after endobronchial injection by using a flexible bronchoscope (n = 8). Control ablations were performed without accelerant gel (n = 8). Lung tissue was explanted after the animals were killed, and ablation zone volumes were calculated as the primary outcome measure by using triphenyltetrazolium chloride vital staining. Differences in treatment volumes were analyzed by generalized mixed modeling. Results Thermal accelerant ablation zone volumes were larger than control ablations (accelerant vs control ablation, 4.3 cm³ [95% confidence interval: 3.4, 5.5] vs 2.1 cm³ [95% confidence interval: 1.4, 2.9], respectively; P < .001). Among ablations with the thermal accelerant, those performed following percutaneous injection had a larger average ablation zone volume than those performed following endobronchial injection (percutaneous vs endobronchial, 4.8 cm³ [95% confidence interval: 3.6, 6.4] vs 3.3 cm³ [95% confidence interval: 2.9, 3.8], respectively; P = .03). Ablation zones created after endobronchial gel injection were more uniform in size distribution (standard error, percutaneous vs endobronchial: 0.13 vs 0.07, respectively; P = .03). Conclusion Use of thermal accelerant results in larger microwave ablation zone volumes in normal porcine lung tissue. Percutaneous thermal accelerant injection leads to a larger ablation zone volume compared with endobronchial injection, whereas a more homogeneous and precise ablation zone size is observed by using the endobronchial approach. © RSNA, 2019 See also the editorial by Goldberg in this issue.