Radiofrequency ablation of hepatocellular carcinoma: treatment success as defined by histologic examination of the explanted liver

Outcomes and Complications of Image-Guided Percutaneous Tumour Ablation for Hepatocellular Carcinoma at the Irish National Liver Transplant Centre

Background: Image-guided tumour ablation is a minimally invasive treatment for early stage hepatocellular carcinoma (HCC). Our study reviews the complications and long term outcomes in patients treated at a tertiary referral centre. Methods: Retrospective study. All patients with HCC who underwent microwave ablation (MWA) or radiofrequency ablation (RFA) from 1st January 2014 to 31st December 2022 were identified. Treatment response of target lesion, complications, and survival were recorded. Results: One hundred seventy ablations were performed in 118 patients; 70% MWA, 30% RFA. Median radiological follow-up 21 months (range 3-107). Follow-up imaging was reported using LI-RADS and mRECIST. At first follow-up imaging, 94 patients had complete response (primary efficacy rate 80.3%) while 19.7% (n = 23) had residual disease. Fifteen of these had repeat ablation; 10 had complete response (secondary efficacy rate 85.6%). By end of study duration, 70.5% (n = 79) achieved sustained local complete response from single ablation without documented recurrence. 14.3% (n = 16) required more than one ablation of target lesion. Overall, 84.8% (n = 95) demonstrated long term local complete response to ablation. Complication occurred in 5.9% (n = 10); 40.0% Grade I, 40.0% Grade II, 10.0% Grade III, 10.0% Grade IV as per the CIRSE Classification. 1-, 3-, and 5-year overall survival (OS) rate was 97%, 68%, and 61% respectively. Mean OS was 5.3 years (median 4.7). No difference in OS (P = .7) or local progression free survival (P = .5) between patients treated with MWA versus RFA. Conclusion: This study demonstrates excellent long-term response to TA, with acceptable complication profile. No difference in survival between RFA versus MWA.

Combination locoregional and systemic therapies in hepatocellular carcinoma

Locoregional therapies play a fundamental role in the treatment of patients with early and intermediate and locally advanced hepatocellular carcinomas. With encouraging recent advances in immunotherapy-based systemic therapies, locoregional therapies are being both promoted and challenged by new systemic therapy options. Combined locoregional and systemic therapies might enhance treatment outcomes compared with either option alone. This Series paper summarises the existing data on locoregional and systemic therapies for hepatocellular carcinoma, and discusses evidence from studies investigating their combination with a focus on their synergistic efficacy and safety.

The debate between electricity and heat, efficacy and safety of irreversible electroporation and radiofrequency ablation in the treatment of liver cancer: A meta-analysis

Both irreversible electroporation (IRE) and radiofrequency ablation (RFA) are viable ablation methods for localized treatment of liver tumors. We conducted a meta-analysis to access the efficacy and safety of IRE and RFA in liver cancer treatment. Clinical studies on IRE and RFA for the treatment of liver cancer were collected from PubMed and CNKI until June 2023. We screened the literature for ablation success rates at 1 month post-operation, extracting keywords such as "ablation success rate," "technical success rate," "recurrence rate," and "complication" for meta-analysis. A total of 37 articles were included: 24 related to RFA involving 1,685 cases and 13 related to IRE involving 524 cases. The results demonstrate that ablation success rates at post-operative 1 month for IRE and RFA were 86% (95% CI: 82-89%) and 87% (95% CI: 81-92%), respectively. Technical success rates were 96% (95% CI: 88-100%) and 99% (95% CI: 96-100%). In addition, the recurrence rate was 16% (95% CI: 12-22%) in RFA group and 16% (95% CI: 9-23%) in IRE group. In terms of safety, the RFA had a complication rate of 28% (95% CI: 10-50%) and the IRE had a rate of 26% (95% CI: 13-43%). In conclusion, IRE and RFA exhibit similar ablation success rates at 1 month post-operation and comparable complication rates, making them both safe and effective treatment options.

Diabetes Mellitus Negatively Impacts Outcomes of HBV-Related Hepatocellular Carcinoma Following Thermal Ablation

Purpose

Diabetes mellitus (DM) negatively impacts chronic hepatitis B patients, but its role in those with HBV-related hepatocellular carcinoma (HCC) undergoing ablation remains unclear. This study aims to evaluate the influence of DM on recurrence patterns and overall survival (OS) among patients with HBV-related HCC undergoing ablation.

Patients and Methods

We retrospectively enrolled 372 patients receiving thermal ablation for HBV-related HCC, including 96 (25.8%) patients with DM. Factors associated with local tumor progression (LTP), distant recurrence, and OS were analyzed. The prognostic value of DM in IMbrave050-defined high-risk population was validated.

Results

DM did not correlate with LTP, whereas patients with DM had significantly higher risk of distant recurrence (median time to recurrence 23.7 versus 46.2 months, p=0.032), poorer OS (median OS 75.6 versus 106 months, p=0.011), and poorer post-recurrence survival (70.7 versus 106 months, p=0.009). In multivariate analysis, DM (hazard ratio (HR)=1.466, p=0.012), FIB-4 score, multiple tumors, and AFP level were independent predictors of distant recurrence, while DM (HR=1.424, p=0.028), ALBI score, tumor size, AFP and creatinine levels were significantly associated with OS. A DM-based risk score effectively discriminated the risk of distant recurrence. The IMbrave050 criteria could stratify the risk of LTP but not distant recurrence. DM status further discriminated the risk of distant recurrence and mortality in the IMbrave050-defined high-risk population.

Conclusion

Patients with DM had an increased risk of distant recurrence and mortality after thermal ablation for HBV-related HCC, highlighting the importance of increasing awareness of DM and implementing rigorous post-ablation monitoring for diabetic HCC patients.

Yttrium-90 radioembolization treatment strategies for management of hepatocellular carcinoma

As the third leading cause of cancer-related deaths worldwide, hepatocellular carcinoma (HCC) represents a significant global health challenge. This paper provides an introduction and comprehensive review of transarterial radioembolization (TARE) with Yttrium-90 (Y90), a widely performed transcatheter procedure for HCC patients who are not suitable candidates for surgery. TARE involves the targeted delivery of radioactive microspheres to liver tumors, offering a promising treatment option for managing HCC across various stages of the disease. By evaluating Y90 TARE outcomes across early, intermediate, and advanced stages of HCC, the review aims to present a thorough understanding of its efficacy and safety. Additionally, this paper highlights future research directions focusing on the potential of combination therapies with systemic and immunotherapies, as well as personalized treatments. The exploration of these innovative approaches aims to improve treatment outcomes, reduce adverse events, and provide new therapeutic opportunities for HCC patients. The review underscores the importance of ongoing research and clinical trials to optimize TARE further and integrate it into comprehensive HCC treatment paradigms.

Impact of HCV eradication on recurrence pattern and long-term outcomes in patients with HCV-related hepatocellular carcinoma undergoing radiofrequency ablation

BACKGROUND

The benefits of HCV eradication on distinct recurrence patterns and long-term hepatic outcomes in patients with hepatocellular carcinoma (HCC) undergoing radiofrequency ablation (RFA) remain uncertain. This study aims to assess the impact of HCV eradication on HCC recurrence patterns and long-term hepatic outcomes after RFA and to identify predictors of recurrence in patients achieving sustained virological response (SVR).

METHODS

We retrospectively enrolled 274 patients receiving RFA for HCV-related HCC, including 73 and 88 patients treated with interferon-based (IFN) and direct-acting antivirals (DAA) therapy, respectively. We analysed factors associated with local tumour progression (LTP), distant recurrence, overall survival, and hepatic decompensation.

RESULTS

SVR was achieved in 49.3% of patients undergoing IFN therapy and 93.2% of patients undergoing DAA therapy. HCV eradication was not associated with LTP but significantly correlated with reduced risk of distant recurrence (by DAA: hazard ratio (HR) = 0.449, p = 0.006), overall survival (by IFN: HR = 0.242, p < 0.001; by DAA: HR = 0.274, p < 0.001) and hepatic decompensation (by IFN: HR = 0.313, p = 0.004; by DAA: HR = 0.281, p < 0.001). The benefits of achieving SVR in terms of overall survival and hepatic decompensation remained significant in subgroups of patients with and without recurrence. Patients with SVR showed a significant decline in FIB-4 score and a higher proportion of ALBI grade improvement. Among SVR patients, the IMbrave050 criteria predicted LTP but not distant recurrence, whereas the FIB-4 score after SVR, rather than the baseline FIB-4, predicted distant recurrence.

CONCLUSIONS

HCV eradication was associated with a significant reduction in distant recurrence, mortality and hepatic decompensation following RFA in patients with HCV-related HCC.

Radiofrequency ablation: mechanisms and clinical applications

Radiofrequency ablation (RFA), a form of thermal ablation, employs localized heat to induce protein denaturation in tissue cells, resulting in cell death. It has emerged as a viable treatment option for patients who are ineligible for surgery in various diseases, particularly liver cancer and other tumor-related conditions. In addition to directly eliminating tumor cells, RFA also induces alterations in the infiltrating cells within the tumor microenvironment (TME), which can significantly impact treatment outcomes. Moreover, incomplete RFA (iRFA) may lead to tumor recurrence and metastasis. The current challenge is to enhance the efficacy of RFA by elucidating its underlying mechanisms. This review discusses the clinical applications of RFA in treating various diseases and the mechanisms that contribute to the survival and invasion of tumor cells following iRFA, including the roles of heat shock proteins, hypoxia, and autophagy. Additionally, we analyze‌ the changes occurring in infiltrating cells within the TME after iRFA. Finally, we provide a comprehensive summary of clinical trials involving RFA in conjunction with other treatment modalities in the field of cancer therapy, aiming to offer novel insights and references for improving the effectiveness of RFA.

Characterization of Microwave Generator Energy and Ablation Volumes following Transarterial Embolization in an In Vivo Porcine Liver Model

PURPOSE

To characterize the relationship between ablation zone volume (AZV) and microwave ablation (MWA) energy in an in vivo porcine liver model following arterial embolization.

MATERIALS AND METHODS

With Institutional Animal Care and Use Committee (IACUC) approval, 11 female swine underwent either right (n = 5) or left (n = 6) hepatic artery embolization under fluoroscopic guidance. Subsequently, ultrasound (US)-guided MWA was performed in each liver segment (left lateral, left medial, right medial, and right lateral) at either 30 W (n = 4 lobes), 60 W (n = 4), 65 W (n = 20), 90 W (n = 8), 120 W (n = 4), or 140 W (n = 4) continuously for 5 minutes. Postprocedural volumetric segmentation was performed on standardized multiphase T1 magnetic resonance (MR) imaging sequences.

RESULTS

Mean AZVs in embolized lobes (15.8 mL ± SD 10.6) were significantly larger than those in nonembolized lobes (11.2 mL ± SD 6.5, P < .01). MWA energy demonstrated significant positive linear correlation with both embolized (R2 = 0.66, P < .01) and nonembolized (R2 = 0.64, P < .01) lobes. The slope of the linear models corresponded to a 0.95 mL/kJ (SD ± 0.16) and 0.54 mL/kJ (SD ± 0.09) increase in ablation volume per applied kilojoule of energy (E) in embolized and nonembolized lobes, respectively. In the multivariate model, embolization status significantly modified the relationship between E and AZV as described by the following interaction term: 0.42∗E∗(embolization status) (P = .031).

CONCLUSIONS

Linear models demonstrated a near 1.8-fold increase in ratio of AZV per unit E, R(AZV:E), when applied to embolized lobes relative to nonembolized lobes. Absolute AZV differences between embolized and nonembolized lobes were greater at higher-power MWA.

[Ablation of liver tumors : From pre-interventional imaging to post-interventional assessment]

The aim of this article is to provide an overview on the most frequently applied image-guided, percutaneous, local ablative techniques for treatment of primary and secondary liver tumors. The technical procedures of microwave ablation (MWA) and radiofrequency ablation (RFA) are presented. The pre-interventional diagnostics, indications and feasibility are also discussed, taking the current national guidelines into consideration. Finally, treatment outcomes and recommendations on post-interventional imaging following local tumor ablation are presented.

Current use of percutaneous image-guided tumor ablation for the therapy of liver tumors: lessons learned from the registry of the German Society for Interventional Radiology and Minimally Invasive Therapy (DeGIR) 2018-2022

OBJECTIVES

Percutaneous image-guided tumor ablation of liver malignancies has become an indispensable therapeutic procedure. The aim of this evaluation of the prospectively managed multinational registry of the voluntary German Society for Interventional Radiology and Minimally Invasive Therapy (DeGIR) was to analyze its use, technical success, and complications in clinical practice.

MATERIALS AND METHODS

All liver tumor ablations from 2018 to 2022 were included. Technical success was defined as complete ablation of the tumor with an ablative margin.

RESULTS

A total of 7228 liver tumor ablations from 136 centers in Germany and Austria were analyzed. In total, 31.4% (2268/7228) of patients were female. Median age was 67 years (IQR 58-74 years). Microwave ablation (MWA) was performed in 65.1% (4703/7228), and radiofrequency ablation (RFA) in 32.7% (2361/7228). Of 5229 cases with reported tumor etiology, 60.3% (3152/5229) of ablations were performed for liver metastases and 37.3% (1950/5229) for hepatocellular carcinoma. The median lesion diameter was 19 mm (IQR 12-27 mm). In total, 91.8% (6636/7228) of ablations were technically successful. The rate of technically successful ablations was significantly higher in MWA (93.9%, 4417/4703) than in RFA (87.3%, 2061/2361) (p < 0.0001). The total complication rate was 3.0% (214/7228) and was significantly higher in MWA (4.0%, 189/4703) than in RFA (0.9%, 21/2361, p < 0.0001). Additional needle track ablation did not increase the rate of major complications significantly (24.8% (33/133) vs. 28.4% (23/81), p = 0.56)).

CONCLUSION

MWA is the most frequent ablation method. Percutaneous image-guided liver tumor ablations have a high technical success rate, which is higher for MWA than RFA. The complication rate is generally low but is higher for MWA than RFA.

CLINICAL RELEVANCE STATEMENT

Percutaneous image-guided liver ablation using microwave ablation and radiofrequency ablation are effective therapeutic procedures with low complication rates for the treatment of primary and secondary liver malignancies.

KEY POINTS

• Percutaneous image-guided liver tumor ablations have a high technical success rate, which is higher for microwave ablation than radiofrequency ablation. • Microwave ablation is the most frequent ablation method ahead of radiofrequency ablation. • The complication rate is generally low but is higher for microwave ablation than radiofrequency ablation.

Locoregional Therapies for Hepatocellular Carcinoma prior to Liver Transplant: Comparative Pathologic Necrosis, Radiologic Response, and Recurrence

PURPOSE

To compare pathologic tumor necrosis rates after locoregional therapies (LRTs) for hepatocellular carcinoma (HCC) prior to liver transplantation and evaluate radiologic-pathologic correlation along with posttransplant HCC recurrence.

MATERIALS AND METHODS

Consecutive patients with solitary HCC bridged or downstaged with LRT from 2010 to 2022 were included. LRTs were transarterial chemoembolization (TACE), radioembolization (yttrium-90 [90Y]), ablation, and stereotactic body radiotherapy (SBRT). Upfront combination therapy options were TACE/ablation and TACE/SBRT. Subsequent therapy crossover due to local recurrence was allowed. Posttreatment imaging closest to the time of transplant, explant histopathologic necrosis, and tumor recurrence after transplant were reviewed.

RESULTS

Seventy-three patients met inclusion criteria, of whom 5 (7%) required downstaging. 90Y alone (n = 36) and multimodal therapy (pooled upfront combination and crossover therapy, n = 23) resulted in significantly greater pathologic necrosis compared with TACE alone (n = 14; P = .01). High dose 90Y radiation segmentectomy (≥190 Gy; n = 27) and TACE/ablation (n = 7) showed highest rates of complete pathologic necrosis (CPN)-63% (n = 17) and 71% (n = 5), respectively. Patients with CPN had a mean lesion size of 2.5 cm, compared with 3.2 cm without CPN (P = .04), irrespective of LRT modality. HCC recurrence was more common in patients without CPN (16%, 6/37) than in those with CPN (3%, 1/36; P = .11). Using Liver Imaging Reporting and Data System (LI-RADS), a nonviable imaging response was 75% sensitive and 57% specific for CPN.

CONCLUSIONS

Radiation segmentectomy and multimodal therapy significantly improved CPN rates compared with TACE alone. A LI-RADS treatment response of nonviable did not confidently predict CPN.

Radiation Segmentectomy for Hepatocellular Carcinoma

The application of trans-arterial radioembolization (TARE) with Yttrium-90, historically a palliative treatment option for patients with advanced hepatocellular carcinoma (HCC), is evolving. Radiation segmentectomy (RADSEG), the segmental delivery of an ablative radiation dose, is a treatment option for patients with earlier-stage HCC. This review presents an in-depth exploration of RADSEG, emphasizing its technical considerations, dosimetry advancements, and patient selection. The integration of RADSEG into the Barcelona Clinic Liver Cancer (BCLC) paradigm will be highlighted. RADSEG outcomes concerning safety and efficacy will be explored and compared with traditional locoregional cancer treatments like trans-arterial chemoembolization (TACE), percutaneous thermal ablation, and surgical resection, with an eye on future directions and considerations.

Chemoembolization Plus Ablation: Current Status

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide. The treatment landscape for HCC has evolved significantly over the past decade, with several modalities available to treat various stages of disease. The Barcelona Clinic Liver Cancer (BCLC) system provides a foundation for treatment guidance. However, given the complex nature of HCC, a more nuanced approach is often required, especially for lesions sized between 3 and 5 cm. This review aims to analyze the available treatments for early-stage HCC lesions between 3 and 5 cm, with a focus on the therapeutic potential and efficacy of transarterial chemoembolization (TACE)-ablation. Additional therapies including TACE, ablation, transarterial radioembolization, and surgical resection are also reviewed and compared with TACE-ablation. TACE-ablation is a viable therapeutic option for early-stage HCC lesions between 3 and 5 cm. Surgical resection remains the gold standard. Although recent studies suggest radiation segmentectomy may be a curative approach for this patient population, further studies are needed to compare the relative efficacies between TACE-ablation and radiation segmentectomy.

Understanding the role of radiologists in complex treatment decisions for patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver and represents a significant global health burden. Management of HCC can be challenging due to multiple factors, including variable expectations for treatment outcomes. Several treatment options are available, each with specific eligibility and ineligibility criteria, and are provided by a multidisciplinary team of specialists. Radiologists should be aware of the types of treatment options available, as well as the criteria guiding the development of individualized treatment plans. This awareness enables radiologists to contribute effectively to patient-centered multidisciplinary tumor boards for HCC and play a central role in reassessing care plans when the treatment response is deemed inadequate. This comprehensive review aims to equip radiologists with an overview of HCC staging systems, treatment options, and eligibility criteria. The review also discusses the significance of imaging in HCC diagnosis, treatment planning, and monitoring treatment response. Furthermore, we highlight the crucial branch points in the treatment decision-making process that depend on radiological interpretation.

Update on Locoregional Therapies for Liver Cancer: Radiation Segmentectomy

Over 900,000 people worldwide were diagnosed with liver cancer in 2022 alone, with hepatocellular carcinoma (HCC) accounting for 75-85% of cases. Treatment for HCC includes some combination of systemic therapies, surgery, liver transplantation, ablation, and intra-arterial therapies with transarterial chemoembolization (TACE) or transarterial radioembolization (TARE). Currently, the Barcelona Clinic Liver Cancer (BCLC) guidelines have acknowledged liver transplantation, surgical resection, and thermal ablation as curative therapies in very early to early stage HCC (BCLC-0 and BCLC-A). While these modalities are the preferred curative treatments for a very early to early stage disease, there are challenges associated with these options, such as organ availability and patient eligibility. Current data shows the role of radiation segmentectomy as a curative therapeutic option for very early to early stage HCC that is unresectable and not amenable to ablation. As future data continues to elucidate the ability for radiation segmentectomy to achieve complete pathologic necrosis, the goal is for the BCLC staging model to acknowledge its role as a curative treatment in this patient population and incorporate it into the ever-evolving guidelines.

Liver Imaging Reporting and Data System version 2018 for diagnosing hepatocellular carcinoma in alcoholic liver cirrhosis and virus-related cirrhosis

PURPOSE

We aimed to evaluate and compare the diagnostic performance of Liver Imaging Reporting and Data System (LI-RADS) v2018 for hepatocellular carcinoma (HCC) ≤ 3.0 cm on gadoxetic acid-enhanced MRI according to the etiology of cirrhosis.

METHODS

Thirty-eight patients with alcoholic liver cirrhosis (ALC) and 37 with hepatitis C virus-related cirrhosis (HCV) who underwent preoperative MRI and subsequent surgical resection or transplantation were included. For comparison groups, patients with hepatitis B virus-related cirrhosis (HBV) were included by 1:1 matching with HCV and ALC groups according to age, lesion size, and Child-Pugh classification. The imaging characteristics of background liver and focal lesions were analyzed. The diagnostic performance of LI-RADS was compared between HCV and HBV groups, and between ALC and HBV groups.

RESULTS

ALC group showed significantly higher frequency of hepatic steatosis (25.8 % vs. 6.1 %, p =.04) and lower frequency of nonperipheral washout on portal venous-phase in HCC (63.2 % vs. 97.1 %, p <.001) compared with HBV group. ALC group showed significantly lower sensitivity than HBV group (52.6 % vs. 88.6 %, p<.001). No significant differences in diagnostic performance were found between HCV and HBV groups. In ALC group, hepatobiliary-phase hypointensity provided significantly higher sensitivity (76.3 % vs. 52.6 %, p =.008).

CONCLUSION

The sensitivity of LI-RADS for diagnosing HCC ≤ 3.0 cm was significantly lower in the ALC group than in the HBV group.

Predictive Factors of Treatment Outcomes After Percutaneous Radiofrequency Ablation of Hepatocellular Carcinoma in the Hepatocaval Confluence: A Propensity Score Matching Analysis

RATIONALE AND OBJECTIVES

To compare the efficacy and complications of ultrasound-guided percutaneous radiofrequency ablation of hepatocellular carcinoma (HCC) in the hepatocaval confluence with those of HCC in the non-hepatocaval confluence and to explore the risk factors that lead to radiofrequency ablation failure and patient local tumor progression (LTP).

MATERIALS AND METHODS

From January 2017 to January 2022, 86 patients with HCC in the hepatocaval confluence who had radiofrequency ablation were included. A 1:1 propensity-matched group of patients with HCC in the non-hepatocaval confluence with comparable clinical baseline traits, such as tumor diameter and tumor number, served as the control group. The two groups' complications, primary efficacy rate (PER), technical success rate (TSR), and prognosis were estimated.

RESULTS

After PSM, no significant difference of TSR (91.7% vs 95.8%, p = 0.491) and PER (95.8% vs 97.2%, p = 1.000) and 1-, 3-, and 5-year LTP rate (12.5% vs 9.9%, 28.2% vs 27.7%, 40.8% vs 43.8%, p = 0.959) and 1-, 3-, and 5-year DFS rate (87.5% vs 87.5%, 62.3% vs 54.2%, 18.1% vs 22.6%, p = 0.437) and 1-, 3-, and 5-year OS rate (94.3% vs 95.7%, 72.7% vs 69.6%, 20.9% vs 33.6%, p = 0.904) was detected between the two groups. The tumor-to-IVC distance was an independent risk factor for radiofrequency ablation failure in HCC patients in the hepatocaval confluence (OR = 0.611, p = 0.022). Besides, tumor diameter was an independent risk factor for predicting LTP in patients with HCC in the hepatocaval confluence (HR = 2.209, p = 0.046).

CONCLUSION

HCC in the hepatocaval confluence can be effectively treated with radiofrequency ablation. To maximize treatment efficacy, the tumor-to-IVC distance and tumor diameter should be assessed before the operation begins.

Transarterial Chemoembolization Combined with Simultaneous Thermal Ablation for Solitary Hepatocellular Carcinomas in Regions with a High Risk of Recurrence

OBJECTIVES

We evaluated the safety and efficacy of transarterial chemoembolization combined with percutaneous thermal ablation (radiofrequency or microwave ablation) in the treatment of solitary hepatocellular carcinoma tumors ranging from 2 to 4.5 cm at subdiaphragmatic, subcapsular, or perivascular locations.

MATERIALS AND METHODS

Fifteen patients (12 men, mean [range] age of 66.6 ± 10.88 [34-75] y) who received transarterial chemoembolization combined with simultaneous percutaneous radiofrequency ablation (n = 5) or microwave ablation (n = 10) for hepatocellular carcinoma in regions with high risk of recurrence (subdiaphragmatic, subcapsular, or perivascular) between 2012 and 2018 were evaluated. We retrospectively investigated tumor diameter and localization, success rate, safety, local efficacy (imaging at month 1 after treatment), local tumor response (3 months posttreatment), local tumor progression, intrahepatic distant recurrence, overall survival and complications.

RESULTS

Tumor diameter ranged from 20 to 45 mm (mean 31.7 ± 7.37 mm). Hepatocellular carcinoma diameter was 2 to 3 cm in 7 patients and 3.1 to 4.5 cm in 8 patients. The technical success rate was 100%, with no life-threatening complications. At enhanced imaging at 1-month follow-up, the complete necrosis rate was 100%; at 3 months, 100% of patients had a complete response. During a mean follow-up of 26 ± 13.6 months, 7 patients (46.7%) had tumor progression. Three patients (20%) had local tumor response, and 4 patients (26.7 %) experienced distant recurrences in the untreated liver. The mean local tumor progression and mean intrahepatic distance recurrence times were 11 months and 29.5 months, respectively. Overall survival rates were 100% at 1 year, 73% at 3 years, and 47% at 5 years.

CONCLUSIONS

Transarterial chemoembolization combined with simultaneous percutaneous thermal ablation is safe, feasible, and effective in enhancing the local control rate for solitary hepatocellular carcinoma ranging from 2 to 4.5 cm in regions with high risk of recurrence.

Visualization Score of Gadoxetic Acid-Enhanced Magnetic Resonance Imaging: The Effect on the Diagnostic Accuracy for Hepatocellular Carcinoma

BACKGROUND

The visualization score of hepatobiliary-phase (HBP) images has been introduced as an image quality index for gadoxetic acid-enhanced MRI. It may be associated with hepatic function and could have an implication on the diagnostic accuracy for hepatocellular carcinoma (HCC).

PURPOSE

To investigate the association between the visualization score of gadoxetic acid-enhanced MRI and clinical factors and to evaluate its effect on the diagnostic accuracy for HCC ≤ 3.0 cm.

STUDY TYPE

Retrospective.

POPULATION

A total of 493 focal lesions from 397 patients.

FIELD STRENGTH/SEQUENCE

A 5-T or 3.0 -T with pre/postcontrast T1-weighted 3D gradient echo sequence, and T2-weighted fast spin-echo sequence ASSESSMENT: Child-Pugh classification and albumin-bilirubin (ALBI) score were assessed. Three readers evaluated the visualization score of each MRI examination (A, no or minimal; B, moderate; and C, severe limitations), and major features (arterial-phase hyperenhancement, washout, enhancing capsule, threshold growth) and ancillary features of each focal lesion.

STATISTICAL TESTS

Univariable and multivariable logistic regression analyses were performed to determine significant clinical factors associated with a suboptimal visualization score (B or C). Generalized estimating equations were used to compare the sensitivity and specificity for diagnosing HCC between the two group (visualization score A vs. B or C). A P value < 0.05 was considered statistically significant.

RESULTS

Of the 397 MRI examinations, the incidence of suboptimal visualization score was 13%. A suboptimal visualization score was significantly associated with Child-Pugh classification B or C (adjusted odds ratio [OR] = 15.2) and ALBI grade 2 or 3 (OR = 4.7). Compared with the visualization score A group, the suboptimal visualization score group showed significantly lower sensitivity (56.8% vs. 75.2%) and less frequent washout in HCC (62.2% vs. 84.0%).

DATA CONCLUSION

The visualization score on gadoxetic acid-enhanced MRI can be an important image quality index and the diagnostic accuracy for HCC ≤ 3.0 cm may not be sufficient in the suboptimal visualization score group.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 3.

Value of threshold growth as a major diagnostic feature of hepatocellular carcinoma in LI-RADS

BACKGROUND & AIMS

The Liver Reporting and Data System (LI-RADS) version 2018 simplified the definition of threshold growth to '≥50% size increase in a mass in ≤6 months'. However, the diagnostic value of threshold growth for hepatocellular carcinoma (HCC) remained unclear. We evaluated the value of threshold growth, as defined by LI-RADS v2018, in diagnosing HCCs.

METHODS

Patients who underwent preoperative gadoxetate disodium-enhanced MRI because of the presence of LI-RADS category 2, 3, or 4 rather than category 5 on prior CT/MRI between January 2017 and December 2020 were retrospectively evaluated. Pathologic or clinical diagnoses were used as reference standards. Imaging features were evaluated by three readers according to LI-RADS v2018. The frequency and diagnostic odds ratio of threshold growth were calculated. The diagnostic performance of LI-RADS category 5 was separately evaluated when threshold growth was and was not considered a major feature, and results were compared using generalized estimation equations. Subgroups of patients who underwent CT/MRI during the previous 3-6 months were analyzed.

RESULTS

Analysis of 340 observations in 243 patients found that the frequency of threshold growth was 18.8% and it gradually increased over time. Threshold growth was significantly associated with HCC (diagnostic odds ratio 5.2; 95% CI 2.1-12.7; p <0.001). Use of threshold growth as a major feature significantly increased sensitivity in both the overall (66.4% vs. 57.3%, p <0.001) and subgroup (73.4% vs. 58.2%, p <0.001) cohorts, but had no effect on specificity in either the overall (97.5% vs. 98.3%, p = 0.319) or subgroup (95.9% vs. 98.0%, p = 0.323) cohorts.

CONCLUSION

The revised threshold growth of LI-RADS v2018 was significantly associated with HCC. Use of threshold growth as a major diagnostic feature of HCC can improve the sensitivity of LI-RADS v2018.

IMPACT AND IMPLICATIONS

We found that the revised threshold growth in the Liver Imaging Reporting and Data System version 2018 (LI-RADS v2018) was a significant predictor of hepatocellular carcinoma (HCC). The use of threshold growth as a major imaging feature of HCC significantly increased the sensitivity of LI-RADS v2018, especially small HCCs (≤3.0 cm), compared with its non-use. Because these small HCCs are eligible for curative treatments, the additional detection of small HCCs is clinically meaningful.

Safety and Feasibility of Analgosedation for Electrochemotherapy of Liver Lesions

Interventional Oncology treatments grant low-risk mini-invasive alternatives to surgery for cancer patients. Percutaneous ablative therapies represent a cornerstone for treatment of liver cancer patients. Among these, a newly emerging one is represented by electrochemotherapy. Improvements in analgesia and sedation can nowadays offer optimal support for ablative procedures, serving as a valid alternative to general anesthesia. The intention of this retrospective monocentric study is to report our preliminary experience on feasibility and safety of electrochemotherapy for treatment of complex liver tumors unfit for thermal ablation, using analgosedation instead of general anesthesia. Five patients were enrolled in the study, undergoing electrochemotherapy under analgosedation. Mean procedural time and hospitalization time were recorded. Immediate post-procedural cone-beam CT showed complete coverage of the lesion without complications. One-month CT examination showed an overall response rate of 100% (four complete responses, one partial response). Electrochemotherapy under analgosedation seems to be a safe, feasible, and effective option for liver cancer patients not amenable to other ablative techniques.

Multiple arterial-phase MRI with gadoxetic acid improves diagnosis of hepatocellular carcinoma ≤3.0 cm

BACKGROUND AND AIMS

Multiple arterial-phase magnetic resonance imaging (MA-MRI) was introduced to overcome the limitations of gadoxetic acid-enhanced MRI, but its clinical impacts on hepatocellular carcinoma (HCC) diagnosis have not been well assessed. We investigated whether MA-MRI with gadoxetic acid could improve the diagnosis of HCC ≤3.0 cm in comparison with single arterial-phase MRI (SA-MRI).

METHODS

This retrospective study included 397 patients from two tertiary institutions who underwent gadoxetic acid-enhanced MRI (243 patients with 271 lesions in cohort-1 underwent SA-MRI, and 154 patients with 166 lesions in cohort-2 underwent MA-MRI). The patients had 437 hepatic lesions ≤3.0 cm with pathologic confirmation. The arterial-phase image quality and diagnostic performance of SA-MRI and MA-MRI were analysed and compared. To minimize the effects of selection bias because of potential confounding between the two groups, propensity score-matching was additionally performed.

RESULTS

MA-MRI showed a significantly higher percentage of optimal arterial-phase timing (94.2% vs. 74.5%, p < .001) and lower incidence of inadequate examinations (1.3% vs. 5.8%, p = .034) than SA-MRI. MA-MRI had a significantly higher non-rim arterial-phase hyperenhancement (APHE) detection rate (94.9% vs. 85.5%, p = .005) and sensitivity for diagnosing HCC (87.4% vs. 70.0%, p < .001) than SA-MRI, but no significant difference in specificity (92.9% vs. 93.1%, p = .966). In 123 pairs of propensity score-matched patients, MA-MRI had significantly higher sensitivity (89.1% vs. 74.5%, p = .006) than SA-MRI with equal specificity (92.3% vs. 92.3%, p > .999).

CONCLUSIONS

Compared with SA-MRI, MA-MRI with gadoxetic acid can detect more non-rim APHE and significantly improve sensitivity for diagnosing HCC ≤3.0 cm, without a significant decrease in specificity.

Virtual Treatment Zone From Cone Beam CT Commonly Alters Treatment Plan and Identifies Tumor at Risk for Under-Treatment in US or US Fusion-Guided Microwave Ablation of Liver Tumors

Tumor ablation is included in several major cancer therapy guidelines. One technical challenge of percutaneous ablation is targeting and verification of complete treatment, which is prone to operator variabilities and human imperfections and are directly related to successful outcomes, risk for residual unablated tumor and local progression. The use of "Prediction Ablation Volume Software" may help the operating Interventional Radiologist to better plan, deliver, and verify before the ablation, via virtual treatment zones fused to target tumor. Fused and superimposed images provide 3-dimensional information from different timepoints, just when that information is most useful. The aim of this study is to evaluate the technical success and efficacy of an ablation treatment flowchart provided by a cone beam computed tomography (CBCT) "Prediction Ablation Volume Software." This is a single-center retrospective study. From April 2021 to January 2022, 29 nonconsecutive evaluable patients with 32 lesions underwent liver ablation with Prediction Ablation Volume Software. Each patient was discussed in a multidisciplinary tumor board and underwent an enhanced computed tomography or magnetic resonance imaging approximately 1 month before the procedure, as well as ∼1 month after. Technical success was defined as treatment of the tumor according to the protocol, covered completely by the Prediction Ablation Volume. Technical efficacy was defined as assessment of complete ablation of the target tumor at imaging follow up (∼1 month). Technical success, technical efficacy, and procedural factors were studied. Technical success was achieved in 30 of 32 liver lesions (94%), measuring 20 mm mean maximum diameter. The antenna was repositioned in 16 of 30 (53%) evaluable target lesions. Residual tumor was detected at 1 month imaging follow up in only 4 of 30 (13%) of the treated lesion. Technical efficacy was of 87% in this retrospective description of our process. The implementation of a CBCT Prediction Ablation Volume Software and flowchart for the treatment of liver malignancies altered the procedure, and demonstrated high technical success and efficacy. Such tools are potentially useful for procedural prediction and verification of ablation.

Hepatocellular carcinoma downstaging for liver transplantation in the era of systemic combined therapy with anti-VEGF/TKI and immunotherapy

Hepatocellular carcinoma remains a global health challenge affecting close to 1 million cases yearly. Liver transplantation provides the best long-term outcomes for those meeting strict criteria. Efforts have been made to expand these criteria, whereas others have attempted downstaging approaches. Although locoregional approaches to downstaging are appealing and have demonstrated efficacy, limitations and challenges exists including poor imaging modality to assess response and appropriate endpoints along the process. Recent advances in systemic treatments including immune checkpoint inhibitors alone or in combination with tyrosine kinase inhibitors have prompted the discussion regarding their role for downstaging disease prior to transplantation. Here, we provide a review of prior locoregional approaches for downstaging, new systemic agents and their role for downstaging, and finally, key and critical considerations of the assessment, endpoints, and optimal designs in clinical trials to address this key question.

Radiation segmentectomy for curative intent of unresectable very early to early stage hepatocellular carcinoma (RASER): a single-centre, single-arm study

BACKGROUND

Unresectable solitary very early to early stage hepatocellular carcinoma is managed with ablation for curative intent. Radiation segmentectomy is a treatment option that delivers radioactive ⁹⁰yttrium (⁹⁰Y)-bound microspheres transarterially to a segment of liver. The aim of this study was to assess the safety and efficacy of radiation segmentectomy in patients with unresectable hepatocellular carcinoma deemed unfavourable for ablation.

METHODS

RASER was a single-centre, single-arm study that included adults (>18 years) with solitary hepatocellular carcinoma with unfavourable location for ablation, without metastasis or macrovascular invasion. Eligibility criteria included measurable disease 3 cm or less in diameter, Child-Pugh score A-B7, an Eastern Cooperative Oncology Group score of 0, and adequate haematological and organ function. The primary endpoint was target tumour response measured by mRECIST. Patients were followed up with imaging and office visits for up to 24 months. The trial is registered with ClinicalTrials.gov (NCT03248375), and is completed.

FINDINGS

Individuals were enrolled between Aug 3, 2016, and April 4, 2019, and the last patient follow-up occurred on March 31, 2021. Of the 44 individuals assessed for eligibility, 29 patients were included in the study. Initial target lesion complete response was observed in 24 (83%) of 29 patients, and partial response was observed in five (17%) of patients. All patients had an initial objective response and 26 (90%) individuals had a sustained complete response. Four (14%) patients had grade 3 leukopenia and two (7%) had grade 3 thrombocytopenia. There were two (7%) non-laboratory-related grade 3 adverse events (one arterial injury and one ascites). The most frequent (>10% patients) grade 1 or 2 adverse events were fatigue (nine [31%]); nausea, vomiting, or anorexia (seven [24%]); abdominal discomfort (six [21%]), leukopenia (nine [31%]), thrombocytopenia (four [14%]), increased alkaline phosphatase (four [14%]), increased alanine or aspartate aminotransferase (four [14%]), increased bilirubin (four [14%]), and decreased albumin (six [21%]). There was one death that was not treatment related.

INTERPRETATION

Radiation segmentectomy was efficacious, with a low proportion of high-grade adverse events in patients with unresectable very early to early stage hepatocellular carcinoma with suboptimal location for ablation. These results suggest that radiation segmentectomy should be further investigated as a potential curative treatment option for well selected patients.

FUNDING

Boston Scientific.

Simplified LI-RADS for Hepatocellular Carcinoma Diagnosis at Gadoxetic Acid-enhanced MRI

Background Although various modifications to the Liver Imaging Reporting and Data System (LI-RADS) at gadoxetic acid-enhanced MRI have been suggested, LI-RADS shows suboptimal sensitivity for hepatocellular carcinoma (HCC) and is perceived to be too complex. Purpose To evaluate clinical usefulness of a simplified LI-RADS for diagnosing HCCs of 30 mm or smaller at gadoxetic acid-enhanced MRI. Materials and Methods Patients who underwent gadoxetic acid-enhanced MRI examination and subsequent resection, transplantation, or biopsy for focal solid nodules of 30 mm or smaller between January 2019 and December 2020 at a single tertiary referral institution were retrospectively analyzed. Two strategies for simplified LI-RADS using one size criterion (≥10 mm) were evaluated (strategy A, using classifications for nodules of 10-19 mm for nodules both 10-19 mm and ≥20 mm; strategy B, using classifications for nodules ≥20 mm for nodules both 10-19 mm and ≥20 mm). Multivariable analysis was performed to determine significant ancillary features for HCC. Generalized estimating equations were used to compare diagnostic performance for LR-5 (definite HCC) between LI-RADS version 2018 and simplified LI-RADS. The time required for LI-RADS category assignment was compared between the two systems with use of a paired t test. Results A total of 645 nodules from 510 patients (mean age ± SD, 60 years ± 10; 393 men) were evaluated. Compared with strategy A, strategy B had a higher sensitivity of 74% (347 of 470 nodules [95% CI: 70, 78]) vs 73% (342 of 470 nodules [95% CI: 69, 77]) (P = .02) with the same specificity of 96% (168 of 175 nodules [95% CI: 92, 98]) vs 96% (168 of 175 nodules [95% CI: 92, 98]) (P > .99). In strategy B, transitional phase hypointensity was an independent ancillary feature for HCC (P = .04) in LR-4 of at least 10 mm with arterial phase hyperenhancement and no other major features. In all 645 nodules, simplified LI-RADS with use of both strategy B and transitional phase hypointensity had a higher sensitivity of 82% (387 of 470 nodules [95% CI: 79, 86]) vs 73% (343 of 470 nodules [95% CI: 69, 77]) (P < .001) than LI-RADS version 2018, without lower specificity (94%, 165 of 175 nodules [95% CI: 90, 97] vs 96%, 168 of 175 nodules [95% CI: 92, 98], P = .08). Compared with LI-RADS version 2018, simplified LI-RADS reduced the time for LI-RADS category assignment (44 seconds ± 23 vs 74 seconds ± 22, P < .001). Conclusion A simplified Liver Imaging Reporting and Data System was found to be clinically useful for diagnosing hepatocellular carcinomas of 30 mm or smaller at gadoxetic acid-enhanced MRI. © RSNA, 2022 Online supplemental material is available for this article.

Stereotactic radiofrequency ablation of tumors at the hepatic venous confluence

BACKGROUND

Radiofrequency ablation (RFA) is subject to "heat-sink" effects, particularly for treatment of tumors adjacent to major vessels.

METHODS

In this retrospective study, 104 patients with 137 tumors (40 HCC, 10 ICC and 54 metastatic liver tumors) close to (≤1 cm from) the hepatic venous confluence underwent stereotactic RFA (SRFA) between June 2003 and June 2018. Median tumor size was 3.7 cm (1.4-8.5) for HCC, 6.4 cm (0.5-11) for ICC and 3.8 cm (0.5-13) for metastases. Endpoints comprised safety, local tumor control, overall and disease-free survival.

RESULTS

The overall major complication rate was 16.0% (20/125 ablations), where 8 (40%) were successfully treated by the interventional radiologist in the same anesthetic session and did not prolong hospital stay. 134/137 (97.8%) tumors were successfully ablated at initial SRFA. Local recurrence (LR) developed in 19/137 tumors (13.9%). The median and overall survival (OS) rates at 1-, 3-, and 5- years from the date of the first SRFA were 51.5 months, 73.5%, 67.0%, and 49.7% for HCC, 14.6 months, 60.0%, 32.0% and 32.0% for ICC and 38.1 months, 91.4%, 56.5% and 27.9% for metastatic disease, respectively.

CONCLUSION

SRFA represents a viable alternative to hepatic resection for challenging tumors at the hepatic venous confluence.

Biliary complications and efficacy after ablation of peribiliary tumors using irreversible electroporation (IRE) or radiofrequency ablation (RFA)

OBJECTIVE

To evaluate the biliary complication rates and efficacy of peribiliary tumor ablation using irreversible electroporation (IRE) or radiofrequency ablation (RFA).

MATERIAL AND METHODS

This is a retrospective study of 42 consecutive patients with 44 peribiliary tumors (≤5 mm distance between the tumor margin and the primary or secondary bile duct). Data were collected between January 2014 and September 2020 from patients who underwent percutaneous liver ablation using IRE (n = 13) or RFA (n = 31).

RESULTS

The median length of follow-up was 23.1 months. The mean tumor size was 17.2 ± 5.2 mm in IRE vs. 18.4 ± 7.0 mm in RFA (p= .56). Complete tumor ablation was achieved in 100% with a significantly larger ablation zone in the IRE group (3.8 ± 0.3 cm vs. 2.6 ± 0.6 cm, p<.001). Significant biliary complications occurred in one patient (7.7%) of the IRE group and in five patients (16.1%) of the RFA group. Significant risk factors for biliary complications included the RFA procedure (HR 9.71, p=.032) and proximity of the tumor to the bile duct (HR 0.63, p=.048). The local tumor progression (LTP) rates were 7.7% (IRE) vs. 21.5% (RFA) at 1 year, 23.1% (IRE) vs. 32.7% (RFA) at 2 years and 23.1% (IRE) vs. 44% (RFA) at 3 years, respectively (p=.289).

CONCLUSIONS

The IRE and RFA procedures are safe and effective to treat peribiliary liver tumors. However, the RFA may have a higher risk of significant bile duct injury than IRE. The shorter distance between the bile duct and the tumor is a strong risk factor for biliary complications.

Percutaneous Ablation of Hepatic Tumors at the Hepatocaval Confluence Using Irreversible Electroporation: A Preliminary Study

Background: Tumors at the hepatocaval confluence are difficult to treat, either surgically or ablatively. Methods: A retrospective longitudinal study on patients ineligible for thermal ablation who underwent computed tomography-guided IRE for hepatic tumors at the hepatocaval confluence was conducted. Factors analyzed included patient and tumor characteristics, IRE procedure details, treatment-related complications, and prognosis. Results: Between 2017 and 2021, 21 patients at our institute received percutaneous IRE. Of the 38 lesions, 21 were at the hepatocaval confluence. Complete ablation was achieved in all cases. Local and distant recurrence was observed in 4.8% (1/21) and 42.6% (9/21) of the ablated tumors, respectively. All postcava remained perfused at follow-up, except for 1 (4.8%) hepatic vein near the lesion found to be temporarily occluded and restored within 1 month. The ratio of the maximum diameter of ablation area at 1, 3, and 6 months post procedure compared to that immediately after IRE was 0.68 (0.50–0.84), 0.49 (0.27–0.61), and 0.38 (0.25–0.59), respectively. Progression-free survival of the patients with recurrence was 121 (range, 25–566) days. Four (19.0%) patients died at the end of follow-up with median overall survival of 451.5 (range, 25–716) days. Conclusions: IRE could be a safe and effective treatment for hepatic tumors at the hepatocaval confluence. This article provides valuable prognostic data; further clinical research is needed for better prognosis.

New strategy for Liver Imaging Reporting and Data System category M to improve diagnostic performance of MRI for hepatocellular carcinoma ≤ 3.0 cm

PURPOSE

We aimed to determine a new strategy for Liver Imaging Reporting and Data System category M (LR-M) criteria to improve the diagnosis of HCC ≤ 3.0 cm on magnetic resonance imaging (MRI).

METHODS

A total of 463 pathologically confirmed hepatic observations ≤ 3.0 cm (375 HCCs, 32 other malignancies, 56 benignities) in 384 patients at risk of HCC who underwent gadoxetate-enhanced MRI were retrospectively analyzed. Two radiologists evaluated the presence of major, ancillary, and LR-M features according to LI-RADS v2018. Of the ten LR-M features, those significantly associated with non-HCC malignancy were identified using multivariable logistic regression analysis, and new LR-M criteria for improving the diagnosis of HCC were investigated. Generalized estimating equations were used to compare sensitivity and specificity of LR-5 for diagnosing HCC using the new LR-M criteria with values calculated using the original LR-M criteria. p < 0.05 was considered to indicate a significant difference.

RESULTS

Of ten LR-M features, rim arterial-phase hyperenhancement, delayed central enhancement, targetoid restriction, and targetoid transitional-phase/hepatobiliary-phase appearance were independently significantly associated with non-HCC malignancy (adjusted odds ratio ≥ 6.2; p ≤ 0.02). Using the new LR-M criteria (two or more of these significant features), the sensitivity of LR-5 for diagnosing HCC was higher than that with the original LR-M criteria (69% [95% confidence interval 64-73%] vs. 65% [61-70%], p = 0.002), whereas the specificity was similar (90% [82-95%] vs. 92% [83-96%], p = 0.28).

CONCLUSION

The new LR-M criteria (two or more significant features) can improve the sensitivity of LR-5 for diagnosing HCC ≤ 3.0 cm, without compromising specificity.

Rim Enhancement after Technically Successful Transarterial Chemoembolization in Hepatocellular Carcinoma: A Potential Mimic of Incomplete Embolization or Reactive Hyperemia?

Contrast enhancement at the margins/rim of embolization areas in hepatocellular-carcinoma (HCC) lesions treated with transarterial chemoembolization (TACE) might be an early prognostic indicator for HCC recurrence. The aim of this study was to evaluate the predictive value of rim perfusion for TACE recurrence as determined by perfusion CT (PCT). A total of 52 patients (65.6 ± 9.3 years) underwent PCT directly before, immediately after (within 48 h) and at follow-up (95.3 ± 12.5 days) after TACE. Arterial-liver perfusion (ALP), portal-venous perfusion (PVP) and hepatic-perfusion index (HPI) were evaluated in normal liver parenchyma, and on the embolization rim as well as the tumor bed. A total of 42 lesions were successfully treated, and PCT measurements showed no residually vascularized tumor areas. Embolization was not entirely successful in 10 patients with remaining arterialized focal nodular areas (ALP 34.7 ± 10.1 vs. 4.4 ± 5.3 mL/100 mL/min, p < 0.0001). Perfusion values at the TACE rim were lower in responders compared to normal adjacent liver parenchyma and edges of incompletely embolized tumors (ALP liver 16.3 ± 10.1 mL/100 mL/min, rim responder 8.8 ± 8.7 mL/100 mL/min, rim non-responder 23.4 ± 8.6 mL/100 mL/min, p = 0.005). At follow-up, local tumor relapse was observed in 17/42, and 15/42 showed no recurrence (ALP 39.1 ± 10.1 mL/100 mL/min vs. 10.0 ± 7.4 mL/100 mL/min, p = 0.0008); four patients had de novo disseminated disease and six patients were lost in follow-up. Rim perfusion was lower compared to adjacent recurring HCC and not different between groups. HCC lesions showed no rim perfusion after TACE, neither immediately after nor at follow-up at three months, both for mid-term responders and mid-term relapsing HCCs, indicating that rim enhancement is not a sign of reactive hyperemia and not predictive of early HCC recurrence.

Early Assessment of Response to Radiofrequency Ablation With CT Perfusion Imaging in Rabbit VX2 Liver Tumor Model

Objectives

To discriminate viable tumors from benign periablational enhancement (BPE) in early stage after radiofrequency ablation (RFA) is a major confounding problem. The goal of this study is to evaluate quantitative assessment and diagnostic value of CT perfusion between viable tumors and BPE after RFA in the rabbit liver VX2 tumor model, with pathological results as the standard.

Methods

Twenty-eight VX2 liver tumors were treated with RFA, on days 1, 3, 7, and 14, seven rabbits were randomly chosen for CT perfusion and performed pathology examinations immediately. The perfusion parameters along with the profile of time-density curves (TDCs) and pseudo-color images of the parameters were observed in both BPE and viable tumors, then compared with the pathology results. The perfusion parameters included blood flow (BF), blood volume (BV), time to peak (TTP), permeability (P), arterial liver perfusion (ALP), portal venous perfusion (PVP) and hepatic perfusion index (HPI).

Results

A total of 26/28 rabbits successfully underwent CT perfusion, while 6/26 lesions were confirmed to be viable tumors. The TDCs of BPE were mainly speed-up platform curves (15/26), while the viable tumors showed mainly speed-up speed-down (3/6) and speed-up platform (2/6) curves. The PVP values were significantly higher, and the HPI values were significantly lower for BPE at all time points than viable tumors (P < 0.05). Both of PVP value and HPI value have high efficiency for the differential diagnosis of the viable tumors and BPE at each time point. These characteristics of CT perfusion parameters were consistent with pathological changes.

Conclusions

The TDCs, PVP and HPI have the potential to indicate BPE and viable tumors effectively early after RFA treatment, the results were highly consistent with pathology. CT perfusion has advantages with great efficacy in monitoring the therapeutic effect early after RFA treatment.

Meta-analysis and systematic review of contrast-enhanced ultrasound in evaluating the treatment response after locoregional therapy of hepatocellular carcinoma

PURPOSE

Contrast-enhanced ultrasound (CEUS) is a useful tool to assess treatment response after percutaneous ablation or transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). Here, we performed a systematic review and meta-analysis to evaluate the usefulness of CEUS in identifying residual tumor after locoregional therapy.

METHODS

PubMed, Scopus, and Cochrane library databases were searched from their inception until March 8, 2021, for diagnostic test accuracy studies comparing CEUS to a reference standard for identifying residual tumors after locoregional therapy of HCC. The pooled sensitivity, specificity, accuracy, and diagnostic odds ratio (DOR) were obtained using a bivariate random effects model. Subgroup analyses were performed by stratifying the studies based on study design, type of locoregional therapy, CEUS criteria for residual tumor, timing of CEUS follow up, and type of standard reference.

RESULTS

Two reviewers independently evaluated 1479 publications. After full-text review, 142 studies were found to be relevant, and 43 publications (50 cohorts) were finally included. The overall sensitivity of CEUS in detection of residual disease estimated from the bivariate random effects model was 0.85 (95% CI 0.80-0.89). Similarly, the overall specificity was 0.94 (95% CI 0.91-0.96). The diagnostic accuracy was 93.5%. The DOR was 70.1 (95% CI 62.2-148), and the AUROC was 0.95. Importantly, subgroup analysis showed no apparent differences in the diagnostic performance between locoregional therapy (TACE vs. ablation) and criteria used to define residual enhancement, timing of performing CEUS, study design, or type of reference standard.

CONCLUSION

CEUS is a highly accurate method to identify HCC residual tumor after TACE or percutaneous ablation.

Microwave Ablation as Bridging Therapy for Patients with Hepatocellular Carcinoma Awaiting Liver Transplant: A Single Center Experience

PURPOSE

To determine the pathologic response of computed tomography-guided percutaneous microwave ablation as bridging therapy for patients with hepatocellular carcinoma awaiting liver transplant, and its subsequent effect on survival.

MATERIALS AND METHODS

A single-center retrospective analysis was conducted on 62 patients (M:F = 50:12) with mean age of 59.6 years ± 7.2 months (SD). Sixty-four total MWA procedures were performed for hepatocellular carcinomas within Milan criteria as bridging therapy to subsequent orthotopic liver transplant between August 2014 and September 2018. The pathology reports of the explanted livers were reviewed to assess for residual disease. Residual disease was categorized as complete or incomplete necrosis. Patient demographics, tumor/procedural characteristics, and laboratory values were evaluated. Survival from time of ablation and time of transplantation were recorded and compared between cohorts using log rank tests.

RESULTS

The mean tumor size was 2.4 cm ± 0.7 cm (SD), (range = 1-4.6 cm). 32 (50%) cases required hydrodissection. Histopathologic necrosis was seen in 66% of cases at time of liver transplantation. Median time to liver transplant post-MWA was 12.6 months. [IQR = 8.6-14.8 months]. The median survival from ablation was 60.8 months [IQR = 45.5-73.7 months], and the median survival from transplant was 49.3 months [IQR = 33.7-60.1 months]. There was no significant difference in survival for patients with complete versus incomplete necrosis from ablation or liver transplant (p = 0.49, p = 0.46, respectively).

CONCLUSIONS

Computed tomography-guided percutaneous microwave ablation is an effective bridge to orthotopic liver transplantation for patients with hepatocellular carcinoma.

CEBM LEVEL OF EVIDENCE

Level 3, non-randomized controlled cohort study/follow-up study.

Dasatinib inhibits proliferation of liver cancer cells, but activation of Akt/mTOR compromises dasatinib as a cancer drug

Dasatinib is a multi-target protein tyrosine kinase inhibitor. Due to its potent inhibition of Src, Abl, the platelet-derived growth factor receptor (PDGFR) family kinases, and other oncogenic kinases, it has been investigated as a targeted therapy for a broad spectrum of cancer types. However, its efficacy has not been significantly extended beyond leukemia. The mechanism of resistance to dasatinib in a wide array of cancers is not clear. In the present study, we investigated the effect of dasatinib on hepatocellular carcinoma cell growth and explored the underlying mechanisms. Our results showed that dasatinib potently inhibited the proliferation of SNU-449 cells, but not that of other cell lines, such as SK-Hep-1, even though it inhibited the phosphorylation of Src on both negative and positive regulation sites in all these cells. Dasatinib activated the phosphoinositide-dependent protein kinase1 (PDK1)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway in SK-Hep-1 cells, but not in SNU-449 cells. Blocking the Akt/mTOR signaling pathway strongly promoted the efficacy of dasatinib in SK-Hep-1 cells. In SNU-449 cells, dasatinib promoted apoptosis and the cleavage of caspase-3 and caspase-7, induced cell cycle arrest in the G1 phase, and inhibited the expression of Cyclin-dependent kinase (CDK4)/6/CyclinD1 complex. These findings demonstrate that dasatinib exerts its anti-proliferative effect on hepatocellular cell proliferation by blocking the Src family kinases; however, it causes Akt activation, which compromises dasatinib as an anti-cancer drug.

Evaluation of clinical outcomes of radiofrequency ablation and surgical resection for hepatocellular carcinoma conforming to the Milan criteria: A systematic review and meta-analysis of recent randomized controlled trials

BACKGROUND AND AIM

The few systematic reviews that have compared surgical resection (SR) with radiofrequency ablation (RFA) indicated that hepatectomy was superior to RFA in the treatment of hepatocellular carcinoma (HCC) irrespective of overall survival (OS) or disease-free survival (DFS). However, randomized controlled trials (RCTs) are scarce; therefore, there is a lack of robust evidence on the optimal first-line treatment for HCC patients. The purpose of this study was to include all current RCT studies to compare the clinical efficacy between RFA and SR in patients with HCC who meet the Milan criteria using meta-analysis techniques.

METHODS

We conducted thorough searches of PubMed, Embase, Cochrane, Web of Knowledge, FDA.gov, and ClinicalTrials.gov for comparative studies (published between 1 January 1996 and 31 December 2019; no language restrictions) of RFA and SR. The main endpoints were OS, DFS, and postoperative complications. Only randomized clinical trials were included. The odds ratios (OR) were pooled and calculated with 95% confidence intervals (CI) for both fixed effects and random effects models.

RESULTS

Eight studies comparing RFA and SR were identified, which included 1177 patients treated with RFA (n = 571) or SR (n = 606). The OR values for patients treated with RFA and SR at 1, 3, and 5 years were OR: 0.91, 95% CI: 0.45-1.38; OR: 0.82, 95% CI: 0.56-1.19; and OR: 1.03, 95% CI: 0.61-1.73, respectively. The OS between the two treatments was not significantly different. The 1-year DFS rates resulting from the two treatments were not statistically different (OR: 0.87, 95% CI: 0.63-1.21). Similarly, according to long-term DFS rates for SR compared with RFA, although the OR value was less than 1, there was no statistical significance (OR: 0.79, 95% CI: 0.58-1.07). However, it is worth noting that RFA has advantages over SR in terms of treatment-related complications (OR: 0.65, 95% CI: 0.44-0.80; P < 0.05), postoperative mortality, length of stay, and hospitalization costs.

CONCLUSION

For patients with HCC who meet the Milan criteria, RFA exhibited similar clinical efficacy to SR. However, RFA was superior to SR in terms of minor trauma and may be recommended as the first choice for tumors ≤ 4 cm in diameter.

High rate of complete histopathological response in hepatocellular carcinoma patients after combined transarterial chemoembolization and stereotactic body radiation therapy

BACKGROUND

Liver transplantation (LT) presents a curative treatment option in patients with early stage hepatocellular carcinoma (HCC) who are not eligible for resection or ablation therapy. Due to a risk of up 30% for waitlist drop-out upon tumor progression, bridging therapies are used to halt tumor growth. Transarterial chemoembolization (TACE) and less commonly stereotactic body radiation therapy (SBRT) or a combination of TACE and SBRT, are used as bridging therapies in LT. However, it remains unclear if one of those treatment options is superior. The analysis of explant livers after transplantation provides the unique opportunity to investigate treatment response by histopathology.

AIM

To analyze histopathological response to a combination of TACE and SBRT in HCC in comparison to TACE or SBRT alone.

METHODS

In this multicenter retrospective study, 27 patients who received liver transplantation for HCC were analyzed. Patients received either TACE or SBRT alone, or a combination of TACE and SBRT as bridging therapy to liver transplantation. Liver explants of all patients who received at least one TACE and/or SBRT were analyzed for the presence of residual vital tumor tissue by histopathology to assess differences in treatment response to bridging therapies. Statistical analysis was performed using Fisher-Freeman-Halton exact test, Kruskal-Wallis and Mann-Whitney-U tests.

RESULTS

Fourteen patients received TACE only, four patients SBRT only, and nine patients a combination therapy of TACE and SBRT. There were no significant differences between groups regarding age, sex, etiology of underlying liver disease or number and size of tumor lesions. Strikingly, analysis of liver explants revealed that almost all patients in the TACE and SBRT combination group (8/9, 89%) showed no residual vital tumor tissue by histopathology, whereas TACE or SBRT alone resulted in significantly lower rates of complete histopathological response (0/14, 0% and 1/4, 25%, respectively, P value < 0.001).

CONCLUSION

Our data suggests that a combination of TACE and SBRT increases the rate of complete histopathological response compared to TACE or SBRT alone in bridging to liver transplantation.

Lung microwave ablation - an in vivo swine tumor model experiment to evaluate ablation zones

PURPOSE

To evaluate microwave ablation (MWA) algorithms, comparing pulsed and continuous mode in an in vivo lung tumor mimic model.

MATERIALS AND METHODS

A total of 43 lung tumor-mimic models of 1, 2 or 3 cm were created in 11 pigs through an intra-pulmonary injection of contrast-enriched minced muscle. Tumors were ablated under fluoroscopic and 3D-CBCT-guidance using a single microwave antenna. Continuous (CM) and pulsed mode (PM) were used. According to tumor size, 3 different algorithms for both continuous and pulsed mode were used. The ablation zones were measured using post-procedural 3D-CBCT and on pathologic specimens.

RESULTS

Two radiologists measured the ablation zones on CBCT and they significantly correlated with macroscopic and microscopic pathological findings: r = 0.75 and 0.74 respectively (p < 0.0001) (inter-observer correlation r = 0.9). For 1, 2 and 3 cm tumors mimics lesions (TMLs), mean maximal and transverse ablation diameters were 3.6 [Formula: see text] 0.3 × 2.2 [Formula: see text] 0.3 cm; 4.1 [Formula: see text] 0.5 × 2.6 [Formula: see text] 0.3 cm and 4.8 [Formula: see text] 0.3 × 3.2 [Formula: see text] 0.3 cm respectively using CM; And, 3.0 [Formula: see text] 0.2 × 2.1 [Formula: see text] 0.2 cm; 4.0 [Formula: see text] 0.4 × 2.7 [Formula: see text] 0.4 cm and 4.6 [Formula: see text] 0.4 × 3.2 [Formula: see text] 0.4 cm respectively for PM, without any significant difference except for 1 cm TMLs treated by PM ablation which were significantly smaller (p = 0.009) The sphericity index was 1.6, 1.6, 1.5 and 1.4, 1.5, 1.4 at 1, 2 and 3 cm for CM and PM respectively, p = 0.07, 0.14 and 0.13 for 1, 2 and 3 cm tumors mimics.

CONCLUSION

Microwave ablation for 1-3 cm lung tumors were successfully realized but with a moderate reproducibility rate, using either CM or PM. Immediate post ablation CBCT can accurately evaluate ablation zones.

Periportal fields cause stronger cooling effects than veins in hepatic microwave ablation: an in vivo porcine study

BACKGROUND

Vascular cooling effects are a well-known source for tumor recurrence in thermal in situ ablation techniques for hepatic malignancies. Microwave ablation (MWA) is an ablation technique to be considered in the treatment of malignant liver tumors. The impact of vascular cooling in MWA is still controversial.

PURPOSE

To evaluate the influence of different intrahepatic vessel types, vessel sizes, and vessel-to-antenna-distances on MWA geometry in vivo.

MATERIAL AND METHODS

Five MWAs (902-928 MHz) were performed with an energy input of 24.0 kJ in three porcine livers in vivo. MWA lesions were cut into 2-mm slices. The minimum and maximum radius of the ablation area was measured for each slice. Distances were measured from ablation center toward all adjacent hepatic vessels with a diameter of ≥1 mm and within a perimeter of 20 mm around the antenna. The respective vascular cooling effect relative to the maximum ablation radius was calculated.

RESULTS

In total, 707 vessels (489 veins, 218 portal fields) were detected; 370 (76%) hepatic veins and 185 (85%) portal fields caused a cooling effect. Portal fields resulted in higher cooling effects (37%) than hepatic veins (26%, P < 0.01). No cooling effect could be observed in close proximity of vessels within the central ablation zone.

CONCLUSION

Hepatic vessels influenced MWA zones and caused a distinct cooling effect. Portal fields resulted in more pronounced cooling effect than hepatic veins. No cooling effect was observed around vessels situated within the central white zone.

Downstaging treatment for patients with hepatocelluar carcinoma before transplantation

Liver transplantation (LT), one of the radical methods of treating liver cancer, has brought new hope for the treatment of unresectable liver cancer. Currently, patients who meet transplant criteria can achieve a favorable prognosis, but those who exceed transplant criteria tend not to have very satisfactory outcomes. For patients whose tumor burden exceeds the transplant criteria, downstaging treatment is a promising method to reduce tumor burden to within the transplant criteria that may lead to good posttransplant survival. Multiple treatments, such as transcatheter arterial chemoembolization (TACE), transarterial radioembolization (TARE), percutaneous ethanol injection (PEI), and radiofrequency ablation (RFA), have been used as downstaging treatments. However, there are still some issues that limit the effectiveness of downstaging treatments, such as the inclusion criteria for downstaging, which the choice of downstaging treatment method, and the endpoint of downstaging, all of which are worthy of further discussion. Based on the published literature, this review discusses these issues.

Histological Correlation for Radiofrequency and Microwave Ablation in the Local Control of Hepatocellular Carcinoma (HCC) before Liver Transplantation: A Comprehensive Review

Simple Summary

Liver cancer is a growing problem around the world. Drugs for liver cancer have limited effect, there are not enough donors for liver transplants and many patients are not candidates for surgery to remove the tumor. In many of these cases, hyperthermia can destroy the tumor in situ with minimally invasive methods such as radiofrequency or microwave ablation. In this paper we review the literature evaluating success rates for complete ablation as judged by actual examination of treated tumors that were removed when patients received a liver transplant. While notable successes can be achieved with ablation, the published studies indicate both that complete treatment is not as common as thought and that imaging methods such as computed tomography and magnetic resonance scans do not completely identify residual cancer. There is therefore an important opportunity for improvement in the treatment of this disease.

Abstract

Radiofrequency ablation (RFA) and microwave ablation (MWA) are the most widely studied and applied ablation techniques for treating primary and secondary liver tumors. These techniques are considered curative for small hepatic tumors, with post-ablation outcomes most commonly assessed by an imaging follow up. However, there is increasing evidence of a discrepancy between radiological and pathological findings when ablated lesions are evaluated following liver resection or liver transplantation. A comprehensive review of the available literature reporting the complete pathological response (cPR) following RFA and MWA was performed to estimate the success rate and identify the factors associated with treatment failure. Following RFA, cPR is reported in 26–96% of tumors compared to 57–95% with MWA. Larger tumor size and vessels larger than 3 mm adjacent to the treated tumor are the most important factors identified by previous studies associated with viable residual tumors after RFA. Correlating post-ablation radiological studies with pathological findings shows that computed tomography (CT) and magnetic resonance imaging (MRI) have low sensitivity but high specificity for detecting residual viable or recurrent hepatocellular carcinoma (HCC) tumors. There are promising recent reports combining multiprobe ablation techniques with three-dimensional treatment planning software and stereotactic-aiming instrumentation to achieve more than 90% cPR in both small and large HCC tumors. In conclusion, the reported success for achieving cPR in HCC following RFA and MWA is highly variable in different studies and decreases with increasing lesion size and unfavorable tumor characteristics. Very few studies have reported a high rate of cPR. As these studies are single-center and retrospective, they need to be further validated and reproduced in other clinical settings.

Impact of needle positioning on ablation success of irreversible electroporation: a unicentric retrospective analysis

Irreversible electroporation (IRE) is an ablation procedure in which cell death is induced by ultrashort electrical pulses. In this unicentric retrospective study we investigated the influence of needle positioning on ablation success. 15 IREs with residual tumor after ablation, detected in the first follow-up MRI, were included, and compared with 30 successful ablations. Evaluation of needle geometry revealed significantly higher values for needle divergence (NDiv, 7.0° vs. 3.7°, p = 0.02), tumor-center-to-ablation-center distance (TACD, 11.6 vs. 3.2 mm, p < 0.001), tumor-to-needle distance (4.7 vs. 1.9 mm, p = 0.04), and tumor diameter per needle (7.5 vs. 5.9 mm/needle, p = 0.01) in patients with residual tumor. The average number of needles used was higher in the group without residual tumor after ablation (3.1 vs. 2.4, p = 0.04). In many cases with residual tumor, needle depth was too short (2.1 vs. 6.8 mm tumor overlap beyond the most proximal needle tip, p < 0.01). The use of a stereotactic navigation system in 10 cases resulted in a lower NDiv value (2.1° vs. 5.6°, p < 0.01). Thus, correct needle placement seems to be a crucial factor for success and the assistance of a stereotactic navigation system might be helpful. As most important geometrical parameter TACD could be identified. Main reasons for high TACD were insufficient needle depth and a lesion location out of the needle plane.

Interventional Oncology Approach to Hepatic Metastases

Metastatic liver disease is one of the major causes of cancer-related morbidity and mortality. Locoregional therapies offered by interventional oncologists alleviate cancer-related morbidity and in some cases improve survival. Locoregional therapies are often palliative in nature but occasionally can be used with curative intent. This review will discuss important factors to consider prior to palliative and curative intent treatment of metastatic liver disease with locoregional therapy. These factors include those specific to the tumor, liver function, liver reserve, differences between treatment modalities, and patient-specific considerations.

Interobserver agreement for contrast-enhanced ultrasound of liver imaging reporting and data system: A systematic review and meta-analysis

BACKGROUND

Hepatocellular carcinoma is the most common primary liver malignancy. From the results of previous studies, Liver Imaging Reporting and Data System (LI-RADS) on contrast-enhanced ultrasound (CEUS) has shown satisfactory diagnostic value. However, a unified conclusion on the interobserver stability of this innovative ultrasound imaging has not been determined. The present meta-analysis examined the interobserver agreement of CEUS LI-RADS to provide some reference for subsequent related research.

AIM

To evaluate the interobserver agreement of LI-RADS on CEUS and analyze the sources of heterogeneity between studies.

METHODS

Relevant papers on the subject of interobserver agreement on CEUS LI-RADS published before March 1, 2020 in China and other countries were analyzed. The studies were filtered, and the diagnostic criteria were evaluated. The selected references were analyzed using the "meta" and "metafor" packages of R software version 3.6.2.

RESULTS

Eight studies were ultimately included in the present analysis. Meta-analysis results revealed that the summary Kappa value of included studies was 0.76 [95% confidence interval, 0.67-0.83], which shows substantial agreement. Higgins I 2 statistics also confirmed the substantial heterogeneity (I 2 = 91.30%, 95% confidence interval, 85.3%-94.9%, P < 0.01). Meta-regression identified the variables, including the method of patient enrollment, method of consistency testing, and patient race, which explained the substantial study heterogeneity.

CONCLUSION

CEUS LI-RADS demonstrated overall substantial interobserver agreement, but heterogeneous results between studies were also obvious. Further clinical investigations should consider a modified recommendation about the experimental design.

Liver tumor ablation in difficult locations: Microwave ablation of perivascular and subdiaphragmatic hepatocellular carcinoma

AIM

To assess the safety and efficacy of CT-guided microwave ablation (MWA) of hepatocellular carcinoma (HCC) near large blood vessels and the diaphragm by analyzing procedural complications and local tumor progression (LTP).

METHODS

From October 2013 through January 2019, 80 patients (54 males and 26 females) with 136 tumors who underwent CT-guided MWA of HCC were included in this retrospective analysis. MWA was performed on 43 perivascular HCC (≤5 mm from a vessel measuring ≥5 mm in diameter), 38 subdiaphragmatic HCC (≤5 mm from diaphragm), and 64 control HCC. Risk factors for local tumor progression (LTP), overall survival, and complications were analyzed using the Chi-square and Cox proportional hazards model methods.

RESULTS

The technical success rate of MWA was 100%. Complication incidence was not significantly different between perivascular and control tumors (20.9% vs 10.9%; p = 0.155) or between subdiaphragmatic and control tumors (21.1% vs 10.9%; p = 0.163). The effect of lesion location on LTP disappeared while controlling for age and lesion size. There was no significant difference in median survival time between patients who had only control tumors (38.8 months) compared to patients with at least one perivascular or subdiaphragmatic tumor (42.5 months; p = 0.098).

CONCLUSION

CT-guided percutaneous MWA of perivascular and subdiaphragmatic HCC tumors is safe and effective. The local tumor recurrence and survival was not significantly different compared to control tumors.

Ten-Year Outcomes of Percutaneous Radiofrequency Ablation for Colorectal Cancer Liver Metastases in Perivascular vs. Non-Perivascular Locations: A Propensity-Score Matched Study

Purpose

To compare long-term outcomes of percutaneous radiofrequency ablation for colorectal liver metastases in perivascular versus non-perivascular locations.

Methods

This retrospective study included 388 consecutive patients with colorectal liver metastases (246 men, 142 women; age range 27–86 years) who underwent percutaneous radiofrequency ablation between January 2006 and December 2018. Propensity-score matching was performed for groups with perivascular and non-perivascular colorectal liver metastases. Rates of accumulative local tumor progression, overall survival, intra/extrahepatic recurrence, and complications were compared between the two groups.

Results

We successfully matched 104 patients each in the perivascular and non-perivascular groups (mean age: 60.1 ± 11.5 and 60.1 ± 11.3 years, respectively). Cumulative local tumor progression rates at 6 months, 1 years, 3 years, and 5 years, respectively, were 8.8%,14.8%, 18.9%, and 18.9% in the perivascular group and 8.8%, 13.1%, 15.5%, and 15.5% in the non-perivascular group. The 1-, 3-, 5-, and 10-year overall survival rates, respectively, were 91.3%, 45.6%, 23.9%, and 18.7% in the perivascular group and 88.0%, 47.2%, 27.2%, and 22.6% in the non-perivascular group. No significant between-group differences were detected in cumulative local tumor progression (p=0.567, hazard ratio: 1.224) or overall survival (p = 0.801, hazard ratio: 1.047). The major complication rate was 1.0% (1/104, p > 0.999) in both groups. Tumor size was the only independent prognostic factor for local tumor progression (hazard ratio: 2.314; p = 0.002). On multivariate analysis for overall colorectal liver metastases, tumor diameter >3 cm, tumor location in the right colon, multiple tumors, and extrahepatic metastases before radiofrequency ablation (hazard ratios: 2.046, 1.920, 1.706, and 1.892, respectively; all p < 0.001) and intrahepatic recurrence (hazard ratio: 1.564; p = 0.002) were associated with poor overall survival.

Conclusion

Cumulative local tumor progression, overall survival, and major complications rates did not differ significantly between perivascular and non-perivascular colorectal liver metastases after percutaneous radiofrequency ablation. For perivascular colorectal liver metastases, percutaneous radiofrequency ablation is a safe and effective treatment option.