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

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

Limited Generalizability of Retrospective Single-Center Cohort Study in Comparison to Multicenter Cohort Study on Prognosis of Hepatocellular Carcinoma

Introduction

We aimed to evaluate the generalizability of retrospective single-center cohort studies on prognosis of hepatocellular carcinoma (HCC) by comparing overall survival (OS) after various treatments between a nationwide multicenter cohort and a single-center cohort of HCC patients.

Methods

Patients newly diagnosed with HCC between January 2008 and December 2018 were analyzed using data from the Korean Primary Liver Cancer Registry (multicenter cohort, n=16,443), and the Asan Medical Center HCC registry (single-center cohort, n=15,655). The primary outcome, OS after initial treatment, was compared between the two cohorts for both the entire population and for subcohorts with Child-Pugh A liver function (n=2797 and n=5151, respectively) treated according to the Barcelona-Clinic-Liver-Cancer (BCLC) strategy, using Log rank test and Cox proportional hazard models.

Results

Patients of BCLC stages 0 and A (59.3% vs 35.2%) and patients who received curative treatment (42.1% vs 32.1%) were more frequently observed in the single-center cohort (Ps<0.001). Multivariable analysis revealed significant differences between the two cohorts in OS according to type of treatment: the multicenter cohort was associated with higher risk of mortality among patients who received curative (adjusted hazard ratio [95% confidence interval], 1.48 [1.39-1.59]) and non-curative (1.22 [1.17-1.27]) treatments, whereas the risk was lower in patients treated with systemic therapy (0.83 [0.74-0.92]) and best supportive care (0.85 [0.79-0.91]). Subcohort analysis also demonstrated significantly different OS between the two cohorts, with a higher risk of mortality in multicenter cohort patients who received chemoembolization (1.72 [1.48-2.00]) and ablation (1.44 [1.08-1.92]).

Conclusion

Comparisons of single-center and multicenter cohorts of HCC patients revealed significant differences in OS according to treatment modality after adjustment for prognostic variables. Therefore, the results of retrospective single-center cohort studies of HCC treatments may not be generalizable to real-world practice.

Intratumoral Lactate Depletion Based on Injectable Nanoparticles-Hydrogel Composite System Synergizes with Immunotherapy against Postablative Hepatocellular Carcinoma Recurrence

Thermal ablation is a crucial therapeutic modality for hepatocellular carcinoma (HCC), but its efficacy is often hindered by the high recurrence rate attributed to insufficient ablation. Furthermore, the residual tumors following insufficient ablation exhibit a more pronounced immunosuppressive state, which accelerates the disease progression and leads to immune checkpoint blockade (ICB) resistance. Herein, evidence is presented that heightened intratumoral lactate accumulation, stemming from the augmented glycolytic activity of postablative residual HCC cells, may serve as a crucial driving force in exacerbating the immunosuppressive state of the tumor microenvironment (TME). To address this, an injectable nanoparticles-hydrogel composite system (LOX-MnO2 @Gel) is designed that gradually releases lactate oxidase (LOX)-loaded hollow mesoporous MnO2 nanoparticles at the tumor site to continuously deplete intratumoral lactate via a cascade catalytic reaction. Using subcutaneous and orthotopic HCC tumor-bearing mouse models, it is confirmed that LOX-MnO2 @Gel-mediated local lactate depletion can transform the immunosuppressive postablative TME into an immunocompetent one and synergizes with ICB therapy to significantly inhibit residual HCC growth and lung metastasis, thereby prolonging the survival of mice postablation. The work proposes an appealing strategy for synergistically combining antitumor metabolic therapy with immunotherapy to combat postablative HCC recurrence.

Targeting N7-methylguanosine tRNA modification blocks hepatocellular carcinoma metastasis after insufficient radiofrequency ablation

Radiofrequency heat ablation is an ideal radical treatment for hepatocellular carcinoma (HCC). However, insufficient radiofrequency ablation (IRFA) could lead to high recurrence of HCC. N7-methylguanosine (m7G) on tRNAs, an evolutionally conservative modification in mammals and yeast, modulates heat stress responses and tumor progression, while its function in HCC recurrence after IRFA remains unknown. Here, we found that IRFA significantly upregulates the level of m7G tRNA modification and its methyltransferase complex components METTL1/WDR4 in multiple systems including HCC patient-derived xenograft (PDX) mouse, patients' HCC tissues, sublethal-heat-treated models of HCC cell lines, and organoids. Functionally, gain-/loss-of-function assays showed that METTL1-mediated m7G tRNA modification promotes HCC metastasis under sublethal heat exposure both in vitro and in vivo. Mechanistically, we found that METTL1 and m7G tRNA modification enhance the translation of SLUG/SNAIL in a codon frequency-dependent manner under sublethal heat stress. Overexpression of SLUG/SNAIL rescued the malignant potency of METTL1 knockdown HCC cells after sublethal heat exposure. Our study uncovers the key functions of m7G tRNA modification in heat stress responses and HCC recurrence after IRFA, providing molecular basis for targeting METTL1-m7G-SLUG/SNAIL axis to prevent HCC metastasis after radiofrequency heat ablation treatment.

Recurrence after percutaneous radiofrequency ablation of hepatocellular carcinoma: Analysis of the pattern and risk factors

Background

Hepatocellular carcinoma (HCC) frequently relapses after minimally invasive treatment. This study aimed to observe the influencing factors of different recurrence patterns after radiofrequency ablation (RFA) for the treatment of recurrence.

Methods

The medical records of HCC patients who underwent RFA between January 2010 and January 2019 were retrospectively reviewed. HCC recurrence is classified into three types: local tumour progression (LTP), intrahepatic distant metastasis, and extrahepatic metastasis. Risk factors, overall survival (OS), and disease-free survival (DFS) were assessed for each modality. Among the risk factors are age, gender, liver function tests, blood tests, and tumour size. The OS and DFS curves were measured by the Kaplan-Meier method.

Results

406 patients who had undergone RFA were included in the study. The median survival for OS and DFS were 120 and 43.6 months. During follow-up, 39, 312, and 55 patients developed LTP, intrahepatic distant metastasis, and extrahepatic metastatic recurrence, respectively. The independent risk factors for each type were as follows: WBC > 5.55*109/L was an independent risk factor for local recurrence. Multiple tumours, extrahepatic metastases, and AFP > 200 ng/ml were used for intrahepatic metastases. Age (P = 0.030), recurrence pattern (P < 0.001) and Child-Pugh class B (P = 0.015) were independent predictors of OS.

Conclusions

According to our classification, each pattern of recurrence has different risk factors for recurrence, OS, and DFS.

Reliability of Stereotactic Radiofrequency Ablation (SRFA) for Malignant Liver Tumors: Novice versus Experienced Operators

PURPOSE

To compare the results of a novice with those of experienced interventional radiologists (IRs) for stereotactic radiofrequency ablation (SRFA) of malignant liver tumors in terms of safety, technical success, and local tumor control.

METHODS

A database, including all SRFA procedures performed in a single center between January 2011 and December 2018 was retrospectively analyzed. A total of 39 ablation sessions performed by a novice IR were compared to the results of three more experienced IRs. Comparative SRFA sessions were selected using propensity score matching considering tumor type, age, sex, tumor size, and tumor number as matching variables. Overall, 549 target tumors were treated in 273 sessions. Median tumor size was 2.2 cm (1.0-8.5 cm) for 178 hepatocellular carcinomas (HCCs) and 3.0 cm (0.5-13.0 cm) for 371 metastases. A median of 2 (1-11) tumors were treated per session.

RESULTS

No significant differences were observed when comparing the results of more experienced IRs with those of a novice IR regarding the rates of major complications (6.8% [16/234] vs. 5.1% [2/39]; p = 0.477), mortality (1.3% [2/234] vs. 0% [0/39]; p = 0.690), primary technical efficacy (98.5% [525/533] vs. 98.9% [94/95]; p = 0.735), and local recurrence (5.6% [30/533] vs. 5.3% [5/95]; p = 0.886). However, the median planning/placement time was significantly shorter for the experienced IRs (92 min vs. 119 min; p = 0.002).

CONCLUSIONS

SRFA is a safe, effective, and reliable treatment option for malignant liver tumors and favorable outcomes can be achieved even by inexperienced operators with minimal supervision.

Comparison of deep and moderate neuromuscular blockade in microwave ablation of liver tumours: a randomized-controlled clinical trial

Microwave ablation (MWA) is gaining popularity for the treatment of small primary hepatocellular carcinoma and metastatic lesions especially if patients are not candidates for surgical resection. Deep neuromuscular blockade (DMB) is perceived to improve surgical working conditions compared to moderate neuromuscular blockade (MMB) but no studies have examined the same benefits in MWA of liver tumours. This study aimed to compare the clinical outcomes of DMB and MMB in MWA of liver tumours in terms of liver excursion, performance scores by the interventional radiologists and patients, requirements of additional muscle relaxants and complications. 50 patients were recruited and 45 patients (22 in MMB group, 23 in DMB group) completed the study. The mean liver excursion for the MMB group (1.42 ± 1.83 mm) was significantly higher than the DMB group (0.26 ± 0.38 mm) (p = 0.001). The mean Leiden-Surgical Rating Scale (L-SRS) rated by the two interventional radiologists were 4.5 ± 0.59 and 3.6 ± 0.85 for the DMB and MMB groups, respectively (p = 0.01). There was also statistically significant difference on patient satisfaction scores (0–10: Extremely Dissatisfied–Extremely Satisfied) between DMB (8.74 ± 1.1) and MMB (7.86 ± 1.25) groups (p = 0.01). 5 patients from MMB group and none from DMB group required bolus relaxant during the MWA procedure. Adverse events were also noted to be more severe in the MMB group. In conclusion, DMB significantly reduced liver excursion and movement leading to improved accuracy, safety and success in ablating liver tumour.

Association of Daily Aspirin Therapy With Hepatocellular Carcinoma Risk in Patients With Chronic Hepatitis C Virus Infection

BACKGROUND & AIMS

Aspirin therapy has been associated with reduced risk of colon cancer, but there is only limited evidence for its effects on risk of hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC). We aimed to investigate the association of daily aspirin therapy with HCV-related HCC risk.

METHODS

In this cohort study, based on Taiwan's National Health Insurance Research Database, we screened 237,963 patients with chronic HCV infection for the period of 1997 through 2011. We excluded patients with confounding conditions and 2478 patients who continuously received daily aspirin therapy for 90 days or more (treated group) were randomly matched 1:2 with 4956 patients who had never received antiplatelet therapy (untreated group) by means of propensity scores. Cumulative incidence of, and hazard ratio (HR) for, HCC development were analyzed after we adjusted for patient mortality as a competing risk event.

RESULTS

The cumulative incidence of HCC in the treated group was significantly lower than that in the untreated group over 5 years (4.67%; 95% CI, 3.74%-5.59% vs 7.32%; 95% CI, 6.33%-8.30%; P<.001). In the multivariable regression analysis, aspirin therapy was independently associated with a reduced HCC risk (HR, 0.78, 95% CI, 0.64-0.95; P = .011), after adjustment for age per year, male sex, cirrhosis, liver decompensation, hyperlipidemia, statin use, and interferon therapy. Sensitivity subgroup analyses also verified this association (all HRs<1.0). In addition, older age (HR, 1.03 per year; 95% CI, 1.02-1.04), male sex (HR, 1.46; 95% CI, 1.21-1.77), and cirrhosis (HR, 3.13; 95% CI, 2.55-3.84) were independently associated with an increased HCC risk.

CONCLUSIONS

In a nationwide cohort study in Taiwan, we found aspirin therapy to be significantly associated with a reduced risk of HCV-related HCC.

Impact of an ultrasound-guided radiofrequency ablation training program on the outcomes in patients with hepatocellular carcinoma

PURPOSE

The aim of this study was to retrospectively evaluate the impact of a training program on the safety and efficacy of percutaneous ultrasound-guided radiofrequency ablation (RFA) for the treatment of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

A total of 227 patients with 296 HCC nodules who underwent percutaneous RFA with or without transcatheter arterial chemoembolization at our institution were included. There were 163 men and 64 women with a mean age of 74.2±8.3 (SD) years (range: 41-89 years). Percutaneous ultrasound-guided RFA was performed by three trainees (205 HCC nodules in 157 patients) or a mentor (91 HCC nodules in 70 patients) after preprocedural preparation including planning ultrasonography. We compared background-related, tumor-related, and treatment-related factors, and local recurrence and complication rates between the trainee group and the mentor group. Similarly, we compared these variables among the years 2015, 2016, and 2017 for trainee group.

RESULTS

The proportion of easy-to-treat tumors in the trainee group (109/205; 53.2%) was greater than that in the mentor group (33/91; 36.3%) (P=0.020). No significant differences were observed in procedure difficulty among the years 2015, 2016, and 2017 for trainee group (easy-to-treat HCC nodules: 25/47; 53.2% vs. 39/79; 49.4% vs. 45/79; 57.0%. P=0.775). The local recurrence rate in the trainee group was 8.8% (18/205 HCC nodules) which was equivalent to 7.7% in the mentor group (7/91 HCC nodules). No significant differences were observed in local recurrence rate (8.8% vs. 7.7%, respectively; P=0.621) and major complication rate (1.3% vs. 1.4%, respectively; P=0.999) between the trainee group and the mentor group. No significant differences were observed in local recurrence rates ([5/47; 10.6%] vs. [11/79; 13.9%] vs. [2/79; 2.5%]) (P=0.109) and major complication rates ([1/36; 2.8%] vs. [1/62; 1.6%] vs. [0/59; 0%]) (P=0.701) between the years 2015, 2016, and 2017 for trainee group.

CONCLUSION

A well supervised training program that includes planning ultrasonography fosters the efficacy and treatment quality of RFA for HCC.

Association of Daily Aspirin Therapy With Risk of Hepatocellular Carcinoma in Patients With Chronic Hepatitis B

IMPORTANCE

Antiviral therapy cannot erase hepatocellular carcinoma (HCC) risk in patients with chronic hepatitis B, and it is not indicated for most hepatitis B virus (HBV) carriers. Another effective way of reducing HCC risk needs to be developed. Aspirin may prevent cancer development, but clinical evidence in patients with HBV-related HCC remains limited.

OBJECTIVE

To investigate the association of daily aspirin therapy with HBV-related HCC risk.

DESIGN, SETTING, AND PARTICIPANTS

In this Taiwan nationwide cohort study, we screened 204 507 patients with chronic hepatitis B for the period January 1, 1997, to December 31, 2012. After excluding patients with confounding conditions, 2123 patients who continuously received daily aspirin for 90 or more days (treated group) were randomly matched 1:4 with 8492 patients who had never received antiplatelet therapy (untreated group) by means of propensity scores, consisting of the follow-up index date, baseline characteristics, and potentially chemopreventive drug use during follow-up. Data were analyzed from August 1 to November 30, 2018.

EXPOSURES

Daily aspirin therapy during the study period.

MAIN OUTCOMES AND MEASURES

Both cumulative incidence of and hazard ratios (HRs) for HCC development were analyzed after adjusting patient mortality as a competing risk event.

RESULTS

Of the 10 615 patients included in the analysis, 7690 (72.4%) were men; mean (SD) age was 58.8 (11.8) years. The cumulative incidence of HCC in the treated group was significantly lower than that in the untreated group in 5 years (5.20%; 95% CI, 4.11%-6.29% vs 7.87%; 95% CI, 7.15%-8.60%; P < .001). In the multivariable regression analysis, aspirin therapy was independently associated with a reduced HCC risk (HR, 0.71; 95% CI, 0.58-0.86; P < .001). Sensitivity subgroup analyses also verified this association (all HRs <1.0). In addition, older age (HR, 1.01 per year; 95% CI, 1.00-1.02), male sex (HR, 1.75; 95% CI, 1.43-2.14), and cirrhosis (HR, 2.89; 95% CI, 2.45-3.40) were independently associated with an increased HCC risk, but nucleos(t)ide analogue (HR, 0.54; 95% CI, 0.41-0.71) or statin (HR, 0.62; 95% CI, 0.42-0.90) use was correlated with a decreased HCC risk.

CONCLUSIONS AND RELEVANCE

Daily aspirin therapy may be associated with a reduced risk of HBV-related HCC.

Evaluation of the Effect of Operator Experience on Outcome of Hepatic Artery Embolization of Hepatocellular Carcinoma in a Tertiary Cancer Center

RATIONALE AND OBJECTIVES

There is lack of information on the learning curve and the effect of operator's experience on the quality outcomes of transarterial hepatic embolization (TAE). The aim of this study was to evaluate the effect of operator experience on outcomes of TAE of hepatocellular carcinoma.

MATERIALS AND METHODS

Demographic characteristics and outcomes including overall survival (OS), time to local tumor progression (TLP), and post-procedure complications in patients with hepatocellular carcinoma treated with TAE were collected. Operators' experience was measured in years based on the years after completion of fellowship and the date of first embolization, and was divided into five groups: G1, less than 5 years of operator's experience (YOE) at the time of first embolization; G2, 5-10 YOE; G3, 10-15 YOE; G4, 15-20 YOE; and G5, more than 20 YOE. The effects of operator's experience and outcomes were assessed using linear regression.

RESULTS

From January 2012 to January 2015, 93 patients (age range = 30-86 years) were treated. The number of patients treated by each group was as follows: G1 = 12; G2 = 8; G3 = 23; G4 = 5; and G5 = 45. All groups were similar in regard to degree of cirrhosis, Barcelona Clinic Liver Cancer staging, and Child-Pugh score (P > .05). Median TLP was 8.8 months. TLP was 7.0, 6.8, 19.2, 7.9, and 8.2 months in G1, G2, G3, G4, and G5, respectively (P = .56). OS for 1, 2, and 3 years was 75%, 56%, and 42% for G1; 87%, 54%, and 54% for G2; 91%, 71%, and 45% for G3, 100%, 50%, and 0 for G4; and 84%, 65%, and 40% for G5.

CONCLUSION

Among interventional radiology fellowship-trained operators in a tertiary cancer center, OS, TLP, and post-procedure complications of TAE were not affected by the years of post-fellowship experience.

Effect of Nucleos(t)ide Analogue Therapy on Risk of Intrahepatic Cholangiocarcinoma in Patients With Chronic Hepatitis B

BACKGROUND & AIMS

Chronic infection with hepatitis B virus (HBV) increases risk of intrahepatic cholangiocarcinoma (ICC), but it is not clear whether antiviral therapy reduces risk. We investigated the association between nucleos(t)ide analogue therapy and ICC risk.

METHODS

We performed a nationwide long-term cohort study using Taiwan's National Health Insurance Research Database to obtain data on 185,843 patients with chronic HBV infection from October 1, 2003 through December 31, 2012. We excluded patients with confounding disorders such as infection with hepatitis C virus, HIV, or other hepatitis-associated viruses; liver flukes; biliary stone diseases; cholangitis; congenital biliary anomalies; biliary tract surgeries; or cancer. We identified 10,062 patients who received nucleos(t)ide analogue therapy (the treated group), and used propensity scores to match them (1:1) with patients who received hepatoprotectants (the untreated group). Cumulative incidences of and hazard ratios (HRs) for ICC development were analyzed.

RESULTS

The cumulative incidence of ICC was significantly lower in the treated group after 3 years of therapy (1.28%; 95% CI, 0.56-2.01) than in the untreated group (3.14%; 95% CI, 2.02-4.27) and after 5 years of therapy (1.53%; 95% CI, 0.73-2.33 vs 4.32% in untreated group; 95% CI, 2.96-5.6869). In multivariable regression analysis, nucleos(t)ide analogue therapy was independently associated with a reduced risk of ICC (HR, 0.44; 95% CI, 0.25-0.78; P = .005). Older age (HR 1.05 per year; 95% CI, 1.03-1.07) and cirrhosis (HR, 2.80; 95% CI, 1.52-5.1415) were independently associated with an increased risk of ICC. Sensitivity analyses verified the association between nucleos(t)ide analogue therapy and a reduced ICC risk.

CONCLUSION

A nationwide long-term cohort study in Taiwan showed that nucleos(t)ide analogue therapy for chronic HBV infection is significantly associated with a reduced ICC risk.

Percutaneous Ablation for Hepatocellular Carcinoma

OBJECTIVE

The purpose of this article is to discuss the use, comparative efficacy, and general technical considerations of percutaneous ablation, alone or in combination with other therapies, for the treatment of hepatocellular carcinoma (HCC).

CONCLUSION

Percutaneous ablation is a mainstay treatment for early-stage HCC, offering survival comparable to that of surgical resection for small lesions. It can act as a primary curative therapy or bridge therapy for patients waiting to undergo liver transplant. New ablation modalities and combining tumor ablation with other therapies, such as transarterial chemoembolization, can improve clinical outcomes and allow treatment of larger lesions. Combining thermal ablation with systemic chemotherapy, including immunotherapy, is an area of future development.

Comparable Outcomes of Ultrasound versus Computed Tomography in the Guidance of Radiofrequency Ablation for Hepatocellular Carcinoma

Objectives

To compare the efficacy and safety of ultrasound (US) and computed tomography (CT) in the guidance of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC).

Materials and Methods

We retrospectively analyzed consecutive treatment-naïve patients who received curative RFA for HCC from January 2008 to July 2013. Patients were divided into the US group or the CT group according to their RFA guidance instruments. Patients who were only suitable for US- or CT-guided RFA were excluded. Cumulative incidences of and hazard ratios for HCC recurrence were analyzed after adjusting for competing mortality risk.

Results

We recruited a total of 101 patients in the US group and 51 patients in the CT group. The baseline demographic characteristics were not significantly different in both groups. Initial response rates were similar between the two groups (US vs. CT: 89.1% vs. 92.2%, p = 0.54), and complete tumor ablation was finally achieved for all patients. However, more ablations per session were performed in US group (median 2.0 [1.0–3.0] vs. 1.0 [1.0–2.0]; p<0.01). The 1-, 2- and 3-year local tumor recurrence rates (US vs. CT: 13.0%, 20.9%, and 29.2% vs. 11.2%, 29.8% and 29.8%, respectively) and overall mortality rates (US vs. CT: 5.2%, 9.6% and 16.5% vs. 0%, 3.1% and 23.8%, respectively) were not significantly different. In multivariate analysis, tumor characteristics and underlying liver function, but not US or CT guidance, were independent prognostic factors. The complication rates were similar between the two groups (US vs. CT: 10.9% vs. 9.8%; p = 0.71), and there was no procedure-related mortality.

Conclusions

With comparable major outcomes, either US or CT can be used in the guidance of RFA in experience hands.

Development of a Searchable Database of Cryoablation Simulations for Use in Treatment Planning

PURPOSE

To create and validate a planning tool for multiple-probe cryoablation, using simulations of ice ball size and shape for various ablation probe configurations, ablation times, and types of tissue ablated.

MATERIALS AND METHODS

Ice ball size and shape was simulated using the Pennes bioheat equation. Five thousand six hundred and seventy different cryoablation procedures were simulated, using 1-6 cryoablation probes and 1-2 cm spacing between probes. The resulting ice ball was measured along three perpendicular axes and recorded in a database. Simulated ice ball sizes were compared to gel experiments (26 measurements) and clinical cryoablation cases (42 measurements). The clinical cryoablation measurements were obtained from a HIPAA-compliant retrospective review of kidney and liver cryoablation procedures between January 2015 and February 2016. Finally, we created a web-based cryoablation planning tool, which uses the cryoablation simulation database to look up the probe spacing and ablation time that produces the desired ice ball shape and dimensions.

RESULTS

Average absolute error between the simulated and experimentally measured ice balls was 1 mm in gel experiments and 4 mm in clinical cryoablation cases. The simulations accurately predicted the degree of synergy in multiple-probe ablations. The cryoablation simulation database covers a wide range of ice ball sizes and shapes up to 9.8 cm.

CONCLUSION

Cryoablation simulations accurately predict the ice ball size in multiple-probe ablations. The cryoablation database can be used to plan ablation procedures: given the desired ice ball size and shape, it will find the number and type of probes, probe configuration and spacing, and ablation time required.

Impact of hospital volume on risk-adjusted mortality following oesophagectomy in Japan

Background

Previous studies have reported that patients undergoing oesophagectomy in high-volume hospitals experience lower mortality rates. However, there has been ongoing discussion regarding the validity of evidence for this association. The purpose of this study was to investigate the relationship between hospital volume and risk-adjusted mortality following oesophagectomy in Japan, using a nationwide web-based database.

Methods

The study included patients registered in the database as having undergone oesophagectomy with reconstruction between 2011 and 2013. Outcome measures were 30-day and operative mortality rates. Logistic regression analysis was used to adjust for hospital volume, surgeon volume and risk factors for mortality after oesophagectomy.

Results

A total of 16 556 oesophagectomies at 988 hospitals were included; the overall unadjusted 30-day and operative mortality rates were 1·1 and 3·0 per cent respectively. The unadjusted operative mortality rate in hospitals performing fewer than ten procedures per year (5·1 per cent) was more than three times higher than that in hospitals conducting 30 or more procedures annually (1·5 per cent). Multivariable models indicated that hospital volume had a significant effect on 30-day (odds ratio 0·88 per 10-patient increase; P = 0·012) and operative (odds ratio 0·86 per 10-patient increase; P &lt; 0·001) mortality.

Conclusion

In Japan, high-volume hospitals had lower risk-adjusted 30-day and operative mortality rates following oesophagectomy compared with low-volume hospitals.

Radiofrequency hyperthermia-enhanced herpes simplex virus-thymidine kinase/ganciclovir direct intratumoral gene therapy of hepatocellular carcinoma

PURPOSE

To determine the feasibility of using radiofrequency hyperthermia (RFH) and to enhance the therapeutic effect of herpes simplex virus-thymidine kinase/ganciclovir (HSV-TK/GCV) for the treatment of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Human HCC cells (HepG2) were first transfected with lentivirus/luciferase. For both in vitro confirmation and in vivo validation, luciferase-labeled HCC cells and HCC tumour xenografts on mice received different treatments: (i) combination therapy of intratumoral HSV-TK/GCV-mediated gene therapy plus magnetic resonance imaging heating guidewire (MRIHG)-mediated RFH; (ii) gene therapy only; (iii) RFH only; and (iv) phosphate-buffered saline (PBS) as control. Cell proliferation was quantified. Tumour changes were monitored by ultrasound imaging and bioluminescence optical imaging before and at days 7 and 14 after treatments, which were correlated with subsequent histology.

RESULTS

In vitro, the lowest cell proliferation was seen in the combination therapy group compared with control groups (29 ± 6% vs. 56 ± 9%, 93 ± 4%, and 100 ± 5%, p < .05). Ultrasound imaging of treated animal xenografts showed smaller relative tumour volume in combination therapy group than those in three control groups (0.74 ± 0.19 vs. 1.79 ± 0.24, 3.14 ± 0.49 and 3.22 ± 0.52, p < .05). Optical imaging demonstrated significant decrease of bioluminescence signals of tumours in the combination therapy group, compared to those in three control groups (1.2 ± 0.1 vs. 1.9 ± 0.2% vs. 3.3 ± 0.6% vs. 3.5 ± 0.4%, p < .05). These imaging findings were correlated well with histologic confirmation.

CONCLUSION

RFH can enhance HSV-TK/GCV-mediated gene therapy of HepG2 cell line and mice human HCC xenografts, which may open new avenues for effective management of HCC using MR/RFH integrated interventional gene therapy.

Association between nucleos(t)ide analog and tumor recurrence in hepatitis B virus-related hepatocellular carcinoma after radiofrequency ablation

Radiofrequency ablation (RFA) is the best choice for curative treatment of hepatocellular carcinoma (HCC) cases not suitable for surgical intervention, but efforts should be made to reduce the risk of tumor recurrence. We aimed to investigate the association between nucleos(t)ide analog (NA) therapy for hepatitis B virus (HBV) and the risk of HCC recurrence post-RFA. Using the Taiwan National Health Insurance Research Database between July 1, 2004 and December 31, 2012, we screened 48,807 patients with newly diagnosed HBV-related HCC. We identified 850 patients (200 patients who used NAs for more than 90 days and 650 who never used NA post-RFA) who received RFA as a potentially curative treatment for HCC. Patients in the NA-treated cohort were randomly matched 1:2 with patients in the untreated cohort by age, sex, cirrhosis, and the time period between RFA and initiation of NA therapy. Finally, 133 patients were recruited in the NA-treated group and 266 in the untreated group for analysis. Cumulative incidences of and hazard ratios (HRs) for HCC recurrence were analyzed after adjusting for competing mortality. The HCC recurrence rate of the NA-treated group was significantly lower than that of the untreated group (2-year recurrence rate: 41.8%; 95% confidence interval [CI]: 32.9-50.6 vs. 54.3%; 95% CI: 48.0-60.6; modified log-rank test: P < 0.05). In modified Cox's regression analysis, NA therapy was independently associated with a decreased risk of HCC recurrence (HR, 0.69; 95% CI: 0.50-0.95; P < 0.05). Multivariate stratified analyses verified the association of NA therapy and decreased HCC recurrence in almost all patient subgroups.

CONCLUSION

NA therapy was associated with a decreased risk of HCC recurrence among patients with HBV-related HCC post-RFA.

Electric Ablation with Irreversible Electroporation (IRE) in Vital Hepatic Structures and Follow-up Investigation

Irreversible electroporation (IRE) with microsecond-pulsed electric fields (μsPEFs) can effectively ablate hepatocellular carcinomas in animal models. This preclinical study evaluates the feasibility and safety of IRE on porcine livers. Altogether, 10 pigs were included. Computed tomography (CT) was used to guide two-needle electrodes that were inserted near the hilus hepatis and gall bladder. Animals were followed-up at 2 hours and at 2, 7 and 14 days post-treatment. During and after μsPEF ablation, electrocardiographs found no cardiovascular events, and contrast CT found no portal vein thrombosis. There was necrosis in the ablation zone. Mild cystic oedema around the gall bladder was found 2 hours post-treatment. Pathological studies showed extensive cell death. There was no large vessel damage, but there was mild endothelial damage in some small vessels. Follow-up liver function tests and routine blood tests showed immediate liver function damage and recovery from the damage, which correlated to the pathological changes. These results indicate that μsPEF ablation affects liver tissue and is less effective in vessels, which enable μsPEFs to ablate central tumour lesions close to the hilus hepatis and near large vessels and bile ducts, removing some of the limitations and contraindications of conventional thermal ablation.