Percutaneous Ethanol Injection of Unresectable Medium-to-Large-Sized Hepatomas Using a Multipronged Needle: Efficacy and Safety

Quantitative Dual-Energy CT Image Guidance for Thermochemical Ablation: In Vivo Results in the Rabbit VX2 Model

PURPOSE

To evaluate the feasibility of using dual-energy computed tomography (CT) and theranostic cesium hydroxide (CsOH) for image guidance of thermochemical ablation (TCA) in a rabbit VX2 tumor model.

MATERIALS AND METHODS

In vivo experiments were performed on New Zealand white rabbits, where VX2 tumor fragments (0.3 mL) were inoculated into the right and left flanks (n = 16 rabbits, 32 tumors). Catheters were placed in the approximate center of 1- to 2-cm diameter tumors under ultrasound guidance. TCA was delivered in 1 of 3 treatment groups: untreated control, 5-M TCA, or 10-M TCA. The TCA base reagent was doped with 250-mM CsOH. Dual-energy CT was performed before and after TCA. Cesium (CS)-specific images were postprocessed on the basis of previous phantom calibrations to determine Cs concentration. Line profiles were drawn through the ablation center. Twenty-four hours after TCA, subjects were euthanized, and the resulting damage was evaluated with histopathology.

RESULTS

Cs was detected in 100% of treated tumors (n = 21). Line profiles indicated highest concentrations at the injection site and decreased concentrations at the tumor margins, with no Cs detected beyond the ablation zone. The maximum detected Cs concentration ranged from 14.39 to 137.33 mM. A dose-dependent trend in tissue necrosis was demonstrated between the 10-M TCA and 5-M TCA treatment groups (P = .0005) and untreated controls (P = .0089).

CONCLUSIONS

Dual-energy CT provided image guidance for delivery, localization, and quantification of TCA in the rabbit VX2 model.

Intratumoral Immunotherapy: From Trial Design to Clinical Practice

Systemic immunotherapies such as immune checkpoint blockade targeted at PD(L)1 and CTLA4 have demonstrated their ability to provide durable tumor responses and long-term overall survival benefits for some patients in several solid tumor types. However, a majority of patients remain resistant to these treatments and a significant proportion of them develop severe autoimmune and inflammatory adverse events. Preclinical studies have demonstrated that intratumoral injections of immunostimulatory products (oncolytics, pattern recognition receptor agonists,…) that are able to trigger type I IFN release and enhance tumor antigen presentation on immune cells could generate a strong antitumor immunity and overcome the resistance to systemic immune checkpoint blockade therapies. The intratumoral immunotherapy strategies that are currently in clinical development offer a unique therapeutic and exploratory setting to better understand the immune contexture across tumor lesions of patients with metastatic cancer. Also these local therapeutic products could turn cold tumors into hot and improve the response rates to cancer immunotherapies while diminishing their systemic exposure and toxicities. Intratumoral immunotherapies could prime or boost the immunity against tumors and therefore radically change the combinatorial therapeutic strategies currently pursued for metastatic and local cancers to improve their long-term survival. We aimed to review and discuss the scientific rationale for intratumoral immunotherapy, the challenges raised by this strategy in terms of drug development within clinical trials and the current state-of-the-art regarding the clinical practice of this innovative approach.

HepG2 cells recovered from apoptosis show altered drug responses and invasiveness

BACKGROUND

Cancer relapse, associated with increased drug resistance and rate of metastasis, often follows completion of chemotherapy but the cancer escape mechanisms are still incompletely understood. Percutaneous ethanol injection (PEI) has been used for treating hepatocellular carcinoma (HCC) for decades, while the recurrence after PEI treatment remains a major limitation. Recent evidence mounted that cancer cells could survive from chemical induced apoptosis, suggesting a potential route through which cancer relapse may occur. This study focuses on the consequence of HepG2 recovery from ethanol-induced apoptotic event.

METHODS

The model of HepG2 recovery from ethanol-induced apoptotic event was established by live cell imaging, BrdU assay and Western blotting. MTT assay, wound healing assay and invasion assay were used to investigate the behavior of HepG2 after recovery.

RESULTS

HepG2 cells could recover from ethanol-induced apoptosis. These cells changed their behaviors such as drug resistance, mobility and invasiveness. On average, the recovered HepG2 cell clones were found to be 46% more resistant to ethanol and 84% higher in mobility. The recovered clones became 58.2% more sensitive to 5-fluorouracil.

CONCLUSIONS

HepG2 cells can recover from ethanol-induced apoptotic event. These cells became more resistant to ethanol and more invasive. Although the recovered cell clones were more resistant to ethanol, they became more sensitive to 5-fluorouracil treatment.

Dual mode single agent thermochemical ablation by simultaneous release of heat energy and acid: hydrolysis of electrophiles

PURPOSE

This study aimed to investigate two readily available electrophilic reagents, acetyl chloride (AcCl), and acetic anhydride (Ac(2)O), for their potential in tissue ablation.

MATERIALS AND METHODS

Reagents were diluted in diglyme as solutions up to 8 mol/L and tested in a gel phantom with NaOH solutions and ex vivo in porcine liver. Temperature, pH, and volume measurements were obtained. Infrared and gross pathological images were obtained in bisected specimens immediately after injection.

RESULTS

AcCl was much more reactive than Ac(2)O and AcCl was therefore used in the tissue studies. Temperature increases of up to 37°C were noted in vitro and 30°C in ex vivo tissues using 4 mol/L AcCl solutions. Experiments at 8 mol/L were abandoned due to the extreme reactivity at this higher concentration. A change in pH of up to 4 log units was noted with 4 mol/L solutions of AcCl with slight recovery over time. Ablated volumes were consistently higher than injected volumes.

CONCLUSIONS

Reaction of electrophiles in tissues shows promise as a new thermochemical ablation technique by means of only a single reagent. Further studies in this area are warranted.

In vivo comparison of simultaneous versus sequential injection technique for thermochemical ablation in a porcine model

PURPOSE

To investigate simultaneous and sequential injection thermochemical ablation in a porcine model, and compare them to sham and acid-only ablation.

MATERIALS AND METHODS

This IACUC-approved study involved 11 pigs in an acute setting. Ultrasound was used to guide placement of a thermocouple probe and coaxial device designed for thermochemical ablation. Solutions of 10 M acetic acid and NaOH were used in the study. Four injections per pig were performed in identical order at a total rate of 4 mL/min: saline sham, simultaneous, sequential, and acid only. Volume and sphericity of zones of coagulation were measured. Fixed specimens were examined by H&E stain.

RESULTS

Average coagulation volumes were 11.2 mL (simultaneous), 19.0 mL (sequential) and 4.4 mL (acid). The highest temperature, 81.3°C, was obtained with simultaneous injection. Average temperatures were 61.1°C (simultaneous), 47.7°C (sequential) and 39.5°C (acid only). Sphericity coefficients (0.83-0.89) had no statistically significant difference among conditions.

CONCLUSIONS

Thermochemical ablation produced substantial volumes of coagulated tissues relative to the amounts of reagents injected, considerably greater than acid alone in either technique employed. The largest volumes were obtained with sequential injection, yet this came at a price in one case of cardiac arrest. Simultaneous injection yielded the highest recorded temperatures and may be tolerated as well as or better than acid injection alone. Although this pilot study did not show a clear advantage for either sequential or simultaneous methods, the results indicate that thermochemical ablation is attractive for further investigation with regard to both safety and efficacy.

Thermochemical ablation in an ex-vivo porcine liver model using acetic acid and sodium hydroxide: proof of concept

PURPOSE

To establish proof of concept in tissue, using the exothermic neutralization reaction of acetic acid and sodium hydroxide in ex vivo porcine liver and to conduct an initial probe into the relationships of volume and concentration of reagents to temperatures and the areas affected.

MATERIALS AND METHODS

A total of 0.5 mL or 2 mL of either 5 mole/L or 10 mole/L acid and base solutions was injected simultaneously into the periphery of ex vivo porcine liver using a prototype injection device. Tissue temperature was recorded at the injection site for 5 minutes using a type T thermocouple temperature probe inserted parallel to and near the tip of the injection device. The injections were repeated for infrared thermography, and ablated tissues were sectioned quickly and imaged. A gross photograph was captured in each case to provide correlation.

RESULTS

Maximum temperatures (17°C baseline) ranged from 42.1° ± α3.34°C to 61.7° ± α10°C (P<.05) when injecting 0.5 mL of 5 mole/L reactants and 2 mL of 10 mole/L reactants, respectively. The maximum temperature measured by infrared imaging ranged from 31°-47°C. Using an infrared viewing scale from 19°-40°C, the cross-sectional area of tissue heating above baseline measured from 1.07 cm(2)± 0.45 to 4.95 cm(2)± 0.28 (P <05).

CONCLUSIONS

The reaction of acetic acid and sodium hydroxide releases significant heat energy at the site of injection, and histologic changes are consistent with coagulation necrosis. Increased reagent concentration and volume were associated with larger temperature changes and larger areas of hyperthermia at gross pathology and infrared imaging.

Is percutaneous ethanol injection therapy still effective for hepatocellular carcinoma in the era of radiofrequency ablation?

Percutaneous ethanol injection (PEI) therapy has been replaced by more-effective thermal ablation techniques that have lower local recurrence rates. However, PEI therapy remains useful in certain settings. Since PEI can be performed in any portion of the liver, PEI therapy can be valuable when tumors are located in close proximity to intestinal loops or other positions that are risky for thermal local ablative techniques. PEI therapy is also valuable in other situations where radiofrequency ablation (RFA) is difficult, including technically difficult masses that are not detected with ultrasound (US), are located in the hepatic dome, in the subcapsular area, and exophytically, or are surrounded by large vessels. PEI therapy contributes to combination therapy with transcatheter arterial chemoembolization or RFA in advanced-stage hepatocellular carcinoma (HCC), and also to the treatment of large HCC or extrahepatic metastasis from HCC. These roles of PEI therapy should be stressed for the treatment of HCCs in appropriate clinical situations. This comprehensive review of articles related to PEI therapy illustrates the recent role and indications of this therapy, which is currently valuable for HCC in the era of RFA.

Percutaneous ethanol ablation of hepatocellular carcinoma: periprocedural onset alcohol toxicity and pancreatitis following conventional percutaneous ethanol ablation treatment

A novel case of acute pancreatitis in a patient treated with percutaneous ethanol injection (PEI) ablation for hepatocellular carcinoma is described. The most commonly reported adverse effects of PEI are hepatic or peritoneal hemorrhage, hepatic insufficiency or infarction. There are no previous reports of fatal acute pancreatitis as a result of conventional PEI.

Ethanol ablation of hepatocellular carcinoma Up to 5.0 cm by using a multipronged injection needle with high-dose strategy

PURPOSE

To investigate whether ethanol ablation by using a multipronged needle delivery system (multipronged ethanol ablation) could eradicate hepatocellular carcinoma (HCC) up to 5.0 cm in diameter with a single-session high-dose strategy.

MATERIALS AND METHODS

The hospital ethics committee approved the prospective study, and each patient provided written informed consent. One hundred forty-one patients (125 men, 16 women; mean age, 53 years; range, 27-76 years) with 164 primary or recurrent HCC ranging from 1.3 to 5.0 cm in diameter (mean, 2.9 cm +/- 0.9) were treated with high-dose multipronged ethanol ablation. Patients were unsuitable for surgery, declined surgery and radiofrequency ablation, or had tumors located at unfavorable sites. Primary technique effectiveness (PTE) (complete ablation within two sessions), local tumor progression (LTP), and complications after the treatment were observed. Twenty risk factors of local effectiveness and complications were analyzed by means of univariate and multivariate analysis.

RESULTS

Mean number of treatment sessions was 1.1. The mean volume of ethanol per tumor was 31 mL (range, 8-68 mL). PTE was achieved in 134 (95%) of 141 patients and was significantly associated with tumor pattern (capsulated vs noncapsulated, P = .018). After a mean follow-up period of 25 months, LTP was observed in 16 (12%) of 134 patients, and in nine (56%) patients, LTP occurred in tumors 3.1-5.0 cm in diameter. Alanine aminotransferase level (P = .023) was the independent risk factor for LTP. Three (2%) of 141 patients had major complications.

CONCLUSION

Multipronged ethanol ablation with a high-dose strategy can be used to treat HCC up to 5.0 cm in diameter effectively and safely, often in a single session.

Percutaneous ablation for small hepatocellular carcinoma

Hepatocellular carcinoma is increasingly detected at small size, usually 5 cm or smaller in diameter. For small hepatocellular carcinoma, percutaneous ablation is a potentially curative treatment. Ethanol injection is able to achieve a complete response of 70-80% and a 5-year survival of 40-60% in the treatment of hepatocellular carcinoma of 3 cm or less. Radiofrequency ablation has emerged as the more powerful alternative method. Randomized controlled trials show that radiofrequency ablation offers a higher complete response at fewer treatment sessions and better survival compared with ethanol injection. Microwave ablation has been demonstrated to be equivalent to radiofrequency ablation in both local efficacy and long-term outcome. Laser ablation is mainly applied in clinical settings in Europe. Nowadays, percutaneous ablation is commonly accepted as the best option for patients with small hepatocellular carcinoma who are not candidates for surgical resection or liver transplantation. However, whether it can compete with surgery as the first-line treatment has long been debated. There are some retrospective studies and only a few randomized controlled trials to compare the two modalities. The currently available data are not robust enough to draw a solid conclusion. This review article provides an overview of the current status of percutaneous ablation in management of small hepatocellular carcinoma and also focuses on comparison with surgical resection.

Chemical ablation of liver cancer

Percutaneous chemical ablation is an established image-guided therapy for liver cancer that is relatively simple to perform and requires no specialized equipment. Chemical ablation has been used extensively for hepatocellular carcinoma (HCC), and has achieved outcomes comparable to surgical resection for small, solitary HCC. More recent experience with chemical ablation has combined it with TACE or thermal ablation as part of a multimodality approach to liver cancer.