Prospective Histopathological Analysis of Hepatocellular Carcinoma Treated With Percutaneous Ethanol Injection in Patients on the Waiting List for Liver Transplantation

Percutaneous ethanol injection is an acceptable bridging therapy to hepatocellular carcinoma prior to liver transplantation

PURPOSE

Locoregional therapies (LRT) are employed for bridging patients with hepatocellular carcinoma (HCC) awaiting orthotopic liver transplantation (OLT). Although the main LRT options include transarterial chemoembolization (TACE) and radiofrequency ablation (RFA), percutaneous ethanol injection (PEI) is an alternative with considerably lower costs. This study is a pioneering evaluation of the natural history of PEI bridging to OLT as compared to TACE.

METHODS

All consecutive cirrhotic patients with HCC enlisted for OLT (2011-2020) at a single center were analyzed. Patients were divided into three LRT modality groups: PEI, TACE, and PEI+TACE. The primary study outcome was waitlist dropout due to tumor progression beyond Milan criteria. A comparison of post-transplant outcomes of patients as stratified by LRT modality also was performed.

RESULTS

One hundred twenty-nine patients were included (PEI=56, TACE=43, PEI+TACE=30). The dropout rate due to tumor progression was not different among the three groups: PEI=8.9%, TACE=14%, PEI+TACE=16.7% (p=0.54). Thirteen (76.4%) patients underwent OLT after successful downstaging (3 [75%] in the PEI group, 5 [83.3%] in the TACE group, and 5 [71.4%] in the PEI+TACE group). For the 96 patients undergoing OLT, 5-year post-transplant recurrence-free survival was PEI=55.6% vs. TACE=55.1% vs. PEI+TACE=71.4% (p=0.42). Complete/near-complete pathological response rate was similar among groups (p=0.82).

CONCLUSION

Dropout rates and post-transplant recurrence-free survivals related to PEI were comparable to those of TACE. This study supports the use of PEI alone or in combination with TACE for HCC patients awaiting OLT whenever RFA is not an option.

[Targeted radiological therapy of liver tumors]

BACKGROUND

Interventional radiology offers a variety of treatment options for liver tumors. Depending on the tumor entity and the extent of the disease, patients can be treated with a curative or palliative intent. In order to make a decision on the best course of treatment for the individual patient, knowledge about the possible therapies and their limitations is essential.

OBJECTIVES

The aim of this article is a structured listing of targeted radiological therapies for the treatment of liver tumors and an overview of the specific technical aspects and possible limitations.

MATERIALS AND METHODS

This study involved a selective literature search as well as personal experiences in interventional radiological treatment of liver tumors.

CONCLUSION

The wide range of available therapies requires an individual assessment of each patient taking the achievable results into account. The decision for an interventional radiological therapy should be made in an interdisciplinary tumor board.

Ablation therapy for hepatocellular carcinoma: past, present and future perspectives

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide, and is most commonly found in the setting of liver cirrhosis. Treatment of HCC must consider both the tumors present, as well as the remaining dysfunctional liver that both hinders treatment and can produce additional HCC over time. Ablation is an evolving part of the multimodality treatment approach to HCC that can effectively destroy tumors while preserving surrounding liver parenchyma. New technologies have made ablation an indispensable tool in the treatment of all stages of HCC. This review presents the history, present technologies and future potential of ablation in the treatment of HCC.

Radiofrequency ablation or percutaneous ethanol injection for the treatment of liver tumors

The liver is a common location of both primary and secondary malignancies. For unresectable liver cancer, many local ablative therapies have been developed. These include e.g., percutaneous ethanol injection (PEI), percutaneous acetic acid injection, radiofrequency ablation (RFA), cryoablation, microwave ablation, laser-induced thermotherapy, and high-intensity focused ultrasound. RFA has recently gained interest and is the most widely applied thermoablative technique. RFA allows more effective tumor control in fewer treatment sessions compared with PEI, but with a higher rate of complications. However, there are certain circumstances where PEI therapy represents a better strategy to control liver tumors than RFA, especially in situations where RFA is difficult, for example when large vessels surround the tumor. In the context of hepatocellular carcinoma (HCC), both RFA and PEI are feasible and of benefit in non-operable patients. RFA seems superior to PEI in HCC > 2 cm, and the combination of interventions may be of benefit in selected patients. Liver resection is superior to RFA for patients with HCC meeting the Milan criteria, but RFA can be employed in tumors ≤ 3 cm and where there is an increased expected operative mortality. In addition, some lines of evidence indicate that RFA and PEI can be employed as a bridge to liver transplantation. The use of RFA in colorectal liver metastases is currently limited to unresectable disease and for patients unfit for surgery. The aim of this article is to summarize the current status of RFA in the management of liver tumors and compare it to the cheap and readily available technique of PEI.

Techniques of interventional tumor therapy

INTRODUCTION

The last few years have seen the rapid development of new image-guided interventions for the local treatment of malignant tumors. The goal of this article is to provide an overview of the techniques that are most commonly used today in interventional oncology.

METHODS

Selective literature review on the current state of image-guided interventional techniques for local tumor therapy.

RESULTS

While surgery, radiation oncology, and systemic chemotherapy are still the three main pillars of tumor therapy, a broad range of minimally invasive, image-guided techniques for local tumor treatment is now available. These may be categorized as percutaneous injection of a toxic substance, transarterial embolization, thermal ablation, and internal radiotherapy. The choice of treatment depends on the type, location, and size of tumor. The greatest amount of clinical experience to date has been gathered in the treatment of primary and secondary hepatic malignancy, but there are interventional treatment options for virtually all regions of the body. At present, the utility of this form of treatment is limited for very large or multiple tumors; novel therapeutic options for these situations are now being studied.

DISCUSSION

The outcome of treatment depends on a judicious determination of the indication for it. The indication should be established by interdisciplinary consensus after all treatment options have been considered.

Percutaneous ultrasound-guided ablation of BW7756-hepatoma using ethanol or acetic acid in a rat model

Background

To compare tumor necrosis in hepatoma induced in rats by a single percutaneous injection of ethanol (PEI) or acetic acid (PAI).

Methods

BW7756 hepatomas of 1 mm³ were implanted in the liver of 40 male healthy rats. After 14 days, the 36 surviving rats were treated, in a single session, by ultrasound-guided injection of 300 μl of 95% ethanol (n = 17) or 100 μl of 50% acetic acid (n = 19). They were sacrificed 14 days after treatment and explanted tumoral livers were examined. The same PAI procedure was repeated on 13 additional rats to exclude a suspected occurrence of technical failures during the experiment, due to a surprisingly high rate of deaths within 30 minutes after PAI.

Results

Four rats died within four days after tumor implantation; after PEI, 1/17 (6%) died, whereas after PAI 9/19 (47%) died. The remaining 26 rats, after 14 days post-percutaneous ablation, were sacrificed. Gross and microscopic examinations showed that the hepatoma's nodules treated with PEI had 45.3 ± 19.4% tumor necrosis compared to 49 ± 23.3% (P = NS) for those treated with PAI. Complete tumor necrosis was not found in any animal. Peritoneal invasion was present in 4/16 (25%) and 2/10 (20%) rats treated with PEI or PAI, respectively (P = NS). Autopsy was performed in the 5 additional rats that died within 30 minutes after PAI.

Conclusion

Our results show that there is no significant difference in the percentage of tumor necrosis between two local ablation methods in spite of the different dosages used. However, mortality in the PAI-treated group was greater than in PEI-treated group, presumably due to greater acetic acid systemic diffusion and its metabolic side effects. In human subjects, HCC occurs in the setting of cirrhosis, where the non-tumoral tissue is firmer than the tumor structure, with consequent reduction of drug diffusion. This could be the reason why some human studies have concluded similar or even better safety and efficacy with PAI compared to PEI.

Combination of repeated single-session percutaneous ethanol injection and transarterial chemoembolisation compared to repeated single-session percutaneous ethanol injection in patients with non-resectable hepatocellular carcinoma

AIM: To evaluate the treatment effect of percutaneous ethanol injection (PEI) for patients with advanced, non-resectable HCC compared with combination of transarterial chemoembolisation (TACE) and repeated single-session PEI, repeated single-session PEI alone, repeated TACE alone, or best supportive care.

METHODS: All patients who received PEI treatment during the study period were included and stratified to one of the following treatment modalities according to physical status and tumor extent: combination of TACE and repeated single-session PEI, repeated single-session PEI alone, repeated TACE alone, or best supportive care. Prognostic value of clinical parameters including Okuda-classification, presence of portal vein thrombosis, presence of ascites, number of tumors, maximum tumor diameter, and serum cholinesterase (CHE), as well as Child-Pugh stage, α-fetoprotein (AFP), fever, incidence of complications were assessed and compared between the groups. Survival was determined using Kaplan-Meier and multivariate regression analyses.

RESULTS: The 1- and 3-year survival of all patients was 73% and 47%. In the subgroup analyses, the combination of TACE and PEI (1) was associated with a longer survival (1-, 3-, 5-year survival: 90%, 52%, and 43%) compared to PEI treatment alone (2) (1-, 3-, 5-year survival: 65%, 50%, and 37%). Secondary PEI after initial stratification to TACE (3) yielded comparable results (1-, 3-, 5-year survival: 91%, 40%, and 30%) while PEI after stratification to best supportive care (4) was associated with decreased survival (1-, 3-, 5-year survival: 50%, 23%, 12%). Apart from the chosen treatment modalities, predictors for better survival were tumor number (n < 5), tumor size (< 5 cm), no ascites before PEI, and stable serum cholinesterase after PEI (P < 0.05). The mortality within 2 wk after PEI was 2.8% (n = 3). There were 24 (8.9%) major complications after PEI including segmental liver infarction, focal liver necrosis, and liver abscess. All complications could be managed non-surgically.

CONCLUSION: Repeated single-session PEI is effective in patients with advanced HCC at an acceptable and manageable complication rate. Patients stratified to a combination of TACE and PEI can expect longer survival than those stratified to repeated PEI alone. Furthermore, patients with large or multiple tumors in good clinical status may also profit from a combination of TACE and reconsideration for secondary PEI.