Recent trends and future perspectives in isolated hepatic perfusion in the treatment of liver tumors

Percutaneous Hepatic Perfusion (PHP) with Melphalan as a Treatment for Unresectable Metastases Confined to the Liver

Unresectable liver metastases of colorectal cancer can be treated with systemic chemotherapy, aiming to limit the disease, extend survival or turn unresectable metastases into resectable ones. Some patients however, suffer from side effects or progression under systemic treatment. For patients with metastasized uveal melanoma there are no standard systemic therapy options. For patients without extrahepatic disease, isolated liver perfusion (IHP) may enable local disease control with limited systemic side effects. Previously, this was performed during open surgery with satisfying results, but morbidity and mortality related to the open procedure, prohibited a widespread application. Therefore, percutaneous hepatic perfusion (PHP) with simultaneous chemofiltration was developed. Besides decreasing morbidity and mortality, this procedure can be repeated, hopefully leading to a higher response rate and improved survival (by local control of disease). During PHP, catheters are placed in the proper hepatic artery, to infuse the chemotherapeutic agent, and in the inferior caval vein to aspirate the chemosaturated blood returning through the hepatic veins. The caval vein catheter is a double balloon catheter that prohibits leakage into the systemic circulation. The blood returning from the hepatic veins is aspirated through the catheter fenestrations and then perfused through an extra-corporeal filtration system. After filtration, the blood is returned to the patient by a third catheter in the right internal jugular vein. During PHP a high dose of melphalan is infused into the liver, which is toxic and would lead to life threatening complications when administered systemically. Because of the significant hemodynamic instability resulting from the combination of caval vein occlusion and chemofiltration, hemodynamic monitoring and hemodynamic support is of paramount importance during this complex procedure.

Isolated hepatic perfusion: principles and results

INTRODUCTION

Isolated hepatic perfusion allows the delivery of high dose chemotherapy while decreasing extra-hepatic toxicity, and is used mainly for patients with surgically unresectable liver tumors.

PRINCIPLES

Vascular exclusion of the liver is performed after obtaining satisfactory hemodynamic tolerance, occasionally after cavocaval shunt and/or porto-systemic shunt. Perfusion entry can be arterial and/or portal while the exit is portal or caval. The perfusion circuit can be open or closed, using a circulation pump with or without oxygenation. The chemotherapy regimens used are high dose melphalan (with or without TNF-alpha), oxaliplatin, cisplatin and mitomycin, sometimes associated with moderate hyperthermia. The duration of perfusion ranges between 30 and 90 minutes according to the different protocols used. A percutaneous technique with incomplete liver vascular exclusion is also possible.

RESULTS

The larger series in the literature show a response rate (partial or complete stabilization) between 60 and 80%, with approximately 5% complete morphologic responses. Morbidity and mortality are 40 and 5%, respectively, including specific morbidity related to the perfusion procedure as well as to chemotherapy.

CONCLUSION

Chemotherapy delivered through isolated hepatic perfusion is a new therapeutic alternative, still under development, and can be proposed to patients with surgically unresectable primary or secondary liver tumors within clinical trials. These results seem to be promising, but are still associated with a non-negligible morbidity rate.

RNAi-mediated silencing of insulin receptor substrate-4 enhances actinomycin D- and tumor necrosis factor-alpha-induced cell death in hepatocarcinoma cancer cell lines

Insulin receptor substrate-4 (IRS-4) transmits signals from the insulin-like growth factor receptor (IGF-IR) and the insulin receptor (IR) to the PI3K/AKT and the ERK1/2 pathways. IRS-4 expression increases dramatically after partial hepatectomy and plays an important role in HepG2 hepatoblastoma cell line proliferation/differentiation. In human hepatocarcinoma, IRS-4 overexpression has been associated with tumor development. Herein, we describe the mechanism whereby IRS-4 depletion induced by RNA interference (siRNA) sensitizes HepG2 cells to treatment with actinomycin D (Act D) and combined treatment with Act D plus tumor necrosis factor-alpha (TNF-alpha). Similar results have been obtained in HuH 7 and Chang cell lines. Act D therapy drove the cells to a mitochondrial-dependent apoptotic program involving cytochrome c release, caspase 3 activation, PARP fragmentation and DNA laddering. TNF-alpha amplifies the effect of Act D on HepG2 cell apoptosis increasing c-jun N-terminal kinase (JNK) activity, IkappaB-alpha proteolysis and glutathione depletion. IRS-4 depleted cells that were treated with Act D showed an increase in cytochrome c release and procaspase 3 and PARP proteolysis with respect to control cells. The mechanism involved in IRS-4 action is independent of Akt, IkappaB kinase and JNK. IRS-4 down regulation, however, decreased gamma-glutamylcysteine synthetase content and cell glutathione level in the presence of Act D plus TNF-alpha. These results suggest that IRS-4 protects HepG2 cells from oxidative stress induced by drug treatment.

Hypoxic single-pass isolated hepatic perfusion of hypotonic Cisplatin: safety study in the pig

BACKGROUND

Isolated hepatic perfusion (IHP) of chemotherapy has been proposed to deliver high doses of drug while avoiding systemic toxicity. Hypotonic cisplatin has a high in vitro activity on human colon cancer cells. We studied the safety of a 30-min hypoxic single-pass IHP with hypotonic cisplatin.

METHODS

A preliminary in vitro assay was performed to compare the cytotoxicity of cisplatin and oxaliplatin, in either a normotonic or hypotonic medium. Cisplatin in hypotonic medium was then chosen for the in vivo IHP. Eleven pigs underwent 30 min of IHP with 0, 50, 75, or 100 mg/L of cisplatin in a hypotonic solution under total vascular exclusion of the liver. Clinical and biological parameters were recorded for 30 days, and liver histology was performed at necropsy. The cytotoxic activity of the effluent against resistant human colon cancer cells was tested in vitro.

RESULTS

No hepatic failure was recorded after IHP with cisplatin, but limited foci of necrosis were found at necropsy in animals receiving 75 or 100 mg/L of cisplatin. No clinical, biological, macroscopic, or microscopic toxicity was observed after IHP with 50 mg/L of hypotonic cisplatin. The liver effluent showed high in vitro cytotoxic activity against colon cancer cells.

CONCLUSIONS

A hypoxic single-pass isolated liver perfusion with hypotonic cisplatin is feasible and safe. Effluent from the liver is highly cytotoxic on cancer cells. A clinical study with 50 mg/L of hypotonic cisplatin is warranted in patients with unresectable liver metastases from colon cancer.

Isolated hepatic perfusion for the treatment of liver tumors: sunset or sunrise?

Experience with isolated hepatic perfusion (IHP) is limited to a few centers in the world because of the technical difficulties, surgery-related morbidity, and unproved efficacy in randomized trials. Experimental animal IHP models have led to exploring new ways of improving efficacy, reducing technical difficulties, and minimizing regional and systemic toxicity. Future research should be directed to the identification of suitable biologic or chemotherapeutic agents, defining clinical indications, and development of technical modifications to make it more generally applicable and even repeatable.