Effects of the type of embolization particles on carboplatin concentration in liver tumors after transcatheter arterial chemoembolization in a rabbit model of liver cancer

Clinical Pharmacokinetics and Pharmacodynamics of Transarterial Chemoembolization and Targeted Therapies in Hepatocellular Carcinoma

The management of hepatocellular carcinoma (HCC) is based on a multidisciplinary decision tree. Treatment includes loco-regional therapy, mainly transarterial chemoembolization, for intermediate-stage HCC and systemic therapy with oral tyrosine kinase inhibitors (TKIs) for advanced HCC. Transarterial chemoembolization involves hepatic intra-arterial infusion with either conventional procedure or drug-eluting-beads. The aim of the loco-regional procedure is to deliver treatment as close as possible to the tumor both to embolize the tumor area and to enhance efficacy and minimize systemic toxicity of the anticancer drug. Pharmacokinetic studies applied to transarterial chemoembolization are rare and pharmacodynamic studies even rarer. However, all available studies lead to the same conclusions: use of the transarterial route lowers systemic exposure to the cytotoxic drug and leads to much higher tumor drug concentrations than does a similar dose via the intravenous route. However, reproducibility of the procedure remains a major problem, and no consensus exists regarding the choice of anticancer drug and its dosage. Systemic therapy with TKIs is based on sorafenib and lenvatinib as first-line treatment and regorafenib and cabozantinib as second-line treatment. Clinical use of TKIs is challenging because of their complex pharmacokinetics, with high liver metabolism yielding both active metabolites and their common toxicities. Changes in liver function over time with the progression of HCC adds further complexity to the use of TKIs. The challenges posed by TKIs and the HCC disease process means monitoring of TKIs is required to improve clinical management. To date, only partial data supporting sorafenib monitoring is available. Results from further pharmacokinetic/pharmacodynamic studies of these four TKIs are eagerly awaited and are expected to permit such monitoring and the development of consensus guidelines.

Extracellular pH mapping of liver cancer on a clinical 3T MRI scanner

PURPOSE

To demonstrate feasibility of developing a noninvasive extracellular pH (pH_e ) mapping method on a clinical MRI scanner for molecular imaging of liver cancer.

METHODS

In vivo pH_e mapping has been demonstrated on preclinical scanners (e.g., 9.4T, 11.7T) with Biosensor Imaging of Redundant Deviation in Shifts (BIRDS), where the pH_e readout by 3D chemical shift imaging (CSI) depends on hyperfine shifts emanating from paramagnetic macrocyclic chelates like TmDOTP^5- which upon extravasation from blood resides in the extracellular space. We implemented BIRDS-based pH_e mapping on a clinical 3T Siemens scanner, where typically diamagnetic ¹ H signals are detected using millisecond-long radiofrequency (RF) pulses, and ¹ H shifts span over ±10 ppm with long transverse (T₂ , 10² ms) and longitudinal (T₁ , 10³ ms) relaxation times. We modified this 3D-CSI method for ultra-fast acquisition with microsecond-long RF pulses, because even at 3T the paramagnetic ¹ H shifts of TmDOTP^5- have millisecond-long T₂ and T₁ and ultra-wide chemical shifts (±200 ppm) as previously observed in ultra-high magnetic fields.

RESULTS

We validated BIRDS-based pH in vitro with a pH electrode. We measured pH_e in a rabbit model for liver cancer using VX2 tumors, which are highly vascularized and hyperglycolytic. Compared to intratumoral pH_e (6.8 ± 0.1; P < 10^-9 ) and tumor's edge pH_e (6.9 ± 0.1; P < 10^-7 ), liver parenchyma pH_e was significantly higher (7.2 ± 0.1). Tumor localization was confirmed with histopathological markers of necrosis (hematoxylin and eosin), glucose uptake (glucose transporter 1), and tissue acidosis (lysosome-associated membrane protein 2).

CONCLUSION

This work demonstrates feasibility and potential clinical translatability of high-resolution pH_e mapping to monitor tumor aggressiveness and therapeutic outcome, all to improve personalized cancer treatment planning.

Molecular Imaging of Extracellular Tumor pH to Reveal Effects of Locoregional Therapy on Liver Cancer Microenvironment

PURPOSE

To establish magnetic resonance (MR)-based molecular imaging paradigms for the noninvasive monitoring of extracellular pH (pH_e) as a functional surrogate biomarker for metabolic changes induced by locoregional therapy of liver cancer.

EXPERIMENTAL DESIGN

Thirty-two VX2 tumor-bearing New Zealand white rabbits underwent longitudinal imaging on clinical 3T-MRI and CT scanners before and up to 2 weeks after complete conventional transarterial chemoembolization (cTACE) using ethiodized oil (lipiodol) and doxorubicin. MR-spectroscopic imaging (MRSI) was employed for pH_e mapping. Multiparametric MRI and CT were performed to quantify tumor enhancement, diffusion, and lipiodol coverage of the tumor posttherapy. In addition, incomplete cTACE with reduced chemoembolic doses was applied to mimic undertreatment and exploit pH_e mapping to detect viable tumor residuals. Imaging findings were correlated with histopathologic markers indicative of metabolic state (HIF-1α, GLUT-1, and LAMP-2) and viability (proliferating cell nuclear antigen and terminal deoxynucleotidyl-transferase dUTP nick-end labeling).

RESULTS

Untreated VX2 tumors demonstrated a significantly lower pH_e (6.80 ± 0.09) than liver parenchyma (7.19 ± 0.03, P < 0.001). Upregulation of HIF-1α, GLUT-1, and LAMP-2 confirmed a hyperglycolytic tumor phenotype and acidosis. A gradual tumor pH_e increase toward normalization similar to parenchyma was revealed within 2 weeks after complete cTACE, which correlated with decreasing detectability of metabolic markers. In contrast, pH_e mapping after incomplete cTACE indicated both acidic viable residuals and increased tumor pH_e of treated regions. Multimodal imaging revealed durable tumor devascularization immediately after complete cTACE, gradually increasing necrosis, and sustained lipiodol coverage of the tumor.

CONCLUSIONS

MRSI-based pH_e mapping can serve as a longitudinal monitoring tool for viable tumors. As most liver tumors are hyperglycolytic creating microenvironmental acidosis, therapy-induced normalization of tumor pH_e may be used as a functional biomarker for positive therapeutic outcome.

Theranostic application of lipiodol for transarterial chemoembolization in a VX2 rabbit liver tumor model

The goal of this study was to investigate the role of Lipiodol as a tumor-specific imaging biomarker to determine therapeutic efficacy of cTACE and investigate its inter-dependency with tumor perfusion using radiological-pathological correlation in an animal model of liver cancer.

METHODS

A total of N=36 rabbits were implanted in the left lobe of the liver with VX2 tumors, treated with cTACE using doxorubicin suspended in Lipiodol, and randomly sacrificed at 24 h, 7 days, or 20 days post-TACE. Unenhanced and contrast-enhanced CT scans including a perfusion protocol were obtained before cTACE and immediately before sacrifice. Tumor vascularity and Lipiodol deposition within tumors and hepatic tissue (non-target deposits) were quantified using 3D quantitative assessment tools and measurements of arterial flow, portal flow, and perfusion index (PI). After sacrifice histologic staining, including hematoxylin and eosin (H&E), CD31, and Oil Red O (ORO) were performed on tumor and liver samples to evaluate necrosis, microvascular density (MVD), and Lipiodol retention over time. Transmission electron microscopy (TEM) was performed to assess Lipiodol deposition and clearance over time.

RESULTS

All cTACE procedures were carried out successfully except for one, which was excluded from further analysis. Twenty-four hours post-TACE, tumor PI (p=0.04) was significantly decreased, which was maintained at 7 days (p=0.003), but not at 20 days (p=0.4). A strong correlation (R² = 0.894) was found between the volume of enhancing tumor tissue at baseline and Lipiodol-positive tumor volume post-TACE. Both ORO and TEM showed deposition of Lipiodol across all imaging time points within the VX2 tumors. However, gradual and ultimately near-complete Lipiodol washout was observed over time in the non-tumoral liver. MVD decreased between 24 h and 7 days post-TACE, and then increased 20 days post-TACE (both p<0.01).

CONCLUSIONS

Our data provide radiology-pathology evidence for the function of Lipiodol as a theranostic, tumor-specific drug delivery agent because it is both imageable and tumor-seeking, whereby it is preferentially taken up and retained by tumor cells. Those tumor-specific functions also enable Lipiodol to act as an imaging biomarker for the therapeutic efficacy of cTACE. Together with volumetric quantification of tumor vascularization on CT, Lipiodol could be used as a predictor of a patient's response to cTACE and contribute to the therapeutic management of patients with liver cancer.

Comprehensive Analysis of Factors Affecting Clinical Response and Short-Term Survival to Drug-Eluting Bead Transarterial Chemoembolization for Treatment in Patients With Liver Cancer

This study aimed to investigate the clinical response and short-term survival and further explore the comprehensive factors for predicting clinical outcomes in patients with liver cancer treated by drug-eluting beads transarterial chemoembolization . Forty-nine patients with liver cancer who received drug-eluting beads transarterial chemoembolization treatment were consecutively enrolled in this cohort study. Demographic features, medical histories, clinicopathological properties, biochemical indexes, previous treatments, and chemoembolization reagents were recorded. Ten (20.4%) patients achieved complete response and 31 (63.3%) patients achieved partial response after drug-eluting beads transarterial chemoembolization treatment, with overall response rate of 83.7%. Logistic analysis revealed that high aspartate aminotransferase (P = .041), high carbohydrate antigen 199 (P = .030), and low hemoglobin (P = .020) could independently predict less possibility for complete response achievement. As to survival analysis, high alkaline phosphatase (P = .040), low albumin (P = .033) low hemoglobin (P = .018), portal vein invasion (P = .025), higher Eastern Cooperative Oncology Group performance status (P = .011), and higher Child-pugh stage (P = .001) were independent predictors for worse overall survival. In conclusion, the present study validated that drug-eluting beads transarterial chemoembolization was effective and well tolerated for patients with liver cancer, and high aspartate aminotransferase, high alkaline phosphatase, low albumin, low hemoglobin, portal vein invasion, higher Child-pugh stage, higher Barcelona Clinic Liver Cancer stage, higher Eastern Cooperative Oncology Group performance status were correlated with worse outcomes.

Comparison of pharmacokinetics and drug release in tissues after transarterial chemoembolization with doxorubicin using diverse lipiodol emulsions and CalliSpheres Beads in rabbit livers

CalliSpheres^® Beads (CB) is the first drug-eluting bead (DEB) product in China. Our aim was to compare the effect on the pharmacokinetics of doxorubicin (DOX) and its local concentration between lipiodol emulsions and CB in the process of TACE in rabbit livers. Twenty-five rabbits were distributed into two groups; Group 1 received lipiodol emulsions with DOX, and Group 2 received CB loaded with DOX (CBDOX). DOX was measured in the peripheral blood at different times after treatment. Livers were sampled at 1 week and 1 month for Group 2 after embolization. DOX concentration and distribution were measured in the liver. The administration of DOX by TACE with CBDOX resulted in peripheral blood DOX concentrations of 39.85 ± 13.86 ng/mL at 5 min, with a gradual decrease to 6.89 ± 1.62 ng/mL at 24 h, after treatment. Plasma concentration of DOX after chemoembolization with lipiodol was 225.91 ± 64.88 ng/mL at 5 min and decreased with time by 24 h to 5.06 ± 0.48 ng/mL. In CBDOX group, the drug impregnated an area as far as 200 μm from the bead edge. The tissue concentration of doxorubicin (tissC_DOX) ranged from 40.27 μg/mL to 245.70 μg/mL at 1 week and from 5.64 μg/mL to 28.09 μg/mL at 1 month. Plasma concentrations of DOX resulting from CBDOX embolization were significantly lower than that for cTACE. CB could deliver relatively high concentrations of DOX to an area as far as 200 μm from the bead edge for at least 1 month.

Drug-eluting bead transarterial chemoembolization in the treatment for unresectable soft tissue sarcoma refractory to systemic chemotherapy: a preliminary evaluation of efficacy and safety

PURPOSE

To preliminarily evaluate the clinical efficacy and safety of drug-eluting bead transarterial chemoembolization (DEB-TACE) for unresectable soft tissue sarcoma refractory to systemic chemotherapy.

METHODS

Ten patients with refractory sarcoma who underwent DEB-TACE therapy between January 2015 and January 2017 were identified. Clinical information and radiological data were retrospectively collected to analyze tumor response, overall survival (OS), progression-free survival and adverse events (AEs). Tumor response to DEB-TACE was assessed with modified Response Evaluation Criteria in Solid Tumors (mRECIST) guidelines applied to computed tomography or magnetic resonance imaging.

RESULTS

All DEB-TACE procedures were successfully performed for ten patients with 15 tumor lesions. The median follow-up duration was 19 months and the median survival time was 21 months (range 11-30 months). The 1- and 2-year OS rate was 90 and 30%, respectively. According to the guidance of mRECIST, complete response, partial response, stable disease and progressive disease were noted in zero (0%), three (30%), four (40%) and three (30%) patients, respectively. The disease control rate and objective response rate was 70 and 30%, respectively. There were no serious AEs in patients after DEB-TACE.

CONCLUSIONS

Our data showed that DEB-TACE was effective and safe for patients with soft tissue sarcoma. Therefore, DEB-TACE can be considered as an alternative treatment option for unresectable soft tissue sarcoma refractory to conventionally systemic chemotherapy.

Drug-eluting embolic microspheres for local drug delivery - State of the art

Embolic microspheres or beads used in transarterial chemoembolization are an established treatment method for hepatocellular carcinoma patients. The occlusion of the tumor-feeding vessels by intra-arterial injection of the beads results in tumor necrosis and shrinkage. In this short review, we describe the utility of using these beads as devices for local drug delivery. We review the latest advances in the development of non-biodegradable and biodegradable drug-eluting beads for transarterial chemoembolization. Their capability to load different drugs, such as chemotherapeutics and anti-angiogenic compounds with different physicochemical properties, like charge and hydrophilicity/hydrophobicity, are discussed. We specifically address controlled and sustained drug release from the microspheres, and the resulting in vivo pharmacokinetics in the plasma vs. drug distribution in the targeted tissue.

Modified transarterial chemoembolization with locoregional administration of sorafenib for treating hepatocellular carcinoma: feasibility, efficacy, and safety in the VX-2 rabbit liver tumor model

PURPOSE

We aimed to assess the feasibility, efficacy and safety of a local application of sorafenib within a conventional transarterial chemoembolization in the VX-2 tumor-bearing rabbit model.

METHODS

VX-2 tumors were induced in the left liver lobe of 10 New Zealand White rabbits. After two weeks, growth was verified by contrast-enhanced computed tomography (CT). Five rabbits were treated by transarterial chemoembolization using an emulsion of sorafenib and ethiodized oil (referred to as SORATACE; n=5). Rabbits receiving oral sorafenib for two weeks (n=2) and untreated rabbits (n=3) served as controls. After two weeks, contrast-enhanced CT was performed, followed by animal necropsy.

RESULTS

The change in tumor diameter between baseline and follow-up was significantly different in the SORATACE group compared with the other groups; tumor shrinkage was observed in the SORATACE group only (P = 0.016). In both control groups, preserved hypervascularity was seen in the follow-up CT in all but one tumor. All tumors in the SORATACE group were devascularized in the follow-up CT. Importantly, substantial parenchymal damage in nontargeted areas of the tumor-bearing liver lobe was seen in rabbits treated with SORATACE.

CONCLUSION

SORATACE demonstrated high efficacy in the treatment of experimental VX-2 liver tumors but was also associated with substantial liver parenchymal toxicity.

Pharmacokinetic strategies to improve drug penetration and entrapment within solid tumors

Despite the discovery of a large number of anticancer agents, cancer still remains among the leading causes of death since the middle of the twentieth century. Solid tumors possess a high degree of genetic instability and emergence of treatment resistance. Tumor resistance has emerged for almost all approved anticancer drugs and will most probably emerge for newly discovered anticancer agents as well. The use of pharmacokinetic approaches to increase anticancer drug concentrations within the solid tumor compartment and prolong its entrapment might diminish the possibility of resistance emergence at the molecular pharmacodynamic level and might even reverse tumor resistance. Several novel treatment modalities such as metronomic therapy, angiogenesis inhibitors, vascular disrupting agents and tumor priming have been introduced to improve solid tumor treatment outcomes. In the current review we will discuss the pharmacokinetic aspect of these treatment modalities in addition to other older treatment modalities, such as extracellular matrix dissolving agents, extracellular matrix synthesis inhibitors, chemoembolization and cellular efflux pump inhibition. Many of these strategies showed variable degrees of success/failure; however, reallocating these modalities based on their influence on the intratumoral pharmacokinetics might improve their understanding and treatment outcomes.

Development of a High-Throughput Molecular Imaging-Based Orthotopic Hepatocellular Carcinoma Model

We have developed a novel orthotopic rat hepatocellular (HCC) model and have assessed the ability to use bioluminescence imaging (BLI), positron emission tomography (PET), and ultrasound for early tumor detection and monitoring of disease progression.  Briefly, rat HCC cells were stably transfected with click beetle red as a reporter gene for BLI. Tumor cells were injected under direct visualization into the left or middle lobe of the liver in 37 rats. In six animals, serial PET, BLI, and ultrasound imaging were performed at 10-time points in 28 days. The remainder of the animals underwent PET imaging at 14 days. Tumor implantation was successful in 34 of 37 animals (91.9%). In the six animals that underwent serial imaging, tumor formation was first detected with BLI on Day 4 with continued increase through Day 21, and hypermetabolic activity on PET was first noted on Days 14-15 with continued increase through Day 28. PET activity was seen on Day 14 in the 28 other animals that demonstrated tumor development. Anatomic tumor formation was detected with ultrasound at Days 10-12 with continued growth through Day 28. The first metastases were detected by PET after Day 24.        We have successfully developed and validated a novel orthotopic HCC small animal model that permits longitudinal assessment of change in tumor size using molecular imaging techniques. BLI is the most sensitive imaging method for detection of early tumor formation and growth. This model permits high-throughput in vivo evaluation of image-guided therapies.

Rabbit hepatic arterial anatomy variations: implications on experimental design

BACKGROUND

The VX2 rabbit model of liver cancer is commonly used to evaluate the efficacy of locoregional anticancer therapy and knowledge of the hepatic arterial anatomy in the rabbit is important for catheter-directed experiments.

PURPOSE

To describe the normal anatomy and anatomic variations of the celiac axis and hepatic artery in the rabbit.

MATERIAL AND METHODS

Angiograms of 222 rabbits were retrospectively reviewed. The branching pattern of the celiac axis was classified and the diameters of the major branches were measured. Paired t-tests were used to compare the difference between the average sizes of arteries.

RESULTS

Variant celiac axis or hepatic artery anatomy was noted in 25.9% of angiograms, with the gastric branches arising from the proper hepatic artery in 23.3% of cases. The celiac axis could be successfully classified into one of five distinct branching patterns in 193 (86.9%) cases. The mean diameters of the right and left hepatic arteries were 0.67 mm (95% CI [0.64, 0.7]) and 1.25 mm (95% CI [1.19, 1.31]), respectively. The mean diameters of the medial and lateral branches of the left hepatic artery were 0.63 mm (95% CI [0.6, 0.67]) and 0.91 mm (95% CI [0.86, 0.96]), respectively. The right hepatic artery was significantly smaller than the left hepatic artery and the lateral branch of the left hepatic artery (all P values <0.0001).

CONCLUSION

Arterial variants in the rabbit are not uncommon. The proper hepatic artery often gives origin to gastric artery branches. To facilitate superselective intra-arterial intervention, the left lateral lobe of the liver should be targeted for tumor implantation because of the significant size difference between the right and left hepatic arteries.

Effect of transcatheter intraarterial therapies on the distribution of Doxorubicin in liver cancer in a rabbit model

Background and Aims

Transcatheter intraarterial techniques can effectively deliver chemotherapeutic agents to tumor and improve the efficacy of chemotherapy. The present study is designed to evaluate the effect of transcatheter intraarterial techniques on the distribution of doxorubicin in relation to blood vessels in liver cancer.

Methods

VX2 tumors were implanted in the livers of 32 rabbits. The animals were divided into 4 groups of 8 animals each. Group 1 (doxo iv) animals received doxorubicin intravenous injection; group 2 (doxo ia) received doxorubicin hepatic intraarterial infusion; group 3 (doxo ia + E) received doxorubicin hepatic intraarterial infusion followed by embolization; group 4 (doxo + L ia + E) received hepatic intraarterial infusion of doxorubicin mixed with Lipiodol followed by embolization. Ten minutes or 4 hours after treatment, the animals were sacrificed and tumors were sampled. Immunofluorescence techniques were used to evaluate the distribution of doxorubicin in relation to blood vessels.

Results

Doxorubicin fluorescence was distributed around tumor blood vessels and decreased with distance from the blood vessels. Tumor cells in avascular and adjacent regions were not exposed to detectable concentrations of doxorubicin. Tumors in the group 2, 3 and 4 had a significant increase in doxorubicin penetration compared with the group 1 tumors (P<0.05). Among the three groups of transcatheter therapies, doxorubicin penetration distance in group 3 was significantly larger than that in group 2 and 4 (P<0.05), and no significant difference was found between group 2 and 4 tumors (P>0.05) at 10 minutes. In contrast, at 4 hours and in total, both group 3 and 4 tumors had significant increases in drug penetration compared with group 2 (P<0.05), and no significant difference was noted between group 3 and 4 tumors (P>0.05).

Conclusion

Transcatheter intraarterial therapies improve doxorubicin penetration in liver cancer; nevertheless their effect on drug distribution is somewhat limited.

Hepatic embolotherapy in interventional oncology: technology, techniques, and applications

Embolotherapy continues to play a growing role in the management of primary and secondary hepatic malignancies. In this review article, we examine the basis of therapy with a focus on neovascularization, which makes treatments via the hepatic artery possible. An overview of the three generations of embolic and therapeutic agents follows. The techniques, technologies, and complications of bland embolization, transarterial chemoembolization, drug-eluting beads, and selective internal radiotherapy are covered to give the reader an overview of this exciting field in interventional radiology.

Imaging of HCC

Imaging techniques play a crucial role in the management of patients with liver cirrhosis in whom a nodular hepatic lesion is detected. The most severe complication of patients with liver cirrhosis is the development of a hepatocellular carcinoma (HCC), and the prognosis of the disease depends on the tumoral stage. Surveillance programs based on ultrasonography (US) are recommended in cirrhotic patients with possibility to be treated if an HCC is detected, in order to improve the patient's survival. Nevertheless, early detection and diagnostic confirmation of HCC remains a challenge despite technological advances. The non-invasive criteria to characterize small HCCs in patients with cirrhosis are based on the evaluation of the vascular profile of the lesion. Dynamic multidetector computed tomography (MDCT) and dynamic magnetic resonance imaging (MRI) are the suitable techniques for this purpose. When diagnosis is not achieved, fine US-guided fine needle biopsy (FNB) is indicated. Cellular-MRI contrast agents may have a role in lesions with atypical vascular pattern in which FNB is not feasible. The assessment of the disease extent is another important goal for imaging techniques. Again, dynamic MDCT and dynamic MRI may be used for staging purposes. Although MRI is more accurate in the detection of additional nodules ranging 1-2 cm, both remain relatively insensitive for the detection of tiny satellite nodules below 1 cm. The therapeutic decision can be made in any particular patient on the basis of the tumoral extension, the liver function, and the general status. After curative and palliative therapeutic procedures, the monitoring of the response is mandatory to decide the next approach: to follow-up, to repeat the treatment, to modify the treatment indication, or to suspend the treatment. In this review, we discuss the most recent information on the imaging of HCC.

Drug delivery embolization systems: a physician's perspective

INTRODUCTION

The number of patients suffering from primary and secondary liver tumoral diseases is on the increase worldwide. The development of new technologies and drugs requires an increasingly multidisciplinary approach in the management of these diseases. Therapies should be based on scientifically supported guidelines and at the same time should be designed to suit the individual patient. In this decision-making process, an understanding of the advantages and disadvantages of every treatment is very important. The efficacy of transarterial chemoembolization (TACE) in improving survival and its role in the management of hepatocellular carcinoma (HCC) have been demonstrated in several clinical trials. The introduction of drug-eluting beads seems to have overcome some of the limitations of conventional TACE.

AREAS COVERED

This review provides an overview of the spread of primary and secondary liver cancers, then it explains the basis for the use of conventional TACE and its potential benefits and, finally, outlines its clinical application and possible future uses.

EXPERT OPINION

The management of the treatment of focal liver lesions is a difficult process, which must involve various specialists such as the interventional radiologist. The use of drug-eluting microspheres seems to improve the results of TACE both in HCC and in colorectal liver metastases.

Transcatheter arterial chemoembolization for liver cancer: is it time to distinguish conventional from drug-eluting chemoembolization?

Conventional transcatheter arterial chemoembolization and chemoembolization with drug-eluting beads are increasingly being performed interchangeably in many institutions throughout the world. As both therapies continue to being tested in many phase II and III studies and in combination with other therapies, especially targeted agents, for treatment of primary and metastatic liver cancer, it is imperative to review their current status and evaluate their impact on patient survival. This review critically assesses patient selection, indications, contraindications, techniques, materials, safety, and clinical outcomes of patients treated with conventional chemoembolization and chemoembolization with drug-eluting beads.

Influence of hepatic artery occlusion on tumor growth and metastatic potential in a human orthotopic hepatoma nude mouse model: relevance of epithelial-mesenchymal transition

Hepatic artery ligation (HAL), transarterial embolization (TAE), and transarterial chemoembolization (TACE) have been treatment choices for unresectable hepatocellular carcinoma (HCC). Obstruction of tumor blood supply is one of the most important mechanisms of these therapeutics measures. Here we introduced HAL into a metastatic human HCC orthotopic nude mouse model (using MHCC97L and HepG2 cell lines) to examine the effects of hepatic blood flow obstruction on the metastatic potential of hepatic tumor cells, and to investigate the mechanisms underlying these effects. Our results indicated that HAL inhibited tumor growth but concomitantly elicited tumor adaptation and progression, with increased potential for invasion and distant metastases. The underlying proinvasive mechanism of HAL appeared to be associated with enhanced intratumoral hypoxia and epithelial-mesenchymal transition (EMT) due to hypoxia. This was in accord with the in vitro response of MHCC97L and HepG2 cells to hypoxia. The therapeutic effects of HAL could be enhanced by the phosphatidyl inositol 3-kinase (PI3K) inhibitor LY294002, through arrest of EMT in hepatic tumor cells. It could be useful in the development of mechanism-based combination therapies to enhance the initial antitumor response.

Considerations for implantation site of VX2 carcinoma into rabbit liver

PURPOSE

To assess whether the implantation site of VX2 carcinoma into rabbit liver affects successful vessel selection for transcatheter arterial interventions.

MATERIALS AND METHODS

Twenty-four New Zealand White rabbits were randomly assigned to two groups. All implantations were performed by open laparotomy with minced tumor cells inserted into a 16-gauge Angiocath needle. Group I rabbits (n = 12) had tumor implanted into the left medial lobe of the liver and group II rabbits (n = 12) had tumor implanted into the left lateral lobe. Two weeks after implantation, selective angiography was performed for subsequent chemoembolization, which was part of a different study. Tested variables included maximum tumor diameter, tumor feeding artery size, and tumor vascularity.

RESULTS

Successful tumor growth was achieved in all rabbits. Selective angiography was possible in 33.3% of rabbits in group I and 66.6% of rabbits in group II (P < .05). Tumor size and vascularity were similar between groups. Mean lengths of tumor feeder arteries from the bifurcation of the left hepatic artery were 4.1 mm +/- 1.2 in group I (left medial lobe) and 10.8 mm +/- 3.0 in group II (left lateral lobe; P < .05). The angulation of the left medial lobar artery (group I) off the left hepatic artery was acute in eight of 12 rabbits (66.6%), but only four of 12 rabbits in group II (33.3%) showed acute angulation of the left lateral lobar artery off the left hepatic artery (P < .05). Mean angiography time was significantly shorter in group II.

CONCLUSIONS

For selective hepatic arterial interventions, the left lateral lobe of the liver may be favorable as an implantation site for VX2 tumors in rabbits.

Microspheres and nonspherical particles for embolization

Last years, calibrated microspheres have proven their superiority in targeting embolization over non spherical particles in many applications. For the very near future they represent the best tool for controlling drug delivery in chemoembolization, under the two conditions that they would be image detectable and that the "dosimetry" would be tailored to pathological process.

Optimal strategies for combining transcatheter arterial chemoembolization and radiofrequency ablation in rabbit VX2 hepatic tumors

PURPOSE

To determine the optimum combination strategy of transcatheter arterial chemoembolization and radiofrequency (RF) ablation in an experimentally induced hepatic tumor model.

MATERIALS AND METHODS

Twenty-five New Zealand White rabbits with VX2 carcinoma-induced hepatic tumors were randomly divided into five treatment groups, which received (i) chemoembolization followed 15 minutes later by RF ablation; (ii) RF ablation followed by chemoembolization; (iii) chemoembolization alone; (iv) RF ablation alone; and (v) bland embolization followed by RF ablation. Animals were euthanized at 48 hours to determine tumor infarction and coagulation, which were compared with analysis of variance. Representative histopathologic slides were compared.

RESULTS

Significantly larger areas of coagulation were produced by chemoembolization followed by RF ablation (22.0 cm(3) +/- 7.7) compared with RF ablation followed by chemoembolization (13.1 cm(3) +/- 3.2) and RF ablation alone (10.0 cm(3) +/- 4.5; P < .05). RF ablation followed by chemoembolization showed larger treatment areas than chemoembolization alone (25.0 cm(3) +/- 9.6 vs 12.1 cm(3) +/- 4.6; P < .001), with chemotherapeutic agent preferentially depositing around the coagulation zone. Histopathologic analysis revealed greater vascular thrombosis and necrosis and reduced islands of viable tumor cells in the chemoembolization/RF ablation group versus the groups treated with chemoembolization alone or bland embolization/RF ablation.

CONCLUSIONS

Larger treatment volumes were produced when chemoembolization was performed before RF ablation than when RF ablation preceded chemoembolization or when RF ablation or chemoembolization were performed alone. Larger treatment volumes were also produced when chemoembolization rather than bland embolization was performed before RF ablation, indicating the importance and synergy of the chemotherapeutic regimen. These results suggest that the reduction of tumor blood flow combined with the effect of hyperthermia and local chemotherapy creates the largest dimensions of treatment.

Percutaneous US-guided implantation of Vx-2 carcinoma into rabbit liver: a comparison with open surgical method

PURPOSE

To evaluate technical feasibility and experimental usefulness of percutaneous US-guided implantation of Vx-2 carcinoma in rabbit liver.

MATERIALS AND METHODS

Forty-eight New Zealand White male rabbits were used. Solid tumor mass of Vx-2 carcinoma was harvested from carrier rabbit, and minced tumor cells were implanted. Twenty-four rabbits underwent percutaneous US-guided tumor implantation, and the same number of rabbits underwent open laparotomy tumor implantation. Tested parameters included technical success, procedural time, amount of anesthesia, recovery time, complications, tumor size, and regional tumor seeding.

RESULTS

A new percutaneous US-guided implantation was technically feasible in all rabbits. Evaluation parameters showed that the percutaneous US-guided implantation method is less invasive than the open laparotomy method. Targeting rate for left lateral lobe of implantation site was comparable in both methods (91.7% of percutaneous US-guided; 95.8% in open laparotomy). The success rate of tumor growth in the liver was 100% in both groups. However, in the group with US-guidance, tumor seeding developed more frequently in five of 24 rabbits (20.8%) than in open laparotomy group (2/24, 8.3%). Five rabbits had thoracoabdominal wall needle tract seeding, and two rabbits had tumor seeding at both thoracoabdominal wall and intraperitoneal space.

CONCLUSIONS

Percutaneous US-guided implantation of Vx-2 carcinoma in rabbit liver is a less invasive alternative to open laparotomy, achieving equally successful tumor growth in the liver. Although percutaneous US-guidance implantation method may not be considered for long-term survival study design because of the possibility of tumor seeding, it can be considered for nonsurvival study design.

Distribution of iron oxide-containing Embosphere particles after transcatheter arterial embolization in an animal model of liver cancer: evaluation with MR imaging and implication for therapy

PURPOSE

To test whether different-sized iron oxide-containing Embosphere (IOE) particles can be detected by dedicated magnetic resonance (MR) imaging when injected intraarterially in an animal model of liver cancer and whether their distribution could be accurately predicted by MR imaging before confirmation with histopathologic analysis.

MATERIALS AND METHODS

Twenty New Zealand White rabbits implanted with VX2 liver tumor were randomly assigned to undergo embolization with 100-300-microm particles (group S; n = 10) or 300-500-microm particles (group L; n = 10). Embolization was performed with the catheter placed in the proper hepatic artery. T2*-weighted multiplanar MR imaging was performed within 24 hours after the procedure to detect paramagnetic IOE susceptibility artifact. MR imaging interpretation parameters included presence of artifact in the artery and/or at the tumor bed. Hematoxylin and eosin- and Prussian blue-stained pathologic slides were also obtained and the presence of IOE was evaluated similarly.

RESULTS

The MR detectability rates for IOEs were 100% in both groups. Paramagnetic susceptibility IOE artifact inside the tumor was detected in 30% of group S animals. On pathologic analysis, IOE particles were detected inside the tumor in 70% of this group. IOEs in group L were found outside the tumor within the hepatic artery on MR imaging and histopathologic study (P < .05).

CONCLUSIONS

MR imaging readily detected IOE particles in an animal model of liver cancer regardless of the particle size. The smaller particles (100-300 microm) were delivered inside the tumor or in close proximity to the tumor margin, justifying their use for drug delivery or precise embolization.

Transarterial chemoembolization for hepatocellular carcinoma with drug-eluting microspheres: preliminary results from an Italian multicentre study

The purpose of this article is to present the early results of a multicentre trial using HepaSphere microspheres loaded with chemotherapeutic agents for transarterial chemoembolization (TACE) in patients with unresectable hepatocellular carcinoma. From December 2005 to March 2007, 50 patients (36 male and 14 female, mean age 68.4 years) were treated by selective TACE using HepaSphere microspheres loaded with doxorubicin or epirubicin. The diameter of the treated lesions ranged from 20 to 100 mm (mean 42.5; maximum of 4 tumor nodules). Tumor response was evaluated by computed axial tomography according to the World Health Organization criteria as modified by the European Association for the Study of Liver Diseases. All of the procedures were technically successful, and there were no major complications. At 1-month follow-up, complete tumor response was observed in 24 of 50 (48%), partial response in 18 of 50 (36%), and stable disease in 8 of 50 (16%) patients, and there were no cases of disease progression. At 6-month follow-up (31 of 50 patients), complete tumor response was obtained in 16 of 31 (51.6%), partial response in 8 of 31 (25.8%), and progressive disease in 7 of 31 (22.6%) patients. Within the initial 9-month follow-up, TACE with HepaSphere was successfully repeated twice in 3 patients, whereas 3 patients underwent the procedure 3 times. Our initial multicentre experience demonstrates that TACE using HepaSphere is feasible, is well tolerated, has a low complication rate, and is associated with promising tumor response. When complete tumor response in not achieved, additional treatments can be performed without difficulties. Longer follow-up on larger series is mandatory to confirm these preliminary results.

Evaluation of different calibrated spherical polyvinyl alcohol microspheres in transcatheter arterial chemoembolization: VX2 tumor model in rabbit liver

PURPOSE

To assess whether porosity and compressibility of calibrated spherical polyvinyl alcohol (PVA) microspheres affect doxorubicin plasma and tumor concentrations after transcatheter arterial chemoembolization (TACE) in a VX2 rabbit model.

MATERIALS AND METHODS

Fifteen rabbits were divided into three groups of five rabbits each. Three different types of calibrated spherical PVA microspheres with variable levels of porosity and compressibility were blindly evaluated. TACE was performed by injecting a mixture of doxorubicin (5 mg) and iodized oil (0.5 mL) followed by injection of the embolic material (0.3-0.5 mL). Plasma concentrations of doxorubicin and doxorubicinol were analyzed 20, 40, 60, and 120 minutes and 2 days after TACE, and liver tissue and tumor doxorubicin concentrations were measured 2 days after TACE.

RESULTS

All calibrated spherical PVA microspheres showed similar patterns of plasma doxorubicin and doxorubicinol release and tumor concentration of doxorubicin. There were no significant differences of drug levels in either plasma or tumor in each group (P > .05).

CONCLUSIONS

After TACE in a rabbit model of liver cancer, testing of three different types of spherical PVA microspheres with varying degrees of porosity and compressibility showed no significant differences in the plasma doxorubicin release pattern and tumor doxorubicin uptake.

A comparison of chemoembolization endpoints using angiographic versus transcatheter intraarterial perfusion/MR imaging monitoring

PURPOSE

Transcatheter arterial chemoembolization (TACE) is an established treatment for unresectable liver cancer. This study was conducted to test the hypothesis that angiographic endpoints during TACE are measurable and reproducible by comparing subjective angiographic versus objective magnetic resonance (MR) endpoints of TACE.

MATERIALS AND METHODS

The study included 12 consecutive patients who presented for TACE for surgically unresectable HCC or progressive hepatic metastases despite chemotherapy. All procedures were performed with a dedicated imaging system. Angiographic series before and after TACE were reviewed independently by three board-certified interventional radiologists. A subjective angiographic chemoembolization endpoint (SACE) classification scheme, modified from an established angiographic grading system in the cardiology literature, was designed to assist in reproducibly classifying angiographic endpoints. Reproducibility in SACE classification level was compared among operators, and MR imaging perfusion reduction was compared with SACE levels for each observer.

RESULTS

Twelve patients successfully underwent 15 separate TACE sessions. SACE levels ranged from I through IV. There was moderate agreement in SACE classification (kappa = 0.46 +/- 0.12). There was no correlation between SACE level and MR perfusion reduction (r = 0.16 for one operator and 0.02 for the other two).

CONCLUSIONS

Angiographic endpoints during TACE vary widely, have moderate reproducibility among operators, and do not correlate with functional MR imaging perfusion endpoints. Future research should aim to determine ideal angiographic and functional MR imaging endpoints for TACE according to outcome measures such as imaging response, pathologic response, and survival.

Irinotecan drug eluting beads used as a treatment of advanced intra hepatic cholangiocarcinoma

This report describes a 74-year-old male with unresectable intrahepatic cholangiocarcinoma (ICC). However surgical procedure is the only curative treatment, it often seems to be ineffective because of the aggressive behaviour of the disease. The role of systemic chemotherapy in the ICC is undefined with a median survival between 6.43 to 12.17 months obtained by using the combination chemotherapy of gemcitabine with cisplatin. In the present case, we performed a targeted treatment using drug eluting beads (DEB) with irinotecan (IRI) administered as transarterial-chemoembolization (TACE). After one session, the tumour vascularity decreased significantly at the one month evaluation on computed tomography (CT) scan of the liver. This case report suggested that minimally invasive transcatheter DEB embolization could be a promising, safe and effective treatment for selective patients with unresectable ICC.

Chemoembolization of hepatocellular carcinoma with drug eluting beads: efficacy and doxorubicin pharmacokinetics

BACKGROUND/AIMS

This study assesses the safety, pharmacokinetics and efficacy of transarterial chemoembolization using drug eluting beads (DEB), an embolizing device that slowly releases chemotherapy to decrease systemic toxicity.

METHODS

Twenty-seven Child-Pugh A cirrhotics (76% male, 59% HCV) with untreated large/multifocal HCC received chemoembolization with doxorubicin loaded DEBs at doses adjusted for bilirubin and body surface (range: 47-150 mg). Clinical and analytical data were recorded at 24 and 48 h, 7, 14 and 30 days after first and second TACE. Response rate was assessed by CT at 6 months. Blood samples were obtained in 13 patients at 5, 20, 40, 60, 120 min, 6, 24, 48 and 168 h to determine doxorubicin Cmax and AUC.

RESULTS

DEB-TACE was well tolerated with an acceptable safety profile. Two cases developed liver abscess, one leading to death. Response rate was 75% (66.6% on intention-to-treat). Doxorubicin Cmax and AUC were significantly lower in DEB-TACE patients (78.97+/-38.3 ng/mL and 662.6+/-417.6 ng/mLmin) than in conventional TACE (2341.5+/-3951.9 ng/mL and 1812.2+/-1093.7 ng/mLmin, p=0.00002 and p=0.001, respectively). After a median follow-up of 27.6 months, 1- and 2-year survival is 92.5% and 88.9%, respectively.

CONCLUSIONS

Chemoembolization using DEBs is an effective procedure with a favorable pharmacokinetic profile.