In Vivo Evaluation of a New Embolic Spherical Particle (HepaSphere) in a Kidney Animal Model

Effects of HepaSphere microsphere encapsule epirubicin with a new loading method transarterial chemoembolization: in vitro and in vivo experiments

METHODS

HS microspheres were loaded in a solution of hypertonic saline and contrast medium at different ratios. Morphology, size distribution, and drug loading capacity of the microsphere were evaluated. Rabbits with hepatic VX2 tumors underwent conventional TACE, drug-eluting beads TACE with HS microsphere loading epirubicin by recommended method (dTACE) or a new loading method (ndTACE). The plasma and tissue epirubicin concentration, tumor necrosis, and the microsphere distribution within the tumor were assessed.

RESULTS

It was found that the mean diameter of HS microspheres was effectively reduced to 102 ± 14 μm after loading with 10.0% NaCl and Ultravist (370 mg I /mL) at a ratio of 2: 8 ml. The loading capacity reached 78.7%. It was noted that the concentration of tumor epirubicin was significantly higher (p = 0.016) in the ndTACE group (11,989.8 ± 5776.6 ng/g) than the concentration in the dTACE (6516.5 ± 3682.3 ng/g) and in cTACE groups (1564.1 ± 696.1 ng/g, p < 0.001). Further, the tumor necrosis in group with the new loading method (ndTACE) was 92.4%.

CONCLUSIONS

The size of HS microsphere can be effectively reduced when it is loaded with a mixture of hypertonic saline and non-ionic contrast material. HS microsphere loaded with epirubicin using the new method (ndTACE) can increase the drug concentration in tumor and hence exert better improved antitumor effect.

Microspheres as a Carrier System for Therapeutic Embolization Procedures: Achievements and Advances

The targeted delivery of anti-cancer drugs and isotopes is one of the most pursued goals in anti-cancer therapy. One of the prime examples of such an application is the intra-arterial injection of microspheres containing cytostatic drugs or radioisotopes during hepatic embolization procedures. Therapy based on the application of microspheres revolves around vascular occlusion, complemented with local therapy in the form of trans-arterial chemoembolization (TACE) or radioembolization (TARE). The broadest implementation of these embolization strategies currently lies within the treatment of untreatable hepatocellular cancer (HCC) and metastatic colorectal cancer. This review aims to describe the state-of-the-art TACE and TARE technologies investigated in the clinical setting for HCC and addresses current trials and new developments. In addition, chemical properties and advancements in microsphere carrier systems are evaluated, and possible improvements in embolization therapy based on the modification of and functionalization with therapeutical loads are explored.

Long-term Histopathologic Follow-up of a Spherical Embolic Agent; Observation of the Transvascular Migration of HepaSphereTM

Very few studies have been published on the long-term histopathologic follow-up of spherical embolic agents after their injection. To our knowledge, there are no reports in the literature regarding pathological analysis of the transvascular migration of HepaSphere particles. We here report a case of a patient with hepatocellular carcinoma (HCC) who underwent liver transplantation 12 months after drug eluting microsphere transcatheter arterial chemoembolization (DEM-TACE), and long-term histopathologic follow-up of the microspheres was performed. Furthermore, to our knowledge, this is the first report in which transvascular migration of a HepaSphere particle was confirmed histologically. A 60-year-old male with chronic hepatitis B was treated with entecavir and seroconversion was obtained. The patient had decompensated cirrhosis, and desired to undergo living donor liver transplantation (LDLT). However, 2 HCC tumors of 3  cm or less were detected in his liver. The transplantation surgeon proposed DEM-TACE as a bridge therapy. The HCCs were located in the right lobe and lateral segment of the liver. A 1.9  F preshaped microcatheter (ProgreatΣ, Terumo, Japan) was selectively inserted into the A3 and anterior segmental branch, 10  mg of epirubicin was injected into each artery, and the arteries were embolized with 7  mg and 13  mg of HepaSphere loaded with epirubicin, respectively. Two months later, contrast-enhanced CT displayed a complete response. At that time, lung metastasis was suspected, but after partial lung resection, the patient was diagnosed as having inflammatory granuloma. One year after DEM-TACE treatment, LDLT was performed. No cancerous cells were detected in the area where the tumor was present, but 22 HepaSphere particles were detected. All particles were present in the interstitium. Furthermore, the transvascular migration of a HepaSphere particle was histologically confirmed. The largest and smallest HepaSphere diameters were 241.6  ±  52.5  µm and 186.5  ±  41.4  µm, respectively, and deformity was 22.6% ± 13.0 %. All the HepaSpheres detected in the examined pathological specimen were noted to be extravascular.

DEB-TACE: a standard review

Drug-eluting bead transarterial chemoembolization (DEB-TACE) is a relative new endovascular treatment based on the use of microspheres to release chemotherapeutic agents within a target lesion with controlled pharmacokinetics. This aspect justifies the immediate success of DEB-TACE, that nowadays represents one of the most used treatments for unresectable hepatocellular carcinoma. However, there is no consensus about the choice of the best embolotherapy technique. In this review, we describe the available microspheres and report the results of the main comparative studies, to clarify the role of DEB-TACE in the hepatocellular carcinoma management. We underline that there is no evidence about the superiority of DEB-TACE over conventional TACE in terms of efficacy, but there may be some benefits with respect to safety especially with the improvement of new technologies.

Safety and efficacy of doxorubicin-eluting superabsorbent polymer microspheres for the treatment of liver metastases from neuroendocrine tumours: preliminary results

Background

The aim of the study was to retrospectively evaluate the symptom control, tumour response, and complication rate in patients with liver-predominant metastatic neuroendocrine tumours treated with transarterial chemoembolization using doxorubicin-eluting superabsorbent polymer (SAP) microspheres.

Patients and methods

Patients with neuroendocrine liver metastases who underwent hepatic transarterial chemoembolization using doxorubicin-eluting SAP-microspheres (50–100 μm Hepasphere/Quadrasphere Microsphere® particles, Merit Medical, South Jordan, Utah, USA) were included in this study. Pre-and post-procedure imaging studies were evaluated to assess short and intermediate-term tumour response using modified RECIST criteria. Symptom relief and procedure-related complications were evaluated.

Results

A total of 27 embolization procedures were performed on 17 patients. Twelve of 17 patients (70%) were symptomatic, including carcinoid syndrome (n = 8) and severe, uncontrollable hypoglycemia (n = 4). Eight of 12 patients (67%) had complete symptom relief, and the remaining 4 (33%) had partial relief. One patient developed ischemic cholecystitis (6%). No other hepatobiliary complications occurred. Short-term and intermediate-term imaging follow-up was available for 15/17 patients (88%) and 12/14 patients (86%) respectively. At short-term follow-up (< 3 months), 14 patients (93%) showed partial response and the remaining patient had progressive disease (7%). At intermediate-term imaging follow-up (> 3 months), partial response, stable disease and progressive disease were found respectively in 7 (58%), 3 (25%) and 2 (17%) patients.

Conclusions

Chemoembolization with doxorubicin-eluting SAP-microspheres is a safe and effective treatment option for neuroendocrine liver metastases and is associated with a low complication rate. In particular, no clinically evident liver necrosis or bile duct complications were encountered.

Short-term efficacy of transarterial chemoembolization with epirubicin-loaded superabsorbent polymer microspheres for hepatocellular carcinoma: comparison with conventional transarterial chemoembolization

PURPOSE

This study aimed to compare the short-term efficacy of transarterial chemoembolization (TACE) with epirubicin-loaded superabsorbent polymer embolics (SAP) and conventional TACE in TACE-naïve patients with unresectable hepatocellular carcinoma (HCC).

METHODS

Fifty consecutive patients (mean age, 72.8 years; hepatitis C, 46%; BCLC-A or B, 52% or 48%) treated with TACE with SAP during 2013-2015 and 55 consecutive patients (mean age, 71.8 years; hepatitis C, 40%; BCLC-A or B, 51% or 49%) treated with conventional TACE during 2011-2013 were evaluated. Safety evaluations were based on CTCAE ver. 4.0. Short-term efficacies, i.e., at 1 month after TACE, were assessed using the European Association for the Study of the Liver criteria. Overall survival rates were calculated using the Kaplan-Meier method. Short-term response markers were analyzed by univariate and multivariate analyses.

RESULTS

There was no significant difference in the incidence of any grade of adverse events. The objective response rates were 50% and 62% in patients treated with TACE with SAP and with conventional TACE, respectively (P = 0.358). The overall survival rates were not significantly different (P = 0.810); the 1-year survival rates and the median survival time of the patients treated with TACE with SAP and with conventional TACE were 76% and 74%, and 18 months and 21 months, respectively. Overall survival was related to the short-term response. An alpha-fetoprotein level <1,000 ng/mL was a significant short-term response marker on multivariate analysis.

CONCLUSIONS

For TACE-naïve patients, TACE with SAP and conventional TACE had comparable safety and short-term efficacies.

Transcatheter arterial chemoembolization with spherical embolic material for locally advanced breast cancer: first report of HepaSphere™ treatment for primary breast cancer

A 57-year-old female was diagnosed as having primary breast cancer (invasive carcinoma of no special type), which was immunohistochemically negative for oestrogen receptor, androgen receptor and human epidermal growth factor receptor Type 2. The main tumour was 54 × 35 mm in size and was located in the internal upper area of the left breast. The tumour had markedly invaded the skin and a daughter nodule was observed in the external upper area of the ipsilateral breast. An enlarged lymph node measuring 12mm in diameter was present in the axilla and an affected parasternal lymph node was also observed. A blood test showed no abnormalities and the patient was negative for tumour markers. We performed three sessions of transcatheter arterial chemoembolization with docetaxel-loaded HepaSphere™. The treatment procedure was successfully performed in all the three sessions. No adverse events higher than Grade 3 were observed. The sizes of the primary lesion and axillary lymph node decreased to 26 × 14 mm (37% reduction) and 10mm, respectively. The parasternal lymph node completely resolved. 2 months later, left total mastectomy and axillary lymph node dissection were performed. The histopathological post-therapy effect was considered to be a mild response (Grade 1a) in the breast lesion and a complete response (Grade 3) in the axillary lymph node. The mean±standard deviation of the minor axis of the vessels embolized with spherical particles was 183.0±96.5 μm. Our results indicate that transcatheter arterial chemoembolization used together with HepaSphere can be an alternative and effective therapy for locally advanced breast cancer.

Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres

BACKGROUND

Intra-arterial brachytherapy with yttrium-90 (⁹⁰Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of ⁹⁰Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model.

METHODS

In each of six pigs, ~25-33 % of the kidney volume was embolized with ⁹⁰Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8-9 weeks after the procedure to assess the locations of the microspheres and extent of tissue necrosis from ⁹⁰Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed.

RESULTS

Kidneys embolized with ⁹⁰Y-radioembolization decreased in mass by 30-70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the ⁹⁰Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 10⁶) of bland microspheres.

CONCLUSION

This study showed that radioembolization with ⁹⁰Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of ⁹⁰Y resin microspheres for the localized treatment of kidney tumors.

A Single-Center Retrospective Comparison of Doxorubicin-Loaded HepaSphere Transarterial Chemoembolization with Conventional Transarterial Chemoembolization for Patients with Unresectable Hepatocellular Carcinoma

PURPOSE

To compare doxorubicin-loaded HepaSphere transarterial chemoembolization versus conventional transarterial chemoembolization in terms of survival, time to recurrence, acute reversible hepatotoxicity, postembolization syndrome, and chemoembolization-related mortality and morbidity.

MATERIALS AND METHODS

One hundred twenty-six patients (103 men, 23 women; mean age, 64.3 y) with unresectable hepatocellular carcinoma (HCC) who underwent conventional chemoembolization between January 2007 and March 2011 or drug-eluting embolic (DEE) chemoembolization (after the protocol change) between March 2011 and October 2014 were included in a retrospective analysis. Primary outcome measures were survival and time to recurrence. Secondary outcome measures were frequency of recurrence, technical success, acute reversible hepatotoxicity, postembolization syndrome, and chemoembolization-related mortality and morbidity.

RESULTS

The technical success rate was 97.1%. There were no significant differences between the conventional and DEE chemoembolization groups with regard to mean survival duration (39.0 vs 37.4 mo), recurrence (32.9% vs 39.6%), postembolization syndrome (90% vs 89%), and chemoembolization-related mortality (5.5% vs 1.9%) and morbidity (9.6% vs 9.4%; P > .05). The time to recurrence was shorter in DEE chemoembolization-treated patients than in conventional chemoembolization-treated patients (5.0 vs 11.5 mo; P = .006), and acute reversible hepatotoxicity occurred more frequently after conventional chemoembolization (P = .019).

CONCLUSIONS

Conventional chemoembolization and DEE chemoembolization were safe and effective interventions for unresectable HCC. DEE chemoembolization was not better than conventional chemoembolization in terms of survival and was associated with a shorter time to recurrence. Acute reversible hepatotoxicity occurred more frequently after conventional chemoembolization.

Chemoembolization of hepatocellular carcinoma with HepaSphere™

This review discusses the current data on Hepasphere™ in the treatment of hepatocellular carcinoma. HepaSphere is a drug-loadable microsphere that can be bound with doxorubicin, epirubicin, cisplatin or oxaliplatin. In vitro and in vivo studies confirm lower systemic exposure to the drug and fewer systemic doxorubicin-related side effects. Studies suggest that this technique is better tolerated than conventional lipiodol-based chemoembolization (c-TACE). In intermediate and early stage hepatocellular carcinoma - nonresponsive to curative treatments - complete response and partial response rates range from 22.2 to 48% and 43.7 to 51%, respectively. Studies with survival as an end-point are needed and head-to-head comparisons with other drug-eluting beads are necessary.

Idarubicin-loaded ONCOZENE drug-eluting embolic agents for chemoembolization of hepatocellular carcinoma: in vitro loading and release and in vivo pharmacokinetics

PURPOSE

To present in vitro loading and release characteristics of idarubicin with ONCOZENE (CeloNova BioSciences, Inc, San Antonio, Texas) drug-eluting embolic (DEE) agents and in vivo pharmacokinetics data after transarterial chemoembolization with idarubicin-loaded ONCOZENE DEE agents in patients with hepatocellular carcinoma.

MATERIALS AND METHODS

Loading efficacy of idarubicin with ONCOZENE DEE agents 100 µm and DC Bead (Biocompatibles UK Ltd, Farnham, United Kingdom) DEE agents 100-300 µm was monitored at 10, 20, and 30 minutes loading time by high-pressure liquid chromatography. A T-apparatus was used to monitor the release of idarubicin from the two types of DEE agents over 12 hours. Clinical and 24-hour pharmacokinetics data were recorded after transarterial chemoembolization with idarubicin-loaded ONCOZENE DEE agents in four patients with unresectable hepatocellular carcinoma.

RESULTS

Idarubicin loading in ONCOZENE DEE agents was > 99% at 10 minutes. Time to reach 75% of the release plateau level was 37 minutes ± 6 for DC Bead DEE agents and 170 minutes ± 19 for ONCOZENE DEE agents both loaded with idarubicin 10 mg/mL. After transarterial chemoembolization with idarubicin-loaded ONCOZENE DEE agents, three partial responses and one complete response were observed with only two asymptomatic grade 3 biologic adverse events. Median time to maximum concentration for idarubicin in patients was 10 minutes, and mean maximum concentration was 4.9 µg/L ± 1.7. Mean area under the concentration-time curve from 0-24 hours was equal to 29.5 µg.h/L ± 20.5.

CONCLUSIONS

ONCOZENE DEE agents show promising results with very fast loading ability, a favorable in vivo pharmacokinetics profile with a sustained release of idarubicin during the first 24 hours, and encouraging safety and responses. Histopathologic and clinical studies are needed to evaluate idarubicin release around the DEE agents in tumor tissue and to confirm safety and efficacy.

Investigation of acetylated chitosan microspheres as potential chemoembolic agents

The aim was to investigate the potential of chitosan microspheres (CMs) with different acetylation using as a chemoembolic agent. Chitosan microspheres (CMs) were prepared via water-in-oil (W/O) emulsification cross-linking method, and acetylated chitosan microspheres (ACMs) were obtained by acetylation of CMs. Next, we characterized the morphology, size, composition and degrees of deacetylation using scanning electron microscopy (TEM), dynamic laser light scattering (DLS), and Fourier transform infrared spectrometer (FTIR). All microspheres had smooth surfaces and good mechanical flexibility, and all could pass through a 5F catheter. The swelling rate (SR) of CMs decreased significantly with the increase of pH (4.0-10.0) but ACMs did not change under the same conditions. Protein absorption assays suggested that albumin was more greatly adsorbed on CMs than on ACMs. Furthermore, CMs caused more blood clots than ACMs. ACMs caused hemolysis less than CMs (<5% of the time). Data indicated that ACMs had more hemocompatibility. Cytotoxicity tests indicated that ACMs initially had less cell attached proliferation but increased with incubation. In contrast, the relative growth rate of mouse embryo fibroblasts (MEFs) on CMs decreased gradually. The results suggested that ACMs could stimulate the growth of MEFs, and CMs were not cytotoxic to MEFs. Thus, ACMs were more biocompatible with greater potential to be used as chemoembolic material.

Feasibility of temporary protective embolization of normal liver tissue using degradable starch microspheres during radioembolization of liver tumours

PURPOSE

To describe a new approach to protect nontarget healthy liver tissue using degradable starch microspheres (DSM) as a short-term embolizate during radioembolization of liver tumours with (90)Y microspheres.

METHODS

Between December 2011 and July 2012 radioembolization was performed in 54 patients. Five of these patients (three women, two men; mean age 67 years) underwent protective temporary embolization using DSM (EmboCept® S) of normal liver tissue that could not be excluded from the area treated by radioembolization through catheter repositioning. Clinical symptoms, laboratory findings, preinterventional imaging, and (99m)Tc-MAA and bremsstrahlung SPECT/CT, as well as baseline and follow-up imaging with (18)F-FDG PET/CT and MRI, were evaluated in relation to the technical and clinical success of the protective embolization.

RESULTS

Temporary embolization of arteries supplying normal liver tissue using DSM was technically successful in all five patients. (99m)Tc-MAA SPECT/CT performed in the first two patients after DSM injection showed no increased pulmonary shunting compared to the MAA test injection without DSM. Bremsstrahlung SPECT/CT after radioembolization demonstrated satisfactory irradiation of the tumour and successful protection of normal liver tissue. There were only mild hepatotoxic effects (grade 1) on laboratory follow-up examinations, and no adverse events associated with DSM embolization or radioembolization were recorded.

CONCLUSION

Temporary embolization with DSM before radioembolization is feasible and can effectively protect areas of normal liver tissue from irradiation and avoid permanent embolization if other methods such as catheter repositioning are not possible due to the location of the metastases.

Transcatheter arterial embolization with spherical embolic agent for pulmonary metastases from renal cell carcinoma

PURPOSE

This retrospective study aimed to evaluate the safety and local efficacy of transcatheter arterial embolization (TAE) with superabsorbent polymer microspheres (SAP-MS) in patients with pulmonary metastases from renal cell carcinoma (RCC).

METHODS

Sixteen patients with unresectable pulmonary metastases from RCC refractory to standard therapy were enrolled to undergo TAE with the purpose of mass reduction and/or palliation. The prepared SAP-MS swell to approximately two times larger than their dry-state size (100-150 μm [n = 14], 50-100 μm [n = 2]). Forty-nine pulmonary nodules (lung n = 22, mediastinal lymph node n = 17, and hilar lymph node n = 10) were selected as target lesions for evaluation. Local tumor response was evaluated 3 months after TAE according to Response Evaluation Criteria in Solid Tumors (RECIST; version 1.1). The relationship between tumor enhancement ratio by CT during selective angiography and local tumor response was evaluated.

RESULTS

The number of TAE sessions per patient ranged from 1 to 5 (median 2.9). Embolized arteries at initial TAE were bronchial arteries in 14 patients (87.5 %) and nonbronchial systemic arteries in 11 patients (68.8 %). Nodule-based evaluation showed that 5 (10.2 %) nodules had complete response, 17 (34.7 %) had partial response, 15 (30.6 %) had stable disease, and 12 (24.5 %) had progressive disease. The response rate was significantly greater in 22 lesions that had a high tumor enhancement ratio than in 27 lesions that had a slight or moderate ratio (90.9 vs. 7.4 %, p = 0.01). Severe TAE-related adverse events did not occur.

CONCLUSION

TAE with SAP-MS might be a well-tolerated and locally efficacious palliative option for patients with pulmonary metastases from RCC.

Temperature-sensitive poly(N-isopropylacrylamide-co-butyl methylacrylate) nanogel as an embolic agent: distribution, durability of vascular occlusion, and inflammatory reactions in the renal artery of rabbits

BACKGROUND AND PURPOSE

We have developed a new thermosensitive liquid embolic agent, PIB nanogel, that can be solidified at body temperature. We thus further investigated the distribution, durability of vascular occlusion, and inflammatory reactions of PIB in embolization of the renal artery of rabbits.

MATERIALS AND METHODS

The bilateral renal arteries of 9 rabbits were first embolized with PIB at different injection rates. The distribution pattern of PIB was investigated by contact radiography and histology 1 hour after embolization. The right renal arteries of 20 rabbits were then embolized with PIB at the proper injection rate. Angiography and pathologic examination of the kidneys were performed at 1 week and 1, 2, and 3 months after embolization to evaluate the long-term outcomes.

RESULTS

With the injection rate increasing, PIB could reach the more distal branch of the renal artery. The proper injection rate was chosen as 0.10 mL/s due to the homogeneous distribution of PIB from the main renal artery to the precapillary level at this rate. During a 3-month follow-up observation period, no angiographic recanalization was observed. Histologically, we found no disruption of the vessel wall or subintimal bleeding, no extravasation of PIB, and no evidence of neovascularization. Moreover, there was only a mild inflammatory response, manifested by few lymphocytic and monocellular infiltration, without foreign body granuloma formation.

CONCLUSIONS

Embolization of the renal artery with PIB was easy and controllable, which could lead to a homogeneous and persistent occlusion without severe inflammatory changes. PIB might be a suitable material for intravascular embolization.

Advances in image-guided intratumoral drug delivery techniques

Image-guided drug delivery provides a means for treating a variety of diseases with minimal systemic involvement while concurrently monitoring treatment efficacy. These therapies are particularly useful to the field of interventional oncology, where elevation of tumor drug levels, reduction of systemic side effects and post-therapy assessment are essential. This review highlights three such image-guided procedures: transarterial chemoembolization, drug-eluting implants and convection-enhanced delivery. Advancements in medical imaging technology have resulted in a growing number of new applications, including image-guided drug delivery. This minimally invasive approach provides a comprehensive answer to many challenges with local drug delivery. Future evolution of imaging devices, image-acquisition techniques and multifunctional delivery agents will lead to a paradigm shift in patient care.

A microfluidic device for the characterisation of embolisation with polyvinyl alcohol beads through biomimetic bifurcations

A microfluidic based device has been developed for the characterisation of embolisation behaviour with polyvinyl alcohol (PVA) hydrogel beads within a microchannel network with bifurcations which mimic the blood vessel network. Both distal and proximal embolisations were achieved within the PMMA-made microdevice exhibiting comparable embolisation characteristics with those observed in vivo. Results showed that small beads allowed more distal embolisations with a reduced control of the spatial location of occlusion sites. In contrast, large beads generated effective proximal embolisations with an improved reproducibility of embolisation performance. Embolic bead hydrodynamics, partitioning at bifurcations, penetration through microchannels and embolisation locations across the channel network were characterised by quantifying the effects of embolic bead size, bead concentration, channel geometry and fluidic conditions. This development provided further insights into the physical principles governing embolisation performances within the constructed microdevices allowing the improvement of the predictability and controllability of the clinical process outcomes. Furthermore, it can potentially provide a useful platform for preclinical research as an alternative to animal models, with an ultimate goal to reduce the amount of animal testing.

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.

Trans-arterial chemoembolization as a therapy for liver tumours: New clinical developments and suggestions for combination with angiogenesis inhibitors

The liver is the primary site of metastases for many malignancies. Gastrointestinal cancers are especially prone to spread to the liver and other tumours, as breast cancer and melanoma often spread to the liver. On the other hand, hepatocellular cancer (HCC) is the fifth most common malignancy in the world due to its common etiology from chronic liver damage caused by hepatitis or cirrhosis. Treatments of liver tumours vary according to histology and liver invasion and until now trans-arterial chemoembolization (TACE) has represented a main approach in the therapy of liver tumours. This review takes into consideration: (i) the background to utilizing TACE in liver tumours; (ii) TACE methods and the biological rationale for utilizing chemotherapeutic agents coated to a new micro-particle such as DC-Beads and HepaSphere; (iii) clinical experiences employing TACE in different liver tumours; (iv) the pivotal role of angiogenesis and hypoxia-induced angiogenesis following TACE with special references to HCC. Finally, the rationale for the combination of TACE with angiogenesis inhibitors is also discussed.

Chemoembolization for primary and metastatic liver cancer

Transcatheter arterial chemoembolization (TACE) is one of the most commonly performed procedures in interventional radiology and is currently used for the palliative treatment of primary and metastatic hepatic malignancies. A new type of TACE is TACE with drug-eluting microspheres, which is currently gaining wide acceptance worldwide. In this article, we will review some technical components, patient selection, current results, and future directions of TACE and TACE with drug-eluting microspheres for primary and metastatic liver cancer.

Observation of intravascular changes of superabsorbent polymer microsphere (SAP-MS) with monochromatic X-ray imaging

This study was designed to evaluate the intravascular transformation behavior of superabsorbent polymer microsphere (SAP-MS) in vivo macroscopically by using monochromatic X-ray imaging and to quantitatively compare the expansion rate of SAP-MS among different kinds of mixtures. Fifteen rabbits were used for our study and transcatheter arterial embolization (TAE) was performed for their auricular arteries using monochromatic X-ray imaging. We used three kinds of SAP-MS (particle diameter 100-150 mum) mixture as embolic spherical particles: SAP-MS(H) absorbed with sodium meglumine ioxaglate (Hexabrix 320), SAP-MS(V) absorbed with isosmolar contrast medium (Visipaque 270), and SAP-MS(S) absorbed with 0.9% sodium saline. The initial volume of SAP-MS particles just after TAE and its final volume 10 minutes after TAE in the vessel were measured to calculate the expansion rate (ER) (n = 30). Intravascular behavior of SAP-MS particles was clearly observed in real time at monochromatic X-ray imaging. Averaged initial volumes of SAP-MS (H) (1.24 x 10(7) microm(3)) were significantly smaller (p < 0.001) than those of SAP-MS (V) (5.99 x 10(7) microm(3)) and SAP-MS (S) (5.85 x 10(7) microm(3)). Averaged final volumes of SAP-MS (H) were significantly larger than averaged initial volumes (4.41 x 10(7) microm(3) vs. 1.24 x 10(7) microm(3); p < 0.0001, ER = 3.55). There were no significant difference between averaged final volumes and averaged initial volumes of SAP-MS (V) and SAP-MS (S). SAP-MS (H), which first travels distally, reaches to small arteries, and then expands to adapt to the vessel lumen, is an effective particle as an embolic agent, causing effective embolization.

Intra-arterial therapies for hepatocellular carcinoma: where do we stand?

PURPOSE AND DESIGN

Intra-arterial therapies for unresectable hepatocellular carcinoma (HCC) consist of a catheter-based group of treatments where therapeutic and/or embolic agents are intra-arterially directed to target tumors. Here we review these therapies, which may be classified into embolotherapy/chemotherapy-based and radiotherapy-based treatments. Embolotherapy/chemotherapy-based treatments include transcatheter arterial embolization, transarterial chemoembolization, transcatheter arterial chemoeinfusion, and chemoembolization with drug-eluting beads. Radiotherapy-based treatments include radioembolization with yttrium-90 and injection of iodine-131-labeled lipiodol.

RESULTS AND CONCLUSION

Interpretation of the results of clinical trials as well as implementation of meta-analyses involving the efficacy of intra-arterial therapies for unresectable HCC has been challenging and difficult to perform. The levels of evidence for treatment recommendations in oncology provide a common framework to understand the current status of intra-arterial therapies for HCC. Here we use an evidence-based approach to critically review and comprehend the current role and future potential of intra-arterial therapies in unresectable HCC.

Doxorubicin-loaded QuadraSphere microspheres: plasma pharmacokinetics and intratumoral drug concentration in an animal model of liver cancer

The purpose of this study was to evaluate, in vitro and in vivo, doxorubicin-loaded poly (vinyl alcohol-sodium acrylate) copolymer microspheres [QuadraSphere microspheres (QSMs)] for transcatheter arterial delivery in an animal model of liver cancer. Doxorubicin loading efficiency and release profile were first tested in vitro. In vivo, 15 rabbits, implanted with a Vx-2 tumor in the liver, were divided into three groups of five rabbits each, based on the time of euthanasia. Twenty-five milligrams of QSMs was diluted in 10 ml of a 10 mg/ml doxorubicin solution and 10 ml of nonionic contrast medium for a total volume of 20 ml. One milliliter of a drug-loaded QSM solution containing 5 mg of doxorubicin was injected into the tumor feeding artery. Plasma doxorubicin and doxorubicinol concentrations, and intratumoral and peritumoral doxorubicin tissue concentrations, were measured. Tumor specimens were pathologically evaluated to record tumor necrosis. As a control, one animal was blandly embolized with plain QSMs in each group. In vitro testing of QSM doxorubicin loadability and release over time showed 82-94% doxorubicin loadability within 2 h and 6% release within the first 6 h after loading, followed by a slow release pattern. In vivo, the doxorubicin plasma concentration declined at 40 min. The peak doxorubicin intratumoral concentration was observed at 3 days and remained detectable till the study's end point (7 days). Mean percentage tumor cell death in the doxorubicin QSM group was 90% at 7 days and 60% in the bland QSM embolization group. In conclusion, QSMs can be efficiently loaded with doxorubicin. Initial experiments with doxorubicin-loaded QSMs show a safe pharmacokinetic profile and effective tumor killing in an animal model of liver cancer.

Selective internal radiation therapy with SIR-spheres for the treatment of unresectable colorectal hepatic metastases

The purpose of this study was to evaluate the effectiveness of colorectal cancer (CRC) liver metastasis radioembolization with yttrium-90 (Y90), assessing toxicity and survival rates in patients with no response to chemotherapy through our 3-year experience. From February 2005 to January 2008, we treated 41 patients affected by CRC from a cohort of selective internal radiation therapy patients treated at our institution. All patients examined showed disease progression and arrived for our observation with an abdominal CT, a body PET, and a hepatic angiography followed by gastroduodenal artery coiling previously performed by us. We excluded patients with a bilirubin level>1.8 mg/dl and pulmonary shunt>20% but not patients with minor extrahepatic metastases. On treatment day, under fluoroscopic guidance, we implanted a dose of Y90 microspheres calculated on the basis of liver tumoral involvement and the body surface area formula. All patients were discharged the day after treatment. We obtained, according to Response Evaluation Criteria on Solid Tumors, a complete response in 2 patients, a partial response in 17 patients, stable disease in 14 patients, and progressive disease in 8 patients. In all cases, we obtained a carcinoembryonic antigen level decrease, especially in the week 8 evaluation. Technical success rate was 98% and technical effectiveness estimated at 3 months after treatment was 80.5%. Side effects graded by Common Terminology Criteria on Adverse Events were represented by one grade 4 hepatic failure, two grade 2 gastritis, and one grade 2 cholecystitis. The median survival and the progression-free survival calculated by Kaplan-Meier analysis were 354 and 279 days, respectively. In conclusion, according to our 3-year experience, Y90 SIR-Spheres radioembolization is a feasible and safe method to treat CRC liver metastases, with an acceptable level of complications and a good response rate.

Biocompatibility, inflammatory response, and recannalization characteristics of nonradioactive resin microspheres: histological findings

Intra-arterial radiotherapy with yttrium-90 microspheres (radioembolization) is a therapeutic procedure exclusively applied to the liver that allows the direct delivery of high-dose radiation to liver tumors, by means of endovascular catheters, selectively placed within the tumor vasculature. The aim of the study was to describe the distribution of spheres within the precapillaries, inflammatory response, and recannalization characteristics after embolization with nonradioactive resin microspheres in the kidney and liver. We performed a partial embolization of the liver and kidney vessels in nine white pigs. The left renal and left hepatic arteries were catheterized and filled with nonradioactive resin microspheres. Embolization was defined as the initiation of near-stasis of blood flow, rather than total occlusion of the vessels. The hepatic circulation was not isolated so that the effects of reflux of microspheres into stomach could be observed. Animals were sacrificed at 48 h, 4 weeks, and 8 weeks, and tissue samples from the kidney, liver, lung, and stomach evaluated. Microscopic evaluation revealed clusters of 10–30 microspheres (15–30 μm in diameter) in the small vessels of the kidney (the arciform arteries, vasa recti, and glomerular afferent vessels) and liver. Aggregates were associated with focal ischemia and mild vascular wall damage. Occlusion of the small vessels was associated with a mild perivascular inflammatory reaction. After filling of the left hepatic artery with microspheres, there was some evidence of arteriovenous shunting into the lungs, and one case of cholecystitis and one case of marked gastritis and ulceration at the site of arterial occlusion due to the presence of clusters of microspheres. Beyond 48 h, microspheres were progressively integrated into the vascular wall by phagocytosis and the lumen recannalized. Eight-week evaluation found that the perivascular inflammatory reaction was mild. Liver cell damage, bile duct injury, and portal space fibrosis were not observed. In conclusion, resin microspheres (15–30 μm diameter) trigger virtually no inflammatory response in target tissues (liver and kidney). Clusters rather than individual microspheres were associated with a mild to moderate perivascular inflammatory reaction. There was no evidence of either a prolonged inflammatory reaction or fibrosis in the liver parenchyma following recannalization.

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.