Analysis of nontarget embolization mechanisms during embolization and chemoembolization procedures

HAIC Combined with lenvatinib plus PD-1 versus lenvatinib Plus PD-1 in patients with high-risk advanced HCC: a real-world study

BACKGROUND

The treatment of hepatocellular carcinoma (HCC) patients exhibiting high-risk characteristics (Vp4, and/or bile duct invasion, and/or tumor occupancy ≥ 50%) lacks standardized approaches and yields unfavorable results. This study endeavors to evaluate the safety, efficacy, and prognostic impacts of employing hepatic arterial infusion chemotherapy (HAIC), lenvatinib, and humanized programmed death receptor-1 (PD-1) in the treatment of high-risk HCC patients.

METHODS

In this retrospective analysis, HCC patients with high-risk features were treated with either lenvatinib combined with PD-1 (LEN-PD1) or a combination of HAIC, lenvatinib, and PD-1 (HAIC-LEN-PD1). The study assessed the antitumor efficacy by calculating overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and disease control rate (DCR). Treatment-related adverse events (TRAEs) were analyzed to assess the safety profiles.

RESULTS

Between June 2019 and September 2022, a total of 61 patients were included in the LEN-PD1 group, while 103 patients were enrolled in the HAIC-LEN-PD1 group. The OS was 9.8 months in the LEN-PD1 group, whereas the HAIC-LEN-PD1 group exhibited a significantly longer median OS of 19.3 months (HR = 0.43, p < 0.001). Furthermore, PFS was notably extended in the HAIC-LEN-PD1 group compared to the LEN-PD1 group (9.6 months vs. 4.9 months, HR = 0.48, p < 0.001). Patients in the HAIC-LEN-PD1 group had a higher ORR and DCR according to the modified RECIST (76.7% vs. 23.0%, p < 0.001; 92.2% vs. 72.1%, p = 0.001). HAIC-LEN-HAIC group led to more adverse events than LEN-PD1 group, most of which were tolerable and controllable.

CONCLUSION

Lenvatinib, HAIC and PD-1 showed safe and promising anti-tumor activity compared with lenvatinib alone for HCC with high-risk features.

Non-target embolic events during prostatic embolization with ethylene vinyl alcohol copolymer (EVOH)

BACKGROUND

This study evaluated nontarget embolization (NTE) during prostatic artery embolization (PAE) with ethylene vinyl alcohol copolymer (EVOH).

RESULTS

Ten consecutive patients treated by PAE with EVOH for the presence of disabling benign prostatic hyperplasia (BPH)-related lower urinary tract symptoms (LUTS) between June 22 and January 2023 were included in this prospective study. The inclusion criteria were as follows: LUTS attributed to BPH, LUTS duration ≥ 6 months, failure to respond to standard pharmacotherapy, IPSS > 18 or QoL score > 2, and prostate volume > 40 mL. Embolization was performed under general anaesthesia. According to established techniques, a microcatheter was positioned bilaterally within the feeding arteries, and EVOH was injected slowly under X-ray control. Unenhanced pelvic computed tomography scans were carried out before and after embolization to assess the NTE. The safety of the prostatic embolization procedure with EVOH was assessed by collecting adverse effects over 3 months of evaluation that included the International Prostate Symptom Score (IPSS) and quality of life (QoL) score.-up evaluations, occurring at 3, 6, and 12months, included International Prostate Symptom Score. Bilateral PAE was technically successful in 9 patients, and unilateral injection was performed in one patient. The postoperative scanner showed a distribution of the embolization material in the two lobes of the prostate in all patients. The procedure time varied from 120 to 150 (mean: 132) minutes. Eight out of 10 patients developed pollakiuria within 24 h; none of the patients had postoperative pain. Two patients required catheterization for postoperative urinary retention. Catheters were removed successfully at the end of the first day for one of these patients and on the tenth day for the other. At the 3-month follow-up, patients showed significant improvement in the International Prostate Symptom Score (n = 10; mean = -11,5; P < 0.01) and quality of life score (n = 10; mean = -3,40; P < 0.01). Only one patient presented one asymptomatic muscular NTE.

CONCLUSIONS

PAE with EVOH is safe, effective, and associated with few NTEs and no postoperative pain. Prospective comparative studies with longer follow-ups are warranted.

TRIAL REGISTRATION

IDRCB, 2021-AO29-56-35. Registered 27 May 2022, http://clinicaltrials.gov/study/NCT05395299?cond=embolization&term&rank=1 .

Near Infrared-Absorbing Nanoparticle-Mediated Endovascular Photothermal Precision Embolization of Tumor Feeding Vessels for Starvation Treatment

Photothermal therapy has attracted enormous attention as an efficient treatment modality in cancer ablation but still encounters a major bottleneck due to the limited penetration depth of light inside tissues. To overcome the challenge of deep tissue penetration, we present a strategy of endovascular photothermal precision embolization (EPPE), which employs an endovascular optical fiber to induce local embolization only in the entrance of feeding vessels through photothermal heating for the purpose of fully blocking the blood supply of the whole tumor. In EPPE, we apply a highly efficient and biocompatible photothermal agent, i.e., near-infrared (NIR)-light-absorbing diketopyrrolopyrrole-dithiophene-based nanoparticle, which exhibits a high cell-killing efficacy at a concentration of 200 μg/mL using 808 nm laser irradiation of 0.5 W/cm² within 5 min in both 2D cell culture and a 3D tumor spheroid model. We verify the feasibility of EPPE in an ex vivo organ-structured recellularized liver model and further confirm the in vivo efficacy of the photothermal treatment in a rat liver model. The photothermal treatment combined with the embolization effect holds promise to serve as an effective starvation therapy to treat tumors of varying sizes and locations.

Fluid-dynamic control microcatheter used with glue: preliminary experience on its feasibility and safety

Purpose

To evaluate feasibility, safety, and success of peripheral embolization procedures carried out using anti-reflux microcatheter with N-butyl-cyanoacrylate (NBCA) as an embolic agent.

Methods

We retrospectively described 11 patients that suffered from active bleeding in different body districts, who underwent embolization procedure using SeQure microcatheter (Guerbet, France) with NBCA glue (Glubran II, GEM Italy) as an embolic agent. The treatments required NBCA volumes ranged from 0.1 to 0.6 mL, with different dilutions with ethiodized oil (Lipiodol, Guerbet, France), depending on the entity of the bleeding. Technical success, clinical success, and complications were evaluated.

Results

The procedures were successfully concluded in the totality of the patients, achieving full technical and clinical success. In one patient (9.1%), a small upstream of embolic material was encountered, without any consequence.

Conclusion

This preliminary experience shows that the use of SeQure is feasible and safe with NBCA.

Hepatic Arterial Infusion of Oxaliplatin, Fluorouracil, and Leucovorin Versus Transarterial Chemoembolization for Large Hepatocellular Carcinoma: A Randomized Phase III Trial

PURPOSE

In a previous phase II trial, hepatic arterial infusion chemotherapy (HAIC) with infusional fluorouracil, leucovorin, and oxaliplatin (FOLFOX) yielded higher treatment responses than transarterial chemoembolization (TACE) in large unresectable hepatocellular carcinoma. We aimed to compare the overall survival of patients treated with FOLFOX-HAIC versus TACE as first-line treatment in this population.

METHODS

In this randomized, multicenter, open-label trial, adults with unresectable hepatocellular carcinoma (largest diameter ≥ 7 cm) without macrovascular invasion or extrahepatic spread were randomly assigned 1:1 to FOLFOX-HAIC (oxaliplatin 130 mg/m², leucovorin 400 mg/m², fluorouracil bolus 400 mg/m² on day 1, and fluorouracil infusion 2,400 mg/m² for 24 hours, once every 3 weeks) or TACE (epirubicin 50 mg, lobaplatin 50 mg, and lipiodol and polyvinyl alcohol particles). The primary end point was overall survival by intention-to-treat analysis. Safety was assessed in patients who received ≥ 1 cycle of study treatment.

RESULTS

Between October 1, 2016, and November 23, 2018, 315 patients were randomly assigned to FOLFOX-HAIC (n = 159) or TACE (n = 156). The median overall survival in the FOLFOX-HAIC group was 23.1 months (95% CI, 18.5 to 27.7) versus 16.1 months (95% CI, 14.3 to 17.9) in the TACE group (hazard ratio, 0.58; 95% CI, 0.45 to 0.75; P < .001). The FOLFOX-HAIC group showed a higher response rate than the TACE group (73 [46%] v 28 [18%]; P < .001) and a longer median progression-free survival (9.6 [95% CI, 7.4 to 11.9] v 5.4 months [95% CI, 3.8 to 7.0], P < .001). The incidence of serious adverse events was higher in the TACE group than in the FOLFOX-HAIC group (30% v 19%, P = .03). Two deaths in the FOLFOX-HAIC group and two in the TACE group were deemed to be treatment-related.

CONCLUSION

FOLFOX-HAIC significantly improved overall survival over TACE in patients with unresectable large hepatocellular carcinoma.

Reduced nontarget embolization and increased targeted delivery with a reflux-control microcatheter in a swine model

PURPOSE

To evaluate the potential differences in non-target embolization and vessel microsphere filling of a reflux-control microcatheter (RCM) compared to a standard end-hole microcatheter (SEHM) in a swine model.

MATERIALS AND METHODS

Radiopaque microspheres were injected with both RCM and SEHM (2.4-Fr and 2.7-Fr) in the kidneys of a preclinical swine model. Transarterial renal embolization procedures with RCM or SEHM were performed in both kidneys of 14 pigs. Renal arteries were selectively embolized with an automated injection protocol of radio-opaque microspheres. Ex-vivo X-ray microtomography images of the kidneys were utilized to evaluate the embolization by quantification of the deposition of injected microspheres in the target vs. the non-target area of injection. X-ray microtomography images were blindly analyzed by five interventional radiologists. The degree of vessel filling and the non-target embolization were quantified using a scale from 1 to 5 for each parameter. An analysis of variance was used to compare the paired scores.

RESULTS

Total volumes of radio-opaque microspheres injected were similar for RCM (11.5±3.6 [SD] mL; range: 6-17mL) and SEHM (10.6±5.2 [SD] mL; range: 4-19mL) (P=0.38). The voxels enhanced ratio in the target (T) vs. non-target (NT) areas was greater with RCM (T=98.3% vs. NT=1.7%) than with SEHM (T=89% vs. NT=11%) but the difference was not significant (P=0.30). The total score blindly given by the five interventional radiologists was significantly different between RCM (12.3±2.1 [SD]; range: 6-15) and the standard catheter (11.3±2.5 [SD]; range: 4-15) (P=0.0073), with a significant decrease of non-target embolization for RCM (3.8±1.3 [SD]; range: 3.5-4.2) compared to SEHM (3.2±1.5 [SD]; range: 2.9-3.5) (P=0.014).

CONCLUSION

In an animal model, RCM microcatheters reduce the risk of non-target embolization from 11% to 1.7%, increasing the delivery of microspheres of 98% to the target vessels, compared to SEHM microcatheters.

Immobilized thrombin on X-ray radiopaque polyvinyl alcohol/chitosan embolic microspheres for precise localization and topical blood coagulation

Trans-catheter arterial embolization (TAE) plays an important role in treating various diseases. The available embolic agents lack X-ray visibility and do not prevent the reflux phenomenon, thus hindering their application for TAE therapy. Herein, we aim to develop a multifunctional embolic agent that combines the X-ray radiopacity with local procoagulant activity. The barium sulfate nanoparticles (BaSO₄ NPs) were synthesized and loaded into the polyvinyl alcohol/chitosan (PVA/CS) to prepare the radiopaque BaSO₄/PVA/CS microspheres (MS). Thereafter, thrombin was immobilized onto the BaSO₄/PVA/CS MS to obtain the thrombin@BaSO₄/PVA/CS MS. The prepared BaSO₄/PVA/CS MS were highly spherical with diameters ranging from 100 to 300 μm. In vitro CT imaging showed increased X-ray visibility of BaSO₄/PVA/CS MS with the increased content of BaSO₄ NPs in the PVA/CS MS. The biocompatibility assessments demonstrated that the MS were non-cytotoxic and possessed permissible hemolysis rate. The biofunctionalized thrombin@BaSO₄/PVA/CS MS showed improved hemostatic capacity and facilitated hemostasis in vitro. Additionally, in vivo study performed on a rabbit ear embolization model confirmed the excellent X-ray radiopaque stability of the BaSO₄/PVA/CS MS. Moreover, both the BaSO₄/PVA/CS and thrombin@BaSO₄/PVA/CS MS achieved superior embolization effects with progressive ischemic necrosis on the ear tissue and induced prominent ultrastructural changes in the endothelial cells. The findings of this study suggest that the developed MS could act as a radiopaque and hemostatic embolic agent to improve the embolization efficiency.

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Excellent in vitro and in vivo visibility of BaSO₄/PVA/CS MS.

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Excellent cytocompatibility and hemocompatibility of BaSO₄/PVA/CS MS.

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Enhanced hemostatic capacity and hemostasis of thrombin@BaSO₄/PVA/CS MS.

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Potential application of thrombin@BaSO₄/PVA/CS MS for in vivo embolization.

Microfluidic-prepared, monodisperse, X-ray-visible, embolic microspheres for non-oncological embolization applications

Embolotherapy using particle embolics is normally performed with exogenous contrast to assist in visualization. However, the exact location of the embolics cannot be identified after contrast washout. We developed a novel, pseudo-check valve-integrated microfluidic device, that partitions barium- impregnated alginate from crosslinking solution, thereby preventing nozzle failure. This enables rapid and continuous generation of inherently X-ray-visible embolic microspheres (XEMs) with uniform size. The XEMs are visible under clinical X-ray and cone beam CT both in vitro and in vivo. In particular, we demonstrated the embolization properties of these XEMs in large animals, performing direct intra- and post-procedural assessment of embolic delivery. The persistent radiopacity of these XEMs enables real-time evaluation of embolization precision and offers great promise for non-invasive follow-up examination without exogenous contrast. We also demonstrated that bariatric arterial embolization with XEMs significantly suppresses weight gain in swine, as an example of a non-oncological application of embolotherapy.

On-demand degradable embolic microspheres for immediate restoration of blood flow during image-guided embolization procedures

Degradable embolic agents that provide transient arterial occlusion during embolization procedures have been of interest for many years. Ideally, embolic agents are visible with standard imaging modalities and offer on-demand degradability, permitting physicians to achieve desired arterial occlusion tailored to patient and procedure indication. Subsequent arterial recanalization potentially enhances the overall safety and efficacy of embolization procedures. Here, we report on-demand degradable and MRI-visible microspheres for embolotherapy. Embolic microspheres composed of calcium alginate and USPIO nanoclusters were synthesized with an air spray atomization and coagulation reservoir equipped with a vacuum suction. An optimized distance between spray nozzle and reservoir allowed uniform size and narrow size distribution of microspheres. The fabricated alginate embolic microspheres crosslinked with Ca²⁺ demonstrated highly responsive on-demand degradation properties in vitro and in vivo. Finally, the feasibility of using the microspheres for clinical embolization and recanalization procedures was evaluated with interventional radiologists in rabbits. Digital subtraction angiography (DSA) guided embolization of hepatic arteries with these embolic microspheres was successfully performed and the occlusion of artery was confirmed with DSA images and contrast enhanced MRI. T2 MRI visibility of the microspheres allowed to monitor the distribution of intra-arterial (IA) infused embolic microspheres. Subsequent on-demand image-guided recanalization procedures were also successfully performed with rapid degradation of microspheres upon intra-arterial infusion of an ion chelating agent. These instant degradable embolic microspheres will permit effective on-demand embolization/recanalization procedures offering great promise to overcome limitations of currently available permanent and biodegradable embolic agents.

Transarterial Bleomycin-Lipiodol Embolization (B/LE) for Symptomatic Giant Hepatic Hemangioma

BACKGROUND

Large hepatic hemangiomas can cause symptoms such as pain and bleeding. No consensus currently exists on the optimal management of large and symptomatic hemangiomas. The purpose of this study was to evaluate the role of transarterial bleomycin-lipiodol embolization (B/LE) in the treatment of symptomatic large hepatic hemangioma.

MATERIALS AND METHODS

We retrospectively reviewed 23 patients (29 hemangiomas) treated between July 2011 and August 2017. Transarterial B/LE was performed using 7-15 cc of Lipiodol mixed with 30-45 IU of bleomycin by standard three-way stopcocks. All patients were followed clinically and by imaging for an average of 7.5 months. Patterns of bleomycin-lipiodol distribution in the periphery of hemangiomas were categorized into four different grades. Technical success was defined as proper delivery of bleomycin-lipiodol into the hemangioma confirmed by post-embolization computed tomography. Clinical success was defined as more than 50% reduction of hemangioma volume and symptom improvement during follow-ups.

RESULTS

Technical success and clinical success were 100 and 73.9% (17 patients), respectively. Six patients (26.08%) experienced transient post-embolization syndrome. Significant size reduction was seen in patients with grade 4 hemangioma border coverage (P = 0.042).

CONCLUSION

Transarterial B/LE is a safe and efficient alternative for controlling symptoms related to large hemangiomas.

Chitosan-Based Hydrogel Microparticles for Treatment of Carcinoma in a Rabbit VX2 Liver Tumor Model

PURPOSE

To investigate potential of chitosan hydrogel microparticles (CHI) for treatment of VX2 carcinoma.

MATERIALS AND METHODS

Two weeks after liver VX2 implantation, contrast-enhanced computerized tomographic scanning was conducted. Rabbits (n = 2) with successful tumor growth were treated with different sizes of ^99mTc-labeled CHI (60-80 μm and 100-120 μm) via intra-arterial hepatic catheterization. Liver distribution of ^99mTc-labeled CHI was determined by means of autoradiography, a radiation-based photographic technique. In the next part of this study, therapeutic effectiveness was examined with the use of CHI with the size range of 60-80 μm (n = 11). Tumor growth response and levels of blood liver enzymes were studied at baseline and 1 and 2 weeks after CHI treatment.

RESULTS

Successful tumor growth was confirmed in all rabbits (24/24). Intrahepatic CHI with the size range of 60-80 μm resulted in liver localization in more close proximity to tumor nodule versus 100-120 μm. Baseline tumor volume was 1,909 ± 575 mm³ in animals receiving CHI versus 1,831 ± 249 mm³ in control animals (P = .342). In control animals, tumor volume markedly increased by 1,544 ± 512% at 2 weeks after sham operation versus baseline. In animals receiving CHI, tumor volume remained relatively unchanged (54 ± 6% increase; P = .007 vs control). Levels of blood aspartate transaminase (AST) and alanine transaminase (ALT) in animals receiving CHI increased 1 week after treatment (P = .032 vs control for AST; P = .000 vs control for ALT), but returned to control levels at 2 weeks.

CONCLUSIONS

CHI embolization suppressed tumor growth without appreciable damages in liver function.

Transarterial chemoembolization using 40 µm drug eluting beads for hepatocellular carcinoma

AIM

To assess the safety and efficacy of transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC) using a new generation of 40 μm drug eluting beads in patients not eligible for curative treatment.

METHODS

Drug eluting bead TACE (DEB-TACE) using a new generation of microspheres (embozene tandem, 40 μm) preloaded with 100 mg of doxorubicin was performed on 48 early or intermediate HCC patients with compensated cirrhosis. Response to therapy was assessed with Response Evaluation Criteria in Solid Tumors (RECIST) and modified RECIST (mRECIST) guidelines applied to computed tomography or magnetic resonance imaging. Eleven out of the 48 treated patients treated progressed on to receive liver orthotopic transplantation (OLT). This allowed for histological analysis on the treated explanted nodules.

RESULTS

DEB-TACE with 40 μm showed a good safety profile without major complications or 30-d mortality. The objective response rate of treated tumors was 72.6% and 26.7% according to mRECIST and RECIST respectively. Histological examination in 11 patients assigned to OLT showed a necrosis degree > 90% in 78.6% of cases. The overall time to progression was 13 mo (11-21).

CONCLUSION

DEB-TACE with 40 μm particles is an effective treatment for the treatment of HCC in early-intermediate patients (Barcelona Clinic Liver Cancer stage A/B) with a good safety profile and good results in term of objective response rate and necrosis.

Review of the Development of Methods for Characterization of Microspheres for Use in Embolotherapy: Translating Bench to Cathlab

Therapeutic embolotherapy is the deliberate occlusion of a blood vessel within the body, which can be for the prevention of internal bleeding, stemming of flow through an arteriovenous malformation, or occlusion of blood vessels feeding a tumor. This is achieved using a wide selection of embolic devices such as balloons, coils, gels, glues, and particles. Particulate embolization is often favored for blocking smaller vessels, particularly within hypervascularized tumors, as they are available in calibrated sizes and can be delivered distally via microcatheters for precise occlusion with associated locoregional drug delivery. Embolic performance has been traditionally evaluated using animal models, but with increasing interest in the 3R's (replacement, reduction, refinement), manufacturers, regulators, and clinicians have shown interest in the development of more sophisticated in vitro methods for evaluation and prediction of in vivo performance. Herein the current progress in developing bespoke techniques incorporating physical handling, fluid dynamics, occlusive behavior, and sustained drug elution kinetics within vascular systems is reviewed. While it is necessary to continue to validate the safety of such devices in vivo, great strides have been made in the development of bench tests that better predict the behavior of these products aligned with the principles of the 3R's.

Pharmacokinetics, Safety, and Efficacy of Chemoembolization with Doxorubicin-Loaded Tightly Calibrated Small Microspheres in Patients with Hepatocellular Carcinoma

PURPOSE

This study examines safety, efficacy, and pharmacokinetics of chemoembolization with loadable microspheres ≤100 μm for hepatocellular carcinoma.

MATERIALS AND METHODS

A pilot safety study was performed in 19 patients with size and dose escalation and then 52 patients were enrolled prospectively and randomly assigned to chemoembolization with TANDEM™ loaded with 150 or 100 mg of doxorubicin.

RESULTS

The mean diameter of the tumors was 7.28 ± 2.09 cm (range 4-12) and distribution dominant/multiple 51.9/48.1 %. Child A/B distribution was 32/20 (61.5/38.5 %) and etiology HBV/HCV/HBV/HCV-hemochromatosis was 61.6/9.6/9.6/15.4 %. Twenty-five patients were assigned in the low and 27 in the high loading group. There was 1.92 % thirty-day mortality due to lesion rupture. Biliary damage was seen in 3 patients (5.7 %) in the high loading. Mean maximum plasma concentration of doxorubicin C max ± SD was 284.9 ± 276.2 ng/mL for the high and 108.5 ± 77.6 ng/mL for the low loading (p < 0.001). According to m-RECIST overall objective response after two sessions reached 61.22 and 63.82 % at 6 months. Notably, complete target lesion response (CR) after the second session was observed in 28.57 % and maintained in 23.40 % at 6 months. No statistical differences in the local response rates were observed between the two loading groups. Overall survival (OS) at 6 months, 1 , 2, and 3 years was 98.08, 92.3, 88.46, and 82.6 %, respectively. OS and Progression-Free Survival did not demonstrate statistical significance between the two loading groups.

CONCLUSION

Initial evidence shows that (a) TANDEM™ achieves high rates of local response and mid-term survival, (b) high loading provides no clinical benefit and is associated with biliary toxicity.

Transcatheter embolization therapy in liver cancer: an update of clinical evidences

Transarterial chemoembolization (TACE) is a form of intra-arterial catheter-based chemotherapy that selectively delivers high doses of cytotoxic drug to the tumor bed combining with the effect of ischemic necrosis induced by arterial embolization. Chemoembolization and radioembolization are at the core of the treatment of liver hepatocellular carcinoma (HCC) patients who cannot receive potentially curative therapies such as transplantation, resection or percutaneous ablation. TACE for liver cancer has been proven to be useful in local tumor control, to prevent tumor progression, prolong patients' life and control patient symptoms. Recent evidence showed in patients with single-nodule HCC of 3 cm or smaller without vascular invasion, the 5-year overall survival (OS) with TACE was similar to that with hepatic resection and radiofrequency ablation. Although being used for decades, Lipiodol(®) (Lipiodol(®) Ultra Fluid(®), Guerbet, France) remains important as a tumor-seeking and radio-opaque drug delivery vector in interventional oncology. There have been efforts to improve the delivery of chemotherapeutic agents to tumors. Drug-eluting bead (DEB) is a relatively novel drug delivery embolization system which allows for fixed dosing and the ability to release the anticancer agents in a sustained manner. Three DEBs are available, i.e., Tandem(®) (CeloNova Biosciences Inc., USA), DC-Beads(®) (BTG, UK) and HepaSphere(®) (BioSphere Medical, Inc., USA). Transarterial radioembolization (TARE) technique has been developed, and proven to be efficient and safe in advanced liver cancers and those with vascular complications. Two types of radioembolization microspheres are available i.e., SIR-Spheres(®) (Sirtex Medical Limited, Australia) and TheraSphere(®) (BTG, UK). This review describes the basic procedure of TACE, properties and efficacy of some chemoembolization systems and radioembolization agents which are commercially available and/or currently under clinical evaluation. The key clinical trials of transcatheter arterial therapy for liver cancer are summarized.

Endoluminal occlusion devices: technology update

Endoluminal occlusion has been performed since the early beginning of interventional radiology. Over recent decades, major technological advances have improved the techniques used and different devices have been developed for changing conditions. Most of these occlusion devices have been implemented in the vascular territory. Early embolization materials included glass particles, hot contrast, paraffin, fibrin, and tissue fragments such as muscle fibers and blood clots; today, occlusion materials include metallic devices, particles, and liquid materials, which can be indicated for proximal or distal occlusion, high-flow and low-flow situations, and in large-caliber and small-caliber vessels, based on need. Technological progress has led to a decreased size of delivery catheters, and an increase in safety due to release systems that permit the withdrawing and replacement of embolization material. Furthermore, bioactive embolization materials have been developed to increase the efficacy of embolization or the biological effect of medication. Finally, materials have been modified for changing indications. Intravascular stents were initially developed to keep an artery open; however, by adding a covering membrane, these stents can be used to occlude the wall of a vessel or other endoluminal structures. This article gives an overview of the devices most utilized for occlusion of endoluminal structures, as well as their major purpose in the endovascular territory.

Chemoembolization of hepatocellular carcinoma with HepaSphere 30-60 μm. Safety and efficacy study

Background

This study examined the safety, pharmacokinetics, and efficacy of transarterial chemoembolization of hepatocellular carcinoma (HCC) using a newly developed size of a superabsorbent polymer drug-eluting embolic material.

Methods

Forty-five patients with documented HCC (Child–Pugh score A/B: 55.5 %/44.5 %) were embolized with HepaSphere microspheres 30–60 μm with escalation of lesion, dose, and frequency of re-embolization. Local response was evaluated with modified response evaluation criteria in solid tumors (mRECIST). Plasma levels of doxorubicin were measured in 24 patients at baseline and at 5, 20, 40, 60, and 120 min, at 6, 24, and 48 h, and at 7 days, respectively, to determine doxorubicin in plasma (Cmax) and area under the curve (AUC). Measurements of three patients who underwent lipiodol-based conventional chemoembolization (c-TACE) were also performed.

Results

TACE with HepaSphere was well tolerated with an acceptable safety profile and no 30-day mortality. Response rates were calculated on intention-to-treat basis with complete response (CR) in 17.8 % reaching 22.2 % for the target lesion. Overall partial response (PR) was seen in 51.1 %, stable disease in 20 %, and progressive disease in 11.1 % of patients. Overall objective response (CR + PR), including patients treated at all dosages of doxorubicin, was seen in 68.9 % of cases. After a median follow-up of 15.6 months, 1-year survival is 100 %. Doxorubicin AUC was significantly lower in patients with HepaSphere 30–60 μm (35,195 ± 27,873 ng × min/ml) than in patients with conventional TACE (103,960 ± 16,652 ng × min/ml; p = 0.009). Cmax was also significantly lower with HepaSphere 30–60 μm (83.9 ± 32.1 ng/ml) compared with c-TACE (761.3 ± 58.8 ng/ml; p = 0.002).

Conclusion

HepaSphere 30–60 μm is an effective drug-eluting embolic material with a favourable pharmacokinetic profile.

In vivo imaging using polymeric nanoparticles stained with near-infrared chemiluminescent and fluorescent squaraine catenane endoperoxide

Polystyrene nanoparticles stained with squaraine catenane endoperoxide exhibit remarkably high chemiluminescence and enable optical imaging of biodistribution in living mice. Whole-body chemiluminescence imaging was much more effective than fluorescence at identifying lung accumulation of the nanoparticles.

Hepatic arterial embolization complicated by acute cholecystitis

Hepatic arterial embolization (HAE) is a treatment used in the management of primary and some metastatic hepatic tumors. Complications of HAE are similar to those seen in other treatments, particularly transcatheter arterial chemoembolization (TACE), but without the possibility for chemotherapy related side effects. Particle reflux into the cystic artery is generally clinically occult but gallbladder ischemia severe enough to require cholecystostomy tube placement can occur. The authors discuss the case of a patient who underwent HAE and subsequently required a cholecystostomy tube due to development of acute cholecystitis.

Chemoembolization agents for cancer treatment

Chemoembolization has been used in the field of interventional oncology. Although practiced widely, it has only recently been demonstrated that the use of transarterial chemoembolization (TACE) provides a survival benefit based on randomized controlled trials. TACE combines the effect of targeted chemotherapy with the effect of ischemic necrosis induced by arterial embolization. Most of the TACE procedures have been based on iodized oil utilizing its microembolic and drug-carrying characteristics. Recently, there have been efforts to improve the delivery of chemotherapeutic agents to a tumor, which leads to the development of drug-eluting particles. In this review, we will describe the properties and efficacy of some chemoembolization agents which are commercially available and/or currently under clinical investigations. The potential and future of this new form of transcatheter arterial therapy for liver cancer will be discussed.