Current status of embolic agents for liver tumor embolization

Abstract

Gelatin sponge and polyvinyl alcohol particles have been the most popular particulate embolic agents for transarterial chemoembolization (TACE) of liver tumors. Over the last decade, calibrated microspheres have been introduced and increasingly used in liver tumor embolization in Western countries. In addition, drug-eluting beads (DEB) have been introduced for sustained local drug release. Such long-awaited spherical embolic agents will be introduced in Japan in the near future. The advantages of these microspheres are that particles are uniform in size and shape, and easy to inject through a microcatheter. They can travel distally to vessels corresponding to the particle size; in other words, the occlusion level can be predicted according to the particle size chosen. Thus, new bland microspheres and DEB may bring a significant advancement to embolization for primary liver tumors as well as hepatic metastases from various cancers. However, at this point, the published data suggests that both conventional TACE and DEB-TACE are equally effective for treatment of unresectable hepatocellular carcinoma, when patients are carefully selected. Therefore, indication, patient selection, and embolization techniques will be essential in order to individually adapt newer embolic agents based on oncological, anatomical and technical considerations.

Modification of the method to establish a hepatic VX2 carcinoma model in rabbits

“…However, as an embolizing material, the segregation function of the gelatin sponge may inhibit tumor growth, potentially through insufficient blood and nutrient supply (16), although it significantly decreased the incidence of peritoneal nodules in the present study. To the contrary, the present study demonstrated that there was no significant distinction between the conventional and the modified methods with regard to the number, mass and largest diameter of tumor foci in the liver.…”

“…To the contrary, the present study demonstrated that there was no significant distinction between the conventional and the modified methods with regard to the number, mass and largest diameter of tumor foci in the liver. The gelatin sponge has previously been used as an embolizing material in TACE; however, it is seldom used nowadays for its temporary embolizing effect, as it is a loose and absorbable material (16). Therefore, in the modified method, the gelatin sponge served the function of preventing tumor fragment drop-out and tumor cell implantation without completely restricting the supply of oxygen and nutrients to the tumor fragments.…”

Does Drug-Eluting Bead Transcatheter Arterial Chemoembolization Improve the Management of Patients with Hepatocellular Carcinoma? A Meta-Analysis

“…The use of DEBs which release the antineoplastic gent in the lesion in a controlled fashion is a new technique and has been shown to be associated with a reduction in systemic side effects and an increase in dose of the antineoplastic agent in the local lesion [8]–[16]. Pooled data from six clinical trials showed high local response rates ranging from 52% to 81% [17]–[24]. However, there is no strong evidence to show whether the cTACE is better than DEB-TACE in any terms of effectiveness.…”

Utilizing devices from interventional radiology in congenital heart disease

“…PVA works by adhering to and occluding vessels. The chief limitation of PVA is the irregular size and shape of the actual particles, which can cause both aggregation in vessels more proximally than intended and migration into more distal capillary beds [36]. This behavior makes the occlusion level of the particles difficult to control in a targeted fashion, and thus, usage of PVA has been largely superseded by spherical embolic agents (microspheres).…”