Yttrium-90 radioembolization in the management of liver tumors: expanding the global experience

Abstract

Although liver metastases are more common than primary liver malignancies, the incidence of hepatocellular carcinoma (HCC) continues to rise [1]. Surgical and medical therapies play a limited role in the management of advanced hepatic malignancies [2–4]. Locoregional therapies include ablative (e.g. radiofrequency ablation) and transarterial (e.g. chemoembolization) procedures. The unique anatomy of the liver and its tumors (relative hyperperfusion of liver tumors via the hepatic artery) allows targeted delivery of transarterial therapeutic agents. Historically, radiation therapy has played a limited role in the treatment of liver tumors primarily because of the low hepatic tolerance to external beam radiation [5]. Radiation-induced liver disease, a syndrome of anicteric hepatomegaly, ascites and elevated liver enzymes, is one of the most important treatment-related complications of radiation therapy [6]. However, newer technologies associated with external beam radiation have increased the safety profile. Radioembolization is a transarterial locoregional therapy for liver tumors, with numerous radionuclide/carrier combinations having been studied worldwide. There are two formulations of Y microspheres being used. TheraSphere (MDS Nordion, Ottawa, Canada) is composed of 15–30 μm nonbiodegradable glass microspheres with Y as an integral constituent of the glass. It has been FDA-approved for use in HCC patients with or without portal vein thrombosis. SIR-Spheres (SIRTex Medical, Lane Cove, Australia) are composed of resin microspheres and have been FDA-approved for use in metastatic colorectal carcinoma. Both agents have regulatory approval for liver neoplasia in Europe and various countries worldwide. Our group recently published an analysis of 291 patients focusing on the outcomes following radioembolization [7]. We concluded that this treatment was safe and effective in patients with HCC. Patients with coexisting portal vein invasion and poor liver function (Child-Pugh B or C) had poor outcomes. This treatment was shown to be safe if proper precautions and meticulous technique are applied [8]. In this first European experience with glass microspheres, Garin et al. should be commended for thoroughly investigating and providing proof of concept for the use of Y in liver malignancies [9]. Although in our experience angiography and planar SPECT has been sufficient to provide safe treatment, can SPECT/CT further increase the safety profile of this treatment option? Can it provide information on dosimetry? The authors present an interesting concept involving the utilization of SPECT/CT prior to and after administration of Y. It will be interesting to see data from larger cohorts on the role of this technique and its ability to reduce complications following administration of Y. However, we should be cautious in not necessarily supporting the use of this approach, as we have demonstrated in our center that Y can be given safely without SPECT/ CT. Further refinement of the role of SPECT/CT is required. Garin et al. also present a case of a dramatic effect (imaging This Editorial Commentary refers to the article http://dx.doi.org/ 10.1007/s00259-009-1279-6