Radioembolization as an adjunct therapy to the resection of liver tumors.

Liver Unit at Clinica Universidad de Navarra, CIBEREHD, & Navarra Institute for Health Research, Avda. Pio XII 36, 31008 Pamplona, Spain *Author for correspondence: Tel.: +34 948 296 637; Fax: +34 948 296 500; bsangro@unav.es Radioembolization (RE) is a form of brachytherapy in which radioactive microspheres labeled with Yttrium 90 – a pure b emitter – are injected into the hepatic arteries to provide selective internal radiation of liver tumors due to their preferentially arterial blood supply [1]. Depending on the artery in which the microspheres are injected, RE may be performed selectively, lobarly or as a whole-liver treatment. Over the last 10 years, RE has been increasingly used as a locoregional therapy in those situations where the liver harbors all or most tumor burden, such as hepatocellular carcinoma (HCC) and liver metastasis from colorectal cancer (lmCRC) or other tumors. Resection of liver cancer is mainly restricted by the quantity and quality of the future liver remnant (FLR). Quality depends on the presence of an underlying liver damage (hepatitis or cirrhosis for HCC, chemotherapy-induced liver damage for lmCRC), while quantity depends on the size and location of tumor lesions. RE was initially considered only as rescue therapy for patients that had exhausted all possible therapies, including advanced stage HCC with vascular invasion or highburden intermediate stage HCC unlikely to benefit from chemoembolization [2], and chemorefractory CRC liver metastasis treated as third line or beyond [3]. In fact, surgeons in multidisciplinary team discussions were usually not in favor of considering RE for patients with potentially resectable liver tumors. Reasons included but were not limited to a potential risk of more frequent postoperative complications derived from liver irradiation (technical complications) or reduced liver functional reserve (subclinical toxicity). In the last few years we have nevertheless gained a better understanding of the biological effects of RE in the tumor and nontumor liver tissue, and the potential of RE as an adjunctive therapy to resection of liver cancer has become a matter of interest that is worth being examined. “Over the last 10 years, radioembolization has been increasingly used as a locoregional therapy in those situations where the liver harbors all or most tumor burden, such as hepatocellular carcinoma and liver metastasis from colorectal cancer or other tumors.”