Preliminary evaluation of indigenous 90Y-labelled microspheres for therapy of hepatocellular carcinoma

Background & objectives: Yttrium-90 (Y-90)-based radioembolization has been employed to treat hepatocellular carcinoma (HCC) as commercial radioactive glass and polymeric resin microspheres. However, in India and other Asian countries, these preparations must be imported and are expensive, validating the need for development of indigenous alternatives. This work was aimed to develop an economically and logistically favourable indigenous alternative to imported radioembolizing agents for HCC therapy. Methods: The preparation of Y-90-labelled Biorex 70 microspheres was optimized and in vitro stability was assessed. Hepatic tumour model was generated in Sprague-Dawley rats by orthotopic implantation of N1S1 rat HCC cell line. In vivo localization and retention of the Y-90-labelled Biorex 70 microspheres was assessed for seven days, and impact on N1S1 tumour growth was studied by histological examination and biochemical assays. Results: Under optimal conditions, > 95% Y-90-labelling yield of Biorex70 resin microspheres was obtained, and these showed excellent in vitro stability of labelling (> 95%) at seven days. In animal studies, Y-90-labelled Biorex 70 microspheres were retained (87.72 +/- 1.56% retained in liver at 7 days). Rats administered with Y-90-labelled Biorex 70 microspheres exhibited lower tumour to liver weight ratio, reduced serum alpha-foetoprotein level and greater damage to tumour tissue as compared to controls. Interpretation & conclusions: Y-90-labelled Biorex 70 microspheres showed stable retention in the liver and therapeutic effect on tumour tissue, indicating the potential for further study towards clinical use.