UNLABELLED: Peptide receptor-targeted radionuclide therapy of somatostatin receptor-expressing tumors is a promising application of radiolabeled somatostatin analogs. Suitable radionuclides are (90)Y, a pure, high-energy beta-emitter (2.27 MeV), and (177)Lu, a medium-energy beta-emitter (0.5 MeV) with a low-abundance gamma. METHODS: Lewis rats, each bearing both a small (approximately 0.5 cm(2)) and a large (7-9 cm(2)) somatostatin receptor-positive rat pancreatic CA20948 tumor in their flanks, were used. We investigated the radiotherapeutic effects of [(90)Y-tetraazacyclododecanetetraacetic acid (DOTA),Tyr(3)]octreotide, [(90)Y-DOTA,Tyr(3)]octreotate, [(177)Lu-DOTA,Tyr(3)]octreotate, and the combination of (90)Y- and (177)Lu-labeled analogs at the same tumor radiation dose (60 Gy). RESULTS: Radiotherapeutic effects of the (90)Y- and (177)Lu-labeled analogs were found in the rat tumor model. In these animals bearing tumors of different sizes, the antitumor effects of the combination of 50% (177)Lu- plus 50% (90)Y-analogs were superior to those in animals treated with either (90)Y- or (177)Lu- analog alone. In smaller tumors, the (90)Y radiation energy was not completely absorbed in the tumor, whereas in larger tumors the increased number of clonogenic tumor cells at the fixed level of absorbed dose may account for the failure of (177)Lu alone to go completely into remission. CONCLUSION: This study shows the superior antitumor effects of the combination of (177)Lu- and (90)Y-somatostatin analogs when compared with either (90)Y- or (177)Lu-analog alone in animals bearing tumors of various sizes.
UNLABELLED: Peptide receptor-targeted radionuclide therapy of somatostatin receptor-expressing tumors is a promising application of radiolabeled somatostatin analogs. Suitable radionuclides are (90)Y, a pure, high-energy beta-emitter (2.27 MeV), and (177)Lu, a medium-energy beta-emitter (0.5 MeV) with a low-abundance gamma. METHODS: Lewis rats, each bearing both a small (approximately 0.5 cm(2)) and a large (7-9 cm(2)) somatostatin receptor-positive ratpancreatic CA20948 tumor in their flanks, were used. We investigated the radiotherapeutic effects of [(90)Y-tetraazacyclododecanetetraacetic acid (DOTA),Tyr(3)]octreotide, [(90)Y-DOTA,Tyr(3)]octreotate, [(177)Lu-DOTA,Tyr(3)]octreotate, and the combination of (90)Y- and (177)Lu-labeled analogs at the same tumor radiation dose (60 Gy). RESULTS: Radiotherapeutic effects of the (90)Y- and (177)Lu-labeled analogs were found in the rattumor model. In these animals bearing tumors of different sizes, the antitumor effects of the combination of 50% (177)Lu- plus 50% (90)Y-analogs were superior to those in animals treated with either (90)Y- or (177)Lu- analog alone. In smaller tumors, the (90)Y radiation energy was not completely absorbed in the tumor, whereas in larger tumors the increased number of clonogenic tumor cells at the fixed level of absorbed dose may account for the failure of (177)Lu alone to go completely into remission. CONCLUSION: This study shows the superior antitumor effects of the combination of (177)Lu- and (90)Y-somatostatin analogs when compared with either (90)Y- or (177)Lu-analog alone in animals bearing tumors of various sizes.
Authors: Renaud Lhommel; Larry van Elmbt; Pierre Goffette; Marc Van den Eynde; François Jamar; Stanislas Pauwels; Stephan Walrand Journal: Eur J Nucl Med Mol Imaging Date: 2010-04-27 Impact factor: 9.236
Authors: Craig J Galbán; Stefanie Galbán; Marcian E Van Dort; Gary D Luker; Mahaveer S Bhojani; Alnawaz Rehemtulla; Brian D Ross Journal: Prog Mol Biol Transl Sci Date: 2010 Impact factor: 3.622