The invention provides an insulin-like growth factor-1 (IGF-1) receptor ligand carrying a therapeutic radionuclide for treatment of cancer is provided. A method of treating cancer using the IGF-1 receptor ligand carrying a therapeutic radionuclide is also provided. An anti-cancer therapeutic agent containing an IGF-1 receptor ligand linked to a toxin is also provided, as are methods of using the toxin conjugates for treatment of cancer.