Disclosed are a radio-immunoconjugate for diagnosis and treatment of cancer or metastasis and development of metastasis inhibitory formulations using the same. More particularly, the present invention provides a radio-immunoconjugate as material indicating a metastatic cancer that has antibody marked with any lanthanum radionuclide and/or gamma, beta or alpha ray emitting radioisotopes targeting a vascular endothelial growth factor receptor (VEGFR). Such a radio-immunoconjugate is advantageous in that it maintains structural stability of a protein and immune activity thereof and is effectively adsorbed to the surface of vascular endothelial cells, thereby being useful as a pre-metastatic site detection factor. When the radio-immunoconjugate is administered to an animal model with a cancer, the radio-immunoconjugate is accumulated in cancer tissues, and therefore, is useful for development of radioactive metastasis inhibitory formulations.
