IMAGING AND THERAPY OF GASTROINTESTINAL CANCERS WITH RADIOLABELED ANTIBODIES

Radiolabeled antibodies are gaining in application for the imaging and therapy of cancers. Much progress has been made in the use of these new biological reagents for tumors of the gastrointestinal system, and the current status, problems and prospects are reviewed in this paper. It is apparent that murine monoclonal antibodies against cancer-associated antigens are safe and useful for revealing a high percentage of sites of tumor, including some missed by conventional radiological methods. Tumors as small as 0.5 cm can be disclosed, even in organs that are difficult for CT scan interpretation. Major advances in cancer imaging have involved the use of antibody fragments and simple, direct labeling methods for Tc-99m, the most widely used radionuclide in nuclear medicine. The use of radiolabeled antibodies for cancer therapy has been a more difficult endeavor, particularly because of the delivery of inadequate rad doses to tumor. Advances include humanization of monoclonal antibodies and the improved attachment of therapeutic radionuclides, such as Y-90 and Re-186 or Re-188.