Radioimmunoscintigraphy of prostate cancer

The development of hybridoma technology has increased research efforts and clinical applications in the area of radioimmunodetection. Despite the many investigative antibodies directed against prostatic tissue or prostate cancer cell lines, only two have been tested in clinical trials. A 111In-labeled antibody directed against prostate-specific antigen, the best available serum tumor marker for prostate cancer, has shown poor sensitivity in limited clinical radioimmunoimaging trials. Monoclonal antibodies against prostatic acid phosphatase have shown better imaging results, particularly at higher antibody doses (greater than or equal to 40 mg). The limitations of this antibody include the poor results in detecting soft tissue lesions, including the primary lesion; the development of human antimouse antibodies in 50% of the patients at doses greater than or equal to 40 mg; the expense of the antibody; and the fact that better results are currently attainable by other less expensive imaging modalities. If and when a more suitable antibody or fragment is developed, the prospect of improved staging and new treatments using immunologic conjugates carrying therapeutic agents may become realities. Until such time, prostatic cancer will be staged with other currently available imaging modalities and conventional therapies with their limitations will remain state of the art.