Immunoscintigraphy in primary colorectal cancer.

Abstract

Immunoscintigraphy is an experimental diagnostic nuclear medicine imaging technique that targets tumor sites with radiolabeled antibodies reactive with tumor-associated antigens. Primary tumors, regional lymph node metastases, and distant metastases have been imaged in patients with colorectal cancer, and United States Food and Drug Administration (FDA) approval of a commercial preparation of radiolabeled murine monoclonal antibodies for diagnostic use in such patients is expected soon. Immunoscintigraphy is complementary to computed tomography (CT) scanning in the evaluation of the abdomen and pelvis in patients with colorectal cancer, and it has the additional capability of serial whole body imaging for detection of distant metastases. However, the clinical utility of immunoscintigraphy is being investigated, and its precise diagnostic role in patients with primary colorectal cancer has not been adequately defined. The management of selected patients at increased risk of regional or distant spread of tumor likely would benefit from detection of occult disease and a change in clinical staging, but the routine use of immunoscintigraphy in the preoperative evaluation of patients with primary colorectal cancer is more problematic. More studies are required to determine whether it should be used to stage all patients before operation or merely be reserved for selected patients at increased risk for metastatic disease.