Background: The contributions of nuclear imaging tests to the management of cancer are expanding, especially in terms of detection (staging and recurrence), diagnosis, and qualification of patients for certain forms of therapy, and particularly with regard to the tests' ability to identify tumors on a functional basis.
Methods: This article is a selective review of the advances and clinical management applications of cancer imaging with radiolabeled antibodies (radioimmunodetection or immunoscintigraphy), with the objective of demonstrating how this new imaging technology can contribute to oncologic practice. The contribution of another functional imaging modality, positron emission tomography (PET), also is discussed.
Results: Radioimmunodetection and PET imaging have shown particular management contributions in patients with colorectal, breast, or lung carcinoma, as well as in patients with non-Hodgkin's lymphoma (NHL). Two antibody imaging agents, OncoScint and CEA-Scan, currently are available for the detection of colorectal carcinoma, and have shown particular application for disease staging and disclosure of occult lesions. Each of these agents has different characteristics and potential applications. Recent results with CEA-Scan in patients with mammary carcinoma suggest that it may be a useful complementary tool to screening mammography by adding very high specificity. In patients with lung carcinoma, technetium-99m-labeled NR-LU-10 antibody has been shown to be useful in preoperative staging. LymphoScan is under investigation as a staging agent and for revealing residual disease in patients with NHL; it also provides, with a different radioisotope attached and in a humanized antibody form, a therapeutic option for patients with NHL. Similar results can be shown for PET, but this method may not provide the specificity of an antibody-based functional imaging agent, although PET may have a higher lesion sensitivity.
Conclusions: Both radioimmunodetection and PET provide new exciting opportunities for earlier and more sensitive functional imaging tests for cancer. In contrast to PET, antibody agents also can serve to qualify a patient as a candidate for an antibody-based therapy.