Carcinoembryonic antigen immunoscintigraphy complements mammography in the diagnosis of breast carcinoma

BACKGROUND: An adjunctive noninvasive test that is predictable and highly specific for breast carcinoma would complement the high false-positive rate of mammography in certain patients. METHODS: This prospective, multicenter study evaluated the accuracy, safety, and immunogenicity of carcinoembryonic antigen (CEA) antibody imaging in women with known or suspected breast carcinoma. Scintigraphic breast images were obtained approximately 3-8 hours after the administration of technetium 99m ((99)Tc) labeled anti-CEA Fab' and correlated with histopathology. RESULTS: The (99)Tc labeled anti-CEA Fab' detected tumor CEA expression in 46 of 49 women (94%) initially entered with known primary breast carcinoma regardless of histology or serum CEA levels. In women scheduled for biopsy confirmation of mammographic and physical examination findings, 104 (99)Tc labeled anti-CEA Fab' studies had a sensitivity of 61% (17 of 28 cases) and a specificity of 91% (69 of 76 cases). In total, (99)Tc labeled anti-CEA Fab' detected 52 of 62 invasive ductal carcinomas, 5 of 5 invasive lobular carcinomas, and 3 of 6 noninvasive tumors (2 ductal carcinomas in situ and 1 intracystic papillary carcinoma). Tumor size significantly affected sensitivity (P = 0.041), with 11 of 14 missed lesions