IMMUNOSCINTIGRAPHY OF COLORECTAL-CARCINOMA UTILIZING IN-111 LABELED MONOCLONAL-ANTIBODY CONJUGATE CYT-103

Twelve presurgical patients with colorectal carcinoma received a single intravenous infusion of 0.5-20.0 mg of the radiolabeled monoclonal antibody conjugate CYT-103. This product is an immunoconjugate of B72.3 labeled with Indium-111 (In-111). Patients underwent preoperative gamma camera imaging and computed tomographic (CT) scanning of the abdomen and pelvis. Fifteen intraabdominal sites of tumor were found at surgery. Monoclonal antibody imaging detected 87% of these lesions, whereas CT of the abdomen and pelvis detected 47%. Monoclonal antibody imaging identified tumor in 27% of the patients in which CT did not identify any sites of tumor. The results of this study indicate that monoclonal antibody imaging using [In-111]CYT-103 is useful for the preoperative evaluation of colorectal carcinoma patients and the results are complimentary to CT of the abdomen and the pelvis.