PREOPERATIVE AND INTRAOPERATIVE RADIOIMMUNODETECTION OF CANCER PRETARGETED BY BIOTINYLATED MONOCLONAL-ANTIBODIES

The in vivo post-targeting of tumor by means of anti-carcinoembryonic- antigen (CEA) monoclonal antibodies (MAbs) and the avidin-biotin three -step system was tested by immunoscintigraphy and radioimmunoguided su rgery (RIGS) in six patients with primary or recurrent rectal cancer. The patients were preoperatively injected with 1 mg of F023C5 (anti-CE A) and/or B72.3 anti-tumor-associated glycoprotein (TAG-72) biotinylat ed MAb; after 24 hours, 1 mg of avidin was administered, and, after a further 24 hours, biotin labeled to Indium-111 (In-111) was injected. Preoperative imaging was obtained by means of a gamma camera, and a po rtable gamma-detecting probe (Neoprobe 1000) was intraoperatively used to count tumor and surrounding normal tissue. Eight tumor sites were localized in the six patients. Four lesions were identified preoperati vely and six intraoperatively with a mean tumor-to-normal-tissue (T/NT ) ratio of 1:8. This method allowed preoperative scintigraphy and intr aoperative radioimmunodetection to be performed with a single radioact ive compound injection of biotin labeled to In-111 within few days bef ore surgery. Semin. Surg. Oncol. 15:235-238, 1998. (C) 1998 Wiley-Liss , Inc.