Radioimmunoguided Surgery Using Iodine 125 B72.3 in Patients With Colorectal Cancer

Abstract

Preliminary data using B72.3 murine monoclonal antibody labeled with iodine 125 suggested that both clinically apparent as well as occult sites of colorectal cancer could be identified intraoperatively using a hand-held gamma detecting probe. We report the preliminary data of a multicenter trial of this approach in patients with primary or recurrent colorectal cancer. One hundred four patients with primary, suspected, or known recurrent colorectal cancer received an intravenous infusion of 1 mg of B72.3 monoclonal antibody radiolabeled with 7.4 x 10 Bq of iodine 125. Twenty-six patients with primary colorectal cancer and 72 patients with recurrent colorectal cancer were examined. Using the gamma detecting probe, 78% of the patients had localization of the antibody in their tumor; this included 75% of primary tumor sites and 63% of all recurrent tumor sites; 9.2% of all tumor sites identified represented occult sites detected only with the gamma detecting probe. The overall sensitivity was 77% and a predictive value of a positive detection was 78%. A total of 30 occult sites in 26 patients were identified. In patients with recurrent cancer, the antibody study provided unique data that precluded resection in 10 patients, and in another eight patients it extended the potentially curative procedure.

Editorial: Carcinoembryonic Antigen: The Old Dog Finally Learns New Tricks

“…Their study used antibodies directed against the B-72.3 oncofetal antigen conju gated with iodine-135. In the group of 78 patients with recurrent cancer, the antibody study provided unique data precluding resec tion in 10 patients and in another 8 patients located unsuspected métastasés which ex tended the potentially curative procedure [12]. This study gives further credence for the role of radioimmunodetection systems in identifying patient groups who would not benefit from exploratory laparotomy as well as subsets of patients with occult métastasés who might achieve extended palliation or cure by surgical resection.…”

“…Cohen et al [12] studied 104 patients using this technique. Twenty-six patients underwent primary resec tion and 78 patients underwent exploratory laparotomy for suspected recurrent colorectal cancer.…”

Management of Recurrent Colorectal Cancer: Another Look at Carcinoembryonic Antigen-Detected Recurrence

“…In a recent study of intraoperative ultrasound for gastrointestinal malignancy, 30 patients were evaluated in traoperatively with ultrasound for possible hepatic resection. Ultrasound demonstrated more métastasés than suspected in 10 of 19, and 20 of 30 had the surgical approach guided or altered by intraoperative ultrasound [44], Radioimmunoguided surgery is currently being investigated and preliminary results suggest that intraoperative information ob tained by the preoperative injection of radiolabeled monoclonal antibody followed by the intraoperative use of a gamma-detecting probe (radioimmunoguided surgery) can identify recurrences not detected by inspec tion and palpation alone [45]. Among 86 pa tients explored for recurrent colorectal cancer.…”

Radioimmunoguided surgery benefits in carcinoembryonic antigen-directed second-look surgery in the asymptomatic patient after curative resection of colorectal cancer

“…Several reports have shown benefits in primary and recurrent colorectal cancer procedures and indicate a potential for RIGS to increase survival rates in these patients [15][16][17][18]. Our study investigates the use of RIGS system in asymptomatic patients with previous surgery for primary colorectal cancer who are candidates for secondlook operations based solely on rising CEA serum levels.…”