Second-look surgery for colorectal cancer. The second time around.

Eighty-six colorectal cancer patients who entered the Radioimmunoguided Surgery (RIGS) protocol study were evaluated for 2-, 3-, 4-, and 5-year survival following second-look surgical procedures. Strict preoperative evaluation criteria eliminated patients with extra-abdominal tumor involvement. A saturated potassium iodide preparation was given before the intravenous administration of the B72.3 monoclonal antibody (1 mg) radiolabeled with 2 mCi of iodine-125 by the IODOGEN method. Precordial monitoring of the biologic clearance by the handheld, gamma-detecting probe (Neoprobe 1000 instrument) was conducted at weekly intervals until the average count was less than 20 counts in 2 seconds. Once the drug cleared from the blood, surgery was performed. The mean time interval between injection and operation was 24 days, with a range of 21 to 28 days and a median of 23 days. At surgery the abdomen was explored through the traditional methods of palpation and inspection, and the surgeon committed to a planned procedure. The abdomen was then re-explored with the handheld, gamma-detecting probe and the surgeon stated another intraoperative assessment. After using both traditional and RIGS detection methods, the surgeon stated whether his or her surgical plans changed because of the additional intraoperative information provided by the RIGS system. Fifty-three patients (62%) were deemed resectable by the traditional methods of palpation and inspection, but only 40 (47%) were specified as resectable by RIGS exploration. Two-, three-, four-, and five-year survival data could be gathered for each of the three groups: RIGS resectable (n = 40), traditional nonresectable (n = 33), and RIGS nonresectable (n = 13). At 2 years 95% of the resectable, 36% of the traditional nonresectable, and 53% of RIGS nonresectable patients survived. At 3 years 83%, 7%, and 30% of these patients survived, respectively. For the resectable patients, 74% survived at 4 years and 60% at 5 years, with no survivors from either nonresectable group. Use of the RIGS system increased accurate selection of resectable patients undergoing second-look surgery for recurrent colorectal cancer.