[Radioimmunoscintigraphy with monoclonal antibodies in recurrences and metastases of colorectal tumors].

An experimental follow-up plan based on immunoscintigraphy was evaluated in 48 patients, who had undergone resection for colorectal cancer. The results were compared with those concerning other 317 patients submitted to a traditional follow-up (physical examination, blood analysis, endoscopy, ultrasonography, CT scan, barium enema, etc.). Immunoscintigraphy was performed with Iodine 131--or Indium 111--labeled anti-CEA and-19.9 monoclonal antibody, using a gamma-detecting probe (GDP) enabling to perform radioimmunodetections. In addition, radioimmunoguided surgery was performed in two cases of highly suspected recurrence, and radioimmunoguided endoscopy was made in two cases of suspected recurrence after anterior resection for tumor of the rectum. Our gamma-detecting probe differs from the other ones because of its collimator which enables to detect all the radioisotopes that are used for external scanning and because of its particular shape that enables to perform endoscopic radioimmuno detections. The experimental follow-up plan showed cancer recurrence in 27% of the patients vs. 13% of extensive instrumental investigations. Radioimmunoguided surgery appears to provide a higher level of radicality. The same GDP used for intraoperative immunoscintigraphies seems to be effective in the endoscopic study of the pelvis after anterior resection, a clinical occurrence which can hardly be investigated by means of other instrumental diagnostic procedures.