MULTICENTER IMMUNOSCINTIGRAPHIC STUDY USING INDIUM-111-LABELED CEA-SPECIFIC AND/OR 19-9 MONOCLONAL-ANTIBODY F(AB')2 FRAGMENTS

Six European nuclear medicine centres per formed immunoscintigraphy first retrospectively in 34 patients using indium-111-labelled carcinoembryonic antigen (CEA)-specific and/or 19-9 F(ab')2 fragments. Results for sensitivity and specificity in tumour sites were 94% and 87%, respectively, for the pelvis and 73% and 100% for the extrahepatic abdomen. A second prospective series concerned 58 other patients previously operated on for colorectal adenocarcinoma (27 colon, 31 rectum). Two-thirds of these patients had a suspected recurrence signalled by an isolated rise in tumour markers, and 46 patients examined by immunoscintigraphy, X-ray computed tomography and ultrasonography were found to have a recurrence (a total of 62 tumour sites). Sensitivity and specificity with immunoscintigraphy were 90% and 97%, respectively, for the pelvis and 62% and 95% for the extrahepatic abdomen. For 29 patients injected with CEA-specific fragments, sensitivity was 90% and specificity 94% for the pelvis. For 25 patients injected with 19-9 fragments, pelvic sensitivity and specificity were 80% and 100%, respectively, whereas sensitivity for the extrahepatic abdomen was only 29% since several cases of peritoneal carcinosis were not visualized. In the prospective series, comparison of the three imaging techniques for all tumour sites (including liver and in 5 cases thorax) gave a sensitivity and specificity of 82% and 91 %, respectively, for immunoscintigraphy, 52% and 95% for X-ray computed tomography and 59% and 100% for ultrasonography. These results thus confirm the advantage of using111In-labelled CEA-specific or 19-9 to visualize and localize recurrences of colorectal cancer. © 1990 Springer-Verlag.