Histological correlation of 17 prospective immunoscintigraphies of recurrences of colorectal carcinomas using indium-111-labeled anti-CEA and(or) 19-9 monoclonal antibodies

Seventeen patients (mean age 55 years) with suspected recurrence in previously operated and histologically confirmed colorectal adenocarcinomas were explored by immunoscintography (IS) associating planar and emission computed tomography (ECT) and using the 111In-labeled anti carcinoembryonic antigen (CEA) and(or) 19-9 monoclonal antibodies (MoAbs). The results of IS were compared blind with those of computed tomography (CT) and ultrasonography (US). The final diagnosis of recurrence and(or) metastasis was done in 16 cases by second-look surgery and in another patient by rectal biopsy. Overall per-patient sensitivity for the pelvis and extrahepatic abdomen was 69% for IS and 31% and 25% respectively for computed tomography and ultrasonography. No false positive of IS, as well as US and CT, for the pelvis and the extrahepatic abdomen was seen. Based on the number of anatomical sites tested, sensitivity of IS was 91% in the pelvis. In our series, scintigraphic computer subtraction did not allow adequate resolution of the problem of intense liver uptake of 111In-labeled MoAbs. It is concluded that IS using 111In-labeled anti CEA and(or) 19-9 MoAbs should be carried out prospectively in patients at high risk of recurrence of colorectal cancer. (orig.)