Role of immunoscintigraphy in clinical assessment of gastrointestinal tumors

From June 1986 until April 1989 31 patients with gastrointestinal tumors were studied at follow-up for recurrences by immunoscintigraphy (IS) using F(ab)2 fragments of monoclonal antibodies anti CEA and anti CA 19-9. IS was employed to confirm the presence of metastases already found (group A) and to verify metastases suspected following physical and instrumental examinations and/or increases in CEA and/or CA 19-9 (group B). Thrity-four IS findings have been evaluated to date: 19 in group A, with 18 true positive and 1 false negative results; 15 in group B. In these patients there were 12 cases of pathologic high fixation: 6 were confirmed using standard examinations after a median follow-up of 1 month (range 1-12); 6 cases had no metastatic evolution at the suspected site after a follow-up of 5-28 months. In 3 cases IS was negative, these patients are disease free at 13, 14 and 24 months. In group B, 5 of 8 abdominal intense fixations were early diagnoses of local or peritoneal recurrences. The overall accuracy was 79.4% and it was not affected by circulating CEA levels; sensitivity was 96%. IS can be considered useful as a primary diagnostic examination in the follow-up of patients with suspected abdominal metastases.