Current status of immunoscintigraphy in colorectal cancer--results of 5 years' clinical experiences.

In 100 patients with suspected colorectal cancer, findings of conventional diagnostic methods were compared with immunoscintigraphy results. In a first trial 131-J-labelled F (ab') 2-fragments against CEA and CA 19-9 were used in 42 patients. Evidence was confirmed by surgical exploration in 69% of cases and by close follow-up examination in 31%. In a second trial 58 patients were included, and 81% of these were explored surgically. Conventional diagnostic methods achieved better results in both series in imaging liver and extrahepatic tumor manifestations, and in both series immunoscintigraphy was especially disappointing with regard to extrahepatic tumor diagnosis (sensitivity 23% and 38%, respectively). Accuracy could not be improved by technical modifications such as change of antibodies, radiolabels or imaging techniques. The value of immunoscintigraphy as a helpful tool for the operative management of metastatic or recurrent colorectal cancer must, therefore, be viewed critically.