DIAGNOSTIC-ACCURACY OF TC-99M-ANTI-CEA IMMUNOSCINTIGRAPHY IN PATIENTS WITH LIVER METASTASES FROM COLORECTAL-CARCINOMA

17 patients with 43 liver metastases from colorectal carcinoma were studied by immunoscintigraphy (IS) using a Tc-99m-labelled monoclonal anti-CEA antibody (BW 431/26). Sensitivity and diagnostic accuracy were 21% for all liver lesions, but 47% considering the number of patients (at least one positive finding out of multiple metastases) and 77% in patients with a single metastasis. SPECT imaging did not improve sensitivity markedly in this series. There was no correlation with CEA serum levels. Liver metastases of intermediate size with moderate tumour necrosis seem to be favourable to IS. Major reason for the low sensitivity is the poor tumour-to-background ratio caused by high unspecific uptake of Tc-99m-labelled antibodies in the RES of the liver. At the moment, IS seems be only a supplementary method to conventional diagnostic procedures.