[Immunoscintigraphy and SPECT in patients with pancreatic cancer]

Encouraged by reports on immunoscintigraphy of colorectal carcinomas and by the results of our own immunohistochemical and immunoscintigraphic studies in nude mice with transplanted pancreatic carcinoma, we studied the diagnostic potential of immunoscintigraphy with a cocktail of 131I-labeled monoclonal antibodies against the tumor markers CA 19-9 and CEA in 21 patients with pancreatic cancer disease. The results were compared with those of 10 patients suffering from colorectal tumors, 2 cases with bile duct carcinoma and 1 with gastric cancer. Planar scintigraphy with 2-4 views was done repeatedly within 6 days after i.v infusion of 2 mCi of the antibody cocktail. SPECT was performed 3-4 days p.i., recently at 1 or 2 days, too. Primary tumors and metastases in the upper abdominal parts were more difficult to detect and to localise in comparison to colorectal cancer in the lower parts of the abdomen, because of relatively high tracer accumulation in kidneys, liver and spleen. Tumor enhancement in planar scintigrams was, in most cases, not recognized prior to 5 or 6 days p.i., but by SPECT 3 days p.i. or even earlier. Localisation and topographic determination were much easier and more frequent with SPECT, so that tumor detection became more reliable and sensitive. Large tumors could be detected in some cases without tumor marker concentrations in serum being elevated. Immunoscintigraphy of pancreatic carcinomas and of other cancer manifestations in the upper abdomen up to now seems to be of limited diagnostic value, the techniques involved need to be improved.