Labelled antibody imaging in pancreatic cancer, cholangiocarcinoma, chronic pancreatitis and sclerosing cholangitis.

Pancreatic and biliary carcinomas are difficult to differentiate clinically from their benign counterparts, chronic pancreatitis and sclerosing cholangitis. Immunohistochemical differences in CEA expression have previously been demonstrated in these conditions. We have therefore investigated the use of a monoclonal anti-CEA antibody (11-285-14) in distinguishing between these conditions in vivo. Twenty-five patients with these four conditions underwent radioimmunolocalisation studies. Diagnosis was confirmed by laparotomy and biopsy (n = 21), CT scanning (n = 1) or ERCP (n = 3). Positive images were obtained in 11/12 pancreatic cancers and 2/3 biliary tumours. However, 4/8 cases of chronic pancreatitis and 1/2 cases of sclerosing cholangitis also had positive images. This high false positive rate suggests that antibody imaging is unable to differentiate reliably between benign and malignant pancreatico-biliary conditions.