Radioimmunolocalization of tumours of the pancreas and biliary tree

Although localization of tumours by radiolabelled antibodies is in principle a specific method, in practice the technique is dependent upon qualitative and quantitative differences in antigen expression between malignant and benign tissue. Pancreatic disease is similar to other gastrointestinal malignancies in which RIL has been evaluated. The expression of a small number of antigens has been demonstrated to enable some differentiation between pancreatic cancer and principally chronic pancreatitis. To date the cross-reactivity of antibodies has resulted in limited specificity but it does appear that CEA, CA19-9, TAG-72 and BW494 are appropriate target antigens. Studies in RIL have indicated that BW494 has the optimal characteristics, although studies with chronic pancreatitis are limited. Further information on the fate of the administered antibody and the interactions with tumour-associated antigen is required before clinical application can be considered. At present this technique does not have a role in primary diagnosis. In the near future, however, RIL may prove useful as a complementary investigation to conventional methods particularly in the assessment of recurrent malignancy.