Comparison of iodine-123-vasoactive intestinal peptide receptor scintigraphy and indium-111-CYT-103 immunoscintigraphy.

Abstract

UNLABELLED:

Recently, we have shown that the expression of receptors for vasoactive intestinal peptide (VIP) on intestinal adenocarcinomas can be used for in vivo targeting of primary or metastatic tumor sites using 123I-labeled VIP. Several other receptors and antigens including the TAG-72 protein have also been implemented for in vivo localization purposes. In this study, we have compared the in vitro and in vivo binding of 123I-VIP and of the 111In-labeled monoclonal antibody (MAb) directed against TAG-72 (OncoScint; 111In-CR-103) in patients with intestinal adenocarcinomas in a single-blinded, prospectively randomized trial.

METHODS:

Twenty patients were administered either 123I-VIP (150-200 MBq; 1 microgram) or 111In-CYT-103 (150 MBq; 1 mg) for one imaging study. After interim analysis demonstrated superior imaging with 123I-VIP, the next 10 patients (accounting for a total of 50 patients) enrolled in this trial underwent both studies in random order to allow for a direct comparison.

RESULTS:

In total, 123I-VIP scans were true-positive in 28 of 30 patients (93%) versus 17 of 30 patients administered 111In-CYT-103 (56%). In the subgroup of 10 patients enrolled in the second part of the study, primary intestinal adenocarcinomas were imaged in five of five patients with 123I-VIP and in only two of these patients with 111In-CYT-103. Liver metastases were visualized in five of six patients by 123I-VIP receptor scanning and in four of these patients with 111In-CYT-103. The in vitro results indicated significant binding of 123I-VIP to primary colorectal tumors as well as to HT29 and COLO320 adenocarcinoma cells. In vitro, adenocarcinoma cells also expressed abundant numbers of the TAG-72 antigen.

CONCLUSION:

Intestinal adenocarcinomas co-express VIP receptors and the IAG-72 antigen. Despite significant in vitro binding of both agents, however, the VIP receptor scan is more sensitive in localizing intestinal adenocarcinomas and metastatic spread.

• Authors: M Raderer, A Becherer, A Kurtaran, P Angelberger, S Li, M Leimer, G Weinlaender, G Kornek, K Kletter, W Scheithauer, I Virgolini
• Journal: Journal of nuclear medicine : official publication, Society of Nuclear Medicine (J Nucl Med) Vol. 37 Issue 9 Pg. 1480-7 (Sep 1996) ISSN: 0161-5505 [Print] United States
• PMID: 8790198 (Publication Type: Clinical Trial, Comparative Study, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Monoclonal
• Indium 111In-satumomab pendetide
• Indium Radioisotopes
• Iodine Radioisotopes
• Oligopeptides
• Receptors, Vasoactive Intestinal Peptide
• Vasoactive Intestinal Peptide
• Pentetic Acid

Topics

• Adenocarcinoma (diagnostic imaging, secondary)
• Antibodies, Monoclonal
• Female
• Gastrointestinal Neoplasms (diagnostic imaging)
• Humans
• Indium Radioisotopes
• Iodine Radioisotopes
• Liver Neoplasms (diagnostic imaging, secondary)
• Male
• Middle Aged
• Oligopeptides
• Pancreatic Neoplasms (diagnostic imaging)
• Pentetic Acid (analogs & derivatives)
• Prospective Studies
• Radioimmunodetection
• Receptors, Vasoactive Intestinal Peptide (analysis)
• Single-Blind Method
• Tumor Cells, Cultured
• Vasoactive Intestinal Peptide