Imaging gastrointestinal tumours using vascular endothelial growth factor-165 (VEGF165) receptor scintigraphy

Background: Recent studies have shown that vascular endothelial growth factor (VEGF) receptor is overexpressed in vascular endothelial cells of various human tumours as well as in human tumour cells. The aim of this study was to evaluate the usefulness of scanning with VEGF(165) labeled with I-123 for tumor localisation in patients with gastrointestinal tumours. Patients and methods: Human recombinant VEGF(165) was radiolabelled with I-123 by electrophilic radioiodination using the chloramine T method. [I-123]VEGF(165) was administered intravenously [mean dose 184+/-18 MBq (less than or equal to130 pmol; less than or equal to5 mug) per patient] to 18 patients with gastrointestinal tumours. Dynamic acquisition was initiated immediately after administration and carried out until 30 min post-injection. Whole body images were done in anterior and posterior views at various time points. All patients underwent single-photon emission tomography imaging 1.5 h post-injection. Scanning with [I-123]VEGF(165) was compared with computed tomography and magnetic resonance imaging. Results: Intravenous injection of [I-123]VEGF(165) did not cause any side-effects. Binding of [I-123]VEGF(165) to primary tumours and metastases was visible shortly after injection. In patients with pancreatic adenocarcinomas, primary tumours were visualised in seven of nine, lymph node metastases in three of four, liver metastases in three of six and lung metastases in one of three. Cholangiocarcinomas were visualised by imaging in one of two patients. Hepatocellular carcinomas were visible by imaging in two of four patients. [I-123] VEGF(165) scans were weakly positive in one patient with abdominal schwannoma and in one patient with peritoneal carcinosis. Conclusions: These results indicate that scanning with [I-123] VEGF(165) can visualise gastrointestinal tumours and metastases expressing receptors for VEGF(165). [I-123]VEGF(165) receptor scintigraphy may be useful for visualisation of tumour angiogenesis.