Uptake of radiolabeled somatostatin analog is detectable in patients with metastatic foci of sarcoma

BACKGROUND. Somatostatin receptors are present on many types of epithelial tumors, and ligands targeting these receptors are used to treat patients wi th neuroendocrine malignancies. Preclinical studies have demonstrated the p resence of somatostatin receptors on a variety of mesenchymal tumors by in vitro receptor autoradiography. The use of radiolabeled somatostatin analog s to assess the presence of somatostatin receptors in vivo has been establi shed, but use of this technique to evaluate human sarcomas has not been rep orted previously. METHODS. Seventeen patients (13 females and 4 males) with metastatic sarcom a underwent imaging via somatostatin-receptor scintigraphy. Scans were perf ormed using indium -111 pentetreotide. Planar studies and single photon emi ssion computed tomography imaging were performed at 4 and 24 hours, and res ults of scintigraphy were correlated with computed tomography findings. RESULTS. Twelve of 17 scans showed increased uptake in regions of known met astatic disease. There was no apparent correlation with scan positivity and patient age, histology, site of disease, or duration of diagnosis. CONCLUSIONS. Seventy-one percent of patients with advanced soft-tissue sarc omas had positive scintigraphy scans demonstrating tumor expression of soma tostatin receptors subtype 2 in vivo. Imaging with indium-lll pentetreotide could be studied as an adjunct to conventional imaging modalities for asse ssment of sarcoma patients. Further research is needed to determine the pro gnostic implications of somatostatin receptor subtype 2 positivity, includi ng larger studies to evaluate any potential correlation with metastatic beh avior and other clinical outcomes. (C) 1999 American Cancer Society.