INDIUM-111-DTPA-OCTREOTIDE SCINTIGRAPHY MODULATION BY TREATMENT WITH UNLABELED SOMATOSTATIN ANALOG IN SMALL-CELL LUNG-CANCER

Aims and background: Small-cell lung cancer (SCLC) tissue expresses somatostatin receptors and can be visualized by means of the indium-111-labelled somatostatin analogue DTPA-D-Phe-octreotide. The aim of the study was to investigate whether treatment with a cold somatostatin analogue can affect the imaging of somatostatin receptor scintigraphy. Methods: Three patients with SCLC were treated with 200 mu g of cold octreotide three times a day subcutaneously for 7 days. Whole body and planar scintigraphy was performed before and after the treatment. Results: In-111-DTPA-octreotide uptake was increased in cancer lesions, whereas fixation in normal tissues (liver, spleen, kidneys) decreased. Conclusions: This is the first demonstration of an enhancement of SCLC imaging following unlabelled somatostatin analogue administration. Similar results have been described by other authors in a limited number of carcinoid tumors.