Somatostatin receptor scintigraphy during treatment with lanreotide in patients with neuroendocrine tumors

To investigate possible changes in somatostatin receptor expression during treatment with high dose lanreotide, eight patients with neuroendocrine tum ors were investigated by [In-111-DTPA-D-Phe(1)]-octreotide scintigraphy bef ore and during treatment. The spleen-to-background ratio decreased in all p atients, whereas tumor-to background ratio revealed a heterogeneous pattern with an average increase of 50% (-79% to +1,087%). This finding indicates that lanreotide treatment may influence the binding of radioactively labele d somatostatin to the spleen, while changes in the binding to functioning s omatostatin receptors in tumor cells are more complex: and not clearly rela ted to treatment. (C) 2000 Elsevier Science Inc. All rights reserved.