Intensification of 111In-DTPA-octreotide scintigraphy by means of pretreatment with cold octreotide in small cell lung cancer.

Small cell lung cancer (SCLC) expresses somatostatin receptors that can be traced with 111In-DTPA-octreotide scintigraphy. Although this technique is currently employed for staging and follow-up of neuroendocrine tumors of the gastrointestinal tract, its role in the clinical work-up of SCLC is at present under discussion. A better imaging contrast is desirable and recent reports suggest that this aim could be achieved by pretreatment with cold octreotide. Here we report on the results of 111In-DTPA-octreotide scintigraphy in 12 SCLC patients carried out before and after octreotide treatment. The patients were treated for 7 days with octreotide 200 micrograms three times a day s.c. Uptake was studied at 5 h with whole body planar and SPET imagings. In all cases studied, pretreatment with octreotide was followed by enhancement of tumor imaging. In one patient a better contrast of the lesions was found at the parenchymal and mediastinal levels as well as at brain level, allowing a clear definition of otherwise questionable metastases. After octreotide treatment, a decrease in background uptake in the subdiaphragmatic area was observed in most cases, allowing a better imaging of liver metastases. The enhancement effect was confirmed by semiquantitative analysis of scintigraphic uptake. Taken together, our results seem to indicate that cold octreotide enhancement can improve 111In-DTPA-octreotide imaging and optimize its clinical role in SCLC.