111In-DTPA-D-Phe-1-octreotide scintigraphy of small cell lung cancer.

Twenty-one patients with small cell lung cancer (SCLC) were investigated with 111in-octreotide (111-In-OCT) scintigraphs, 5 hours after the i.v. injection of 111 MBq of the radiotracer. Whole-body and planar scintigraphy as well as SPECT of the thorax were required. The scintigraphic results were compared to those of other conventional diagnostic procedures used for the staging and follow-up of SCLC patients. 111In-OCT detected 86% (48/56) of the lesions already known at the time of scintigraphy, being positive for all 20 SCLC lesions and negative for one lung adenocarcinoma. 111In-OCT showed a high sensitivity for mediastinal metastases (94%) and good sensitivity for bone (75%) and abdominal lymph node metastases (71%). It did not detect 2 liver metastases but revealed 5 unknown lesions which were then confirmed by other diagnostic examinations. 111In-OCT was also effective in patients with low levels of NSE. Three patients received cold octreotide for seven days to investigate whether this treatment might affect SCLC imaging. Scans were performed before and after treatment. The 111In-OCT uptake increased in the cancer lesions while the fixation in normal tissues decreased, demonstrating enhancement of SCLC imaging following cold octreotide administration.