111In-DOTA-lanreotide scintigraphy in patients with tumors of the lung.

UNLABELLED: Imaging with radiolabeled somatostatin (SST) analogs has recently been established for the localization of various human SST receptor (hsstr)-positive tumors, including neuroendocrine tumors, lymphomas, and non-small cell lung cancer (NSCLC).

METHODS: 111In-1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid-lanreotide (DOTA-LAN) scintigraphy (150 MBq; 7 nmol per patient) was performed on 47 patients (28 patients with primary tumors, 19 patients with lung metastases from other tumors) to evaluate the tumor binding in patients with histologically confirmed lung cancer. A group of 27 tumor patients without documented lung lesions served as the control group. Early and delayed planar and SPECT images were acquired. Whole-body scintigraphy was performed at 0.5, 4-6, 24, and 48 h after injection for tumor dose estimation. In addition, hsstr subtype expression and radioligand binding characteristics were studied in vitro using lung tumor samples (n = 15).

RESULTS: 111In-DOTA-LAN indicated the primary lung tumor in 16 of 16 NSCLC patients. Lymph node metastases were visualized in 6 of 6 NSCLC patients, and bone metastases were seen in 3 of 3 NSCLC patients. 111In-DOTA-LAN scintigraphy indicated lung carcinoid in 5 of 5 patients and small cell lung cancer lesions in 6 of 6 patients. Multiple lung metastases were shown in all 6 patients with non-Hodgkin's lymphoma and in the 1 patient with Hodgkin's disease, 5 of 5 colorectal adenocarcinoma patients, 4 of 4 carcinoid patients, 2 of 2 neuroendocrine carcinoma (NEC) patients, and 1 of 1 angiosarcoma patient. Pulmonary tumor sites not indicated by CT or MRI were visualized in 6 of 47 tumor patients (i.e., 13%; lung metastases in 1 carcinoid patient and 1 NEC patient, lymph node metastases in 1 carcinoid patient and 2 NSCLC patients, bone metastases in 1 carcinoid patient). The estimated lung tumor dose ranged between 0.2 and 5 mGy/MBq. Focal lung uptake of 111In-DOTA-LAN was not observed in any of the 27 control patients. In vitro binding studies indicated high-affinity binding sites for 111In-DOTA-LAN in NSCLC samples (dissociation constants, 0.5 and 4 nmol/L) with predominant expression of hsstr4.

CONCLUSION: 111In-DOTA-LAN yields high tumor binding for various human lung tumors. Consecutively, radiopeptide therapy may offer a potential new treatment alternative for some lung tumor patients.