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

Imaging with radiolabeled somatostatin (SST) analogs has recently been esta blished for the localization of various human SST receptor (hsstr)-positive tumors, including neuroendocrine tumors, lymphomas, and non-small cell lun g cancer (NSCLC). Methods: In-111-1,4,7,10-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 bind ing in patients with histologically confirmed lung cancer. A group of 27 tu mor patients without documented lung lesions served as the control group. E arly and delayed planar and SPECT images were acquired. Whole-body scintigr aphy 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). Re sults: In-111-DOTA-LAN indicated the primary lung tumor in 16 of 16 NSCLC p atients. Lymph node metastases were visualized in 6 of 6 NSCLC patients, an d bone metastases were seen in 3 of 3 NSCLC patients. In-111-DOTA-LAN scint igraphy indicated lung carcinoid in 5 of 5 patients and small cell lung can cer 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 patien ts, 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 patien t and I NEC patient, lymph node metastases in 1 carcinoid patient and 2 NSC LC patients, bone metastases in 1 carcinoid patient). The estimated lung tu mor dose ranged between 0.2 and 5 mGy/MBq. Focal lung uptake of In-111-DOTA -LAN was not observed in any of the 27 control patients. In vitro binding s tudies indicated high-affinity binding sites for In-111-DOTA-LAN in NSCLC s amples (dissociation constants, 0.5 and 4 nmol/L) with predominant expressi on of hsstr4. Conclusion: In-111-DOTA-LAN yields high tumor binding for var ious human lung tumors. Consecutively, radiopeptide therapy may offer a pot ential new treatment alternative for some lung tumor patients.