[Diagnostic value of somatostatin receptor scintigraphy with indium-111 pentetreotide in small-cell bronchial carcinoma].

Small-cell lung cancer (SCLC) cells may express somatostatin receptors [14]. Receptor-positive tissue can be visualised in vivo by scintigraphy with radiolabelled somatostatin analogues. In a prospective study we examined 18 patients with histologically proven SCLC for the diagnostic value of somatostatin receptor scintigraphy using indium-111 pentetreotide. Planar whole body scanning was performed 4 and 24 hours after administration. Additional SPECT imaging of the thorax and the abdomen was done at 24 hours. The results were compared with conventional staging procedures: ultrasound, x-ray, computed tomography and bone scintigraphy. In all 18 patients the primary tumour was correctly identified. Out of 13 patients with mediastinal lymphoma formation 10 patients showed positive SRS. In 2 more patients SRS showed mediastinal uptake while CT scanning was negative. The detection of distant metastases in patients with extensive disease was true positive in 8 cases (OSS, HEP, BRA), false negative in 4 cases (PLE, ADR, HEP), corresponding to a sensitivity of 67%. In 2 patients cerebral metastases were no longer detectable by SRS after previous local irradiation. Even though the method is limited in respect of revealing distant metastases in the upper abdominal area due to physiological uptake in liver, spleen and kidneys, differentiation between limited disease (LD) and extensive disease (ED) was possible in all cases. We conclude that [111In]pentetreotide scintigraphy is a suitable method for the detection of SCLC primary tumours and a substantial tool for differentiation between LD and ED if combined with ultrasonography of the upper abdomen.