Objectives: The prognosis of patients with small cell lung cancer (SCLC) is dismal with a median survival not exceeding 18 months. For the fact that the tumor stage remains the most significant prognostic factor, efforts have been made to improve its accuracy. We evaluated the role of somatostatin receptor scintigraphy (SRS) in the diagnosis and initial staging of SCLC in comparison with the conventional staging procedure.
Methods: We administered radiolabeled somatostatin analog Indium 111 (111In)-diethylenetriamine pentaacetic acid (also known as Indium In-111 pentetreotide or OctreoScan) in 32 newly diagnosed patients with SCLC, 19 of which of had limited disease and 13 of which had extensive disease. All patients had been previously examined with other imaging modalities, specifically CT and/or MRI.
Results: Staging with 111In-OctreoScan successfully located the primary tumor site with a sensitivity of 92%. Although detection of mediastinal lymph node dissemination was also relatively high (83%), the SRS failed to detect most of the metastatic lesions outside the thorax (9 of 36, 25%), while its sensitivity for the detection of malignant lesions in the liver, adrenals, and bones, was 56%, 33% and 17%, respectively.
Conclusions: Although 111In-OctreoScan may be used in addition to current SCLC staging methods, there are insufficient data for maintaining that SRS may replace conventional staging.