Yield of Total Body GA-67 Scintigraphy in the Staging of Non-Small Cell Lung Cancer

Abstract

One hundred and one patients with histologically proved non-small cell lung cancer underwent whole body gallium-67 (TB Ga-67) scintigraphy as a part of their routine pretreatment evaluation. Twenty-eight of these patients were subsequently operated and pathologically staged for hilar and mediastinal disease. Two other patients underwent mediastinoscopy, but were judged unresectable at that time. All had computed tomography (CT) of the thorax, as well as radionuclide or CT scans of suspicious metastatic areas, and were carefully followed-up. When possible, a biopsy was performed of each suspected metastasis. Primary lung tumors concentrated Ga-67 in 94 patients. Sensitivity, specificity, and accuracy for hilar and mediastinal node metastases were 58%, 89%, and 77%, respectively. There were no false-negative gallium scans as regards secondary involvement of both liver and bone, whereas only 1 of the 4 brain metastases was detected by the technique. Sensitivity, specificity, and accuracy for all metastatic sites were 82%, 38%, and 56%, respectively. Fifty-five patients were classified as having a more advanced stage of disease by TB Ga-67 scintigraphy than at the initial clinical evaluation. However, 42 gallium-staged patients were ultimately re-classified differently according to all available clinical data. Using TB Ga-67 scintigraphy, 21 patients were found to have occult metastases which would not otherwise have been recognized; for the above reason, an unnecessary intervention was avoided in 6 of them.