FDG PET/CT for Staging Lung Carcinoma: An Update

In non-small cell lung carcinoma (NSCLC) carcinoma, the CT-part of the FDG PET/CT examination is of primary importance for T (tumor)-status assessment, while information derived from the primary tumor on the FDG-part of the examination may provide additional information on N- (lymph node) status. FDG PET/CT imaging was shown to have an overall sensitivity of 85% and a specificity of 84% for identifying LN involvement in NSCLC. Parameters that may predict the presence and quantify the risk of LN-involvement in NSCLC missed on FDG PET/CT imaging are tumor size and its increase over time, tumor differentiation degree, the number of days elapsed from the time of initial diagnosis, an adenocarcinoma subtype, a central versus peripheral location of the primary tumor and a solid versus mixed solid-ground glass radiologic character. Nomograms incorporating several of these variables have been published and made available for clinical usage. Furthermore, FDG PET/CT imaging was shown to have an overall higher sensitivity for identifying extra-thoracic metastases than convential morphological imaging and this especially for bone and adrenal lesions. In small cell lung carcinoma (SCLC), limited available data have shown FDG PET/CT imaging to be systematically more accurate for staging purposes when compared to conventional staging and to lead to a change in disease stage (limited versus extensive disease) in up to 15% of SCLC-patients.