MEDIASTINAL STAGING OF NON-SMALL-CELL LUNG-CANCER WITH POSITRON EMISSION TOMOGRAPHY

To determine the usefulness of positron emission tomography with fluor o-2-deoxyglucose (PET-FDG) in assessing mediastinal disease in patient s with non-small-cell lung cancer (NSCLC) and to compare its yield to that of computed tomography (CT), we performed a prospective consecuti ve sample investigation in a university hospital and its related clini cs. In 30 patients with NSCLC with clinical stage I (T1 -2, NO, MO) di sease, we compared the results of chest CT and PET-TUG with the findin gs at surgical exploration of the mediastinum. Seven (77%) of nine pat ients with surgically proven mediastinal metastasis were identified by the PET-FDG results, with four false-positives in 21 patients with ne gative lymphnode dissections (p = 0.004). Using the results of patholo gic examination of mediastinal lymph nodes as the criterion standard, the diagnostic sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) for PET-FDG imaging of mediastinal metastases were 78%, 81%, 80%, 64%, and 89%, respective ly. The sensitivity, specificity, accuracy, PPV, and NPV for chest CT in the detection of mediastinal metastasis were 56%, 86%, 77%, 63%, an d 87%, respectively. CT and PET-FDG results agreed in 21 patients. The diagnostic accuracy of the combined imaging modalities was 90%. We co ncluded that mediastinal uptake of FDG correlates with the extent of m ediastinal involvement of NSCLC and may contribute to preoperative sta ging. PET-FDG imaging complements chest CT in the noninvasive evaluati on of NSCLC, and strategies for its use merit further investigation.