Positron Emission Tomography-Computed Tomography Compared with Invasive Mediastinal Staging in Non-small Cell Lung Cancer: Results of Mediastinal Staging in the Early Lung Positron Emission Tomography Trial

Abstract

Patients with non-small cell lung cancer (NSCLC) require careful preoperative staging to define resectability for potential cure. Fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG PET-CT) is widely used to stage NSCLC. If the mediastinum is positive on PET-CT examination, some practitioners conclude that the patient is inoperable and refer the patient for nonsurgical treatment. In this analysis of a previously reported trial comparing PET-CT with conventional imaging in the diagnostic work-up of patients with clinical stage I, II, or IIIA NSCLC, we determined the accuracy of PET-CT in mediastinal staging compared with invasive mediastinal staging either by mediastinoscopy alone or by mediastinoscopy combined with thoracotomy. All 149 patients had mediastinal nodal staging at mediastinoscopy alone (14), thoracotomy alone (64), or both (71). The sensitivity of PET-CT was 70% (95% confidence interval [CI], 48-85%), and specificity was 94% (95% CI, 88-97%). Of 22 patients with a PET-CT interpreted as positive for mediastinal nodes, 8 did not have tumor. The positive predictive value and negative predictive value were 64% (95% CI, 43-80%) and 95% (95% CI, 90-98%), respectively. Based on PET-CT alone, eight patients would have been denied potentially curative surgery if the mediastinal abnormalities detected by PET-CT had not been evaluated with an invasive mediastinal procedure. PET-CT assessment of the mediastinum is associated with a clinically relevant false-positive rate. Our study confirms the need for pathologic confirmation of mediastinal lymph node abnormalities detected by PET-CT.