Clinical Characteristics of False-Positive Lymph Node on Chest CT or PET-CT Confirmed by Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration in Lung Cancer

Abstract

Background: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a standard procedure to evaluate suspicious lymph node involvement of lung cancer because computed tomography (CT) and 18F-fluorodeoxyglucose positron emission tomography-CT (PET-CT) have limitations in their sensitivity and specificity. There are a number of benign causes of false positive lymph node such as anthracosis or anthracofibrosis, pneumoconiosis, old or active tuberculosis, interstitial lung disease, and other infectious conditions including pneumonia. The purpose of this study was to evaluate possible causes of false positive lymph node detected in chest CT or PET-CT.

Methods: Two hundred forty-seven patients who were initially diagnosed with lung cancer between May 2009 and December 2012, and underwent EBUS-TBNA to confirm suspicious lymph node involvement by chest CT or PET-CT were analyzed for the study.

Results: Of 247 cases, EBUS-TBNA confirmed malignancy in at least one lymph node in 189. The remaining 58 patients whose EBUS-TBNA results were negative were analyzed. Age ≥65, squamous cell carcinoma as the histologic type, and pneumoconiosis were related with false-positive lymph node involvement on imaging studies such as chest CT and PET-CT.

Conclusion: These findings suggest that lung cancer staging should be done more carefully when a patient has clinically benign lymph node characteristics including older age, squamous cell carcinoma, and benign lung conditions.

Keywords: Chest; Lung Neoplasms; Lymph Node; Positron Emission Tomography Computed Tomography; Tomography, X-Ray Computed.

Figure 1. Comparison of false-positive rate (%) of lymph node involvement according to different diagnostic modalities. CT: computed tomography; PET-CT: positron emission tomography-CT.

Figure 2. Receiver operating characteristic curve analysis showing the maximum sensitivity and specificity of age (65 years) of cut-off value for discrimination of false-positive patients with lung cancer. AUC: area under the curve.