Comparison of Endobronchial Ultrasound, Positron Emission Tomography, and CT for Lymph Node Staging of Lung Cancer: Results
EBUS-TBNA showed normal lymphocytes and therefore evaluated as N0 disease prior to surgery. However histology showed metastasis in half of the resected lymph node (Fig 3, bottom, C). In 76 patients, aspirates of mediastinal lymph nodes were negative for malignancy with normal lymphocytes without tumor cells, which were shown to be benign by surgery as well (Table 3). As a result, the sensitivity, specificity, positive predictive value, negative predicted value, and accuracy of EBUS-TBNA in the prediction of mediastinal lymph node staging were 92.3%, 100%, 100%, 97.4%, and 98.0%, respectively (Table 4). When the results of the three modalities were analyzed using the X tests describing the correct prediction of the lymph node status, the outcome was highly significant (p < 0.00001). This means that there is a significant difference in the accuracy of the three different modalities.
The mean examination time of EBUS-TBNA defined as the time from the first visualization of the nodes to the termination of the last puncture was 14.9 min (SD, 7.3 min; range, 4 to 29 min). The EBUS-TBNA procedure was uneventful, and there were no complications. All patients tolerated the procedure very well.
Our report is the first study to compare CT, PET, and EBUS-TBNA for mediastinal staging of potentially operable lung cancer patients. EBUS-TBNA was performed in 102 potentially resectable patients with lung cancer or suspected lung cancer. The sensitivity, specificity, and accuracy of EBUS-TBNA for the prediction of mediastinal lymph node staging were 92.3%, 100%, and 98.0%, respectively. EBUS-TBNA was highly sensitive and specific compared to CT and PET. As a single procedure for mediastinal lymph node staging, EBUS-TBNA allows tissue diagnosis, which is extremely helpful and provides superior diagnostic accuracy compared to PET.
There are many studies comparing CT and PET for mediastinal staging, and a metaanalysis comparing the two modalities has shown that PET is more accurate than CT. For CT, the median sensitivity and the specificity were 61% (interquartile range, 50 to 71%) and 79% (interquartile range, 66 to 89%), respectively. For FDG-PET, the median sensitivity and specificity were 85% (interquartile range, 67 to 91%) and 90% (interquartile range, 82 to 96%), respectively. In addition, FDG-PET was more sensitive but less specific when CT showed enlarged lymph nodes.