Identifying factors causing failure of nodal staging by endobronchial ultrasound-guided transbronchial needle aspiration in non-small cell lung cancer

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is recommended for nodal staging in non-small cell lung cancer (NSCLC). Although this method may rarely fail, reports on the causes are few. We therefore retrospectively investigated the factors causing failure of nodal staging by EBUS-TBNA.

The present study demonstrated the risk of false positives with ROSE and the involvement of driver oncogenes as factors associated with nodal staging failure in NSCLC by EBUS-TBNA, in addition to limitations of the procedure itself, including sampling performance and reachability. Especially in adenocarcinoma patients with driver oncogenes, their nodal staging results should be interpreted cautiously.

Consecutive patients who underwent EBUS-TBNA at National Cancer Center Hospital between January 2017 and December 2020 for systematic nodal staging in NSCLC were extracted. The nodal stages at diagnosis including EBUS-TBNA and at treatment were investigated separately, and unmatched cases were defined as failures. Factors associated with them were explored while dividing the cases into punctured and not-punctured groups.

Of the 264 patients, 21 (8.0%) failed the nodal staging: 10 (3.8%) in the punctured group and 11 (4.2%) in the not-punctured group. The latter was subdivided into the following three categories: (I) difficult-to-reach; (II) omission due to false-positive rapid on-site cytologic evaluation (ROSE) results; and (III) non-significant EBUS findings. The nodal staging failure rate was significantly higher in cases with driver oncogenes positive than in those negative (16.1% vs. 3.3%, P=0.026) for adenocarcinomas. Note that all cases categorized as non-significant EBUS findings involved various driver oncogenes. Conclusions: The present study demonstrated the risk of false positives with ROSE and the involvement of driver oncogenes as factors associated with nodal staging failure in NSCLC by EBUS-TBNA, in addition to limitations of the procedure itself, including sampling performance and reachability. Especially in adenocarcinoma patients with driver oncogenes, their nodal staging results should be interpreted cautiously.