Mediastinal lymph node staging in potentially resectable non-small cell lung cancer: a prospective comparison of CT and EUS/EUS-FNA

Mediastinal lymph node staging (N-staging) is essential to optimize the treatment in non-small cell lung cancer (NSCLC). Transesophageal endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) has recently been introduced as a complementary method. However, in most reports, EUS-FNA has been performed in patients who have demonstrated enlarged lymph nodes (LNs) on CT findings. The yield of EUS/EUS-FNA in patients without enlarged mediastinal LNs by CT has so far only been evaluated in a few reports.

Our aim was to compare the diagnostic accuracy of CT and EUS with or without EUS-FNA (EUS/EUS-FNA) prospectively, for N-stage in all patients with potentially resectable NSCLC, including patients with and without mediastinal LN enlargement based on CT findings.

Eighty consecutive patients with potentially resectable NSCLC based on CT findings were enrolled in this prospective comparative study, and underwent EUS/EUS-FNA.

Pathological N-stage was established in 78 patients, while in another 2 cases, malignant pleural effusion was proven by EUS-FNA, and we avoided further N-staging. In the 78 patients, the prevalence of malignant mediastinal LNs was 21%. The accuracy of EUS/EUS-FNA (91%) was significantly higher than that of CT (71%). The negative predictive value of EUS/EUS-FNA was 90%. In addition, EUS-FNA identified 2 patients as N3 disease in 56 patients without mediastinal LN involvement on CT.

EUS/EUS-FNA gave more accurate N-staging in patients with possibly resectable NSCLC than CT, and is thus considered to be useful to determine the optimal treatment strategy.