Preoperative mediastinal staging in patients with cT1-3NxM0 non-small cell lung cancer

Endosonography is accepted as the initial procedure for mediastinal staging in patients with suspected non-small cell lung cancer (NSCLC). However, the diagnostic value of different staging methods in specific subgroups is unclear. The purpose of this study was to assess the performance and outcome of mediastinal staging in lung cancer in a general teaching hospital.

The records of 870 consecutive patients with potentially resectable NSCLC (cT1-3NxM0) were analyzed in a retrospective cohort study between January 2010 and December 2016. Patients were divided into four different groups according to ESTS guidelines. The primary endpoint was the rate of unforeseen mediastinal metastasis in these groups and the sensitivity of different staging methods.

Mediastinal staging was performed in 336 patients of whom 112 (33%) underwent lobectomy. Unforeseen mediastinal metastasis was seen in 10 (9%) patients after negative mediastinal staging. Sensitivity after combined mediastinal staging (endosonography with mediastinoscopy) in the overall group was 94%. In patients without suspected mediastinal lymph nodes but with suspected hilar lymph nodes (N1), or a peripheral tumor >3 cm, sensitivity of endosonography was 33% and mediastinoscopy 75%. Biopsy of at least level 4L, 4R and 7 was taken in 18% of the endosonographies and 58% of the mediastinoscopies.

Combined mediastinal staging (endosonography with mediastinoscopy) is reliable with a sensitivity of 94%. However, the diagnostic value of endosonography in patients with suspected hilar lymph nodes or a peripheral tumor >3 cm is questionable, and in these patients, performing direct mediastinoscopy should be considered.

SIGNIFICANT FINDINGS OF THIS STUDY: The diagnostic value of endosonography in patients without suspected mediastinal lymph nodes but with potential risk factors (suspected N1 disease or peripheral tumor >3 cm) is questionable. Therefore, mediastinoscopy as the first choice should be considered in these patients. WHAT THIS STUDY ADDS?: Accurate mediastinal nodal staging is essential in patients with suspected NSCLC to avoid unnecessary lobectomy. Detailed knowledge about sensitivity and specificity of mediastinal staging techniques in different patient groups can make a difference.