Accurate preoperative staging and restaging of mediastinal lymph nodes in patients with non-small cell lung cancer (NSCLC) is of paramount importance. It will guide choices of treatment and determine prognosis and outcome. Over the last years, different techniques have become available. They vary in accuracy and procedure-related morbidity. The Council of the ESTS initiated a workshop on preoperative mediastinal lymph node staging. This resulted in guidelines for primary staging and restaging. For primary staging, mediastinoscopy remains the gold standard for the superior mediastinal lymph nodes. Invasive procedures can be omitted in patients with peripheral tumors and negative mediastinal positron emission tomography (PET) images. However, in case of central tumors, PET hilar N1 disease, low fluorodeoxyglucose uptake of the primary tumor and LNs ≥ 16 mm on CT scan, invasive staging remains indicated. PET positive mediastinal findings should always be cyto-histologically confirmed. Transbronchial needle aspiration (TBNA), ultrasound-guided bronchoscopy with fine needle aspiration (EBUS-FNA) and endoscopic esophageal ultrasound-guided fine needle aspiration (EUS-FNA) are new techniques that provide cyto-histological diagnosis and are minimally invasive. Their specificity is high but the negative predictive value is low. Because of this, if they yield negative results, an invasive surgical technique is indicated. However, if fine needle aspiration is positive, this result may be valid as proof for N2 or N3 disease. For restaging, invasive techniques providing cyto-histological information are advisable despite the encouraging results supported with the use of PET/CT imaging. Both endoscopic techniques and surgical procedures are available. If they yield a positive result, non-surgical treatment is indicated in most patients.

ESTS guidelines for preoperative lymph node staging for non-small cell lung cancer