Combined Endosonographic Mediastinal Lymph Node Staging in Positron Emission Tomography and Computed Tomography Node-Negative Non-Small Cell Lung Cancer in high-risk patients

Positron emission tomography (PET) with computed tomography (CT) is routinely utilized to investigate lymph node (LN) metastases in non-small cell lung cancer. However, it is less sensitive in normal-sized LNs. This study was performed in order to define the prevalence of mediastinal LN metastases discovered on combined endosonography by endobronchial ultrasound (EBUS) and endoscopic ultrasound (EUS) fine needle aspiration in patients with a radiologically normal mediastinum. This study consists of a retrospective, single-institution, tertiary care referral center review of a prospectively maintained database. Patients were identified from a cohort between January 2009 and December 2014. One hundred and sixty-one patients with biopsy proven, non-small cell lung cancer were identified in whom both the pre-endosonography CT and PET- CT were negative for mediastinal LN metastases. Combined endosonography (EBUS + EUS – FNA) was performed in all patients. Z test was used for statistical analysis. A p-value of 3cm, N1 lymph node involvement on PET– CT/CT, or if there was low SUV ( 3 cm. Six (28%) had occult N1 disease. Thirteen (61%) had occult N2 disease and 2 (9%) had adrenal involvement. None of the upstaged patients had N1 LN involvement on PET–CT or CT scan. Combined endosonographic lymph node staging should be considered in the pre-treatment staging of high risk patients with non-small cell lung cancer in the presence of radiologically normal mediastinal lymph nodes due to the significant rate of radiologically occult lymph node metastases.