A Value of Ultrasonographic Predictors of Malignancy in Left Adrenal Gland in Lung Cancer Patients – a Comparison of EUS-b, CT and PET-CT

Introduction: In resectable lung cancer patients (LCP) enlarged left adrenal glands (LAG) require further invasive evaluation. Single studies have shown utility of endosonography with ultrasound bronchoscope (EUS-b) for LAG assessment. Little is known about combined imaging modalities CT, PET-CT and EUS-b and ultrasound predictors determining malignancy (M1b/c) in LAG using EUS-b. Methods: A two center cohort retrospective study was performed from 2012 to 2019. Enlarged LAG were evaluated by CT and PET-CT and assessed by EUS-b. Following complete endoscopic mediastinal staging, enlarged LAG were sampled by EUS-b-FNA and followed up for 6-months. Results: From 2176 staged LCP in 113 (5.19%) enlarged LAG was biopsied and 51 (45.13%) were positive for malignancy, predominantly Adenocarcinoma (46.9%). Endosonography up-staged 7 (6.2%) patients, and down-staged 11 (9.37%) after false CT or PET-CT findings. No complications after all biopsies were noted. Radiological predictors for LAG metastases (mets) have the highest yield when proposed cut offs were set as follows: HU>23, SUV>4.2 and LAG size >25mm. Hypoechogenic LAG with loss of sea-gull shape in EUS-b indicates 28.67 times bigger likelihood of mets. The sensitivity, specificity, accuracy, NPV and PPV for all measured ultrasound predictors are: 86.21%, 85.45%, 85.84%, 85.45%, 86.21% and if combined them with radiological measurements are: 93.10%, 94.55%, 93.81%, 92.86% and 94.74%, respectively. Conclusions: A hypoechogenicity and a loss of sea-gull shape in EUS-b are the most reliable predictors of malignancy of enlarged LAG. Adding EUS-b improves noninvasive diagnostics for LAG mets in LCP