Endosonographic predictors of malignancy in a left adrenal gland in lung cancer patients - a comparison of EUS-b, CT and PET-CT.

Introduction Patients with resectable lung cancer require invasive evaluation of enlarged left adrenal gland (LAG). There are only few studies showing utility of endosonography with single ultrasound bronchoscope (EUS-b) in LAG assessment. Combination of CT, PET-CT and EUS-b and ultrasonographic predictors of malignancy (M1b/c) in LAG are not well known. Patients and methods A two center cohort retrospective study was performed from 2012 to 2019. Enlarged LAGs were evaluated by CT, PET-CT and EUS-b. Then, a complete endoscopic mediastinal staging was performed, enlarged LAGs were sampled by EUS-b-FNA. Patients were followed up for 6-months. Results During the diagnosis of 2176 staged LCP, 113 (5.19%) enlarged LAGs were biopsied. 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 were noted after any biopsies. Radiological predictors of LAG metastases had the highest yield if cut offs were set as follows: HU>23, SUV>4.2 and LAG size >25mm. Hypoechogenic LAGs with loss of sea-gull shape in EUS-b indicated 28.67 times bigger likelihood of metastases. The sensitivity, specificity, accuracy, NPV and PPV for all measured ultrasound predictors were: 86.21%, 85.45%, 85.84%, 85.45%, 86.21%, combined with radiological measurements: 93.10%, 94.55%, 93.81%, 92.86% and 94.74%, respectively. Conclusions Hypoechogenicity and loss of sea-gull shape in EUS-b are the most reliable predictors of malignancy in enlarged LAG. A combination of radiological assessment based on CT/PET-CT and EUS-b findings improves noninvasive diagnostics for LAG metastases in LCP.