Ultrasound predictors of left adrenal metastasis in patients with lung cancer: a comparison of computed tomography, positron emission tomography-computed tomography, and endoscopic ultrasound using ultrasound bronchoscope.

ABSTRACT

INTRODUCTION: Patients with resectable lung cancer require invasive evaluation of the enlarged left adrenal gland (LAG). Few studies showed the utility of endoscopic ultrasound using ultrasound bronchoscope (EUS­B) in LAG assessment. Moreover, little is known on the combination of computed tomography (CT), positron emission tomography-computed tomography (PET­CT), and EUS­B for predicting left adrenal metastasis. PATIENTS AND METHODS: In this retrospective cohort study performed from 2012 to 2019, patients with left adrenal enlargement were evaluated by CT, PET­CT, and EUS­B, followed by complete endoscopic mediastinal staging. The adrenal glands were sampled by EUS­B-guided fine­needle aspiration. Patients were followed for 6 months. RESULTS: During the staging of lung cancer in 2176 patients, 113 enlarged LAGs (5.19%) were biopsied. Malignancy was reported in 51 LAGs (45.13%). Endoscopic ultrasound upstaged 7 patients (6.2%) and downstaged 11 patients (9.37%) after false CT or PET­CT findings. There were no biopsy­related complications. Radiologic predictors of left adrenal metastases had the highest yield at the following cutoff points Hounsfield units >23, standardized uptake value >4.2, and LAG size >25 mm. Hypoechogenic LAGs with loss of sea­gull shape on EUS­B were associated with a 28.67­fold higher likelihood of metastases. The sensitivity, specificity, accuracy, negative predictive value, and positive predictive value for all ultrasound predictors were 86.21%, 85.45%, 85.84%, 85.45%, and 86.21%, respectively. When combined with radiologic features, the respective values were 93.10%, 94.55%, 93.81%, 92.86%, and 94.74%. CONCLUSIONS: Hypoechogenicity and loss of sea­gull shape on EUS­B are the most reliable predictors of left adrenal metastasis. The combination of CT, PET­CT, and EUS­B improves the noninvasive diagnosis of left adrenal metastases in lung cancer patients.