Small Size Lung Nodules With Irregular Border Are Better Caught in Peripheral Airway Bronchoscopy

Abstract

Tissue sampling of peripheral lung nodules is a challenge in clinical practice. CT guided biopsy has good yield but is associated with high rate of pneumothorax. Bronchoscopic biopsy is a safer method. We studied the variables that potentially affect the yield of diagnostic peripheral bronchoscopy. METHODS:In retrospective study of diagnostic bronchoscopy using radial endobronchial ultrasound (rEBUS) from 11/2015 to 8/2018 in our large academic hospital, we studied the association of different potential variables and diagnostic yield of peripheral lung lesions. The successful result was defined strictly and only if either a positive malignancy or a definite benign disease was detected. Benign disease diagnosis included sarcoidosis, infection (that clinically explained the lesion), or a follow up image for at least 18 months which showed stability of the nodule. Otherwise, the bronchoscopy was counted as unsuccessful. The studied variables include: lesion size, distance from the closest pleural surface, FDG avidity in PET/CT scan, border characteristic, solid or non-solid appearance, location in upper/middle or lower lobe and the type of captured rEBUS view. Logistic regressions were used to associate above characteristics with the yield.RESULTS: 161 peripheral lung lesions were studied. In all cases, bronchoscopy and rEBUS were performed using a thin bronchoscope (4 mm OD), and sampling was done using needle aspiration, forceps biopsy and transbronchial brushing. The overall diagnostic yield was 63%; the larger the size of lesion, the higher the yield. The yield dropped significantly to 42% in nodules with diameter #15 mm. The concentric rEBUS view was strongly associated with higher rates of success (p¼1.6e-6). In nodules #15 mm, an irregular border was more often associated with a concentric view compared to regular border (p¼0.011 by Fisher's Exact Test). CONCLUSIONS:The concentric rEBUS view which is an indication of access into the middle of lesion compared to eccentric view which represents access to its periphery, was strongly associated with higher rates of success, similar to what is known in current literature. Even though the nodules #15 mm had lower biopsy yield, our data show that if these lesions have an irregular border, they will give a concentric view, more conducive to successful biopsy. This is likely a reflection of how the small caliber tools navigate through terminal bronchiole inside the interlobular segments of lung. Concentric view is obtained when the nodule surrounded the terminal bronchiole that is probed by rEBUS tool, and this proximity was observed more in nodules with irregular border. CLINICAL IMPLICATIONS:In early stage lung cancer diagnosis, an irregular border of nodules #15 mm in size could be a predictor of successful biopsy. More studies are needed to evaluate the predictors of successful bronchoscopic biopsy.