Diagnostic Value of Bronchoscopy for Peripheral Metastatic Lung Tumors

SIMPLE SUMMARY: Metastatic lung tumors are relatively common, and their pathological diagnosis is crucial for determining the appropriate treatment strategy. Although bronchoscopy is one biopsy method, its role has not been established for peripheral metastatic lung tumors. The present study aimed to investigate the value of bronchoscopy, using radial endobronchial ultrasound for diagnosis. We analyzed 235 lesions consecutively, and the overall diagnostic yield was 76.6%, which was slightly higher than the reported cumulative sensitivity for general peripheral pulmonary lesions. There were no serious complications. The results demonstrated that bronchoscopy is a valuable technique for peripheral metastatic lung tumors that combines diagnostic accuracy and safety. Moreover, the higher diagnostic yield was associated with the large lesion size, inner location, and visibility on radiography. These findings should contribute to the selection of biopsy methods for metastatic lung tumors and improve the diagnostic yield. ABSTRACT: Although lungs are one of the most frequent sites of metastasis for malignant tumors, little has been reported about the value of bronchoscopy for lung metastases presenting with peripheral pulmonary lesions (PPLs). This retrospective cohort study investigated the diagnostic value of bronchoscopy for peripheral metastatic lung tumors. Consecutive patients who underwent diagnostic bronchoscopy with radial endobronchial ultrasound for PPLs and were finally diagnosed with metastatic lung tumors from April 2012 to March 2019 were included. We analyzed 235 PPLs, with a median size of 18.8 mm. The overall diagnostic yield was 76.6%. In a multivariable analysis, large lesion size (>20.0 mm vs. <20.0 mm: 87.6% vs. 67.7%, p = 0.043, OR = 2.26), inner location (inner 2/3 vs. outer 1/3: 84.8% vs. 69.1%, p = 0.004, OR = 2.79), and visibility on radiography (visible vs. invisible: 83.2% vs. 56.1%, p = 0.015, OR = 3.29) significantly affected the diagnostic yield. Although a positive bronchus sign tended to have a higher yield, no significant difference was observed (81.8% vs. 70.6%, p = 0.063). Only one case of lung abscess was observed, with no serious complications. In conclusion, bronchoscopy is a valuable technique for peripheral metastatic lung tumors, with good diagnostic accuracy and safety.