Does needle size affect the diagnostic yield of endobronchial ultrasound-guided transbronchial needle aspiration for malignant lymphoma?-a narrative review.

[BACKGROUND AND OBJECTIVE] Bronchoscopic diagnosis of malignant lymphoma is challenging, because bronchoscopic tissues are often relatively small. Recently, a 19-gauge needle (19G) was developed to obtain larger tissue cores; however, its effectiveness in improving the diagnostic yields remains controversial. Therefore, in this narrative review, we aimed to summarize recent findings and evaluate the usefulness of different needle sizes for diagnosing malignant lymphoma.

[METHODS] A comprehensive and systematic online literature search of PubMed was conducted using the keywords ("malignant lymphoma" OR "lymphoma") and ("endobronchial ultrasound" OR "endobronchial ultrasound guided" OR "endobronchial ultrasound guided transbronchial needle aspiration" OR "EBUS" OR "EBUS-TBNA" OR "needle size").

[KEY CONTENT AND FINDINGS] Three prospective and 13 retrospective studies were included. Approximately 50% of the procedures were performed under moderate sedation, and the remainder under general anesthesia. Regarding subtype determination, the diagnostic yield of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) ranged from 50% to 65% with a 19G, and from 19% to 88% with a 21G and 22G. Supportive methods such as rapid on-site cytological evaluation (ROSE) and flow cytometry were performed variably, depending on the bronchoscopist's preference or institutional resources.

[CONCLUSIONS] When ROSE and flow cytometry are available, there seems to be no significant difference in diagnostic yield for lymphoma subtype determination between 19G and 21/22G during EBUS-TBNA.