Diagnostic contribution of cytological examination to endobronchial ultrasound-guided transbronchial biopsy for lung malignancies

Although endobronchial ultrasound guided transbronchial biopsy (TBB) with a guide sheath (EBUS-GS) is widely used for diagnosis of peripheral pulmonary lesions, the diagnostic contribution of cytology (bronchial brushing, bronchial washing and biopsy forceps rinse) has not been established. To determine the diagnostic contribution of cytological examination to EBUS-GS-TBB, we reviewed medical records of patients with lung malignancies who had undergone TBB with EBUS-GS (EBUS-GS group, n=187) or TBB without EBUS-GS (conventional TBB [CTBB] group, n=197) at Nagoya University Hospital. Although the mean size of target lesions was significantly larger in the CTBB group than the EBUS-GS group, the total diagnostic rate was equivalent between two groups (EBUS-GS: 73.3%, CTBB: 66.0%). In the EBUS-GS group, cytological procedures increased the diagnostic rate by 9.1% (17/137), compared with only 4.1% (8/130) in the CTBB group. Sensitivity of cytology among biopsy-negative patients was significantly higher in EBUS-GS group than CTBB group (P=0.022). Furthermore, in the EBUS-GS group, among 17 patients whose malignant diagnoses could only be established cytologically, bronchial brushing contributed to the malignant diagnosis in 64.7% (11/17). These data may suggest that cytological examination, especially bronchial brushing, may be an important diagnostic contributor in EBUS-GS-TBB.