Randomised controlled trial on optimal sampling sequence in radial guide sheath endobronchial ultrasound (R-EBUS) transbronchial lung biopsy

Introduction: Optimal sampling sequence in guide sheath R-EBUS is unclear. This prospective single centre pilot randomized controlled trial aimed to determine if the initial method and sequence of sampling affects the diagnostic accuracy of the procedure. Method: Consecutive patients undergoing R-EBUS for lesions >15 mm with a bronchus sign were randomly assigned (1:1:1) to biopsy first (group A), brushings first (group B) or combination (group C). Primary outcome was positive diagnosis from any sampling method. Results: Fifty-four patients were randomised. The overall diagnostic yield of the procedure was 77.8% (95% CI 66%–89%), with no difference between groups. Higher rate of positive cytology from brushings were seen if the biopsies were performed before brushings (77.8% in group A vs 44.4% in group B, p=0.03). The rate of positive cytology from washings was higher if the washings were obtained just after the brushings (61.1% in group A vs 11.1% in group B, p=0.02). There was no difference in the rate of positive biopsy histology in the groups (p=0.27). All three sampling modalities were more likely to be positive in group A (50.0% vs 11.1% in group B and 22.2% in group C, p=0.04). Material for ALK/EGFR testing were present in 92.8% of TTF1+ve adenocarcinoma cases. Complications rate was low and not significantly different between groups Conclusion: Overall rate of a positive R-EBUS procedure was not affected by the initial sampling method or sequence. All three sampling methods were more likely to be positive if biopsies were performed first and washings were performed after brushings.