Pleural Cryobiopsy versus Flexible Forceps Biopsy in Subjects with Undiagnosed Exudative Pleural Effusions Undergoing Semirigid Thoracoscopy: A Crossover Randomized Trial (COFFEE Trial)

Abstract

Background: There is no randomized study comparing pleural cryobiopsy (CB) and flexible forceps biopsy (FFB) in subjects undergoing medical thoracoscopy for the diagnosis of pleural effusions. Objective: In this crossover study, we compared the diagnostic yield of CB versus FFB in subjects undergoing semirigid thoracoscopy. Methods: Subjects undergoing semirigid thoracoscopy for undiagnosed pleural effusions were subjected to both CB and FFB, with the order of performing the biopsy randomized in a 1:1 ratio. The primary outcome was the diagnostic yield obtained with CB versus FFB. The secondary outcomes included the biopsy size, depth, histologic interpretability, artefacts, the difficulty of performing biopsy on an operator-rated visual analog scale, the severity of bleeding observed at the time of the biopsy, and the duration of the procedure. Results: Of the 201 subjects screened, 50 (mean age 52.4 years; 18 women) were included. The diagnostic yield of CB (78.0%) was not different from FFB (76.0%, p = 1.00). CB yielded a larger specimen than FFB (median size 7.0 vs. 4.0 mm; p < 0.001), and a greater depth of specimens (up to the pleural fat or deeper, CB vs. FFB 65.2 vs. 40.8%; p = 0.02). The CB procedure was quicker than FFB (median duration 10 vs. 15 min; p < 0.001). There were no significant differences in the difficulty of performing the biopsy, the severity of bleeding, histologic interpretability, or artefacts in the specimens between the CB and FFB groups. Conclusion: The diagnostic yield of pleural CB was comparable to FFB during semirigid thoracoscopy.