Diagnostic outcomes and safety of cryobiopsy added to conventional sampling methods: an observational study

Abstract Background Cryobiopsy enables specialists to perform high-quality, large, entirely circumferential biopsies; therefore, it may improve the diagnostic yield of peripheral pulmonary lesions (PPLs), as has been previously observed with regard to endobronchial tumors and interstitial lung diseases. Research Question How do the diagnostic accuracy and safety change by cryobiopsy when performed alongside conventional biopsy for PPLs? Study Design and Methods Consecutive patients who underwent cryobiopsy in addition to conventional biopsies for PPL diagnosis at our institution between June 2017 and May 2018 were reviewed retrospectively. The target location was estimated and sampling was performed using conventional devices (i.e., forceps, brush, and/or aspiration needle), and cryobiopsy was performed at the same location. Diagnostic outcomes and cryobiopsy safety when performed in addition to conventional sampling methods were analyzed in this observational study. Results In total, 257 patients were analyzed, and the overall diagnostic yield was 89.9%. Among them, 22 lesions were diagnosable by cryobiopsy exclusively, which improved the rate of diagnosis by 8.6%. Advantages of the use of cryobiopsy were the most apparent when lesions were adjacent to areas assessed via radial endobronchial ultrasound (69.4% vs. 84.3%). Multivariable analysis identified bronchus sign (positive/negative, P=0.001), lobe (other lobes/right upper lobe + left upper segment, P=0.028), and visibility on X-ray (visible/invisible, P=0.047) as factors that significantly affected diagnostic yield. On the other hand, three instances of severe hemorrhage (1.2%), and two of pneumothorax (0.8%) occurred. Although most complications were minor, two patients required hospitalization due to cerebral infarction and lung abscess. Interpretation Cryobiopsy improves the diagnostic yield of PPLs when combined with other conventional sampling methods; however, caution is required due to the possibility of complications.