Diagnostic efficacy of cryobiopsy for peripheral pulmonary lesions with ground-glass opacity: a propensity score-matched analysis

Abstract

Background: Peripheral pulmonary lesions (PPLs) with ground-glass opacity (GGO) are generally difficult to diagnose via bronchoscopy. Cryobiopsy, a recently introduced technique, provides quantitatively and qualitatively superior tissues compared with conventional biopsy methods and can improve diagnostic outcomes. However, its diagnostic accuracy has not been specifically investigated. Therefore, this study aimed to determine whether the combined use of cryobiopsy improves the diagnostic yield for PPLs with GGO.

Methods: Consecutive patients who underwent bronchoscopy combined with radial endobronchial ultrasound and virtual bronchoscopic navigation for PPLs with GGO were retrospectively reviewed between June 2014 and May 2020. Cryobiopsy was introduced at our institution in June 2017. Patients who underwent only conventional biopsy (forceps and/or needle aspiration) between June 2014 and May 2017 were classified as the conventional group, whereas those who underwent cryobiopsy with or without conventional biopsy between June 2017 and May 2020 were categorized as the "cryo" group. The diagnostic performance of the two groups was compared using propensity score-matched analysis.

Results: Overall, 553 cases were identified, including 250 and 303 in the cryo and conventional groups, respectively. Propensity scoring was implemented to match lesion characteristics and intraprocedural findings, leading to the selection of 232 pairs of cases for each matched (m) group. The diagnostic yield in the m-cryo group was significantly higher than that in the m-conventional group [88.8% vs. 63.8%, odds ratio: 4.50 (95% confidence interval: 2.76-7.33), P<0.001]. Although the incidence of grade 2 and 3 bleeding in the m-cryo group was higher than that in the m-conventional group (40.5% vs. 8.6% and 2.6% vs. 0.4%, respectively; P<0.001), grade 4 bleeding was not reported.

Conclusions: The combined use of cryobiopsy provides improved diagnostic yield for PPLs with GGO compared with conventional biopsy methods.

Keywords: Bronchoscopy; cryobiopsy; ground-glass opacity (GGO); peripheral pulmonary lesion (PPL).

Figure 1

Flow diagram of patient selection. GGO, ground-glass opacity; PPL, peripheral pulmonary lesion; VBN, virtual bronchoscopic navigation.

Figure 2

A representative case of a 69-year-old woman who could be diagnosed only with a specimen collected via cryobiopsy. (A) High-resolution CT shows a 22.5-mm part-solid nodule (arrow) in the right upper lobe with a positive bronchus sign. (B) Cryobiopsy was performed at the location where radial endobronchial ultrasound detected the lesion, which exhibited a blizzard sign (bottom right corner). (C) The specimen is 4.3 mm × 3.5 mm in size without noticeable crush artifacts (hematoxylin and eosin stain, ×1.2 magnification). (D) At higher magnification (square), tumor cells forming a lepidic growth pattern were clearly observed, leading to a diagnosis of adenocarcinoma (hematoxylin and eosin stain, ×10 magnification). CT, computed tomography.