Y. Matsumoto*a (Dr), T. Imabayashib (Dr), K. Uchimurab (Dr), H. Furuseb (Dr), T. Tsuchidab (Dr)

a Department of Endoscopy, Respiratory Endoscopy Division/Department of Thoracic Oncology, National Cancer Center Hospital, Tokyo, JAPAN ; b Department of Endoscopy, Respiratory Endoscopy Division, National Cancer Center Hospital, Tokyo, JAPAN

* yumatsum@ncc.go.jp

Background: Additional cryobiopsy to conventional biopsy methods has been reported to increase the diagnostic yield of peripheral pulmonary lesions (PPLs). Recently introduced single-use cryoprobes have superior inducibility to conventional reusable cryoprobes due to their smaller diameters, and are expected to lead high diagnostic yields on their own. We have therefore applied the new cryoprobes alone to the diagnosis of PPLs, and aimed to investigate their utility.

Methods: Consecutive patients who underwent cryobiopsy for PPLs at our institution between June 2017 and April 2022 were retrospectivey reviewed while divided into two groups: single-use cryoprobes alone (single-use group) and resusable cryoprobes combined with standard biopsy devices (reusable group). Cases with certain benign pathological findings but immature course were excluded. A multivariable analysis was performed to examine factors that affected the diagnostic yield. In addition, diagnostic outcomes were compared after balancing characteristics between the two groups by propensity score matching.

Results: We analyzed a total of 825 cases, 216 with single-use and 609 with reusable cryoprobes. The median (range) size of lesions was 22.5 (4.9-120.8) mm, and 25.6% was negative for bronchus sign. The morphology was mainly solid (47.5%), followed by part-solid (45.5%) and pure ground-glass (7.0%). The overall diagnostic yield was 89.2%, and only the positive bronchus sign contributed to it in the multivariable analysis (p<0.001, odds ratio=2.75 [95% confidence interval=1.61-4.69]). After matching, 214 pairs of cases in each group were selected. Among them, the diagnostic yield in the single-use group was comparable to that in the reusable group (86.0% vs. 87.4%, p=0.670), as well as the complication rates (5.1% vs. 2.8%, p=0.213). Meanwhile, the mean ± standard deviation procedure time was shorter in the single-use group (29.9±10.4 min. vs. 32.3±9.2 min., p=0.013).

Conclusion: Single-use cryoprobes showed sufficient performance even alone in the diagnosis of PPLs.

Disclosure of funding source(s):

This study was partially supported by the National Cancer Center Research and Development Fund (29-A-13/2020-A-12).