Study protocol for a randomized trial comparing cryobiopsy and conventional biopsy for peripheral pulmonary lesions

Abstract

Background

The introduction of radial endobronchial ultrasound (R-EBUS) and navigation has improved the diagnostic yield of bronchoscopy for peripheral pulmonary lesions (PPLs). Cryobiopsy could further raise the yield, and the advent of single-use cryoprobes has shown promise in enhancing yields even when used alone. This multicenter randomized controlled trial aims to compare the diagnostic performance of cryobiopsy with that of conventional biopsy during bronchoscopy for PPLs.

Methods

The study will enroll 660 patients with PPLs ≤30 mm. Eligible patients will undergo bronchoscopy with a thin bronchoscope and R-EBUS. If the target lesion is considered reachable based on R-EBUS findings, patients will be allocated equally to the conventional biopsy and cryobiopsy groups. Conventional biopsy will be performed using forceps and/or aspiration needles, whereas cryobiopsy will employ a single-use cryoprobe. The primary endpoint is to compare the histology-based diagnostic yield between the two groups. A subgroup analysis will also be conducted based on predetermined factors to explore the populations in which cryobiopsy is likely to be effective. The secondary endpoints are to evaluate differences in diagnostic value and safety characteristics between the two groups.

Discussion

This will be the first study to evaluate the efficacy of cryobiopsy in diagnostic bronchoscopy for PPLs. The results of this study directly comparing cryobiopsy with conventional biopsy will elucidate differences in their diagnostic performance.

Ethics and dissemination

The National Cancer Center Institutional Review Board approved this study (No. 2022-123, approval date: October 24, 2022).

Trial registration

The University Hospital Medical Information Network Clinical Trials Registry (UMIN000049329).