Safety and Usefulness of Cryobiopsy and Stamp Cytology for the Diagnosis of Peripheral Pulmonary Lesions

Reports on the use of cryobiopsy (CB) for lung cancer diagnosis are limited. The aims of the present study were to evaluate the safety and usefulness of CB using radial endobronchial ultrasonography, without a guide sheath, for the diagnosis of peripheral pulmonary lesions and determine the utility of stamp cytology, an on-site diagnostic technique for determining tumor inclusion in CB samples. We retrospectively analyzed data for 35 patients (36 lesions) with suspected peripheral lung cancer who underwent CB between August 2017 and February 2019 at our medical facility. The diagnostic yield, incidence of complications, and the utility of stamp cytology for diagnosis were investigated. The diagnostic yield of CB was 86.1% (31/36) with histological diagnosis, and 80.5% (29/36) with diagnosis using stamp cytology; the overall yield was 91.6% (33/36). Pneumothorax requiring thoracic drainage occurred in two patients, both of whom had lesions contacting the pleura. Grade 2 and grade 1 bleeding occurred in one and 25 patients, respectively. CB enables the collection of very large, nearly intact tissue samples, thus resulting in an improvement in the true diagnosis rate and facilitating the measurement of multiple biomarkers as well as rapid histological diagnosis.