How many samples would be optimal for endobronchial cryobiopsy?

Cryobiopsy, which provides larger specimens without crush artifact, is a good option for the diagnosis of visible endobronchial tumors. While there are several papers on diagnostic performance, application protocols vary between centers. In this study, we aimed to find the optimal number of cryobiopsies in endobronchial tumors.

We prospectively involved cases with a visible endobronchial tumor in which conventional diagnostic measures failed and/or a therapeutic interventional bronchoscopy was planned. Endobronchial tumor was visualized, and four cryobiopsies were taken with a dedicated flexible probe. The samples were evaluated by a pathologist who was blinded to the order of the biopsies. The cumulative performances of one to four cryobiopsies were compared, and a complication analysis was conducted.

A total of 50 patients were involved. Four cryobiopsies were taken from 49 patients, and a single biopsy was taken from one case. The sensitivities of one, two, three and four biopsies were 82, 93.9, 93.9 and 95.9 %, respectively. The difference in performance of one and two biopsies was significant (p = 0.031), but the third and fourth biopsies were found to be unnecessary (p = 1.0 for second versus third and p = 1.0 for second versus fourth). Bleeding risk increased when ≥3 cryobiopsies were taken (Odds Ratio 2.758).

When the diagnostic benefits and complication rates were considered, two cryobiopsies were found to be optimal for endobronchial tumors. In patients with non-diagnostic conventional bronchoscopy, endobronchial tumors may be diagnosed by cryobiopsy.