Transbronchial mediastinal cryobiopsy in the diagnosis of mediastinal lesions: A randomised trial

Abstract

Background: Guidelines recommend endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) as an initial investigation technique for mediastinal nodal staging in lung cancer. However, EBUS-TBNA can be limited by the inadequacy of intact tissues, which might restrict its diagnostic yield in mediastinal lesions of certain etiologies. We have previously shown that EBUS-guided transbronchial mediastinal cryobiopsy can provide intact samples with greater volume. Methods: This randomised study determined the diagnostic yield and safety of transbronchial mediastinal cryobiopsy monitored by endosonography for the diagnosis of mediastinal lesions. Patients with mediastinal lesion of 1 cm or more in the short axis were recruited. Following identification of the mediastinal lesion by linear EBUS, fine-needle aspiration and cryobiopsy were sequently performed in a randomised order. Primary endpoints were diagnostic yield defined as the percentage of patients for whom mediastinal biopsy provided a definite diagnosis, and procedure-related adverse events. Results: One hundred and ninety-seven patients were enrolled and randomly allocated. The overall diagnostic yield was 79.9% and 91.8% for TBNA and transbronchial mediastinal cryobiopsy, respectively (P=0.001). Diagnostic yields were similar for metastatic lymphadenopathy (94.1% versus 95.6%, P=0.58), while cryobiopsy was more sensitive than TBNA in uncommon tumors (91.7% versus 25.0%, P=0.001) and benign disorders (80.9% versus 53.2%, P=0.004). No significant differences in diagnostic yield were detected between TBNA first and cryobiopsy first groups. We observed 2 cases of pneumothorax and 1 case of pneumomediastinum. Conclusions: Transbronchial cryobiopsy performed under EBUS guidance is a safe and useful approach that offers diagnostic histological samples of mediastinal lesions.