DESCRIPTIVE STUDY OF ENDOBRONCHIAL ULTRASOUND-GUIDED TRANSBRONCHIAL CRYOBIOPSIES IN THE DIAGNOSIS OF MEDIASTINAL LESIONS

<bold>Introduction:</bold> Endobronchial ultrasound-guided transbronchial fine needle aspiration (EBUS-TBNA) can obtain mediastinal cytological samples, but sometimes may be insufficient. EBUS transbronchial cryobiopsy (CryoEBUS) is a novel technique to get biopsies at same locations. We aimed to evaluate its diagnostic performance and safety. <bold>Material and methods:</bold> Cross-sectional study of consecutive patients who underwent CryoEBUS. Epidemiological data, size, location and final diagnosis were collected. <bold>Results:</bold> Fifty-five patients (63+/-15 years;62% male) were included. The most common mediastinal lesions were lymphadenopathies (83%) and the most frequent locations were subcarinal (58%), 4R (17%) and 10L (11%). Eight masses were also studied. The learning curve was considered, and the total sample was split-up into the first 15 cases (phase 1) and the following 40 (phase 2). Phase 1 diagnostic yield for EBUS-TBNA was 73% and for CryoEBUS 53% (p=ns). However, the diagnostic yields of EBUS-TBNA and CryoEBUS were 65% and 83%, respectively (p<0.001) in phase 2. The most frequent diagnoses were lung adenocarcinoma (22%), metastases (13%) and small cell carcinoma (9%). CryoEBUS identified non-small cell lung cancer in 17 patients, whose samples were also suitable for testing multiple biomarkers in 15 of them. The diagnostic yield of CryoEBUS in phase 2 was higher than in phase 1 (83% vs. 53%, p<0.05). We had only one side effect, pneumomediastinum that was resolved. <bold>Conclusions:</bold> CryoEBUS is an effective and safe technique for the diagnosis of mediastinal lesions that could replace more invasive procedures. The diagnostic yield is high, especially when the learning curve is reached.