P2.05-18 Tissue Sampling and Prognostic Biomarkers Analysis of Peripheral Lung Tumors Using R-EBUS. Single Centre Retrospective Study

Tissue sampling of peripheral pulmonary neoplasms for patohistology and analysis of prognostic biomarkers can be challenging. Radial endobronchial ultrasound (R-EBUS) is one of sophisticated guiding bronchoscopic modalities used for more precise localisation of the peripheral lesions. Novel therapeutic strategies rely on different prognostic biomarkers status. In this retrospective study we explored sufficiency of specimens for patohistology and prognostic biomarkers analysis obtained by ultra-thin bronchoscope combined with R-EBUS. Retrospective analysis of bronchoscopy cases positive on malignancies when R-EBUS was used for visualisation of peripheral tumors and tissue was obtained with commercial sampling kit. 80 consecutive cases with pathologic ultrasound pattern found with R-EBUS were analysed. Malignant disease was diagnosed in 49 cases (61%). Mean lesion diameter was 24mm (range 15 to 40mm). The most common histology types were adenocarcinoma, squamous cell carcinoma and small cell carcinoma – 78%, 12% and 4% respectively. Extrathoracic malignancies were diagnosed in 6% of cases. The tissue was sufficient for prognostic biomarker analysis in 91% of the cases – whereas EGFR, ALK, ROS1 and PDL-1 testing was performed for adenocarcinomas and PDL-1 for squamous cell lung carcinomas. In 9% of cases samples were sufficient for histologic typing only. Bronchoscopy with R-EBUS is useful diagnostic method for peripheral lung tumours. Obtained samples can be used for histology subtyping and prognostic biomarkers analysis in most cases as well.