The impact of pathological analysis on endobronchial ultrasound diagnostic accuracy

Endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive procedure used for lung cancer diagnosis and staging. Several aspects, including pathological analysis, may impact on its diagnostic accuracy. Differences in diagnostic accuracy between the different specimen processing techniques have not been demonstrated. Cytological slides are generally adequate for diagnosis, subtyping and genotyping. However, some pathological laboratories may require cell blocks or histological core biopsies for a complete molecular profiling. Rapid on-site evaluation (ROSE) is a technique for immediate evaluation of samples obtained with EBUS-TBNA. The aims of ROSE are to increase sampling adequacy, improving diagnostic yield of EBUS-TBNA and ensuring collection of adequate material for ancillary studies. However, the reported data on the impact of ROSE in the diagnostic yield of EBUS-TBNA and in lung cancer diagnosis and staging are controversial. Some series reported a valuable contribution of ROSE to diagnosis and staging of lung cancer and a high concordance between ROSE and the final diagnosis. However, randomized trials failed in finding differences in diagnostic yield between EBUS-TBNA performed with and without ROSE. The yield of EBUS-TBNA for molecular analyses varies between 72% and 98%, and ROSE may warrant the collection of adequate material for molecular profiling. In lung cancer diagnosis and staging a recommended number of three to four passes during EBUS-TBNA at each target is a minimum requirement to obtain enough material for molecular analysis. The use of ROSE may reduce the number of passes for molecular profiling and the number of additional invasive diagnostic procedures. EBUS-TBNA is a procedure with a high accuracy rate and ROSE may contribute to a further improvement of the results. The possibility to avoid additional invasive procedure is an important advantage leading to an overall improvement of patient care.