The Impact of Robotic Assistance-Based Navigation Systems on the Adequacy of EBUS-Guided Cytology Specimens - Experience From a Large University Hospital

Summary: Introduction: Endobronchial ultrasound (EBUS) guided fine needle aspiration (FNA) specimens are the standard of care for diagnosing thoracic lesions. Ancillary workup can be performed on cytology specimens, eliminating need for core biopsies. There is, however, dearth of data on expected institutional adequacy rates and the factors potentially influencing them. Materials and Methods: Retrospective analysis of cytology specimens obtained via EBUS from July to December in 2022 and 2023 was undertaken. Patient charts were reviewed for type of EBUS performed and navigation utilized, on-site adequacy interpretation and final adequacy comments. Statistical analysis was performed to assess adequacy both on rapid on-site evaluation (ROSE) and final reporting, and how the type of navigation system affected adequacy. Results: EBUS was performed on 227 patients yielding 608 cytology specimens, ranging from 1-7 sites per patient. 153 specimens were obtained from the lung and 455 from mediastinal nodes or miscellaneous masses. On-site assessment was performed on 360 out of 608 sites, amounting to ROSE rate of 59.2%. Overall adequacy during ROSE and final reporting was 69.2% and 78.8%, respectively (Table 1). Robotic assistance was employed for sampling lung lesions only, and was used in 123 out of 153 lung specimens. Inadequacy rate with robotic assistance during ROSE was 34.9%, much higher than the 20% inadequacy seen with conventional EBUS (Table 2). However, it becomes comparable to conventional EBUS on final reporting (approximately 17%), a paradoxical finding which may be explained away by additional passes in cell block requested in cases with robotic assistance due to inadequacy on ROSE. Conclusions: The use of robotic navigation can impact the quality and quantity of tissue obtained during on-site assessment, and may potentially affect our ability to guide optimum patient care using ancillary testing. Institution wide collaborative studies are necessary to study the significance of this variable to maximize clinical yield of EBUS-guided cytology specimens.