DIAGNOSTIC ACCURACY OF BRONCHIAL BRUSHING CYTOLOGY AND IMPRINT CYTOLOGY FOR DIAGNOSIS OF LUNG CANCER USING FLEXIBLE BRONCHOSCOPY

Objective: The goal of our study was to assess the sensitivity and specificity as well as the positive and negative predictive value of bronchial brushing cytology (BBC) and imprint cytology, and their usefulness in the diagnosis of lung cancer using flexible bronchoscopy. Materials and methods: This study was conducted at the Department of Pathology, Cytology, and Forensic Medicine of the University Hospital Mostar. Data were collected from the archives for the period from January 2016 to December 2020. Data for 1936 patients were retrieved. A selection of 508 patients who had a histopathological and/or cytological confirmation of lung cancer were included in this study. Samples were obtained by flexible fiberoptic bronchoscopy. Brushing specimens were obtained with a sterile, single-use brush that was enclosed within a catheter sheath, and after that bronchial washing was performed. Tissue sampling techniques were performed using forceps endobronchial and transbronchial biopsies. The cytology and histopathology slides were viewed independently by three clinical cytologists and pathologists. Results : Using histopathological findings for lung cancer diagnosis we have found a significant degree of concordance between cytology and pathology ( κ = 0.135; P < 0.001). However, 107 patients were cytologically positive for lung cancer while being pathologically negative. Upon further investigation into their medical histories we found the following results: in 69 patients, lung cancer had already been suspected by some other method (radiological/CT imaging or atypical findings during bronchoscopy) and the cytological confirmation of malignant cells was sufficient to start surgical or oncological treatment of the patient, while 38 patients had false positive cytology reports. BBC had shown a specificity of 98.77 %, sensitivity of 83.3 %, positive predictive value of 93.5 %, and negative predictive value of 96.5 %. Imprint cytology had a specificity of 98.3 %, sensitivity of 96.5 %, positive predictive value of 94.8 %, and negative predictive value of 98.9 %. Conclusion: In our research BBC and imprint cytology were shown to be useful methods for the diagnosis of lung cancer, and should be considered in clinical centers where biopsy samples can only be obtained using non-guided flexible bronchoscopy or where endobronchial ultrasound bronchoscopy is not available.