Role of Bronchial Brush and Bronchial Wash Cytology in the Diagnosis of Lung Cancer: A Comparative Study

Background: Lung cancer is one of the most common cancer around the world which is associated with significant mortality. Cytological techniques are used as first-line diagnostic tools in suspected lung tumors, based on which crucial management decisions are made. Bronchial brush (BB) and bronchial wash (BW) are two commonly employed techniques with variable diagnostic yield of lung cancer. Objective: The main objective of the present study was to compare cytological pattern of Bronchial Wash and Bronchial Brush in diagnosing Lung Cancer. Methods: This cross-sectional comparative study was conducted in the admitted patients under Department of Respiratory Medicine, National Institute of Diseases of the Chest & Hospital (NIDCH), Mohakhali, Dhaka, between January 2022 and December 2022. A total of 55 patients, clinically suspected of lung cancer and had a positive report on bronchial biopsy were included in the study. After written informed consent, a rapid diagnostic workup was made by clinical history, thorough physical examinations and necessary investigations. Bronchial biopsy was considered as a gold standard and cytology samples of bronchial brush (BB) and bronchial wash (BW) were obtained for the prediction of lung cancer. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value were calculated separately for BB and BW. Collected data were compiled and appropriate analyses were done by using computer-based software, Statistical Package for Social Sciences (SPSS) version 25.0. Results: In this study, out of 55 patients, male patients were predominant (65.5%), the male to female ratio was 1.9:1 with mean age was 54.7±12.1 years. More than two third (69.1%) patients were smoker. Among the bronchial brush specimens squamous cell carcinoma was found in 28(50.9%) cases, adenocarcinoma in 9(16.4%), small cell carcinoma in 7(12.7%), carcinoid lung cancer in 2(3.6%) and remaining 9(16.4%) cases were normal. Histological cell type in bronchial wash were 10(18.2%) squamous cell carcinoma, 4(7.3%) adenocarcinoma, 13(23.6%) small cell carcinoma, 1(1.8%) carcinoid lung cancer and 27(49.1%) normal finding. Sensitivity of bronchial brush was 82.8% in squamous cell carcinoma, 66.7% in adenocarcinoma, 55.6% in small cell carcinoma and 40.0% in carcinoid. Sensitivity of bronchial wash was 34.5% in squamous cell carcinoma, 33.3% in adenocarcinoma, 88.9% in small cell carcinoma and 20.0% in carcinoid. Conclusion: Our results show that bronchial brush is a much superior technique in diagnosing lung cancer, as it demonstrates far better sensitivity in comparison to bronchial wash. So, this study concluded that the diagnostic yield of bronchial brush cytology is higher than that of bronchial wash cytology in the lung. Bronchial brush has better efficacy in typing squamous cell carcinoma followed by adenocarcinoma, carcinoid while bronchial wash is superior in typing small cell carcinoma. Chest Heart J. 2022; 46(2) : 50-57