Cytology of bronchial biopsy rinse fluid to improve the diagnostic yield for lung cancer

Sampling techniques are combined during bronchoscopy to increase the diagnostic yield for endobronchial malignant tumours. Bronchial biopsy provides the definitive histological diagnosis in most cases, but accompanying cytological procedures such as washing, brushing, needle aspiration or imprint cytology can increase diagnostic yield. In this prospective study, a different cytological technique, that could enhance the diagnostic yield of bronchoscopy without increasing its time or cost, was tested. Flexible bronchoscopy was performed in 93 patients suspected of having pulmonary neoplasms. Bronchial biopsies were initially placed in a balanced salt solution. When bronchoscopy was finished, all visible tissue fragments were removed and placed in formalin to undergo histopathological examination and the rinse fluid was sent for cytological examination. Washing was performed routinely but no cytological brushing was employed. Eighty-two patients had final diagnoses of malignant neoplasm. In four (4.8%) of these patients, the only positive result came from the cytological examination of the bronchial biopsy rinse fluid. No false-positive results were found. The agreement with the histological results was 81.8%. The addition of bronchial biopsy rinse-fluid examination increased the sensitivity of bronchoscopy from 65.8% to 70.7% (McNemar's p=0.009). The cytological study of bronchial biopsy rinse fluid offers reliable positive results in an additional 4.8% of cases, thus enhancing bronchoscopic diagnostic yield for malignant endobronchial tumours while neither prolonging the procedure nor increasing costs.