Impact of routine sputum cytology in a population at high risk for bronchial carcinoma

SETTING: Sub-Saharan Africa carries a high burden of lung cancer, with limited access to specialised health care. OBJECTIVE: To investigate the diagnostic value of sputum cytology and its potential in reducing the need for invasive diagnostic procedures in a high-risk population. DESIGN: We collected spontaneously expectorated sputum from 108 patients referred for a diagnostic procedure for suspected lung cancer between June 2010 and June 2012, and examined the diagnostic yield of sputum cytology for malignant cells as well as factors predicting a positive result. RESULTS: Bronchial carcinoma was diagnosed in 90 patients (83.3%), of whom 35 (38.9%) had sputum cytology positive for malignant cells with 100% diagnostic accuracy. Positive sputum cytology was significantly associated with endobronchial tumour and obstruction seen during bronchoscopy (OR 4.69 and OR 8.89, respectively), and with a histology of squamous cell carcinoma (OR 1.9). All but one patient with positive sputum were inoperable (97.1%), and we estimated that up to a third of all invasive procedures could be avoided if sputum cytology was used for triage. CONCLUSION: Sputum cytology had a high yield and accuracy in this high-risk group. Its routine use in selected patients is likely to result in reduced costs and less patient risk and discomfort.