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

Sub-Saharan Africa carries a high burden of lung cancer, with limited access to specialised health care.

To investigate the diagnostic value of sputum cytology and its potential in reducing the need for invasive diagnostic procedures in a high-risk population.

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.

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.

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.