Assessment of induced sputum in the diagnostic of broncogenic carcinoma

Abstract

Aim: Non-invasive diagnostic of bronchogenic carcinoma is useful and practical, contributing to therapeutic management. Objective: to assess sensitivity and specificity of the cytology of induced sputum and spontaneous sputum for diagnostics of bronchogenic carcinoma and the rate of positivity of induced sputum cytology in relation to the characteristics of the lesion. Patients: forty-two patients with bronchogenic carcinoma were studied between April 1998 and April 1999. Induced sputum cytology by inhalation of 3% hypertonic solution (n = 42) and spontaneous sputum cytology (n = 35) were collected. Results and Discussion: Sensitivity was 7.7% and 19.2%, and specificity was 100% and 85.7%, respectively, for cytology of spontaneous and induced sputum (n=33). Correlation between cytology of both types of sputum was low. Sensitivity of induced sputum was higher than spontaneous sputum, and inversely, cytology of induced sputum presented high specificity, and low sensitivity. The relationship between cytology of induced sputum and invasion of main bronchial tubes and/or trachea by tumour presented borderline statistical significance (p=0.086). Tumor location, endoscopic visibility and histologic type were not related to sensitivity and specificity of the sputum.