We tested the hypothesis that moderate dysplasia in sputum is an important indicator of occult central airway lung cancer in high-risk subjects (defined as those having ≥ 30 pack-years of tobacco smoking and airflow obstruction).
The study population (79 patients) was defined as follows: (1) current or former heavy smokers with at least 30 pack-years of cigarette use; (2) airflow obstruction, defined by an FEV1 of < 75% predicted and an FEV1/FVC ratio of < 75%; (3) moderate dysplasia in sputum cytology; and (4) no evidence of malignancy on a chest radiograph at the time that bronchoscopy was scheduled. Lung cancer was found by combined white-light and fluorescence bronchoscopy in 5 of 79 consecutive high-risk subjects (6.3%; 95% confidence interval [CI], 0.7 to 11.7%). Three cancers were invasive and two were carcinoma in situ. Seven additional subjects (8.9%; 95% CI, 2.6 to 15.0%) had severe dysplasia. Thus, 12 of 79 patients (15.2%; 95% CI, 7.2 to 23.2%) had malignancy or severe preneoplastic changes. Moderate dysplasia in sputum appears to be an important marker of risk for occult endobronchial malignancy in high-risk subjects.