Detection of early lung cancer in high risk population: a prospective study

Abstract

Background Lung cancer is the leading cause of cancer mortality with 5 year survival of 14% The poor outcome are due to: 1) the great majority of lung cancers are found at a very late stage 2) no effective treatment for advanced lung cancer. Since the 5-year survival of stage 0 and stage IV lung cancer are >90% and 1% respectively, a potential way to improve the outcome is to detect lung cancer when curative treatment can still be applied. Objectives To detect early lung cancer and premalignant lesions in high risk group by using sputum cytology as surrogate marker, and autofluorescence bronchoscopy (SAFE-1000) to locate the abnormal site. Subject & Methods Ever smokers with age more than 40 years and accumulated 20 pack-years were recruited and early morning sputum collected for cytological examination. Subjects with sputum atypia would be examined with white light bronchoscopy (WLB) and autofluorescence bronchoscopy (SAFE-1000) in the same session sequentially. Abnormal regions would be biopsied for histological diagnosis. Results 300 high risk population approached and sputum collected in 150. Sputum atypia were found in ~60% and 73 had bronchoscopy examination performed. Lung cancer found in seven and 86% were in early stages. Precancerous lesions were detected in 2 subjects. 9.5% of subjects undergone bronchoscopy had lung cancer and at least 2.3% of the high risk population had lung cancer. Conclusion Sputum cytology examination followed by bronchoscopic examination is an effective method in detecting early lung cancer in high risk population.