Lung Cancer Mass Screening with Sputum Cytology in Japan

Abstract

Sputum cytology is the only method that can detect early hilar type lung cancer. No other method such as CT or bronchoscopy could be an alternative for huge mass screening. According to the results of famous randomized control studies conducted in 1970s and 1980s in the US and those of Miyagi Prefecture in 1990s, sputum cytology showed that higher sensitivity for lung cancer detection and better prognosis in the 1990s. In addition, Miyagi Cancer Registry revealed that the incidence of lung squamous cell carcinoma was higher than that of adenocarcinoma in male smokers in 1990s. Also the Registry showed that the number of male squamous cell carcinoma patients of the lung was almost equal to that of male adenocarcinoma patients. The ratio of male smokers in Japan is double that of the US. These findings suggest that lung cancer screening with sputum cytology is important in Japan. However, the detection ratio of lung cancer with sputum cytology varied in prefectures in Japan. Thus, it is evident that quality control for sputum cytology is necessary in each prefecture.