肺癌是高度惡性的癌症，大部分的人被發現時都已經是末期，死亡率很高。過去發展的肺癌篩檢方法，例如：胸部X光加上痰液檢查，並不能降低肺癌病人的死亡率。低劑量電腦斷層掃描是新發展的肺癌篩檢工具，它針對容易罹患肺癌的抽菸高風險族群，能降低肺癌的死亡率20%，降低所有死因的死亡率7%。但篩檢的過程中會衍生肺結節的肺癌假陽性過高、長期追蹤的輻射暴露、過度診斷的問題出來。期望未來有更新的技術加入肺癌篩檢，使肺癌篩檢能被推廣至更多的人，並降低醫療花費。

Lung cancer is a highly malignant disease and the overall mortality is high because most of patients present with advanced disease. Previous lung cancer screening studies, including chest X-ray and sputum cytology, showed insignificant difference in mortality between study and control groups. Low dose computed tomography(LDCT) is a new developed lung cancer screening tool. It demonstrated a 20% reduction in lung cancer-related mortality and 7% reduction in all-cause mortality among selected high risk smoking screenees. However, negative effects, such as false positive findings of pulmonary nodules, radiation exposure, and overdiagnosis may result from LDCT screening. We need to investigate a more cost-effective lung cancer screening protocol in the near future. (J Intern Med Taiwan 2014; 25: 403-409)