Lung Cancer Screening with Sputum Cytologic Examination, Chest Radiography, and Computed Tomography: An Update for the U.S. Preventive Services Task Force

BACKGROUND: Lung cancer is the leading cause of cancer-related death in the United States and worldwide. No major professional organizations, including the U.S. Preventive Services Task Force (USPSTF), currently recommend screening for lung cancer. PURPOSE: To examine the evidence evaluating screening for lung cancer with chest radiography, sputum cytologic examination, and low-dose computed tomography (CT) to aid the USPSTF in updating its recommendation on lung cancer screening. DATA SOURCES: MEDLINE, the Cochrane Library, reviews, editorials, and experts. STUDY SELECTION: Studies that evaluated mass screening programs for lung cancer involving the tests of interest were selected. All studies were reviewed, but only studies with control groups were rated in quality since these would most directly influence the USPSTF screening recommendation. DATA EXTRACTION: Data were abstracted to data collection forms. Studies were graded according to criteria developed by the USPSTF. DATA SYNTHESIS: None of the 6 randomized trials of screening for lung cancer with chest radiography alone or in combination with sputum cytologic examination showed benefit among those screened. All studies were limited because some level of screening occurred in the control population. Five case-control studies from Japan suggested benefit to both high- and low-risk men and women. All studies were limited by potential healthy screenee bias. Six cohort studies showed that when CT was used to screen for lung cancer, lung cancer was diagnosed at an earlier stage than in usual clinical care. However, these studies did not have control groups, making mortality evaluation difficult. In addition, the studies demonstrated a high rate of false-positive findings. CONCLUSIONS: Current data do not support screening for lung cancer with any method. These data, however, are also insufficient to conclude that screening does not work, particularly in women. Two randomized trials of screening with chest radiography or low-dose CT are currently under way and will better inform lung cancer screening decisions.