BACKGROUND: Low-radiation-dose spiral CT (LDCT) scanning is capable of detecting lung neoplasms in asymptomatic individuals. To determine whether such detection can reduce lung cancer mortality, a randomized controlled trial (RCT) of LDCT scanning is necessary.

METHODS: The feasibility of conducting an RCT in asymptomatic individuals who are at high risk for lung cancer was explored in the Lung Screening Study (LSS), a 12-month special project of the ongoing Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial. During the fall of 2000, six PLCO screening centers recruited a total of 3,318 heavy or long-term smokers who were not participants in the PLCO trial and randomized them to receive either a screening LDCT scan (1,660 participants) or screening posteroanterior view chest radiograph (CXR) [1,658 participants].

RESULTS: The screens were completed on 96% of subjects in the LDCT scan arm and 93% of subjects in the CXR arm. A total of 20.5% of screened subjects in the LDCT scan arm and 9.8% of those in the CXR arm had findings that were suspicious for lung cancer. Thirty lung cancers in subjects in the LDCT arm and 7 lung cancers in patients in the CXR arm were diagnosed following a positive screening result. Additional data from the LSS indicated that, among persons who were at elevated risk for lung cancer, CT scan use was not pervasive, interest in participating in an RCT of LDCT scanning was strong, and few subjects randomized to CXR either refused their examination or sought a CT scan after their study CXR.

INTERPRETATION: The results of the LSS demonstrated convincingly the feasibility of an RCT of LDCT scanning in the United States.