Results of initial low-dose computed tomographic screening for lung cancer.

BACKGROUND: Lung cancer is the largest contributor to mortality from cancer. The National Lung Screening Trial (NLST) showed that screening with low-dose helical computed tomography (CT) rather than with chest radiography reduced mortality from lung cancer. We describe the screening, diagnosis, and limited treatment results from the initial round of screening in the NLST to inform and improve lung-cancer-screening programs. METHODS: At 33 U.S. centers, from August 2002 through April 2004, we enrolled asymptomatic participants, 55 to 74 years of age, with a history of at least 30 pack-years of smoking. The participants were randomly assigned to undergo annual screening, with the use of either low-dose CT or chest radiography, for 3 years. Nodules or other suspicious findings were classified as positive results. This article reports findings from the initial screening examination. RESULTS: A total of 53,439 eligible participants were randomly assigned to a study group (26,715 to low-dose CT and 26,724 to chest radiography); 26,309 participants (98.5%) and 26,035 (97.4%), respectively, underwent screening. A total of 7191 participants (27.3%) in the low-dose CT group and 2387 (9.2%) in the radiography group had a positive screening result; in the respective groups, 6369 participants (90.4%) and 2176 (92.7%) had at least one follow-up diagnostic procedure, including imaging in 5717 (81.1%) and 2010 (85.6%) and surgery in 297 (4.2%) and 121 (5.2%). Lung cancer was diagnosed in 292 participants (1.1%) in the low-dose CT group versus 190 (0.7%) in the radiography group (stage 1 in 158 vs. 70 participants and stage IIB to IV in 120 vs. 112). Sensitivity and specificity were 93.8% and 73.4% for low-dose CT and 73.5% and 91.3% for chest radiography, respectively. CONCLUSIONS: The NLST initial screening results are consistent with the existing literature on screening by means of low-dose CT and chest radiography, suggesting that a reduction in mortality from lung cancer is achievable at U.S. screening centers that have staff experienced in chest CT. (Funded by the National Cancer Institute; NLST ClinicalTrials.gov number, NCT00047385.).

Results of the two incidence screenings in the National Lung Screening Trial.

BACKGROUND: The National Lung Screening Trial was conducted to determine whether three annual screenings (rounds T0, T1, and T2) with low-dose helical computed tomography (CT), as compared with chest radiography, could reduce mortality from lung cancer. We present detailed findings from the first two incidence screenings (rounds T1 and T2). METHODS: We evaluated the rate of adherence of the participants to the screening protocol, the results of screening and downstream diagnostic tests, features of the lung-cancer cases, and first-line treatments, and we estimated the performance characteristics of both screening methods. RESULTS: At the T1 and T2 rounds, positive screening results were observed in 27.9% and 16.8% of participants in the low-dose CT group and in 6.2% and 5.0% of participants in the radiography group, respectively. In the low-dose CT group, the sensitivity was 94.4%, the specificity was 72.6%, the positive predictive value was 2.4%, and the negative predictive value was 99.9% at T1; at T2, the positive predictive value increased to 5.2%. In the radiography group, the sensitivity was 59.6%, the specificity was 94.1%, the positive predictive value was 4.4%, and the negative predictive value was 99.8% at T1; both the sensitivity and the positive predictive value increased at T2. Among lung cancers of known stage, 87 (47.5%) were stage IA and 57 (31.1%) were stage III or IV in the low-dose CT group at T1; in the radiography group, 31 (23.5%) were stage IA and 78 (59.1%) were stage III or IV at T1. These differences in stage distribution between groups persisted at T2. CONCLUSIONS: Low-dose CT was more sensitive in detecting early-stage lung cancers, but its measured positive predictive value was lower than that of radiography. As compared with radiography, the two annual incidence screenings with low-dose CT resulted in a decrease in the number of advanced-stage cancers diagnosed and an increase in the number of early-stage lung cancers diagnosed. (Funded by the National Cancer Institute; NLST ClinicalTrials.gov number, NCT00047385.).

Examining whether lung screening changes risk perceptions: National Lung Screening Trial participants at 1-year follow-up.

BACKGROUND: The National Lung Screening Trial (NLST) research team reported reduced lung cancer mortality among current and former smokers with a minimum 30 pack-year history who were screened with spiral computed tomography scans compared with chest x-rays. The objectives of the current study were to examine, at 1-year follow-up: 1) risk perceptions of lung cancer and smoking-related diseases and behavior change determinants, 2) whether changes in risk perceptions differed by baseline screening result; and 3) whether changes in risk perceptions affected smoking behavior. METHODS: A 25-item risk perception questionnaire was administered to a subset of participants at 8 American College of Radiology Imaging Network/NLST sites before initial and 1-year follow-up screens. Items assessed risk perceptions of lung cancer and smoking-related diseases, cognitive and emotional determinants of behavior change, and knowledge of smoking risks. RESULTS: Among 430 NLST participants (mean age, 61.0 years; 55.6% men; 91.9% white), half were current smokers at baseline. Overall, risk perceptions and associated cognitive and emotional determinants of behavior change did not change significantly from prescreen trial enrollment to 1-year follow-up and did not differ significantly by screening test result. Changes in risk perceptions were not associated with changes in smoking status (9.7% of participants quit, and 6.6% relapsed) at 1-year follow-up. CONCLUSIONS: Lung screening did not change participants' risk perceptions of lung cancer or smoking-related disease. A negative screening test, which was the most common screening result, did not appear to decrease risk perceptions nor provide false reassurance to smokers.

Normative reference values of thoracic aortic diameter in American College of Radiology Imaging Network (ACRIN 6654) arm of National Lung Screening Trial.

PURPOSE: This study aims to establish normative reference values for thoracic aortic diameter (AD) in participants in the National Lung Screening Trial. METHODS: Thoracic AD on 322 prevalence computed tomography was recorded at the sinotubular junction, mid-ascending, transverse arch, mid-descending, and diaphragmatic hiatus. RESULTS: Mean AD (cm) and upper limits of normal for men and women were recorded for at each location. Smoking did not correlate with AD. Age, gender, and body surface area (BSA) were the most significant factors. CONCLUSIONS: Thoracic AD reference values are reported. They do not correlate with smoking, but they did for age, gender, and BSA.

Identifying and collecting pertinent medical records for centralized abstraction in a multi-center randomized clinical trial: the model used by the American College of Radiology arm of the National Lung Screening Trial.

BACKGROUND: In clinical trials and epidemiologic studies, information on medical care utilization and health outcomes is often obtained from medical records. For multi-center studies, this information may be gathered by personnel at individual sites or by staff at a central coordinating center. We describe the process used to develop a HIPAA-compliant centralized process to collect medical record information for a large multi-center cancer screening trial. METHODS: The framework used to select, request, and track medical records incorporated a participant questionnaire with unique identifiers for each medical provider. De-identified information from the questionnaires was sent to the coordinating center indexed by these identifiers. The central coordinating center selected specific medical providers for abstraction and notified sites using these identifiers. The site personnel then linked the identifiers with medical provider information. Staff at the sites collected medical records and provided them for central abstraction. RESULTS: Medical records were successfully obtained and abstracted to ascertain information on outcomes and health care utilization in a study with over 18,000 study participants. Collection of records required for outcomes related to positive screening examinations and lung cancer diagnosis exceeded 90%. Collection of records for all aims was 87.32%. CONCLUSIONS: We designed a successful centralized medical record abstraction process that may be generalized to other research settings, including observational studies. The coordinating center received no identifying data. The process satisfied requirements imposed by the Health Insurance Portability and Accountability Act and concerns of site institutional review boards with respect to protected health information.