National Lung Screening Trial

NLST Findings

  • 53,454 participants were enrolled between August 2002 and April 2004.
  • Eligible patients had no symptoms of lung cancer, were between 55 and 74 years of age, had a history of smoking at least 30 pack-years, and, if former smoker, had quit within the last 15 years.
  • Patients were randomized to receive screening with LDCT (average dose <1.5 mSv) or chest radiography and then an additional exam at 1 and 2 years.
  • There was 93%-95% adherence to all three screening exams.
  • Patients were followed up for 5 years.
  • Scans that revealed any abnormality or non-calcified nodule greater than or equal to 4 mm were classified as positive.
  • LDCT had a 39% positive rate vs. 16% in the CXR group over the screening phase of the study.
  • Over the course of the study 24.2% of LDCTs were classified as positive and 23.3% were false positive. 6.9% of radiographic studies were classified as positive and 6.5% were false positive. (Approximately 95% of the “positive” studies in both groups did not turn out to be cancer.)
  • Overall 4.0% of the LDCT group and 4.8% of the chest radiography group underwent surgery (either mediastinoscopy, thoracoscopy, or thoracotomy). 1.8% of the LDCT group and 3.5% of the chest radiography group underwent percutaneous biopsy. 3.8% of the LDCT group and 4.5% of the chest radiography group underwent bronchoscopy as the highest level of intervention. 
  • The incidence of complications in patients receiving diagnostic evaluations for a positive finding was less than 1.6%.
  • 1060 lung cancers were diagnosed in the LDCT group and 941 were diagnosed in the chest radiography group. 
  • In the LDCT group, 50% of diagnosed cancers were stage I, 7.1% were stage II, 21.2% were stage III, and 21.7% were stage IV as compared to 31.1% stage I, 7.9% stage II, 24.8% stage III, and 36.1% stage IV in the chest radiography group.
  • The relative reduction in the rate of death from lung cancer with LDCT as compared to chest radiography was 20.0%. Twenty-four percent of all deaths in the trial were from lung cancer.

National Lung Screening Trial Research Team (Aberle DR, Adams AM, et al.) Reduced Lung-Cancer Mortality with Low-Dose Computed Tomography Screening. N Engl J Med 2011;365:395-409.