title: Cumulative incidence of false-positive test results in lung cancer screening: a randomized trial.
abstract: BACKGROUND
  Direct-to-consumer promotion of lung cancer screening has increased, especially low-dose computed tomography (CT). However, screening exposes healthy persons to potential harms, and cumulative false-positive rates for low-dose CT have never been formally reported.
  
  
  OBJECTIVE
  To quantify the cumulative risk that a person who participated in a 1- or 2-year lung cancer screening examination would receive at least 1 false-positive result, as well as rates of unnecessary diagnostic procedures.
  
  
  METHODS
  Randomized, controlled trial of low-dose CT versus chest radiography. (ClinicalTrials.gov registration number: NCT00006382)
  
  
  METHODS
  Feasibility study for the ongoing National Lung Screening Trial.
  
  
  METHODS
  Current or former smokers, aged 55 to 74 years, with a smoking history of 30 pack-years or more and no history of lung cancer (n = 3190).
  
  
  METHODS
  Random assignment to low-dose CT or chest radiography with baseline and 1 repeated annual screening; 1-year follow-up after the final screening. Randomization was centralized and stratified by age, sex, and study center.
  
  
  METHODS
  False-positive screenings, defined as a positive screening with a completed negative work-up or 12 months or more of follow-up with no lung cancer diagnosis.
  
  
  RESULTS
  By using a Kaplan-Meier analysis, a person's cumulative probability of 1 or more false-positive low-dose CT examinations was 21% (95% CI, 19% to 23%) after 1 screening and 33% (CI, 31% to 35%) after 2. The rates for chest radiography were 9% (CI, 8% to 11%) and 15% (CI, 13% to 16%), respectively. A total of 7% of participants with a false-positive low-dose CT examination and 4% with a false-positive chest radiography had a resulting invasive procedure.
  
  
  CONCLUSIONS
  Screening was limited to 2 rounds. Follow-up after the second screening was limited to 12 months. The false-negative rate is probably an underestimate.
  
  
  CONCLUSIONS
  Risks for false-positive results on lung cancer screening tests are substantial after only 2 annual examinations, particularly for low-dose CT. Further study of resulting economic, psychosocial, and physical burdens of these methods is warranted.
  
  
  BACKGROUND
  National Cancer Institute.
authors.affiliation: National Institutes of Health, National Cancer Institute, Bethesda, and Information Management Services, Rockville, Maryland 20892, USA. croswellj@od.nih.gov
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Croswell
authors.forename: Stuart G
authors.initials: SG
authors.lastname: Baker
authors.forename: Pamela M
authors.initials: PM
authors.lastname: Marcus
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Clapp
authors.forename: Barnett S
authors.initials: BS
authors.lastname: Kramer
mesh_terms: D000368:Aged; D055088:Early Detection of Cancer / Q000379:methods / Q000592:standards*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008400:Mass Chest X-Ray; D008403:Mass Screening / Q000379:methods / Q000592:standards*; D008875:Middle Aged; D010349:Patient Compliance; D014057:Tomography, X-Ray Computed; D019564:Unnecessary Procedures