title: Lung cancer screening with CT: Mayo Clinic experience.
abstract: OBJECTIVE
  To evaluate a large cohort of patients at high risk for lung cancer by using screening with low-dose spiral computed tomography (CT) of the chest.
  
  
  METHODS
  A prospective cohort study was performed with 1,520 individuals aged 50 years or older who had smoked 20 pack-years or more. Participants underwent three annual low-dose CT examinations of the chest and upper abdomen. Characteristics of pulmonary nodules and additional findings were tabulated and analyzed.
  
  
  RESULTS
  Two years after baseline CT scanning, 2,832 uncalcified pulmonary nodules were identified in 1,049 participants (69%). Forty cases of lung cancer were diagnosed: 26 at baseline (prevalence) CT examinations and 10 at subsequent annual (incidence) CT examinations. CT alone depicted 36 cases; sputum cytologic examination alone, two. There were two interval cancers. Cell types were as follows: squamous cell tumor, seven; adenocarcinoma or bronchioloalveolar carcinoma, 24; large cell tumor, two; non-small cell tumor, three; small cell tumor, four. The mean size of the non-small cell cancers detected at CT was 15.0 mm. The stages were as follows: IA, 22; IB, three; IIA, four; IIB, one; IIIA, five; IV, one; limited small cell tumor, four. Twenty-one (60%) of the 35 non-small cell cancers detected at CT were stage IA at diagnosis. Six hundred ninety-six additional findings of clinical importance were identified.
  
  
  CONCLUSIONS
  CT can depict early-stage lung cancers. The rate of benign nodule detection is high.
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Swensen
authors.forename: James R
authors.initials: JR
authors.lastname: Jett
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Hartman
authors.forename: David E
authors.initials: DE
authors.lastname: Midthun
authors.forename: Jeff A
authors.initials: JA
authors.lastname: Sloan
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Sykes
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Aughenbaugh
authors.forename: Medy A
authors.initials: MA
authors.lastname: Clemens
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D009367:Neoplasm Staging; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D036542:Tomography, Spiral Computed