title: Screen-detected lung cancer: a retrospective analysis of CT appearance.
abstract: OBJECTIVE
  The aim of this study was to retrospectively evaluate characteristics of lung cancers diagnosed in a low-dose computed tomographic lung cancer screening study.
  
  
  METHODS
  As part of the International Early Lung Cancer Action Program, a cohort of 4782 at-risk participants were screened. A total of 86 cancers in 84 individuals were detected and evaluated for location, morphology (density, border), size, histology, stage at diagnosis, treatment, and survival. Follow-up imaging for computation of growth rates was available in 41 cases.
  
  
  RESULTS
  Eighty-six cancers were detected in 84 individuals (60 women, 24 men). Of these, seven (8%) were incidence cancers. Most cancers were radiologically described as solid (n = 52 [61%]). The median tumor size was 18 × 13 mm (range, 6-56 mm). Histopathologic diagnoses revealed 10 (11.6%) bronchoalveolar carcinomas, 55 (64%) adenocarcinomas, 11 (12.8%) squamous-cell carcinomas, two (2.3%) large-cell carcinomas, three (3.5%) carcinoids, and five (5.8%) small-cell lung cancers. Of the 41 cases with follow-up computed tomographic scans, 36 nodules had increased in size. The mean doubling time for all cancers was 259 days (median, 154 days). In women (n = 25), the mean doubling time was 313 days (median, 156 days), while in men (n = 11), the mean doubling time was 137 days (median, 92 days). Overall, 55 lung cancers (68%) were stage I. Most cancers (n = 62 [73%]) were surgically resected.
  
  
  CONCLUSIONS
  In this cohort, screening detected lung cancer in early treatable stages, and women had more slow-growing adenocarcinomas than men. Most screen-detected lung cancers were surgically resectable.
authors.affiliation: Department of Medical Imaging, University Health Network, Women's College Hospital, Toronto, ON, Canada.
authors.forename: Monika R
authors.initials: MR
authors.lastname: Dhopeshwarkar
authors.forename: Heidi C
authors.initials: HC
authors.lastname: Roberts
authors.forename: Narinder S
authors.initials: NS
authors.lastname: Paul
authors.forename: Zhi
authors.initials: Z
authors.lastname: Dong
authors.forename: Ming
authors.initials: M
authors.lastname: Tsao
authors.forename: Ravi J
authors.initials: RJ
authors.lastname: Menezes
mesh_terms: D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009367:Neoplasm Staging; D011829:Radiation Dosage; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects; D014057:Tomography, X-Ray Computed / Q000379:methods*