title: Lung cancer detection with digital chest tomosynthesis: baseline results from the observational study SOS.
abstract: BACKGROUND
  Observational studies consistently support strategies for early cancer diagnosis and treatment. Owing to its high prevalence, mortality rate, and easily identifiable at-risk population groups, lung cancer seems ideal for early detection programs. We present the baseline results of the SOS study, a single-arm observational study of digital chest tomosynthesis for lung cancer detection in an at-risk population.
  
  
  METHODS
  Accrual of study participants started in December 2010 and ended in December 2011. Participants considered eligible were smokers or former smokers aged 45 to 75 years, with a smoking history of at least 20 pack-years, without malignancy in the 5 years before the start of the study. A tomosynthesis examination was performed at baseline and another the year after.
  
  
  RESULTS
  Of the 1919 candidates assessed, 1843 (96%) were enrolled into the study: the mean age was 61 years (range, 48-73 years); 1419 (77%) were current smokers. The most prevalent comorbidities were hypertension, chronic obstructive pulmonary disease, and cardiovascular diseases. A total of 1843 tomosynthesis studies were obtained. Pulmonary abnormalities were detected in 268 subjects (14.5%). First-line basal computed tomography (CT) was subsequently carried out in 132 subjects (7.2%), 68 (4.9%) of which were referred for follow-up CT. Positron-emission tomography/CT was performed on 27 individuals (1.46%), and lung cancer was detected in 18 (0.98%) of them.
  
  
  CONCLUSIONS
  The detection rate of noncalcified lung nodules for tomosynthesis was comparable with rates reported for CT. A small subgroup underwent low-dosage CT and entered a follow-up program. Overall, lung cancer was detected in approximately 1% of cases. Digital chest tomosynthesis holds promise as a first-line lung cancer screening tool.
authors.affiliation: Thoracic Surgery Unit, Department of Surgery, S. Croce City Hospital, Cuneo, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Terzi
authors.forename: Luca
authors.initials: L
authors.lastname: Bertolaccini
authors.forename: Andrea
authors.initials: A
authors.lastname: Viti
authors.forename: Liliana
authors.initials: L
authors.lastname: Comello
authors.forename: Donatella
authors.initials: D
authors.lastname: Ghirardo
authors.forename: Roberto
authors.initials: R
authors.lastname: Priotto
authors.forename: Maurizio
authors.initials: M
authors.lastname: Grosso
mesh_terms: D000368:Aged; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009367:Neoplasm Staging; D015995:Prevalence; D011379:Prognosis; D011856:Radiographic Image Enhancement; D013902:Radiography, Thoracic; D012907:Smoking; D014057:Tomography, X-Ray Computed