title: Low-dose CT: a useful and accessible tool for the early diagnosis of lung cancer in selected populations.
abstract: OBJECTIVE
  An evaluation is made of the effectiveness of low-dose computed tomography (LDCT) in diagnosing early stage lung cancer in the Autonomous Community of Madrid (Spain).
  
  
  METHODS
  The study comprised subjects over 50 years of age who were active smokers (or who had stopped smoking up to 6 months previously) who smoked more than 30 cigarettes daily for at least 15 years, or 20 cigarettes daily for 20 years, or more than 10packs/year and in contact with asbestos at work. The study group was evaluated using LDCT. For all participants in whom LDCT showed no pathological findings, or in those cases classified as benign, a new LDCT scan was performed 2 years after the first. In case of doubt regarding the benign nature of the findings, an assessment algorithm was applied.
  
  
  RESULTS
  Among the initial 482 candidates in the study group, 466 LDCT scans were performed at baseline, revealing 9 extrapulmonary lesions and 114 pulmonary lesions in 98 subjects. The latter raised diagnostic doubts in 32 cases; of these, 15 were confirmed as benign by high resolution computed tomography (HRCT). In the remaining 17 cases, stage IAp adenocarcinoma was diagnosed at baseline (0.2%). With LDCT after 2 years, an additional four adenocarcinomas were diagnosed-all in stage IAp (0.98%). The complete study, including prevalence cut-off and incidence calculation after 2 years, resulted in the diagnosis of five cancers (1.1%) and two false positive cases (28%).
  
  
  CONCLUSIONS
  The use of low-dose computed tomography in risk groups is valid for the early diagnosis of bronchogenic cancer. Nevertheless, significant problems remain, particularly those associated with false positive interpretations. The results of randomized studies on lung cancer mortality such as the US NLST trial and the Dutch-Belgian NELSON trial have to be awaited before any conclusion regarding the effectiveness of LDCT screening can be drawn.
authors.affiliation: Servicio de Neumología, Hospital Central de la Defensa, Glorieta del Ejército s/n, 28047 Madrid, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Callol
authors.forename: Francisco
authors.initials: F
authors.lastname: Roig
authors.forename: Alfredo
authors.initials: A
authors.lastname: Cuevas
authors.forename: Jose Ignacio
authors.initials: JI
authors.lastname: de Granda
authors.forename: Francisco
authors.initials: F
authors.lastname: Villegas
authors.forename: Javier
authors.initials: J
authors.lastname: Jareño
authors.forename: Eva
authors.initials: E
authors.lastname: Arias
authors.forename: Jose M
authors.initials: JM
authors.lastname: Albiach
mesh_terms: D000367:Age Factors; D042241:Early Diagnosis; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D014057:Tomography, X-Ray Computed