title: Assessment of lung cancer mortality reduction after chest X-ray screening in smokers: a population-based cohort study in Varese, Italy.
abstract: BACKGROUND
  The effectiveness of screening for lung cancer (LC) in smokers on a population level, as distinct from the special circumstances that may apply in a randomized trial of selected volunteers, has not been thoroughly investigated. Here we evaluate by the standardized mortality ratio (SMR) indicator the impact of a chest X-ray (CXR) screening programme carried out at community level on LC mortality in smokers.
  
  
  METHODS
  All smokers of >10 pack-years, of both genders, ages 45-75 years, resident in 50 communities of the Province of Varese, Italy, screening-eligible, in 1997 were invited by their National Health Service (NHS) general practitioner physicians to a nonrandomized programme of five annual CXR screenings. The entire invitation-to-screen cohort (n=5815 subjects) received NHS usual care, with the addition of CXR exams in volunteer participants (21% of invitees), and was observed through December 2006. To overcome participants' selection bias of LC mortality assessment, for the entire invitation-to-screen cohort we estimated the LC-specific SMR, based on the local reference population receiving the NHS usual care.
  
  
  RESULTS
  Over the 8-year period 1999-2006, a total of 172 cumulative LC deaths were observed in the invitation-to-screen cohort; 210 were expected based on the reference population. Each year in the invited cohort the observed LC deaths were fewer than expected. The cumulative LC SMR was 0.82 (95% CI, 0.67-0.99; p=0.048), suggesting that LC mortality was reduced by 18% with CXR screening.
  
  
  CONCLUSIONS
  Implementation of a CXR screening programme at community level was associated with a significant reduction of LC mortality in smokers.
authors.affiliation: Center for Thoracic Surgery, University of Insubria, Ospedale di Circolo, Varese, Italy. lorenzo.dominioni@uninsubria.it
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Dominioni
authors.forename: Albino
authors.initials: A
authors.lastname: Poli
authors.forename: William
authors.initials: W
authors.lastname: Mantovani
authors.forename: Salvatore
authors.initials: S
authors.lastname: Pisani
authors.forename: Nicola
authors.initials: N
authors.lastname: Rotolo
authors.forename: Massimo
authors.initials: M
authors.lastname: Paolucci
authors.forename: Fausto
authors.initials: F
authors.lastname: Sessa
authors.forename: Valentina
authors.initials: V
authors.lastname: Conti
authors.forename: Vincenzo
authors.initials: V
authors.lastname: D'Ambrosio
authors.forename: Antonio
authors.initials: A
authors.lastname: Paddeu
authors.forename: Andrea
authors.initials: A
authors.lastname: Imperatori
mesh_terms: D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000401:mortality; D008297:Male; D008400:Mass Chest X-Ray / Q000379:methods*; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods; D012307:Risk Factors; D012907:Smoking; D015996:Survival Rate / Q000639:trends