title: Clinical characteristics and survival in never smokers with lung cancer.
abstract: OBJECTIVE
  To analyze the frequency, clinical characteristics and survival of patients with lung cancer (LC) who have never smoked in comparison to patients who smoke.
  
  
  METHODS
  A retrospective study in patients diagnosed with LC by cytohistology between 1999 and 2011. Survival was estimated by the Kaplan-Meier method. The χ(2) test was used to estimate the relationship between the variables.
  
  
  RESULTS
  A total of 2161 patients were diagnosed with LC, 396 (18.3%) of whom had never smoked. The mean age (±standard deviation) in this group was 72.85±10.52; 64.6% were women and 35.4% men. According to the cytohistology, 55.6% were adenocarcinoma, 20.5% squamous cell, 15% small cell, 2.7% large cell and 6.2% other subtypes. The diagnosis was made in advanced stage (iv) in 61.4%, and 14.4% of the patients received surgical treatment. Survival was 12.4%, with no differences between the two groups. In the group of never smokers, women had better survival than men.
  
  
  CONCLUSIONS
  Of the patients diagnosed with LC, 18.3% had never smoked. It was diagnosed mainly in women, at advanced stages and the most common histological type was adenocarcinoma. There were no survival differences compared to the group of smokers.
authors.affiliation: Servicio de Neumología, Complexo Hospitalario Universitario de Ourense, Ourense , España. Electronic address: parentelamelas@gmail.com.
authors.forename: Isaura
authors.initials: I
authors.lastname: Parente Lamelas
authors.affiliation: Servicio de Neumología, Complexo Hospitalario Universitario de Ourense, Ourense , España.
authors.forename: José
authors.initials: J
authors.lastname: Abal Arca
authors.affiliation: Servicio de Neumología, Complexo Hospitalario Universitario de Ourense, Ourense , España.
authors.forename: Nagore
authors.initials: N
authors.lastname: Blanco Cid
authors.affiliation: Unidad de Investigación, Servicio de Medicina Preventiva, Complexo Hospitalario Universitario de Ourense, Ourense , España.
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Alves Pérez
authors.affiliation: Servicio de Neumología, Complexo Hospitalario Universitario de Ourense, Ourense , España.
authors.forename: Raquel
authors.initials: R
authors.lastname: Dacal Quintas
authors.affiliation: Servicio de Neumología, Complexo Hospitalario Universitario de Ourense, Ourense , España.
authors.forename: Hugo
authors.initials: H
authors.lastname: Gómez Márquez
authors.affiliation: Servicio de Neumología, Complexo Hospitalario Universitario de Ourense, Ourense , España.
authors.forename: Rogelio Alejandro
authors.initials: RA
authors.lastname: García Montenegro
authors.affiliation: Servicio de Neumología, Complexo Hospitalario Universitario de Ourense, Ourense , España.
authors.forename: Pedro
authors.initials: P
authors.lastname: Marcos Velázquez
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000453:epidemiology*; D018288:Carcinoma, Small Cell / Q000453:epidemiology*; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000453:epidemiology; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D005767:Gastrointestinal Diseases / Q000453:epidemiology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000453:epidemiology; D011379:Prognosis; D016016:Proportional Hazards Models; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology; D012189:Retrospective Studies; D012907:Smoking / Q000453:epidemiology*; D016540:Smoking Cessation
keywords: Cáncer de pulmón; Epidemiology; Epidemiología; Fumadores; Lung cancer; Never smokers; Nunca fumadores; Smokers; Supervivencia; Survival