title: Bronchioloalveolar carcinoma is not associated with younger age at diagnosis: an analysis of the SEER database.
abstract: BACKGROUND
  Bronchioloalveolar carcinoma (BAC) is a unique subtype of non-small cell lung cancer (NSCLC) that is associated with female gender, Asian ethnicity, and never-smoking status. Although BAC is commonly reported to occur more frequently in young people with lung cancer, there is a lack of evidence to support this association.
  
  
  METHODS
  We analyzed the association between age at diagnosis and NSCLC histology among 293,417 incident cases of NSCLC in the Surveillance Epidemiology, and End Results (SEER) database during the years 1973 to 2002.
  
  
  RESULTS
  The mean age of patients with BAC (66.99 years) was similar to the mean age of all patients with NSCLC (66.44 years). The proportion of patients younger than 50 years of age was significantly smaller among patients with BAC than the overall cohort (6.06% compared with 6.90%). Although a greater percentage of women and Asian patients with lung cancer were younger than 50 years old, the proportion of patients with BAC was similar to the proportion of men and non-Asians with BAC. Finally, the prevalence of BAC histology among patients younger than 50 years did not change significantly after revision of the 1999 World Health Organization pathologic criteria for the diagnosis of BAC (risk ratio 0.93 versus 0.87, p = 0.31).
  
  
  CONCLUSIONS
  BAC is not associated with a younger mean age at diagnosis, nor is it associated with an age of less than 50 years at diagnosis. Patients with mixed BAC probably have similar age characteristics compared with patients with pure BAC.
authors.affiliation: Department of Surgery, Division of Cardiothoracic Surgery, University of California, San Francisco 94131, USA. draz@itsa.ucsf.edu
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Raz
authors.forename: David M
authors.initials: DM
authors.lastname: Jablons
mesh_terms: D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000209:etiology*; D000367:Age Factors; D000368:Aged; D044466:Asian People; D002289:Carcinoma, Non-Small-Cell Lung / Q000209:etiology; D019992:Databases as Topic; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D018426:SEER Program