title: Lung cancer in patients younger than 40 years in a multiracial Asian country.
abstract: OBJECTIVE
  This study aimed to determine whether the clinicopathological features of lung cancer in patients younger than 40 years differ from that of older patients in an Asian country.
  
  
  METHODS
  We undertook a review of the clinicopathological data of all patients with confirmed primary lung cancer at the Department of Medicine, University of Malaya Medical Centre, Kuala Lumpur, Malaysia, from October 1991 to September 1999.
  
  
  RESULTS
  Of the 580 patients with lung cancer, 36 (6.2%; 23 males, 13 females) were 21-39 years old at diagnosis. The percentage of people who had never smoked was higher among the younger patients (58.3% vs 19.1%, P < 0.001). Although adenocarcinoma was the most common cell type in both groups, its incidence was higher in the younger patients (24/36 (66.7%) vs 228/544 (41.9%), P = 0.007). The mean World Health Organization performance status at presentation was worse in the younger patients (2.4 vs 2, P = 0.007). In the case of non-small cell lung cancer, all the younger patients presented with either stage IIIb or metastatic disease compared to 77.2% of the older patients (P < 0.001).
  
  
  CONCLUSIONS
  Younger lung cancer patients were more likely than older patients to have never smoked, to have adenocarcinoma, and to present with poorer performance status and with more advanced-stage non-small cell lung cancer.
authors.affiliation: Department of Medicine, University of Malaya Medical Centre, Kuala Lumpur, Malaysia. liamck@medicine.med.um.edu.my
authors.forename: C K
authors.initials: CK
authors.lastname: Liam
authors.forename: K H
authors.initials: KH
authors.lastname: Lim
authors.forename: C M
authors.initials: CM
authors.lastname: Wong
mesh_terms: D000230:Adenocarcinoma / Q000208:ethnology* / Q000209:etiology / Q000473:pathology / Q000628:therapy; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D018287:Carcinoma, Large Cell / Q000208:ethnology* / Q000209:etiology / Q000473:pathology / Q000628:therapy; D002289:Carcinoma, Non-Small-Cell Lung / Q000208:ethnology* / Q000209:etiology / Q000473:pathology / Q000628:therapy; D018288:Carcinoma, Small Cell / Q000208:ethnology* / Q000209:etiology / Q000473:pathology / Q000628:therapy; D002294:Carcinoma, Squamous Cell / Q000208:ethnology* / Q000209:etiology / Q000473:pathology / Q000628:therapy; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000208:ethnology* / Q000209:etiology / Q000473:pathology / Q000628:therapy; D008296:Malaysia / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011159:Population Surveillance; D011446:Prospective Studies; D017678:Sex Distribution; D012907:Smoking / Q000009:adverse effects