title: Pack-years of cigarette smoking as a prognostic factor in patients with stage IIIB/IV nonsmall cell lung cancer.
abstract: BACKGROUND
  This study was undertaken to characterize the relation between the survival of patients with stage IIIB/IV nonsmall cell lung cancer (NSCLC) and pack-years of cigarette smoking (graded according to the American Joint Committee on Cancer staging system).
  
  
  METHODS
  Data were analyzed from patients with stage IIIB/IV NSCLC who had completed a prospective smoking questionnaire. The impact of pack-years of cigarette smoking, age, sex, Karnofsky performance status (KPS), and the presence of weight loss >5% was evaluated on overall survival using univariate and multivariate analyses.
  
  
  RESULTS
  Smoking history and clinical data were available for 2010 patients with stage IIIB/IV NSCLC (1004 women and 1006 men). Approximately 70% of patients (1409 patients) had smoked >15 pack-years, 13% (270) were former and current smokers who had smoked < or = 15 pack-years, and 16% (331) were never-smokers (<100 lifetime cigarettes). Never-smokers had a longer median survival compared with former or current smokers (17.8 months vs 11.3 months; log-rank P < .001). Among smokers, patients with a < or = 15 pack-year history of smoking had a longer median survival than patients who had smoked >15 pack-years (14.6 months vs 10.8 months; log-rank P = .03). As the number of pack-years increased, the median overall survival decreased (log-rank P < .001). Multivariate analysis indicated that a history of smoking was an independent prognostic factor (hazard ratio, 1.36; P < .001).
  
  
  CONCLUSIONS
  More cigarette smoking, measured in pack-years, was associated with decreased survival after a diagnosis of stage IIIB/IV NSCLC. Trials assessing survival in patients with stage IIIB/IV NSCLC should report a detailed cigarette smoking history for all patients.
authors.affiliation: Thoracic Oncology Service, Division of Solid Tumor Oncology, Department of Medicine, Memorial Sloan-Kettering Cancer Center, Weill Medical College of Cornell University, New York, New York 10021, USA.
authors.forename: Yelena Y
authors.initials: YY
authors.lastname: Janjigian
authors.forename: Kevin
authors.initials: K
authors.lastname: McDonnell
authors.forename: Mark G
authors.initials: MG
authors.lastname: Kris
authors.forename: Ronglai
authors.initials: R
authors.lastname: Shen
authors.forename: Camelia S
authors.initials: CS
authors.lastname: Sima
authors.forename: Peter B
authors.initials: PB
authors.lastname: Bach
authors.forename: Naiyer A
authors.initials: NA
authors.lastname: Rizvi
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Riely
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012907:Smoking / Q000009:adverse effects*; D016019:Survival Analysis; D016896:Treatment Outcome