title: Association between smoking during radiotherapy and prognosis in head and neck cancer: a follow-up study.
abstract: BACKGROUND
  The study objective was to confirm a previous finding that patients with stage III/IV squamous head and neck cancer (SHNC) who smoke during radiotherapy (RT) experience reduced survival.
  
  
  METHODS
  An observational cohort study. Patients' smoking status was assessed weekly by questionnaire plus blood cotinine. Patients were assessed every 3 to 4 months for survival. Logistic regression and Cox proportional hazards analyses were used to detect the independent contribution of smoking on survival.
  
  
  RESULTS
  Of 148 patients, 113 smoked during RT. Blood cotinine and smoking questionnaire responses were highly correlated (Spearman R = .69; p < .0005). Abstainers and very light smokers experienced better survival than light, moderate, and heavy smokers (median, 42 vs 29 months; p = .07). Tumor and nodal status and years smoked were the most important prognostic factors. Smoking during RT was not an independent predictor of survival, but baseline smoking status was (p = .016).
  
  
  CONCLUSIONS
  Smoking status should be documented in all future trials of RT in SHNC to allow for pooled analyses with sufficient power to address this question.
authors.affiliation: McMaster University, Hamilton, Ontario Canada. george.browman@hrcc.on.ca
authors.forename: George P
authors.initials: GP
authors.lastname: Browman
authors.forename: E Ann
authors.initials: EA
authors.lastname: Mohide
authors.forename: Andrew
authors.initials: A
authors.lastname: Willan
authors.forename: Ian
authors.initials: I
authors.lastname: Hodson
authors.forename: Gene
authors.initials: G
authors.lastname: Wong
authors.forename: Laval
authors.initials: L
authors.lastname: Grimard
authors.forename: Robert G
authors.initials: RG
authors.lastname: MacKenzie
authors.forename: Samy
authors.initials: S
authors.lastname: El-Sayed
authors.forename: Edward
authors.initials: E
authors.lastname: Dunn
authors.forename: Sylvia
authors.initials: S
authors.lastname: Farrell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D015331:Cohort Studies; D003367:Cotinine / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D007202:Indicators and Reagents / Q000032:analysis; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D011878:Radiotherapy / Q000009:adverse effects*; D012907:Smoking / Q000009:adverse effects* / Q000097:blood; D011795:Surveys and Questionnaires; D016019:Survival Analysis
chemical_list: D007202:Indicators and Reagents; D003367:Cotinine