title: Smoking at diagnosis is an independent prognostic factor for cancer-specific survival in head and neck cancer: findings from a large, population-based study.
abstract: BACKGROUND
  Some studies suggest smoking may result in poorer clinical outcomes in head and neck cancer, but the evidence is heterogeneous and some of it is poor quality. In a large, population-based, study we investigated: (i) whether smoking at diagnosis is an independent prognostic factor for cancer-specific survival in head and neck cancer; and (ii) whether the association varies by site and treatment.
  
  
  METHODS
  Head and neck cancers (ICD10 C01-C14, and C30-32) diagnosed from 1994 to 2009 were abstracted from the National Cancer Registry Ireland, and classified by smoking status at diagnosis. Follow-up was for 5 years or until December 31, 2010. Multivariate Cox proportional hazards models were used to compare cancer-specific death rates in current, ex-, and never smokers. Subgroup analyses by site and treatment were conducted.
  
  
  RESULTS
  In total, 5,652 head and neck cancers were included. At diagnosis, 24% were never smokers, 20% ex-smokers, and 56% current smokers. Compared with never smokers, current smokers had a significantly raised death rate from cancer [multivariate HR, 1.36; 95% confidence interval (CI), 1.21-1.53]. The association was similar after restriction to squamous cell tumors. A significantly increased cancer-related death rate was seen for current smokers with oral cavity, pharyngeal, and laryngeal cancers. The association was stronger in surgically treated patients [HR, 1.49; 95% CI, 1.25-1.79; P(interaction) = 0.01]. Neither radiotherapy nor chemotherapy modified the effect of smoking.
  
  
  CONCLUSIONS
  Patients with head and neck cancer who smoke at diagnosis have a significantly increased cancer death rate.
  
  
  CONCLUSIONS
  Greater efforts are needed to encourage and support smoking cessation in those at risk of, and diagnosed with, head and neck cancer.
authors.affiliation: National Cancer Registry Ireland, Cork, Ireland. linda.sharp@ncri.ie.
authors.forename: Linda
authors.initials: L
authors.lastname: Sharp
authors.affiliation: National Cancer Registry Ireland, Cork, Ireland.
authors.forename: Joseph
authors.initials: J
authors.lastname: McDevitt
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.
authors.forename: Anne-Elie
authors.initials: AE
authors.lastname: Carsin
authors.affiliation: National Cancer Registry Ireland, Cork, Ireland.
authors.forename: Christopher
authors.initials: C
authors.lastname: Brown
authors.affiliation: National Cancer Registry Ireland, Cork, Ireland.
authors.forename: Harry
authors.initials: H
authors.lastname: Comber
mesh_terms: D000368:Aged; D006258:Head and Neck Neoplasms / Q000209:etiology* / Q000401:mortality; D006801:Humans; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*