title: Head and neck cancer among lifelong never-smokers and ever-smokers: matched-pair analysis of outcomes after radiation therapy.
abstract: OBJECTIVE
  An increasing proportion of patients with head and neck cancer have no history of smoking. The purpose of this analysis was to compare the clinical outcomes between patients without a history of smoking (never-smokers) and those with a previous history of smoking (ever-smokers) treated by radiation therapy.
  
  
  METHODS
  Seventy patients with newly diagnosed squamous cell carcinoma of the oropharynx or oral cavity without a previous history of smoking were matched to a control ever-smoker with a positive tobacco history (>10 pack-years) based on age, gender, ethnicity, Karnofsky Performance Status, primary tumor site, disease stage, primary treatment, radiation dose, and start date. Outcome was compared using Kaplan-Meier analysis. Normal tissue effects were graded according to the Radiation Therapy Oncology Group/European Organization for the Treatment of Cancer radiation toxicity criteria.
  
  
  RESULTS
  With a median follow-up of 33 months, lifelong never-smokers had an increased 3-year overall survival (86% vs. 69%), disease-free survival (82% vs. 65%), and local-regional control (85% vs. 70%) compared with the ever-smoker control population (P < 0.05, for all). These differences remained statistically significant when patients treated by postoperative or definitive radiation therapy were analyzed separately. The incidence of grade 3+ complications was also significantly lower among never-smokers compared with ever-smokers (10% vs. 29%, P = 0.01).
  
  
  CONCLUSIONS
  Prognosis differed significantly between never-smokers and ever-smokers with head and neck cancer treated by radiation therapy. Further studies analyzing the biologic and molecular reasons underlying these differences are planned.
authors.affiliation: Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, CA, USA. allen.chen@ucdmc.ucdavis.edu
authors.forename: Allen M
authors.initials: AM
authors.lastname: Chen
authors.forename: Leon M
authors.initials: LM
authors.lastname: Chen
authors.forename: Andrew
authors.initials: A
authors.lastname: Vaughan
authors.forename: Donald Gregory
authors.initials: DG
authors.lastname: Farwell
authors.forename: Quang
authors.initials: Q
authors.lastname: Luu
authors.forename: James A
authors.initials: JA
authors.lastname: Purdy
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Vijayakumar
mesh_terms: D000328:Adult; D000368:Aged; D002140:California / Q000453:epidemiology; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology / Q000209:etiology / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D016555:Matched-Pair Analysis; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000532:radiotherapy; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000517:prevention & control; D009367:Neoplasm Staging; D010610:Pharyngeal Neoplasms / Q000532:radiotherapy; D011379:Prognosis; D011832:Radiation Injuries / Q000453:epidemiology; D011878:Radiotherapy / Q000009:adverse effects; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D016896:Treatment Outcome