title: Tobacco smoking during radiation therapy for head-and-neck cancer is associated with unfavorable outcome.
abstract: OBJECTIVE
  To evaluate the effect of continued cigarette smoking among patients undergoing radiation therapy for head-and-neck cancer by comparing the clinical outcomes among active smokers and quitters.
  
  
  METHODS
  A review of medical records identified 101 patients with newly diagnosed squamous cell carcinoma of the head and neck who continued to smoke during radiation therapy. Each active smoker was matched to a control patient who had quit smoking before initiation of radiation therapy. Matching was based on tobacco history (pack-years), primary site, age, sex, Karnofsky Performance Status, disease stage, radiation dose, chemotherapy use, year of treatment, and whether surgical resection was performed. Outcomes were compared by use of Kaplan-Meier analysis. Normal tissue effects were graded according to the Radiation Therapy Oncology Group/European Organization for the Treatment of Cancer toxicity criteria.
  
  
  RESULTS
  With a median follow-up of 49 months, active smokers had significantly inferior 5-year overall survival (23% vs. 55%), locoregional control (58% vs. 69%), and disease-free survival (42% vs. 65%) compared with the former smokers who had quit before radiation therapy (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 or greater late complications was also significantly increased among active smokers compared with former smokers (49% vs. 31%, p = 0.01).
  
  
  CONCLUSIONS
  Tobacco smoking during radiation therapy for head-and-neck cancer is associated with unfavorable outcomes. Further studies analyzing the biologic and molecular reasons underlying these differences are planned.
authors.affiliation: Department of Radiation Oncology, University of California Davis Cancer Center, 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: Radhika
authors.initials: R
authors.lastname: Sreeraman
authors.forename: D Gregory
authors.initials: DG
authors.lastname: Farwell
authors.forename: Quang
authors.initials: Q
authors.lastname: Luu
authors.forename: Derick H
authors.initials: DH
authors.lastname: Lau
authors.forename: Kerri
authors.initials: K
authors.lastname: Stuart
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; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000532:radiotherapy*; D016022:Case-Control Studies; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality; D016609:Neoplasms, Second Primary / Q000453:epidemiology; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects* / Q000401:mortality; D016896:Treatment Outcome