Head and neck cancer among lifelong never-smokers and ever-smokers: matched-pair analysis of outcomes after radiation therapy.
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.
Chen
Allen M
AM
Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, CA, USA. allen.chen@ucdmc.ucdavis.edu
Chen
Leon M
LM
Vaughan
Andrew
A
Farwell
Donald Gregory
DG
Luu
Quang
Q
Purdy
James A
JA
Vijayakumar
Srinivasan
S
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