title: Smoking is a poor prognostic factor for male nasopharyngeal carcinoma treated with radiotherapy.
abstract: OBJECTIVE
  To evaluate the effect of smoking on prognosis of male nasopharyngeal carcinoma by comparing the treatment outcomes between smokers and non-smokers.
  
  
  METHODS
  A total of 2450 nasopharyngeal carcinoma patients were enrolled, including 1865 male patients. Matching was performed between smokers and non-smokers in male patients according to age, UICC clinical stage, T stage, N stage and treatment. Survival outcomes were compared using Kaplan-Meier analysis and Cox regression. Smoking index was calculated by multiplying cigarette packs per day and smoked time (year).
  
  
  RESULTS
  In male patients, smokers had significantly lower 5-year overall survival (70.1% vs. 77.5%, P<0.001) and locoregional recurrent free survival (76.8% vs.82.4%, P = 0.002) compared with non-smokers. Matched-pair analysis showed that smokers kept a high risk of death compared with non-smokers (HR = 2.316, P<0.001). High degree of smoking index (>15 pack-years) had a poor effect on overall survival (HR = 1.225, P = 0.016). When smoking index was more than 45 and 60 pack-years, the risk for death increased to 1.498 and 1.899 fold compared with non-smokers (P = 0.040, 0.001), respectively.
  
  
  CONCLUSIONS
  Smoking was a poor prognostic factor for male nasopharyngeal carcinoma. The heavier the patients smoked, the poorer prognosis they suffered.
authors.affiliation: Department of Radiation Oncology, Sun Yat-Sen University, Guangzhou, People's Republic of China; Zhongshan School of Medcine, Sun Yat-Sen University, Guangzhou, People's Republic of China.
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.affiliation: Department of Radiation Oncology, Sun Yat-Sen University, Guangzhou, People's Republic of China; Zhongshan School of Medcine, Sun Yat-Sen University, Guangzhou, People's Republic of China.
authors.forename: Lu-Jun
authors.initials: LJ
authors.lastname: Shen
authors.affiliation: Department of Radiation Oncology, Sun Yat-Sen University, Guangzhou, People's Republic of China; Zhongshan School of Medcine, Sun Yat-Sen University, Guangzhou, People's Republic of China.
authors.forename: Bo-Fei
authors.initials: BF
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Sun Yat-Sen University, Guangzhou, People's Republic of China; State Key Laboratory of Oncology in Southern China, Cancer Center, , Sun Yat-Sen University, Guangzhou, People's Republic of China.
authors.forename: Jin
authors.initials: J
authors.lastname: Gao
authors.affiliation: Department of Radiation Oncology, Sun Yat-Sen University, Guangzhou, People's Republic of China; State Key Laboratory of Oncology in Southern China, Cancer Center, , Sun Yat-Sen University, Guangzhou, People's Republic of China. Electronic address: xiayf@sysucc.org.cn.
authors.forename: Yun-Fei
authors.initials: YF
authors.lastname: Xia
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects*; D016896:Treatment Outcome
keywords: Matched-pair analysis; Nasopharyngeal carcinoma; Prognostic factor; Radiotherapy; Smoking; Smoking index