title: Prognostic influence of smoking on esophageal squamous cell carcinoma.
abstract: BACKGROUND
  Smoking is well-known as a risk factor for esophageal squamous cell carcinoma. However, little is known about the effect of this factor on survival.
  
  
  METHODS
  Esophageal cancer patients who underwent esophagectomy without any preoperative therapy were retrospectively reviewed. Patients' postoperative overall and disease-free survivals were compared between 2 groups (non-heavy smokers and heavy smokers).
  
  
  RESULTS
  A total of 109 cases were evaluated in this study. The 5-year OS rate of the non-heavy smokers was 53.2% and 32.3% for the heavy group. The 5-year DFS rate of the non-heavy smokers was 51.1% and 27.4% for the heavy group. Kaplan-Meier survival analysis revealed that heavy smokers had significantly poorer OS (P=0.018) and DFS (P=0.009) than non-heavy smokers. In multivariate analysis, smoking was found to be an independent prognostic factor for OS (P=0.003; HR: 2.186; 95% CI: 1.309-3.650) and DFS (P=0.001; HR: 2.471; 95% CI: 1.467-4.163).
  
  
  CONCLUSIONS
  Smoking was associated with survival among patients with ESCC, and it was recognized as an independent factor in both OS and DFS.
authors.affiliation: Department of Radiation Oncology, Qilu Hospital of Shandong University Jinan, People's Republic of China.
authors.forename: Nana
authors.initials: N
authors.lastname: Wang
authors.affiliation: Department of Radiation Oncology, Qilu Hospital of Shandong University Jinan, People's Republic of China.
authors.forename: Bingxu
authors.initials: B
authors.lastname: Tan
authors.affiliation: Department of Radiation Oncology, Qilu Hospital of Shandong University Jinan, People's Republic of China.
authors.forename: Fangli
authors.initials: F
authors.lastname: Cao
authors.affiliation: Department of Radiation Oncology, Qilu Hospital of Shandong University Jinan, People's Republic of China.
authors.forename: Qingxu
authors.initials: Q
authors.lastname: Song
authors.affiliation: Department of Radiation Oncology, Qilu Hospital of Shandong University Jinan, People's Republic of China.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Radiation Oncology, Qilu Hospital of Shandong University Jinan, People's Republic of China.
authors.forename: Yibin
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Department of Radiation Oncology, Qilu Hospital of Shandong University Jinan, People's Republic of China.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Cheng
keywords: Smoking; esophageal squamous cell carcinoma; prognosis