title: Influence of cigarette smoking on survival and tumor invasiveness in clinical stage IA lung adenocarcinoma.
abstract: BACKGROUND
  The objective of this study was to investigate the association between cigarette smoking, cancer survival, and pathological features of clinical stage IA lung adenocarcinoma.
  
  
  METHODS
  Between August 1992 and December 2007, 1,070 consecutive patients with clinical stage IA lung adenocarcinoma underwent complete resection with systematic lymph node dissection. Univariate analysis by log-rank tests was performed to determine unfavorable prognostic factors, and the Cox proportional hazards regression model was used to identify the potential independent predictors.
  
  
  RESULTS
  The overall 5-year survival rate of patients with greater than 20 pack-years (PY>20) was 71%, significantly lower than patients with 20 or less pack-years (PY≤20; 86%; p<0.001). Postoperative pathological prognostic factors, including moderate or poor histologic differentiation, lymphatic permeation, intratumoral vascular invasion, visceral pleural invasion, and lymph node metastasis, were detected more often in patients with greater than 20 PY. Sixty-five percent of the patients in this study had pathological stage IA tumors, and their overall 5-year survival rates with 20 or less PY and greater than 20 PY were 97% and 86%, respectively (p<0.001).
  
  
  CONCLUSIONS
  In patients with clinical stage IA adenocarcinoma, a history of heavy smoking was associated with poor outcomes and was a statistically significant predictor of histologic tumor invasion.
authors.affiliation: Department of Thoracic Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Maeda
authors.forename: Junji
authors.initials: J
authors.lastname: Yoshida
authors.forename: Genichiro
authors.initials: G
authors.lastname: Ishii
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Hishida
authors.forename: Mitsuyo
authors.initials: M
authors.lastname: Nishimura
authors.forename: Kanji
authors.initials: K
authors.lastname: Nagai
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D000077192:Adenocarcinoma of Lung; D000368:Aged; D000704:Analysis of Variance; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness / Q000473:pathology; D009364:Neoplasm Recurrence, Local / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D009367:Neoplasm Staging; D011013:Pneumonectomy / Q000379:methods / Q000401:mortality; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D012907:Smoking / Q000009:adverse effects* / Q000401:mortality; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D016896:Treatment Outcome