title: Tumor doubling time and prognostic assessment of patients with primary lung cancer.
abstract: BACKGROUND
  Relationships between tumor doubling time (DT) and other prognostic factors and the risk of death related to these factors are not yet fully understood.
  
  
  METHODS
  Tumor doubling time of primary lung carcinomas of 174 patients, detected in a limited number of local municipalities during a limited period, was calculated using the Schwartz formula. Survival rate of the 174 patients was compared with reference to categories of prognostic factors (univariate analyses) and significant factors affecting survival were identified by multivariate analyses using the Cox proportional hazard model.
  
  
  RESULTS
  Tumor doubling time had a log normal distribution. There was a significant difference in mean DT in relation to sex, smoking history, presence of symptoms, cell type, primary tumor factor, and stage. Univariate analyses showed a significant difference in survival in relation to DT, age, sex, method of tumor detection, smoking history, symptoms, therapy, cell type, primary tumor (T) factor, regional lymph node (N) factor, distant metastasis (M) factor, and stage. Multivariate analyses using the Cox's proportional hazard model in a stepwise fashion identified a final set of five significant variables: N factor (P = 0.0001); therapy (P = 0.0016); M factor (P = 0.0017); T factor (P = 0.0018), and DT (P = 0.0152).
  
  
  CONCLUSIONS
  Tumor doubling time was an independent and significant prognostic factor for lung cancer patients.
authors.affiliation: Department of Thoracic Surgery, Tohoku University, Sendai, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Usuda
authors.forename: Y
authors.initials: Y
authors.lastname: Saito
authors.forename: M
authors.initials: M
authors.lastname: Sagawa
authors.forename: M
authors.initials: M
authors.lastname: Sato
authors.forename: K
authors.initials: K
authors.lastname: Kanma
authors.forename: S
authors.initials: S
authors.lastname: Takahashi
authors.forename: C
authors.initials: C
authors.lastname: Endo
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: A
authors.initials: A
authors.lastname: Sakurada
authors.forename: S
authors.initials: S
authors.lastname: Fujimura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002455:Cell Division; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D015996:Survival Rate