title: The effect of bioequivalent radiation dose on survival of patients with limited-stage small-cell lung cancer.
abstract: BACKGROUND
  To investigate the biological radiation dose-response for patients of limited-stage small-cell lung cancer (LS-SCLC) treated with high radiation dose.
  
  
  METHODS
  Two hundred and five patients of LS-SCLC treated with sequential chemotherapy and thoracic radiotherapy with involved-field between 1997 and 2006 were reviewed retrospectively. Biologically effective dose (BED) was calculated for dose homogenization and was corrected with the factor of overall radiation time. Patients were divided into low BED group (n = 70) and high BED group (n = 135) with a cut-off of BED 57 Gy (equivalent to 60 Gy in 30 fractions over 40 days). Outcomes of the two groups were compared.
  
  
  RESULTS
  Median follow-up was 20.7 months for all analyzable patients and 50.8 months for surviving patients. Considering all patients, median survival was 22.9 months (95% confidence interval, 20.6-25.2 months); 2- and 5-year survival rates were 47.2% and 22.3%, respectively. Patients in high BED group had a significantly better local control (p = 0.024), progression-free survival (p = 0.006) and overall survival (p = 0.005), with a trend toward improved distant-metastasis free survival (p = 0.196). Multivariable Cox regression demonstrated that age (p = 0.003), KPS (p = 0.009), weight loss (p = 0.023), and BED (p = 0.004) were significant predictors of overall survival.
  
  
  CONCLUSIONS
  Our data showed that a high BED was significantly associated with favourable outcomes in the Chinese LS-SCLC population, indicating that a positive BED-response relationship still existed even in a relatively high radiation dose range.
authors: Department of Radiation Oncology, Fudan University Shanghai Cancer Centre, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
authors: Bing
authors: B
authors: Xia
authors: Gui-Yuan
authors: GY
authors: Chen
authors: Xu-Wei
authors: XW
authors: Cai
authors: Jian-Dong
authors: JD
authors: Zhao
authors: Huan-Jun
authors: HJ
authors: Yang
authors: Min
authors: M
authors: Fan
authors: Kuai-Le
authors: KL
authors: Zhao
authors: Xiao-Long
authors: XL
authors: Fu
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