title: Multivariate analyses of locoregional recurrences and skin complications after postmastectomy radiotherapy using electrons or photons.
abstract: OBJECTIVE
  We retrospectively analyzed factors of locoregional (LR) recurrence and skin complications in patients after postmastectomy radiotherapy (PMRT).
  
  
  METHODS
  From January 1988 to December 1999, a total of 246 women with Stage II and III breast cancer received PMRT. Doses of 46 to 52.2 Gy/23 to 29 fractions were delivered to the chest wall (CW) and peripheral lymphatic drainage with 12 to 15 MeV single-portal electrons or 6MV photons. Of the patients, 84 patients received an additional 6 to 20 Gy boost to the surgical scar using 9 MeV electrons. We used the Cox regression model for multivariate analyses of CW, supraclavicular nodes (SCN), and LR recurrence.
  
  
  RESULTS
  N3 stage (positive nodes >9) (p = 0.003) and diabetes (p = 0.004) were independent factors of CW recurrence. Analysis of ipsilateral SCN recurrence showed that N3 stage (p < 0.001) and electrons (p = 0.006) were independent factors. For LR recurrence, N3 (p < 0.001), T3 to T4 (p = 0.033) and electrons (p = 0.003) were significant factors. Analysis of skin telangiectasia revealed that electrons (p < 0.001) and surgical scar boost (p = 0.003) were independent factors.
  
  
  CONCLUSIONS
  Photons are superior to single-portal electrons in patients receiving postmastectomy radiotherapy because of better locoregional control and less skin telangiectasia. In patients in whom the number of positive axillary nodes is >9, more aggressive treatment may be considered for better locoregional control.
authors.affiliation: Department of Radiation Oncology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Taiwan.
authors.forename: Eng-Yen
authors.initials: EY
authors.lastname: Huang
authors.forename: Hui-Chun
authors.initials: HC
authors.lastname: Chen
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Sun
authors.forename: Fu-Min
authors.initials: FM
authors.lastname: Fang
authors.forename: Hsuan-Chih
authors.initials: HC
authors.lastname: Hsu
authors.forename: Ching-Yeh
authors.initials: CY
authors.lastname: Hsiung
authors.forename: Yu-Jie
authors.initials: YJ
authors.lastname: Huang
authors.forename: Chang-Yu
authors.initials: CY
authors.lastname: Wang
authors.forename: Chong-Jong
authors.initials: CJ
authors.lastname: Wang
mesh_terms: D001943:Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D004583:Electrons / Q000009:adverse effects / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local; D017785:Photons / Q000009:adverse effects / Q000627:therapeutic use; D016016:Proportional Hazards Models; D011832:Radiation Injuries / Q000209:etiology*; D012189:Retrospective Studies; D012867:Skin / Q000528:radiation effects*