Multivariate analyses of locoregional recurrences and skin complications after postmastectomy radiotherapy using electrons or photons.
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.
Huang
Eng-Yen
EY
Department of Radiation Oncology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Taiwan.
Chen
Hui-Chun
HC
Sun
Li-Min
LM
Fang
Fu-Min
FM
Hsu
Hsuan-Chih
HC
Hsiung
Ching-Yeh
CY
Huang
Yu-Jie
YJ
Wang
Chang-Yu
CY
Wang
Chong-Jong
CJ
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*