title: Re-irradiation for locally recurrent refractory breast cancer.
abstract: OBJECTIVE
  To report an analysis of treatment outcomes of a cohort of patients re-irradiated for locally recurrent refractory breast cancer (LRRBC).
  
  
  METHODS
  Between 2008 and 2013, 47 women (mean age = 60 years) were re-irradiated for LRRBC. Outcomes were measured using Kaplan-Meier log rank to compare curves and Cox regression for multivariate analysis. Outcomes included overall survival (OS), time to re-treatment, survival without systemic progression, and survival without local recurrence.
  
  
  RESULTS
  Fifty-six instances of re-irradiation were completed and analyzed. The mean cumulative 2 Gy equivalent dose (EQD2) to the whole breast and tumour cavity (α/β = 3) was 99.8 Gy and 109.1 Gy, respectively. Most patients initially had significant symptoms before RT due to local recurrence. The median time to re-treatment and to systemic failure was 41 and 50 months, respectively. Median follow-up for OS was 17 months and OS was 0.73 (SE = 0.07) at 1 year and 0.67 (SE = 0.07) at 2 years. Local control was 0.62 (SE = 0.07) and 0.5 (0.08) at 1 and 2 years, respectively. Acute radiation dermatitis was G1-2, G3 and G4 in 45, 4 and 1 cases, respectively. One patient presented with necrosis. The most common long term toxicity was G3 fibrosis (n = 4) and telangiectatic changes (n = 3). Multivariable analysis indicated that skin involvement (Hazard Ratio = 6.6 (1.4-31), p = 0.016) and time to local recurrence <2yr (HR 3.1 (1.04-9.7) p = 0.042) predicted local recurrence.
  
  
  CONCLUSIONS
  High dose re-irradiation is feasible for locally RRBC. This approach can have a significant benefit in this very high-risk group.
authors.affiliation: Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, Canada.|Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Canada.|Departamento de Hemato-Oncologia, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Tomas
authors.initials: T
authors.lastname: Merino
authors.affiliation: Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, Canada.
authors.forename: William T
authors.initials: WT
authors.lastname: Tran
authors.affiliation: Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, Canada.|Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Canada.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Czarnota
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000532:radiotherapy*; D016016:Proportional Hazards Models; D011832:Radiation Injuries / Q000453:epidemiology; D000069475:Re-Irradiation / Q000009:adverse effects* / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: breast cancer; radiotherapy; re-irradiation; recurrent; refractory breast cancer