title: Impact of the radiation boost on outcomes after breast-conserving surgery and radiation.
abstract: OBJECTIVE
  We examined the impact of radiation tumor bed boost parameters in early-stage breast cancer on local control and cosmetic outcomes.
  
  
  METHODS
  A total of 3,186 women underwent postlumpectomy whole-breast radiation with a tumor bed boost for Tis to T2 breast cancer from 1970 to 2008. Boost parameters analyzed included size, energy, dose, and technique. Endpoints were local control, cosmesis, and fibrosis. The Kaplan-Meier method was used to estimate actuarial incidence, and a Cox proportional hazard model was used to determine independent predictors of outcomes on multivariate analysis (MVA). The median follow-up was 78 months (range, 1-305 months).
  
  
  RESULTS
  The crude cosmetic results were excellent in 54%, good in 41%, and fair/poor in 5% of patients. The 10-year estimate of an excellent cosmesis was 66%. On MVA, independent predictors for excellent cosmesis were use of electron boost, lower electron energy, adjuvant systemic therapy, and whole-breast IMRT. Fibrosis was reported in 8.4% of patients. The actuarial incidence of fibrosis was 11% at 5 years and 17% at 10 years. On MVA, independent predictors of fibrosis were larger cup size and higher boost energy. The 10-year actuarial local failure was 6.3%. There was no significant difference in local control by boost method, cut-out size, dose, or energy.
  
  
  CONCLUSIONS
  Likelihood of excellent cosmesis or fibrosis are associated with boost technique, electron energy, and cup size. However, because of high local control and rare incidence of fair/poor cosmesis with a boost, the anatomy of the patient and tumor cavity should ultimately determine the necessary boost parameters.
authors: Temple University School of Medicine, Philadelphia, PA 19111, USA.
authors: Colin
authors: C
authors: Murphy
authors: Penny R
authors: PR
authors: Anderson
authors: Tianyu
authors: T
authors: Li
authors: Richard J
authors: RJ
authors: Bleicher
authors: Elin R
authors: ER
authors: Sigurdson
authors: Lori J
authors: LJ
authors: Goldstein
authors: Ramona
authors: R
authors: Swaby
authors: Crystal
authors: C
authors: Denlinger
authors: Holly
authors: H
authors: Dushkin
authors: Nicos
authors: N
authors: Nicolaou
authors: Gary M
authors: GM
authors: Freedman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001940:Breast / Q000473:pathology / Q000528:radiation effects; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D003131:Combined Modality Therapy / Q000379:methods; D005260:Female; D005355:Fibrosis; D006801:Humans; D015412:Mastectomy, Segmental / Q000379:methods; D008875:Middle Aged; D009367:Neoplasm Staging; D009929:Organ Size; D016896:Treatment Outcome; D047368:Tumor Burden; D055815:Young Adult