title: Fractionation for whole breast irradiation: an American Society for Radiation Oncology (ASTRO) evidence-based guideline.
abstract: OBJECTIVE
  In patients with early-stage breast cancer treated with breast-conserving surgery, randomized trials have found little difference in local control and survival outcomes between patients treated with conventionally fractionated (CF-) whole breast irradiation (WBI) and those receiving hypofractionated (HF)-WBI. However, it remains controversial whether these results apply to all subgroups of patients. We therefore developed an evidence-based guideline to provide direction for clinical practice.
  
  
  METHODS
  A task force authorized by the American Society for Radiation Oncology weighed evidence from a systematic literature review and produced the recommendations contained herein.
  
  
  RESULTS
  The majority of patients in randomized trials were aged 50 years or older, had disease Stage pT1-2 pN0, did not receive chemotherapy, and were treated with a radiation dose homogeneity within ±7% in the central axis plane. Such patients experienced equivalent outcomes with either HF-WBI or CF-WBI. Patients not meeting these criteria were relatively underrepresented, and few of the trials reported subgroup analyses. For patients not receiving a radiation boost, the task force favored a dose schedule of 42.5 Gy in 16 fractions when HF-WBI is planned. The task force also recommended that the heart should be excluded from the primary treatment fields (when HF-WBI is used) due to lingering uncertainty regarding late effects of HF-WBI on cardiac function. The task force could not agree on the appropriateness of a tumor bed boost in patients treated with HF-WBI.
  
  
  CONCLUSIONS
  Data were sufficient to support the use of HF-WBI for patients with early-stage breast cancer who met all the aforementioned criteria. For other patients, the task force could not reach agreement either for or against the use of HF-WBI, which nevertheless should not be interpreted as a contraindication to its use.
authors.affiliation: Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA. bsmith3@mdanderson.org
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Smith
authors.forename: Soren M
authors.initials: SM
authors.lastname: Bentzen
authors.forename: Candace R
authors.initials: CR
authors.lastname: Correa
authors.forename: Carol A
authors.initials: CA
authors.lastname: Hahn
authors.forename: Patricia H
authors.initials: PH
authors.lastname: Hardenbergh
authors.forename: Geoffrey S
authors.initials: GS
authors.lastname: Ibbott
authors.forename: Beryl
authors.initials: B
authors.lastname: McCormick
authors.forename: Julie R
authors.initials: JR
authors.lastname: McQueen
authors.forename: Lori J
authors.initials: LJ
authors.lastname: Pierce
authors.forename: Simon N
authors.initials: SN
authors.lastname: Powell
authors.forename: Abram
authors.initials: A
authors.lastname: Recht
authors.forename: Alphonse G
authors.initials: AG
authors.lastname: Taghian
authors.forename: Frank A
authors.initials: FA
authors.lastname: Vicini
authors.forename: Julia R
authors.initials: JR
authors.lastname: White
authors.forename: Bruce G
authors.initials: BG
authors.lastname: Haffty
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D019583:Dose Fractionation, Radiation; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental / Q000592:standards; D008875:Middle Aged; D009367:Neoplasm Staging; D018787:Radiation Oncology / Q000592:standards; D016032:Randomized Controlled Trials as Topic