Fractionation for whole breast irradiation: an American Society for Radiation Oncology (ASTRO) evidence-based guideline.
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.
Smith
Benjamin D
BD
Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA. bsmith3@mdanderson.org
Bentzen
Soren M
SM
Correa
Candace R
CR
Hahn
Carol A
CA
Hardenbergh
Patricia H
PH
Ibbott
Geoffrey S
GS
McCormick
Beryl
B
McQueen
Julie R
JR
Pierce
Lori J
LJ
Powell
Simon N
SN
Recht
Abram
A
Taghian
Alphonse G
AG
Vicini
Frank A
FA
White
Julia R
JR
Haffty
Bruce G
BG
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