American Society for Radiation Oncology (ASTRO) today issued a new clinical
guideline for the use of whole breast radiation therapy for breast cancer that
expands the population of patients recommended to receive accelerated treatment
known as hypofractionated therapy.
cancer is the most common malignancy treated with radiation therapy in the
United States, and whole breast irradiation (WBI) is the most frequently used
type of radiation delivered for these tumors. With hypofractionated WBI,
patients receive larger doses of radiation across fewer treatment
sessions—typically completing treatment in three to four weeks, compared with
five to seven weeks for conventional treatment.
current evidence from clinical trials and large cohort studies, the new
guideline recommends hypofractionated WBI for breast cancer patients regardless
of age, tumor stage and whether they have received chemotherapy. It replaces
the existing ASTRO WBI guideline published in 2011.
accelerated treatment was recommended only for certain patients, including
older patients and those with less advanced disease, but recent long-term
results from several large trials strongly support the safety and efficacy of
accelerated treatment for most breast cancer patients,” said Benjamin Smith,
MD, co-chair of the guideline task force and an associate professor of
radiation oncology at the University of Texas MD Anderson Cancer Center in
Houston. "Conventional therapy does not provide an incremental benefit in either
tumor control or side effects compared to hypofractionated WBI."
the data supporting accelerated treatment, large numbers of eligible breast
cancer patients are not receiving shorter courses of radiation therapy. A 2013 JAMA study
found an adoption rate of approximately 30 percent, and a 2017 analysis for Kaiser
indicated that fewer than half of patients over age 50 with early-stage disease
receive the accelerated treatment.
radiation therapy offers patients a more convenient and lower cost option for
their treatment without compromising the likelihood that their cancer will
return or increasing their risk of side effects,” said Reshma Jagsi, MD, DPhil,
co-chair of the task force and a professor of radiation oncology at the
University of Michigan in Ann Arbor. "A shorter course of radiation equates
to more time with family, less time away from work and lower treatment costs.
We hope that this guideline encourages providers to counsel their patients on
options including hypofractionation."
guideline provides clinical guidance for dosing, planning and delivering WBI
with or without an additional "boost" of radiation therapy to the
tumor bed. Full recommendations and supporting evidence are provided in the guideline; key
recommendations are as
Delivery and Dosing of WBI
(without irradiation of regional nodes)
decisions, including decisions between hypofractionated and conventional
approaches, should be individualized to each patient and shared between the
patient and their physician(s).
women with invasive breast cancer receiving WBI with or without inclusion of
the low axilla, the preferred dose-fractionation scheme is hypofractionated WBI
to a dose of 4000 Centigray (cGy) in 15 fractions or 4250 cGy in 16 fractions.
decision to offer hypofractionated therapy should be independent of the
following factors: tumor grade; whether the tumor is in the left or right
breast; prior chemotherapy; prior or concurrent trastuzumab or endocrine
therapy; and breast size, provided that homogenous dosing can be achieved. It may
be independent of the following factors: hormone receptor status; HER2 receptor
status; margin status following surgical resection; and age.
patients with DCIS, hypofractionated WBI may be used as an alternative to
decisions related to use and dosing of the boost should be discussed between the
patient and provider(s) and consider individual patient, tumor, and treatment
factors. These decisions also should
be independent of whether the patient received conventional or hypofractionated
For invasive cancer cases, a tumor bed
boost is recommended for patients
with a positive margin following surgical resection, patients age 50 and
younger, and patients age 51 to 70 if they have a high-grade tumor. Omitting a tumor
bed boost is suggested for patients with invasive cancer who are older than 70 and
have low-to-intermediate-grade, hormone-positive tumors resected with widely
DCIS, a boost is recommended for patients age 50 and younger, patients with
high-grade tumors and/or those with positive or close margins following
resection. A boost may be omitted for patients with DCIS who are older than 50;
have been screen detected; have smaller, low-to-intermediate grade tumors; and have
widely negative margins following surgery.
for boost dosing, sequencing and radiation delivery techniques are outlined in
Techniques for Treatment Planning
plans should be individualized after consideration of many factors, including
tumor characteristics, patient anatomy and comorbidities.
conformal (3-D CRT) treatment planning with a forward planned, field-in-field
technique is recommended to achieve homogenous radiation dosing and full coverage
of the tumor bed.
that incorporate deep inspiration breath hold, target and organ-at-risk
contouring and optimal patient positioning are recommended to minimize the
radiation dose affecting nearby organs and normal tissue, including the heart,
lungs and opposite breast.
guideline was based on a systematic literature review of studies published from
January 2009 through January 2016. A total of 528 abstracts were retrieved from
PubMed, and the 100 articles that met inclusion criteria were evaluated by a
15-member task force of radiation oncologists who specialize in breast cancer,
a medical physicist and a patient representative. The guideline was approved by
ASTRO’s Board of Directors following a period of public comment. The guideline
has been endorsed by the Royal Australian and New Zealand College of
Radiologists (RANZCR) and the Society of Surgical Oncology (SSO).
clinical guidelines are intended as a tool to promote appropriately
individualized, shared decision-making between physicians and patients. None
should be construed as strict or superseding the appropriately informed and
considered judgments of individual physicians and patients.
Therapy for the Whole Breast: An American Society for Radiation Oncology
(ASTRO) Evidence-Based Guideline” is available as a free access article in Practical
Radiation Oncology, ASTRO’s clinical practice journal. For
a copy of the guideline or to interview Dr. Smith, Dr. Jagsi or outside experts
in breast cancer, contact ASTRO’s media relations team at email@example.com or
ABOUT ASTROThe American Society for Radiation Oncology (ASTRO) is the world’s
largest radiation oncology society, with more than 10,000 members who are
physicians, nurses, biologists, physicists, radiation therapists, dosimetrists
and other health care professionals who specialize in treating patients with radiation
therapies. The Society is dedicated to improving patient care through
professional education and training, support for clinical practice and health
standards, advancement of science and research, and advocacy. ASTRO
publishes three peer-reviewed journals, the International Journal of Radiation
Oncology • Biology • Physics (redjournal.org),
Practical Radiation Oncology (practicalradonc.org) and Advances in Radiation Oncology (advancesradonc.org); developed and maintains an extensive patient website,
RT Answers (RTanswers.org);
and created the Radiation Oncology Institute (roinstitute.org),
a nonprofit foundation to support research and education efforts around the
world that enhance and confirm the critical role of radiation therapy in
improving cancer treatment. To learn more about ASTRO, visit www.astro.org,
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