ASTRO Releases Guideline for Whole-Breast Radiation Therapy
The American Society for Radiation Oncology (ASTRO) has issued a clinical guideline for the use of whole-breast radiation therapy that expands the eligibility criteria for hypofractionated therapy.
The new guideline recommends hypofractionated whole-breast radiation for patients regardless of age, tumor stage, and whether they have received chemotherapy. The most recent ASTRO whole-breast radiation guideline had been published in 2011.
"Previously, 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 associate professor of radiation oncology, University of Texas MD Anderson Cancer Center, in a statement (March 12, 2018).
The guideline offers clinical guidance for dosing, planning, and delivering whole-breast radiation with or without a radiation boost to the tumor bed. The key recommendations are as follows:
- For women with invasive breast cancer receiving whole-breast radiation with or without inclusion of the low axilla, the preferred dose-fractionation scheme is hypofractionated whole-breast radiation to a dose of 4000 Centigray (cGy) in 15 fractions or 4250 cGy in 16 fractions.
- The 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.
- For patients with ductal carcinoma in situ (DCIS), hypofractionated whole-breast radiation may be used as an alternative to conventional fractionation.
- For invasive cancer cases, a tumor bed boost is recommended for patients with a positive margin following surgical resection, patients aged 50 and younger, and patients aged 51 to 70 with a high-grade tumor. Omitting a tumor bed boost is suggested for patients with invasive cancer who are older than 70 years and have low-to-intermediate-grade, hormone-positive tumors resected with widely negative margins.
- For DCIS, a boost is recommended for patients aged 50 and younger, patients with high-grade tumors, or those with positive or close margins following resection. A boost may be omitted for patients with DCIS who are older than 50 years; have been screen detected; have smaller, low-to-intermediate grade tumors; and have widely negative margins following surgery.
- Three-dimensional conformal treatment planning with a forward planned, field-in-field technique is recommended to achieve homogenous radiation dosing and full coverage of the tumor bed.
- Approaches 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.
A 15-member task force of radiation oncologists who specialize in breast cancer, a medical physicist, and a patient representative were included in the guideline panel.—Zachary Bessette