The 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 follows:

Delivery and Dosing of WBI (without irradiation of regional nodes)


Treatment decisions, including decisions between hypofractionated and conventional approaches, should be individualized to each patient and shared between the patient and their physician(s).

For 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.

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 DCIS, hypofractionated WBI may be used as an alternative to conventional fractionation.

Radiation Boost

All 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 WBI.

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 negative margins.

For 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.

Recommendations for boost dosing, sequencing and radiation delivery techniques are outlined in the guideline.

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