ASTRO issues guidelines for whole breast radiation therapy

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March 12, 2018

Benjamin D. Smith

A new guideline issued by the American Society for Radiation Oncology recommends the use of hypofractionated whole breast irradiation for patients with breast cancer regardless of tumor stage, age or chemotherapy receipt.

“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,” Benjamin D. Smith, MD, associate professor of radiation oncology at The University of Texas MD Anderson Cancer Center and co-chair of the ASTRO guideline task force, said in a press release. “Conventional therapy does not provide an incremental benefit in either tumor control or side effects compared to hypofractionated whole breast irradiation.”

ASTRO assigned a task force that consisted of 15 radiation oncologists, a medical physicist and a patient representative to create guideline recommendations based on a systematic literature review of 100 articles.

The guidelines recommend a preferred dose-fractionation scheme of hypofractionated whole breast irradiation to a dose of 4,000 cGy in 15 fractions or 4,250 cGy in 16 fractions for women who receive whole breast irradiation with or without inclusion of the lower axilla.

As long as homogenous dosing can be achieved, clinicians should consider offering hypofractionated therapy regardless of tumor grade, which breast the tumor is located in, breast size, previous chemotherapy, and prior or concurrent trastuzumab or endocrine therapy, Smith and colleagues wrote. The therapy also may be offered independent of age, HER-2 receptor status, margin status following surgical resection and hormone receptor status.

Hypofractionated whole breast irradiation also may be used as an alternative to conventional fractionation among women with ductal carcinoma in situ.

ASTRO recommends decisions related to a possible radiation boost, as well as dosage of the boost, be based on discussions between patients and providers. Those decisions should account for individual patient, tumor and treatment factors.

In invasive cases, tumor bed boosts are recommended for patients who have a positive margin following surgical resection, as well as patients aged 50 years or younger. Among patients aged 51 to 70 years, a tumor bed boost is recommended for those who have high-grade tumors. However, ASTRO recommends against tumor bed boosts for patients with invasive cancer who are aged older than 70 years, and those who have low- to intermediate-grade hormone-positive tumors that are resected with widely negative margins.

The guideline recommends boosts for patients with DCIS who are aged 50 years or younger, as well as patients who have high-grade tumors and those who have positive or close margins after resection. Boosts may be omitted for patients with DCIS aged older than 50 years, those whose disease has been detected through screening, those with smaller low- to intermediate-grade tumors, and those with widely negative margins after surgery.

All treatment plans should be developed after the consideration of tumor characteristics, comorbidities and patient characteristics. Smith and colleagues recommended 3-D conformal treatment planning to help achieve homogenous radiation dosing and to achieve full coverage of the tumor bed. Further, care providers should minimize dosage to organs such as the heart, lungs and opposite breast, as well as other nearby normal tissue.

“Hypofractionated 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,” Reshma Jagsi, MD, DPhil, co-chair of the task force and professor of radiation oncology at University of Michigan, said in the press release. “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.” – by Andy Polhamus

Disclosures: Smith reports research funding from The University of Texas MD Anderson Cancer Center and Varian; a consultant role with Global Oncology One; an unspecified relationship with Oncora Medical; and previous research funding from Conquer Cancer Foundation, Cancer Prevention and Research Institute of Texas. Please see the full study for a list of all other authors’ relevant financial disclosures.

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