Hypofractionation is the preferred means of giving whole breast irradiation to women with invasive breast cancer, according to updated guidance from the American Society for Radiation Oncology.
A dose of 4,000 cGy given in 15 fractions or 4,250 cGy in 16 fractions is recommended, with or without inclusion of the low axilla, and regardless of a variety of factors such as tumor grade, prior chemotherapy, and patient age.
“Previously, accelerated treatment was recommended only for certain patients, including older patients and those with less advanced disease,” Benjamin Smith, MD, one of the cochairs of the guideline task force, said in an ASTRO news release.
Dr. Smith, of the University of Texas MD Anderson Cancer Center, Houston, added that recent long-term data from several large trials “strongly support the safety and efficacy of accelerated treatment for most breast cancer patients.”
Treatment decisions and plans still need to be individualized, but the updated ASTRO guidance notes that whole breast irradiation (WBI) can be offered to most women with invasive breast cancer independent of breast size and whether or not the cancer is in the left or right breast, provided that homogeneous dosing can be achieved. Hormone receptor, HER2 status, and postsurgical margin status also appear not to matter.
Historically, conventional fractionation (CF) with or without a tumor bed boost was used for WBI, Dr. Smith and associates wrote in the guidelines, which were published online in Practical Radiation Oncology. This consisted of daily doses of 180-200 cGy for a total dose of 4,500-5,000 cGy.
“Recognizing the limitations of CF for convenience and cost, randomized trials in the 1990s and 2000s investigated if moderate hypofractionation [HF], defined as daily doses of 265-330 cGy, could yield oncologic and functional/cosmetic outcomes similar to CF-WBI,” they said.