ASTRO 2018: Long-Term Effects of Once-Weekly vs. Conventional Breast Radiation
Posted: Thursday, November 1, 2018
In a 10-year study of women who were treated with radiation therapy for early-stage breast cancer, those who received larger, less-frequent doses had similar rates of late-stage side effects as women who were treated with conventional radiation therapy. The results of the phase III FAST trial were presented at the 2018 Annual Meeting of the American Society for Radiation Oncology (ASTRO) in San Antonio (Abstract LBA2).
“This study says it’s possible to find a regimen that would allow early-stage breast cancer patients to be treated only once a week over 5 weeks rather than daily over the same time period,”stated lead author Murray Brunt, MD, of University Hospitals of North Midlands and Keele University, United Kingdom, in an ASTRO press release.
Women 50 years of age and older with invasive breast carcinoma (n = 915) were randomly assigned to 1 of 3 regimens of whole-breast radiation therapy. Following breast-conserving surgery, participants receivedconventional treatment with 50 Gy of radiation delivered in 25 daily fractions over 5 weeks, 5 once-weekly fractions of 28.5 Gy, or 5 once-weekly fractions of 30 Gy.
Normal tissue effects were similar between the conventional therapy group and the 28.5-Gy group at 5 and 10 years after treatment. However, moderate/severe late effects to normal breast tissue were significantly higher for patients who received the 30-Gy regimen, including moderate/severe instances of breast shrinkage, breast hardness, fluid buildup, and spider veins. Local recurrence rates were low at 10 years for all schedules.
“As a next step, we want to investigate shortening the radiation therapy schedule to 1 week,” stated Dr. Brunt. His research team is currently testing 5 fractions delivered over 5 consecutive days, which “would have significant clinical and practical implications.”
