Lower Radiation Doses as Effective as Standard Dosing in Early Breast Cancer

The utilization of lower overall radiation doses, given on a particular schedule, appears as effective as the standard higher dosing for patients with early breast cancer. These results were recently published in the Lancet Oncology.

Radiation continues to be an important treatment component for patients with early breast cancer. However, radiation is associated with an increased risk of short and long-term side effects. Researchers are continually exploring the potential of different radiation schedules to keep side effects to a minimum while maintaining effectiveness of treatment.

Researchers recently conducted two clinical trials, referred to as the START A and START B trials to compare different scheduling and doses of radiation therapy for patients with early breast cancer. The trials included approximately 5,000 women from 35 radiotherapy centers in the United Kingdom. All women had early breast cancer that had been completely surgically removed. The patients were then treated with different schedules of radiation, varying with different strengths of the doses of radiation as well as differing frequency of scheduling. The following data is at 10 years of follow up of participants in these trials:

There were no significant differences in overall survival among women treated with overall higher or lower cumulative doses of radiation therapy.
There were no significant differences in recurrences of cancer at or near the site of radiation therapy between the groups receiving different radiation doses.
Side effects associated with radiation therapy, particularly those that affected the skin, were significantly reduced among women receiving lower overall doses of radiation.
The researchers stated that “Long-term follow-up confirms that appropriately dosed hypofractionated radiotherapy is safe and effective for patients with early breast cancer. The results support the continued use of 40 Gy in 15 fractions, which has already been adopted by most UK centres as the standard of care for women requiring adjuvant radiotherapy for invasive early breast cancer.”

It is important that patients understand that there are very specific radiation schedules and doses given that have provided optimal treatment outcomes. This study was a comparison of specific regimens with a report of 10 year follow-up data.

Reference: Haviland J, Owen J, Dewar J, et al. The UK standardization of breast radiotherapy (START) trials of radiotherapy hypofractionation for treatment of early breast cancer: 10-year follow-up results of two randomised controlled trials. The Lancet Oncology. Early online publication September 19, 2013. doi:10.1016/S1470-2045(13)70386-3.