Full Radiation Dose May Not Be Necessary for Some Early-Stage Breast Cancers

Five-year results from a U.K. study suggest that treating just the area around where the cancer used to be with radiation may be as good as treating the whole breast with radiation.

The research was published on Sept. 9, 2017 by The Lancet.

The study included 2,016 women age 50 or older who had been diagnosed with early-stage breast cancer between 2007 and 2010. All the cancers were 3 cm or smaller, and all the women had three or fewer positive lymph nodes. All the women had lumpectomy to remove the breast cancer.

After surgery, the women were randomly assigned to one of three radiation regimens.

After 5 years of follow-up, local recurrence rates (breast cancer coming back in the same breast) were:

• 1.1% for women who got the standard dose of radiation
• 0.2% for women who got the full dose of radiation to the area where the cancer was and a slightly lower dose further away
• 0.5% for women who got the standard full dose of radiation only to the area where the cancer was

While these results are very promising, they are still early results. Doctors need longer follow-up information to see whether radiation to just the area where the cancer was offers the same local recurrence rates 7, 9, or 10 years after treatment.