The addition of radiation therapy to lumpectomy appears to reduce the risk of local recurrence to approximately 12 % , of which approximately half will be DCIS .
Half will be invasive breast cancer ; the risk of recurrence is 1 % for women undergoing mastectomy .
The addition of radiation therapy to lumpectomy appears to reduce the risk of local recurrence to approximately 12 % , of which approximately half will be DCIS and half will be invasive breast cancer ; the risk of recurrence is 1 % for women undergoing mastectomy .