Studies have evaluated the role of radiation following lumpectomy in very select groups which have not been able to define a group who do not benefit from the addition of radiotherapy. In the group of patients who received surgery alone, 85% of the breast recurrences occurred in the tumor bed. Due to these two facts, radiotherapy directed only at the tumor bed has been evaluated. Treating this smaller tumor volume has allowed higher doses of radiation to be delivered safely shortening the treatment course from 6-7 weeks to one week.