Or your breast may have a different size or position compared to the other breast. Learn about options for reconstruction after lumpectomy. If the DCIS has been removed with lumpectomy, radiation is usually given to reduce the risk of cancer returning.Your doctor may discuss a couple of radiation options with you: 1  External radiation is given to the entire breast by a machine called a linear accelerator. Radiation treatment is usually given as daily treatments 5 days per week over 5 to 7 weeks. 2  Treating the whole breast with radiation after lumpectomy remains the standard of care. 3  In cases of DCIS, radiation therapy can reduce the risk of the cancer coming back by about 60%.