Is radiation effective for breast cancer?

Yes: After lumpectomy, radiation cuts local recurrence (recurrence in the breast) from 40% to less than 10%. It is also helpful after mastectomy if the lymph nodes are involved.

Very effective.: Radiation therapy (rt) is never a primary treatment for breast cancer, but rather a supplement to surgery for the local treatment of breast cancer. Rt is mandatory following breast conserving surgery: local recurrence rates are decreased from >25% to <5% with rt. Rt is also used after mastectomy for patients that are at high risk for local recurrence.

Sometimes: Radiation is effective after lumpectomy in reducing the risk of local and regional recurrence. Other times it can be given in an advanced breast cancer to slow the growth of the cancer.