Radiation therapy in management of breast cancer.

Randomized trials have demonstrated the efficacy of radiation therapy in the treatment of breast cancer. A reduction in the risk of recurrence has been shown in breast conservation for ductal carcinoma in situ and in invasive cancers after breast conservation and mastectomy. The importance of local control in breast cancer is becoming more apparent. Defining the groups of patients who most benefit from the therapy and improving treatment delivery systems to enhance the therapeutic index are ongoing challenges.