AbstractID: 10102 Title: Radiation Therapy in the Management of Early Stage Breast Cancer Approximately 200,000 women were diagnosed with breast cancer in the past year, representing one fourth of all cancers diagnosed in women. Radiation therapy plays a vital role in the treatment of breast cancer, particularly early stage breast cancer. Treatment of breast cancer comprises about 25% of the caseload in a typical radiation oncology practice. Treatment of early stage breast cancer has evolved over the years from mastectomy to breast conserving therapy with lumpectomy and whole breast radiation therapy, which results in similar outcomes with improved cosmesis and conservation of the breast. Continued research has focused on advances in the technical delivery of radiation therapy and the development of partial breast radiotherapy. This talk will focus on the treatment of early stage breast cancer with an emphasis on advances in treatment planning and partial breast radiotherapy. Educational Objectives 1. To discuss surgical options for early stage breast cancer 2. To understand the role of radiation in the treatment of early stage breast cancer 3. To demonstrate the technical aspects of radiotherapy planning 4. To review the rationale and patient selection for partial breast radiotherapy