Lessons of studies of breast-conserving therapy with and without whole-breast irradiation for patient selection for partial-breast irradiation

Partial-breast irradiation is a promising approach for treating patients with early-stage invasive breast cancer. There are still few studies of partial-breast irradiation that address critical issues, such as criteria for patient selection. However, an enormous body of experience has been accumulated regarding the results in patients treated with “conventional” breast-conserving therapy using whole-breast irradiation and for patients treated with conservative surgery without radiotherapy of any kind. This article will therefore review portions of this existing experience that may aid the development of partial-breast irradiation and give perspective on the overall role that partial-breast irradiation may ultimately play in our therapeutic armamentarium.