Although most studies treating patients with partial-breast irradiation have used brachytherapy, giving such treatment with external-beam techniques has many potential advantages. However, there is only limited published experience using this approach. These include a randomized trial of partial-breast and whole-breast irradiation performed at the Christie Hospital in Manchester, England, and pilot studies (using much more rigorous selection criteria and sophisticated treatment planning) from groups at the University of Southern California, New York University (using prone positioning of patients), and the William Beaumont Hospital (using the supine position). A multi-institutional pilot trial based on the latter technique has been completed, which was designed to test the feasibility of using this approach in the cooperative oncology group setting. The unprecedented rapidity with which the study completed its target accrual indicates the degree of interest in this approach. This review focuses on the rationale and the reported studies of external-beam partial-breast radiation and identifies some specific issues and remaining problems associated with this approach.
