Future Directions: Phase III Cooperative Group Trials

The management of early-stage breast cancer remains an area of active research. Standard breast-conservation therapy is now well established but the logistics of traditional whole-breast adjuvant irradiation limit the widespread use of breast conservation. A modern review of clinical and pathologic data suggests that adjuvant radiation of the entire breast is unnecessary and indicates that partial breast therapy may be appropriate, thus opening the possibilities of APBI. With more than 10 years experience, definitive data regarding the role of APBI have not yet been generated. The GEC-ESTRO multicenter phase III trial now underway in Europe and the NSABP B39/RTOG 0413 open in the United States are two, multi-institutional phase III trials constructed to deliver the answers to the many questions that remain. It is the role of these phase III trials to further define and potentially expand the patient selection criteria, elucidate which dosimetric parameters are critical to success and clarify which APBI technique is appropriate in which situation.