[en] From the beginning of 2000, accelerated and partial breast irradiation (A.P.B.I.) progressively acquired maturity and used more and more sophisticated technologies. At this time, at least six international phase III trials are ongoing. The statistical design of these studies is elaborated in order to show equivalence between A.P.B.I. and whole breast irradiation (W.B.I.) in term of local control. What and when we have to wait from these randomized trials? The presented analysis discusses not only the advantages and different interrogations concerning A.P.B.I., but also the difficulties for radiation oncologists and patients to assume the long period until the publication of the ongoing phase III trial results. A.P.B.I. will find its place beside W.B.I., as well as conservative treatment founded its place beside radical mastectomy 30 years ago. However, clinical investigation conditions appear now different and this is this difference we have to manage rigorously and precisely. (authors)