Early Side Effects of Three-Dimensional Conformal External Beam Accelerated Partial Breast Irradiation to a Total Dose of 40 Gy in One Week (A Phase II Trial)

3D-conformal APBI (with two minitangents and an “en face” electron field) using a total dose of 40 Gy in 10 fractions twice daily over 5 days achieved appropriate PTV_EVAL coverage and offered significant sparing of normal tissue. Early tolerance was excellent.