[Two Cases of Radiation-Induced Breast Angiosarcoma after Breast-Conserving Surgery]

We report 2 cases of radiation-induced breast angiosarcoma after breast-conserving surgery, which is a rare disease with a poor prognosis. Case 1: A 95-year-old woman underwent partial mastectomy(Bp)+axillary lymph node dissection(Ax) and residual breast irradiation as adjuvant therapy at the age of 84. Eleven years after surgery, she complained of left nipple discharge and severe pain; therefore, a left mastectomy(Bt)was performed. The postoperative pathological diagnosis was an angiosarcoma. Case 2: A 61-year-old woman underwent Bp+sentinel lymph node biopsy(SLNB)and residual breast irradiation as adjuvant therapy at the age of 56. In the 6th year after surgery, she complained of pruritus and induration of the left nipple. A biopsy was performed, and angiosarcoma was diagnosed; therefore, a left Bt biopsy was performed. Weekly paclitaxel(w-PTX)was administered as adjuvant therapy. The 2 cases were considered radiation-induced breast angiosarcomas based on the period leading up to the onset of the disease, both after breast cancer surgery and radiation. The first treatment choice is surgical resection; however, no standard surgical method has been established.