[A Case of Advanced Breast Cancer Resected after the Combined Therapy of Palbociclib and Letrozole].

A 50's postmenopausal woman, she was diagnosed with breast cancer, cT2N3aM0, Stage ⅢC, invasive ductal carcinoma, estrogen-receptor(ER)-positive, progesterone-receptor(PgR)-negative, human epidermal growth factor 2(HER2)-negative. A combination therapy of palbociclib(PAL)and letrozole(LET)was administered to the patient. A method of administration was 125 mg of PAL per day(14 days of treatment followed by 14 days off, 2 courses and 18 days of treatment followed by 10 days off, 8 courses)and 2.5 mg of LET per day every day. This therapy was effective, and the clinical stage showed down staging, T2N1M0, Stage ⅡB. Left total mastectomy and sentinel lymph node biopsy and swelled axillar lymph node resection was performed. Postoperative pathological histology revealed ypT2N1a(1/9). Subsequently this medication (125 mg of PAL per day, 21 days of treatment followed by 14 days off and 2.5 mg of LET per day every day)was continued as an adjuvant therapy and postmastectomy radiation therapy(PMRT 50 Gy)was underwent for her. This patient has survived without recurrence 12 months after operation. PAL probably has a certain effect even if oral administration method were changed.