A Case of Luminal B Breast Cancer in Which Preoperative Chemotherapy Was Used Due to Ineffective Preoperative Hormone Therapy

A 66-year-old, postmenopausal woman was referred to our hospital because of abnormal breast cancer screening results. A tumor was found in the upper outer part of the left breast. Biopsy revealed papillotubular carcinoma, ER (Allred score total score [TS] 3 = proportion score [PS] 2 + intensity score [IS] 1), PgR (Allred score TS 3 = PS 2 + IS 1), HER2 (2+), fluorescent in situ hybridization 1.1 (negative), and Ki-67 labeling index 15%. In diagnostic imaging, the tumor size was 35 mm. The diagnosis was T2N0M0 Stage IIA, luminal B-like breast cancer. First, letrozole 2.5 mg/day was administered as preoperative hormone therapy. After 2 months of treatment with letrozole, the tumor size had increased to 44 mm and preoperative hormone therapy was discontinued. She was started on preoperative chemotherapy (4 courses of epirubicin plus cyclophsphamide followed by 4 courses of triweekly docetaxel). The tumor size decreased, becoming undetectable. After these preoperative treatments, nipple-sparing mastectomy, sentinel lymph node biopsy, and breast reconstruction with a primary latissimus dorsi flap were performed. As of 3 years and 6 months after the operation, there has been no recurrence. At first, preoperative hormone therapy is performed for Luminal B-like breast cancer as in this case, if the response is insufficient, preoperative chemotherapy after hormone therapy may be a therapeutic option.