[Preoperative therapy using trastuzumab and weekly paclitaxel in a stage IIIB inoperable locally advanced HER2- positive breast cancer with complete pathologic response].

A 63-year-old woman had a 12 cm tumor on her right breast with broad skin redness, satellite lesions and 8 cm ipsilateral lymph nodes swelling(T4bN2aM0, Stage IIIB). Core needle biopsy and immunohistochemistry of breast tumor showed invasive ductal carcinoma with negative hormone receptor(ER-, PgR-)and overexpression of HER2 (HercepTest 3+). She was treated with weekly paclitaxel(80 mg/m(2), 4 administrations with a week rest)and a com- bination with weekly trastuzumab(initially 4 mg/kg followed by 2 mg/kg every week, totally 11 administrations). After 3courses of administration, the breast tumor, skin redness and axillary swelling were completely disappeared(clinical complete response), then mastectomy with axillary dissection was performed. Histopathology of the breast and lymph nodes showed complete disappear of invasive cancer cells with only 2x1 mm residue of ductal component(pCR, grade 3, DC+). We conclude that the combination of weekly paclitaxel and trastuzumab is a promising neoadjuvant therapy regimen for HER2 positive, ER-negative breast cancer.