Development of distant metastases during adjuvant therapy with trastuzumab (H) in premenopausal patients with HER2-positive breast cancer

11574 Background: Breast cancer patients with positive HER2 have more aggressive disease with increased metastatic potential and poorer prognosis. Methods: From June 2006 to September 2007, 45 premenopausal patients were treated with adjuvantH therapy every 3 weeks at our Institute. Average age of the patients was 45 years (range: 31–52 years). Before the said therapy was applied the patients were treated with adjuvantchemo- and hormonal therapy(if indicated) and radiotherapy. All patients were given 6 cycles of adjuvantFAC chemotherapy. Radiotherapy was applied in 37 (82.22%) patients after completion of adjuvantchemotherapy. Thirty-four (75.55%) patients were steroid receptor dependent and all of them were treated with tamoxifenafter completion of chemotherapy. Tamoxifentherapy was continued during radiotherapy and H therapy. After completion of chemotherapy and radiotherapy (if necessary treatment with H was initiated between day 14 and day 46 (average: day 26). Results: During the H therapy dis...