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

Abstract

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 adjuvant H 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 adjuvant chemo- and hormonal therapy (if indicated) and radiotherapy. All patients were given 6 cycles of adjuvant FAC chemotherapy. Radiotherapy was applied in 37 (82.22%) patients after completion of adjuvant chemotherapy. Thirty-four (75.55%) patients were steroid receptor dependent and all of them were treated with tamoxifen after completion of chemotherapy. Tamoxifen therapy 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 distant metastases developed in three (6.67%) patients. After cycle 3 of the therapy one patient developed bone metastases; one patient had CNS metastases after cycle 4, and one patient had liver metastases after cycle 6 of the therapy. Two of these 3 patients were steroid receptor independent and one was steroid receptor dependent. All of them were previously treated with FAC regimen and radiotherapy. After the appearance of distant metastases was confirmed H therapy was discontinued and these patients were treated according to our standard protocol. Conclusions: This small retrospective study showed that premenopausal patients with HER2 positive breast cancer have higher risk for development of metastatic disease, including brain metastases, even during the treatment with adjuvant H therapy. No significant financial relationships to disclose.