Clinical experience using fulvestrant in hormone responsive metastatic breast cancer

10749 Background: We report our clinical experience using the steroid estrogen receptor antagonist Fulvestrant to treat postmenopausal women with hormone sensitive metastasized breast cancer. We discuss the position of Fulvestrant in the endocrine treatment cascade, taking into account the new application guidelines for aromatase inhibitors. Methods: Data from 16 female patients and one male patient treated with Fulvestrant were analyzed. We describe the time point in the treatment cascade when Fulvestrant was administered and the resulting time to progression (TTP). The reviewed cohort was heterogeneous regarding the initial tumor size, the therapy and the progression of the tumor, respectively. The patients were 54 years of age at the time of diagnosis. The estrogen receptor was positive in all cases. Results: Fulvestrant was usually given as the last step in the endocrine treatment cascade (n = 14). The mean TTP was 5.7 months (n = 13). 3 patients are still under successful treatment with Fulvestrant. No common side effects as usually caused by endocrine therapies with Tamoxifen and aromatase inhibitors were documented. Conclusions: The specific estrogen receptor down-regulator Fulvestrant is a valid and well tolerated endocrine treatment option in heavily pre-treated and metastasized breast cancer patients (TTP 5.7 month). Also in the clinical situation of Tamoxifen resistant tumors, Patients could benefit from Fulvestrant. 3rd generation aromatase inhibitors are now used for the first-line treatment of breast cancer in postmenopausal women. Shifting the sequential endocrine therapy cascade might need a new positioning of Fulvestrant. No significant financial relationships to disclose.