Letrozole is an aromatase inhibitor that is approved in the first-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor unknown locally advanced or metastatic breast cancer. Sorafenib may stop the growth of tumor cells by blocking blood flow to the tumor and by blocking some of the enzymes needed for cell growth. This phase I/II trial is studying the side effects and best dose of sorafenib when given in combination with letrozole and to see how well they work in treating postmenopausal women with metastatic breast cancer.
Histologically confirmed invasive breast cancer Stage IIIB, IIIC with T4 lesion or Stage IV disease Breast cancer must be ER-positive and/or PR-positive Age ³ 18 years of age ECOG performance status 0, 1 or 2 Able to swallow and oral medication Adequate end organ function Written informed consent
Exclusion Criteria:
Prior hormonal therapy for metastatic disease Prior chemotherapy for metastatic disease Prior treatment with sorafenib Brain metastases or leptomeningeal disease Evidence or history of bleeding Thrombolic or embolic events such as cerebrovascular accident including transient ischemic attacks within the past 6 months
