Endocrine therapy alone

With the PFS and OS advantages associated with combination therapy with targeted agents and endocrine therapy as discussed above, single-agent endocrine therapy is less frequently used, especially in the first-line setting. However, its use remains appropriate in select cases as first-line therapy and in later-line therapy after progression on targeted therapies and before the use of chemotherapy in cases in which endocrine-sensitive disease is still thought to be present.

Commonly used single-agent endocrine therapies include tamoxifen, nonsteroidal AI (letrozole, anastrozole), the steroidal AI exemestane, and fulvestrant. In general, premenopausal women with metastatic breast cancer undergo ovarian suppression or ablation and are treated in the same manner as postmenopausal women.