HR+/HER2- Metastatic Breast Cancer: Endocrine Therapy and CDK4/6 Inhibitors

Hormone-driven disease

HR-positive, HER2-negative metastatic breast cancer depends on estrogen signaling. Endocrine therapy blocks that signal, and adding a CDK4/6 inhibitor has become standard first-line care for many patients.

The treatment backbone

• Aromatase inhibitors or fulvestrant suppress estrogen signaling.
• CDK4/6 inhibitors block cell-cycle progression and extend progression-free survival when combined with endocrine therapy.
• Ovarian suppression may be added for premenopausal patients.

Where staging fits

Even in metastatic disease, documenting sites and extent of spread guides local symptom management and sequencing of lines.