LOG IN Hormone-resistant breast cancer is breast cancer that has stopped responding to hormonal treatment. Roughly 70% of breast cancers are hormone receptor–positive (HR+), either estrogen receptor–positive (ER+) or progesterone receptor–positive (PR+), meaning that their growth is fueled by estrogen or progesterone, respectively. Treatment for these HR+ breast cancers work by lowering the levels of estrogen or progesterone in the body, blocking the hormones from attaching to the breast cancer cells.
About 50% to 60% of early-stage HR+ breast cancers become resistant to hormonal therapy, that is, they stop responding to the therapy. Most all advanced-stage HR+ breast cancers become hormone-resistant at some point.
Treatment options for hormone-resistant breast cancer include:
- If premenopausal: with progression on tamoxifen:
- Ovarian ablation or suppression + a nonsteroidal aromatase inhibitor
- Ovarian ablation or suppression + a steroidal aromatase inactivator
- Ovarian suppression + any of the options for postmenopausal women
- If postmenopausal:
- Ovarian ablation or suppression + a nonsteroidal aromatase inhibitor
- Ovarian ablation or suppression + a steroidal aromatase inactivator
- Fulvestrant
- Everolimus + fulvestrant
- Palbociclib + an aromatase inhibitor
- Palbociclib + fulvestrant
- Ribociclib + aromatase inhibitor
- Abemaciclib + fulvestrant
- Megestrol
- Fluoxymesterone
- Abemiciclib