Some breast cancer cells have characteristics that make the cancer easier to treat. We test all newly diagnosed breast cancer cells to see if they have hormone receptors, which fuel cancer growth. About two out of every three breast cancers have at least one type of hormone receptor. At the Abramson Cancer Center, our specialized breast cancer team uses these details to personalize treatment for every patient.
What Is Hormone Receptor-Positive Breast Cancer?
Hormone receptors are proteins found on breast cells. They pick up the estrogen or progesterone signals that promote cell growth, including cancer cell growth if they contain the receptors for those hormones. Breast cancer cells that have receptors for either hormone are considered hormone receptor-positive (HR+), or just hormone-positive.
Breast tumors may be positive for estrogen receptors (ER+), progesterone receptors (PR+) or both (ER/PR+). About 80 percent of all HR+ breast cancers are ER+ or ER/PR+.
If a cancer cell is ER+, it means it can receive signals from estrogen instructing the cells to grow. If a cancer cell is PR+, these signals can come from the progesterone hormone. Knowing whether the tumor needs estrogen and/or progesterone to grow makes it easier to treat the cancer. Breast cancer cells can test positive for hormone receptors regardless of the type of breast cancer or breast cancer stage.
Testing for Estrogen and Progesterone Receptors (PR) for HR+ Breast Cancer
At Penn Medicine, our breast pathologists diagnose breast cancer by testing tumor tissue using samples taken during breast biopsy or surgery. The most common test used to classify hormone receptor status is an immunohistochemistry (IHC) test. This sensitive test will identify a tumor as HR+ if even 1 percent of the tested cells have a hormone receptor.
Breast tissue is also tested for human epidermal growth factor receptor 2 (HER2). Breast cancer that is HER2-positive may respond to targeted therapy. Cancer that tests negative for hormone receptors and HER2 is called triple negative breast cancer.
Treating PR-Positive and ER-Positive Breast Cancer
The growth of HR+ breast cancer is fueled by the body’s hormones, particularly estrogen. By lowering the amount of estrogen in the body, we may stop cancer cells from growing. We use a combination of targeted and standard cancer treatments to treat HR+ breast cancer. Breast cancer treatment at Penn Medicine may include:
- Cancer surgery: Your care team may recommend cancer surgery known as a lumpectomy, which involves partial removal of the breast, or a mastectomy, which involves the full removal of the breast.
- Breast reconstruction: Some breast cancer patients opt to have breast reconstruction which can be done at the same time as (or after) your lumpectomy or mastectomy. During breast reconstruction, your plastic surgery team will recreate the shape and appearance of your breast.
- Chemotherapy: Your care team may also recommend chemotherapy in addition to or without surgery. Chemotherapy treatment involves the use of oral or intravenous (IV) drugs to attack cancer cells anywhere in the body.
- Radiation therapy: Typically used after surgery or chemotherapy, radiation therapy is another treatment designed to kill any remaining cancer cells.
- Targeted therapy: Patients whose cancer is HER2-positive and/or related to a BRCA gene mutation may also be a candidate for targeted molecular therapy. This personalized treatment is directed at hormone receptors, interrupting molecular abnormalities that drive cancer growth.
- Hormone therapy: Hormone therapy is also called endocrine therapy. In the treatment of breast cancer, it is used to block estrogen hormones from binding to cancer cells that have estrogen receptors.
- Breast cancer clinical trials: Breast cancer care is always changing and improving thanks to ongoing research and clinical trials. Some clinical trials allow you to participate from any of our Penn Medicine breast cancer locations so you can receive the care you need close to home.
Our Approach to Hormone Receptor-Positive Breast Cancer
We know how to identify a tumor's characteristics and use that information to personalize breast cancer treatment. These steps are key in effective breast cancer care. At the Abramson Cancer Center’s Breast Cancer Program, you can expect:
- Expert diagnosis: Our specialized breast cancer pathologists only works with breast cancer tissue. We accurately interpret your test results so you quickly get the treatment you need.
- Leaders in targeted therapy: Our renowned oncologists know when targeted therapy is appropriate for HR+ breast cancer and how to use it effectively.
- Support for side effects: We offer breast cancer support and integrative oncology to ease any discomfort and pain associated with treatment.
- Care close to home: We provide breast cancer expertise at all our Penn Medicine breast cancer locations. Oncologists throughout our network collaborate seamlessly to get you advanced breast cancer care.
- Focus on research and prevention of inherited cancer: Through the Basser Center for BRCA, Penn Medicine has been a leader in the research, treatment and prevention of cancers linked to the BRCA gene mutation.
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