The hormones in your body that launched you into puberty and controlled your monthly period can play a role in breast cancer.
Most breast cancers -- about 2 out of every 3 -- are sensitive to the hormones estrogen or progesterone. These tumors have a sort of biological on-off switch called a hormone receptor. Estrogen and progesterone can flip these switches "on" and quicken the cancer cells' growth. Your doctor will test your cancer to see if it has hormone receptors. If it does, she may call it "hormone-receptor positive" or “ER-positive” or “PR-positive.”
For advanced breast cancer, your doctor may want to repeat these tests after a while to see if your cancer has changed. It may respond differently to hormones than before. Test results will help your doctor find the best treatment at any stage.
How It's Different
Compared with other types of breast cancer, hormone-receptor-positive breast cancers, called HR-positive cancers, tend to:
- Grow more slowly
- Respond better to hormone therapy
- Have a better outlook (prognosis)
Testing for Hormone Receptors
In advanced cancer, your doctor will take a small part of the cancer that has spread to your lymph nodes, liver, or other areas of your body. She may use a very fine needle or get the tissue during surgery. Lab tests will show if the cancer has hormone receptors.
If you are taking hormones, you may need to stop before getting the test.
Cancer cells may have:
- Estrogen receptors only. Your doctor will call these ER-positive (ER+) cancers.
- Progesterone receptors only. These are PR-positive (PR+) cancers.
- Both estrogen and progesterone receptors
- Neither estrogen or progesterone receptors, called hormone negative (HR-)