Triple-Negative Breast Cancer
About 15 to 20 percent of breast cancers are triple-negative. But you may have never heard of triple-negative breast cancer before you got your test results. Knowing the basics of breast cancer can help you understand how triple-negative breast cancer is different from other types of breast cancer.
To find out which type of breast cancer you have, your doctors search for the presence or absence of three receptors. Receptors are proteins that live inside or on the surface of a cell and bind to something in the body to cause the cell to react. The three receptors are:
- the estrogen receptor, or ER
- the progesterone receptor, or PR
- the human epidermal growth factor receptor 2, or HER2
In ER-positive breast cancer, PR-positive breast cancer and HER2-positive breast cancer, treatment includes medicines that prevent, slow or stop cancer growth by targeting those receptors. But triple-negative breast cancers need different types of treatments because they test negative for all three receptors. Medicines such as tamoxifen, which targets the estrogen receptor, and trastuzumab (Herceptin), which targets HER2, are not helpful in triple-negative breast cancer. Instead, chemotherapy has been shown to be the most effective treatment.
Researchers are learning more about triple-negative breast cancers, including how they behave and what puts people at risk for them. The goal is to find the best ways to use existing treatments and to develop new ones.
- whether the cancer has traveled to the lymph nodes near your breast
- the size of the main tumor
- details of tests in your pathology report, such as the tumor grade, which shows how quickly the cancer cells are dividing
While breast cancers that don't have estrogen, progesterone or HER2 receptors are all considered triple-negative, there can be some differences at the molecular level. Most triple-negative breast cancers fall in the basal-like subtype. You may see that term used in research or hear it used by your doctors. But not all triple-negative breast cancers are basal-like, and not all basal-like cancers are triple-negative.
There are many ways to study different features of breast cancer such as the basal-like subtype. Someday this research may change the way we think about triple-negative breast cancer, but today whether the cancer is basal-like does not affect your treatment options. Doctors choose treatments because the cancer is triple-negative, not because it is basal-like.
Myth #1: People with triple-negative breast cancer can have the same treatments as all other people with breast cancer.Fact: Many people do not understand there are different types of breast cancer. You might know people who took a hormonal therapy pill for 5 to 10 years to lower their risk of recurrence. These people, and some others, may not understand that this option does not exist for you. On the other hand, you may take some of the same chemotherapy medicines as people with other types of breast cancer.
Myth #2: Triple-negative breast cancers are always hard to treat.Fact: Your doctor may tell you triple-negative breast cancer is “harder to treat” than other types of breast cancer. Many triple-negative cancers are aggressive, but your doctor’s prediction of how well your treatment may work depends not only on its triple-negative status but also on the tumor size and whether the cancer has traveled to the lymph nodes in your armpit. There are some very effective treatments for triple-negative breast cancer.
Myth #3: Only African-Americans get triple-negative breast cancer.Fact: While breast cancers in African-American women are more likely to be triple-negative than those in white women, triple-negative breast cancers affect women of all races.