No one could blame you for having a mountain of questions after receiving a breast cancer diagnosis. That list might be even longer if you receive a diagnosis of triple negative breast cancer: What exactly does that mean? How is triple negative breast cancer different from other diagnoses? And how can you make life easier on yourself if you have this illness? Here, breast cancer experts answer these and other questions.
What is triple negative breast cancer?
It might sound surprising, but in a sense, breast cancer isn’t really one disease, Erica Mayer, M.D., M.P.H., senior physician at the Susan F. Smith Breast Oncology Center at Dana Farber Cancer Institute in Boston, tells SELF. Subtypes of the condition, like triple negative breast cancer, have characteristics that differentiate them from other forms of the disease.
To fully understand triple negative breast cancer—and what makes it different from other breast cancers—you need to know a bit about breast cancer receptors.
“Receptors are proteins that are located on the outside of a cancer cell, and they receive signals from the body that may influence the growth pattern of the cancer cell,” Dr. Mayer says. The receptors that help to determine a breast cancer diagnosis are estrogen receptors (ER), progesterone receptors (PR), and HER2 protein receptors. Doctors separate breast cancer into a few main categories based on the presence or absence of these receptors.
Breast cancers that have estrogen or progesterone receptors are known as hormone receptor-positive, meaning that they grow in response to these hormones. Hormone receptor-positive breast cancers make up about two-thirds of all breast cancer cases, according to the American Cancer Society (ACS). “If a cancer cell has the estrogen receptor, then estrogen circulating in the body has the potential to stimulate that receptor and stimulate the cancer cell to grow,” Dr. Mayer explains. “If we can block a receptor from being stimulated, then we can block cancer cell growth and spread. That’s the basis for many of the therapies we use to treat cancer,” Dr. Mayer explains.
Then there are breast cancers that have too much of the HER2 protein, which account for about 20 percent of diagnoses, according to the ACS. (Some of these are also hormone receptor-positive.) HER2 is a protein that encourages cancer cells to grow, the ACS explains. If you have HER2-positive breast cancer, an excess of this protein in the tumor essentially turns on a “switch” in cancer cells, Leisha Emens, M.D., Ph.D., co-leader of the UPMC Hillman Cancer Immunology and Immunotherapy Program in Pittsburg, tells SELF. Therapies that target the HER2 protein try to flip off the switch, so to speak.
Doctors test tumors for all three of these receptors when people undergo breast biopsies, according to the Mayo Clinic. When tests for all three receptors come back negative, doctors diagnose triple negative breast cancer, which makes up around 12 percent of all breast cancers, according to the ACS.
Doctors used to treat all cases of triple negative breast cancer as just one group, but that’s changing, Rita Nanda, M.D., associate director of Breast Medical Oncology at UChicago Medicine, tells SELF. Doctors now acknowledge at least four different kinds of triple negative breast cancer based on the proteins the tumors express, she says.
Triple-negative breast cancer is considered particularly aggressive. These tumors express different genes than ER/PR-positive and HER2-positive breast cancers, leading to higher risk of recurrence, Dr. Emens says. Plus, the targeted therapies that treat ER/PR-positive and HER2-positive breast cancers haven’t worked for triple negative breast cancer, according to the Centers for Disease Control and Prevention (CDC).
The signs of triple negative breast cancer
Symptoms of triple negative breast cancer aren’t different from other types of breast cancer, Dr. Mayer says. According to the ACS, these symptoms include:
- A new breast lump that may be hard, soft, painful, or painless
- Swelling of the breast
- Breast or nipple tenderness
- An inverted nipple
- Skin peeling, thickening, or redness
- Skin that resembles an orange peel
- Nipple discharge
- Swollen lymph nodes
Triple negative breast cancer risk factors
As with so many complicated health conditions, experts aren’t quite sure what causes triple negative breast cancer. Doctors don’t understand for certain what causes breast cancer in general, Dr. Mayer says, much less the complex triple negative kind. They have some ideas about risk factors involved, though.
Much of the conversation about breast cancer risk factors revolves around hormone exposure since most breast cancers grow in response to hormones. But that’s not an issue with triple negative breast cancer, so other factors take center stage.
In general, breast cancer risk rises as you get older, according to the Mayo Clinic. But triple negative breast cancer is actually more common in premenopausal people than in older ones, Dr. Nanda says. This could be because of triple negative breast cancer’s link with BRCA gene mutations, which are often implicated in cases of people developing breast cancer before age 50.
Mutations in the BRCA1 and BRCA2 genes can raise your risk of breast and ovarian cancers, according to the CDC. When these genes function normally, they help to suppress tumor growth, the National Cancer Institute (NCI) explains. When they have mutations, however, your cells may divide and change too quickly, leading to cancerous tumors. There’s a lot of scientific interest surrounding a possible association between these mutations (especially of the BRCA1 gene) and triple negative breast cancer, though experts don’t yet know how exactly they might be connected.
Keep in mind: Not everyone who gets breast cancer (including the triple negative form) or ovarian cancer has a BRCA gene mutation, Dr. Nanda says. Likewise, not everyone with this gene mutation gets breast cancer or ovarian cancer, according to the CDC.
Your racial and ethnic background can also increase your odds of developing triple negative breast cancer. You may have heard that people of Ashkenazi Jewish or Eastern European heritage are at a greater risk of developing breast cancer. That goes for triple negative breast cancer as well, according to the CDC. (This tracks, as people in these groups are at higher risk of having BRCA gene mutations.)
Triple negative breast cancer also occurs almost twice as often in black people than in white people, according to the ACS. Doctors have theorized that this disparity may be due to BRCA1 gene mutations occurring more often in black people, Dr. Nanda says, but more research is needed to determine a clear link.
In sum, there are a lot of potential risk factors at play when it comes to triple negative breast cancer, but doctors are still working to figure out a cause behind the disease.
Treatment options for triple negative breast cancer
Since triple negative breast cancer doesn’t respond to targeted treatments used for other types of breast cancer, it raises complicated questions about treatment.
For now, experts typically rely on removing as much of the tumor as possible (either through a lumpectomy or mastectomy) in addition to chemotherapy, according to the Mayo Clinic. Experts are testing immunotherapy options that may attack triple negative breast cancer tumors as well. Ongoing research could lead to targeted treatments for triple negative breast cancer, Dr. Nanda says. If you’re interested in learning more, you might consider speaking to your doctor about participating in a clinical trial, Dr. Mayer says.
No matter the treatment strategy that you and your doctor decide is best, self-care is an essential—and easy to overlook—part of dealing with triple negative breast cancer. Here’s how four women with this condition practice self-care. They may give you a few ideas for coping, too.