Triple Negative Breast Cancer Explained

About 10 to 20 percent of breast cancers are triple negative, but you may never have heard of triple negative breast cancer before you received your test results.

Hearing new words and not understanding what they mean may make you feel scared and overwhelmed.

Knowing breast cancer basics can help you understand how triple negative breast cancer is different from other types of breast cancer. To find out what type of breast cancer you have, your doctors search for the presence or absence of three receptors, proteins that live inside or on the surface of a cell and bind to something in the body to cause the cell to react. You may have heard of the oestrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2).

In oestrogen receptor-positive breast cancer, progesterone receptor-positive breast cancer and HER2 positive breast cancer, treatments prevent, slow or stop cancer growth with medicines that target those receptors. But triple-negative breast cancers need different types of treatments because they are oestrogen receptor negative, progesterone receptor negative and HER2 negative. Medicines like tamoxifen, which targets the oestrogen receptor, and trastuzumab (Herceptin), which targets HER2, are not helpful in treating triple-negative breast cancer. Instead, chemotherapy has been shown to be the most effective treatment for triple-negative breast cancer.

Researchers are working to improve their understanding of the biology of triple negative breast cancers, how these types of cancers behave and what puts people at risk for them. Their goals are to find out the best ways to use treatments that already exist and to develop new ones.

“My initial reaction was shock, bordering on depression. Every step I have taken to become educated about cancer and what I can do to change the environment that the cancer was originally able to grow in has empowered me.” —Lori

Most triple negative breast cancers have a basal-like cell pattern. This term means the cells look like the basal cells that line the breast ducts, the tubes in the breast where milk travels. You might have heard your doctor call triple negative breast cancer a basal tumour, basal breast cancer or basal-like disease.

Basal-like breast cancers tend to over express, or make too much of certain genes that encourage cancer growth. Not all triple negative breast cancers are basal-like, and not all basal-like breast cancers are triple negative. About 70 to 90 percent of triple negative breast cancers are basal-like.

Doctors choose treatments because the cancer is triple negative, not because it is basal-like. The  basal status of the cancer does not factor into treatment decisions, but your doctor may tell you if the cancer is basal-like because the term appears in breast cancer resources and information.

“After I found out about my triple negative status, I hit the Internet. My heart sank. A long-time survivor at the Triple Negative Breast Cancer Foundation helped to make the transition smoother. Her words of encouragement and knowledge and her motherly demeanour gave me hope.” — Raymon

MYTH – Women with triple negative breast cancer can have the same treatments as all other women with breast cancer.

FACT – Many people do not understand that there are different kinds of breast cancer. Even some women who have had breast cancer do not understand the differences between triple negative breast cancers and breast cancers that are hormone receptor-positive or HER2 positive.
Women you meet may have taken a hormonal treatment pill for five years to protect them from recurrence (a return of the cancer), or they may know someone who has. These women may not understand that this option does not exist for you. Having to explain the differences between triple negative and other breast cancers can be frustrating, especially if you are just learning about this diagnosis yourself. On the other hand, you may take some of the same chemotherapy medicines as women with other types of breast cancer.

MYTH – 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. While many triple negative cancers are aggressive, your doctor’s prediction of how well your treatment will work depends on the tumour size and whether the cancer has travelled to the lymph nodes in your armpit just as much as it does on its triple negative status. There are some very effective treatments for triple negative breast cancer. Your doctor will work with you to find the treatment that is right for you.

MYTH – Only African-American women get triple negative breast cancer.

FACT – Triple negative breast cancers affect women of all races. Breast cancers in African-American women are more likely to be triple negative than those in white women.

“The most frustrating thing about this diagnosis is everyone thinks I should respond to the same treatments and have the same side effects as Jane Doe. I just want people to understand that every form of breast cancer is different and none of us have the same side effects.” — Raymon

Researchers are still learning why some women are more likely than others to develop triple negative breast cancer. Research supports a relationship between risk and your genes, age, race and ethnicity.

Everyone has BRCA1 and BRCA2 genes, which we get from our mother and father. When they work properly, these genes prevent the development of cancers. However, less than 10 percent of people with breast cancer are born with a mutation, or abnormality, in BRCA1 or BRCA2.

“The second time I was diagnosed, I realized that with our family history, there might be something wrong. A few weeks later, I learned I was positive, as were both my daughters, for a BRCA1 mutation.” — Pam

If you are born with a BRCA1 or BRCA2 gene mutation, you are at increased risk for developing breast, ovarian and other cancers throughout your life. The BRCA1 mutation puts you at higher risk for developing a basal-like breast cancer. Scientists are still trying to find out why BRCA1 mutations increase the risk of developing triple negative breast cancer. Keep in mind, not all breast cancers from BRCA mutations are triple negative.

In fact, BRCA2 mutations are more likely to be present in oestrogen receptor-positive breast cancer.  If you have a family history of breast cancer, you and your relatives could carry a BRCA1 or BRCA2 mutation. You could also be the first person in your family known to develop breast cancer because of a BRCA mutation. Knowing your BRCA status can help you and your doctors discuss an effective treatment plan and learn ways to reduce your risk for recurrence. A genetic counsellor can talk with you about genetic testing.

Several studies suggest that being premenopausal, African-American, Latina or Caribbean increases our risk of developing basal-like or triple negative breast cancer. Among African-American women who develop breast cancer, there is an estimated 20 to 40 percent chance of the breast cancer being triple negative. Researchers do not yet understand why premenopausal women and women in some ethnic groups have higher rates of triple negative breast cancer.

This site has been set up to help you in dealing with triple negative, to share information and experience worldwide and to strive for a cure from a variety of treatments, behaviours and knowledge.