What is Triple-Negative Breast Cancer?
About 10-20 percent of breast cancers are triple-negative breast cancers, but what does this mean?
Triple-negative breast cancer is a type of breast cancer that tests negative for estrogen receptors, progesterone receptors, and excess HER2 protein. Receptors are special proteins that are found inside and on the surface of cells. These receptor proteins are the “eyes” and “ears” of the cells, receiving messages from the bloodstream. Hormone receptors inside and on the surface of healthy breast cells receive messages from the hormones estrogen and progesterone. These hormones attach to the receptors and help them continue to grow and function well. Most, but not all, breast cancer cells also have these hormone receptors.
A smaller percentage of breast cancers (around 20 percent) make too much of the HER2 protein. In healthy breast cells, the HER2 stimulates cell growth. But when breast cancer cells have too much of this protein, the cells grow and divide too quickly.
Hormone blocking therapies and HER2-targeted therapies disrupt the effects of estrogen, progesterone, and the HER2 protein on breast cancer, which then can help slow or even stop the growth of breast cancer cells.
“Because hormones aren’t fueling the cancer’s growth, the cancer is unlikely to respond to hormonal therapy medicine and is also unlikely to respond to medicines that target the HER2 protein,” said Amie Jackson, MD, a medical oncologist with the TriHealth Cancer Institute.
Anyone can be diagnosed with triple-negative breast cancer, but it is more commonly found in people younger than age 50, African-American and Hispanic women, and people with a BRCA gene mutation - an inherited condition that increases the risk of breast cancer.
Triple-negative breast cancer is an aggressive subtype of breast cancer. It is more frequently high grade. The higher the grade, the less the cancer cells resemble normal, healthy breast cells in their appearance and growth patterns. It can be more difficult to treat than other types of breast cancer because there are fewer targeted medicines that treat triple-negative breast cancer. Compared to more common types of breast cancer, triple negative breast cancer is associated with a higher likelihood of spread beyond the breast and a higher chance of recurrence after treatment, according to Dr. Jackson.
“It can naturally be upsetting to find out that you’ve been diagnosed with triple-negative breast cancer. However, it’s important to remember that the lack of hormone receptor and excess HER2 protein are just two factors that you and your physician will take into consideration when developing your treatment plan,” said Dr. Jackson.
Triple-negative breast cancer is typically treated with a combination of surgery, radiation therapy, and chemotherapy, said Dr. Jackson. Research has shown that when triple-negative breast cancer is treated with chemotherapy before surgery (neoadjuvant chemotherapy), and there is a good response, the chance for disease-free survival and overall survival is better. Physicians judge the effectiveness of neoadjuvant treatment by looking at the tissue removed during surgery to see if any active cancer cells are present. If none are present, it is called a “pathologic complete response.”
For certain women with more advanced triple negative breast cancer, Immunotherapy treatments may be considered in addition to chemotherapy. Immunotherapy medicines work by helping your immune system work harder or smarter to attack cancer cells.
Breast cancer is diagnosed primarily through screening, either through a mammogram or finding a lump while feeling your breast. If you find a lump in your breast, please make an appointment with your primary care provider as soon as possible to help get you started on a course of diagnosis and treatment.
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Join us at noon on Friday, May 10, on Facebook for a livestream broadcast about triple-negative breast cancer featuring TriHealth physicians and representative from the Erica J. Holloman Foundation.
Last Updated: May 02, 2019