There are several different subtypes of breast cancer, and treatment can vary depending on the type. In 2022, it was estimated that approximately 287,850 women in the United States would be diagnosed with breast cancer.
About 10%–15% of those cases would be triple-negative breast cancer, although some studies even estimated the incidence to be as high as 24% of newly diagnosed breast cancers.
This article will review some important facts and statistics you should know about this subtype of breast cancer.
Triple-Negative Breast Cancer Overview
Triple-negative breast cancer is breast cancer in which the cancer cells do not have estrogen or progesterone receptors (ER or PR) and don’t make any of the protein called human epidermal growth factor (HER2).
Treatments such as hormone therapies or targeted therapy like Herceptin (trastuzumab) won’t work for triple-negative breast cancer.
How Common Is Triple-Negative Breast Cancer?
Triple negative breast cancer is rare. About 13 out of 100,000 women in the United States are diagnosed with TNBC each year. It is even rarer in men.
Cases of TNBC have been steadily increasing. It is not known why this is; more research is necessary.
Triple-Negative Breast Cancer by Ethnicity
Black women are more likely than any other racial/ethnic group to die of breast cancer. There are significant disparities in diagnosis, treatment, and survival among racial and ethnic groups.
More studies are needed to explore factors such as tumor biology and differences in immune system function, in addition to social, cultural, and public health factors. Systemic racism within the healthcare system also needs to be addressed.
Women with TNBC are twice as likely to be Black than White. Black women are also 28% more likely to die than White women with the same diagnosis. This is due, among other reasons, to a lower likelihood of being treated with surgery and chemotherapy.
Latinx women are also more likely to be diagnosed with TNBC than non-Latinx White women.
Triple-Negative Breast Cancer by Age and Gender
TNBC is more likely to be diagnosed in younger women than older women. One study found that women age 40 and younger were more likely than women age 50–64 to be diagnosed with TNBC.
Male breast cancer makes up 1% of all male cancers and about 1% of all breast cancers worldwide. About 95% of male breast cancers are hormone receptor-positive. Male triple negative breast cancer is very rare.
Causes of Triple-Negative Breast Cancer and Risk Factors
The exact causes of TNBC are not known. Some scientists think it may be related to mutations (changes) in the BRCA1 gene, but more research is needed to explore this.
There is a higher prevalence for TNBC among people of certain age groups, races and ethnicities, and genetic makeups. Lifestyle factors also play a role. Being among these groups, though, does not mean you will develop cancer; it simply means your risk is elevated. These include:
- age: TNBC usually occurs in younger women.
- Race: Black and Latinx women have higher rates than other races.
- Family history: A family history increases the risk of developing breast cancer.
- genetics: Having a BRCA1 or BRCA2 mutation increases your risk.
- Benign breast conditions: Having a history of breast biopsies (removal of tissue to analyze in the lab) or breast biopsies with atypical cells increases your risk.
- Obesity: Being overweight or experiencing obesity increase risk.
- Age of first pregnancy: Being pregnant for the first time over age 30 raises your risk.
- History: Having a personal history of breast cancer factors in.
What Are the Mortality Rates for Triple-Negative Breast Cancer?
The overall five-year survival rate for TNBC is 77.1%. Broken down by stage for TNBC, it is as follows:
- Localized: 91.3%
- Regional: 65.8%
- Distant: 12.0%
The survival rates may be related to the fact that TNBC is often diagnosed at a later stage when it is first found. Treatments are also more limited. Hormone therapies are not effective, as well as targeted therapy like Herceptin. Surgery, chemotherapy, and radiation are the only treatments available.
What Is “Survival Rate”?
The term “survival rate” is defined as the percentage of people who are living with a disease such as cancer for a given amount of time, but survival may be presented in a number of different ways. It does not reflect an individual’s prognosis or the effects of newer treatments.
Screening and Early Detection
Screening and early detection for TNBC are the same as for breast cancer in general. TNBC is only diagnosed after an initial breast cancer diagnosis is made.
Screening tests for breast cancer include:
Once breast cancer is diagnosed, tests will be done to detect different characteristics of the cancer cells, including what receptors they have and whether they make certain proteins.
TNBC is more aggressive and is typically diagnosed at a later stage than other kinds of breast cancer.
Triple-negative breast cancer (TNBC) is a subtype of breast cancer that is typically found in younger women and Black or Latinx women. It is more aggressive, more likely to be diagnosed at a later stage, and more likely to come back after treatment.
It has fewer treatment options than other kinds of breast cancer because of the cell characteristics. Research is ongoing, and advances are being made, especially with more challenging cancers like TNBC.