Who Is at Risk for Triple-Negative Breast Cancer?

While triple-negative breast cancer is rare and only accounts for about 10 to 15 percent of all breast cancers according to the American Cancer Society, it has fewer treatment options than other breast cancers and grows and spreads more rapidly than most other breast cancer types.

This type of cancer lacks certain hormone receptors that contribute to cancer growth. These receptors attach the cell to certain substances in the blood, like hormones. Both healthy breast cells and breast cancer cells need estrogen and progesterone to grow and have receptors that attach to those hormones specifically.

But sometimes, a breast cancer cell does not have receptors for estrogen, progesterone, or human epidermal growth factor 2 (HER2). These cells are called triple negative. Without these receptors, oncologists can only treat triple-negative breast cancer by removing tumors surgically and prescribing chemotherapy and radiation to kill any remaining cells.

Those at High Risk

People with a family history of breast cancer are always at a higher risk of getting cancer. Family members with genetic changes (called mutations) that cause breast cancer pass it on to future generations. Some people with a family history of cancer inherit a mutation in the BRCA genes.

BRCA1 and BRCA2 genes help regulate how breast, ovarian, and other cells grow and divide. Cancer is when these cells grow too rapidly or in an uncontrolled way, so these genes are essential in helping to fight off the disease.

However, according to the Centers for Disease Control and Prevention (CDC), roughly 1 in every 500 women in the United States has a mutation in one of her BRCA genes. And about half of the women with a BRCA gene mutation will get breast cancer by the time they turn 70.

People with a mutation in their BRCA1 gene are at risk of developing triple-negative breast cancer, specifically, per the American Cancer Society. And people of Ashkenazi Jewish heritage are at a higher risk of inheriting BRCA gene mutations that can cause breast cancers, such as triple-negative breast cancer, according to the CDC.

Black women are also at risk of developing triple-negative breast cancer. Recent research published in Breast Cancer Research in June 2022 that analyzed data from over 3,300 people with breast cancer found that women with triple-negative were twice as likely to be Black. And according to the American Cancer Society’s 2021 Cancer Statistics, Black women are 40 percent more likely to die from breast cancer than white women.

The reasons are not entirely well understood by researchers yet. But Rita Nanda, MD, associate professor of medicine and director of the breast oncology program at the University of Chicago, who was not involved with either study, suspects genetic or socioeconomic factors may contribute.

“I also think some of [the disparity] is driven by the fact that Black women generally develop breast cancer at a younger age,” Dr. Nanda says “And we know that younger women are more likely to have triple-negative breast cancer than hormone-positive breast cancer.”

To her point, that Breast Cancer Research study, as well as a study published in Cancer in October 2020, found that women diagnosed with triple-negative breast cancer were, on average, around three years younger than those diagnosed with other types. The Cancer study also found that women under 40 had the highest odds of a triple-negative breast cancer diagnosis.