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The Voice of People With Breast Cancer


Our Voices Blog

TNBC: Who’s at Risk?

Research shows that some people have a greater chance of developing triple-negative breast cancer (TNBC) if they are subject to certain risk factors. These risks include:

  • Age: Premenopausal women and those under the age of 50 have an increased risk of TNBC.
  • BRCA1 gene mutation: About 70 percent of the breast cancers diagnosed in women with an inherited BRCA1 mutation are TNBC.
  • Ethnicity: Black and Hispanic women have a higher rate of TNBC.
  • Breast density: Higher breast density is associated with increased risk of TNBC, especially among premenopausal women.

How is it treated?
Treatment can be difficult for this type of breast cancer. Without receptors, triple negative tumors do not have the proteins they need to respond to common breast cancer treatments like hormone and targeted therapy, which are used for hormone-positive or HER2-positive breast cancer.

Chemotherapy and immunotherapy are the primary systemic treatment options for triple negative breast cancer. Unless the tumour is too extensive, TNBC that is in stage I through stage III is treated with chemotherapy (with or without immunotherapy) followed by surgery. If there are still cancer cells remaining when the surgery takes place, more chemotherapy is often needed. Stage IV TNBC treatment often depends on the patient’s specific circumstances: the presence of a BRCA gene mutation, which proteins the cancer cells do have, and other factors. Luckily, the treatment options for TNBC continues to expand thanks to new and emerging research from clinical trials.

What does the research say?
A 2021 study by researchers in the Perelman School of Medicine found that Black women were almost three times more at risk for TNBC, which often has poorer outcomes. The significance of the risk found in this study was important because researchers had carefully adjusted for breast cancer risk factors in a screened population, and the size of the sample was meaningful; the group included 29,822 (or 15 percent) Black women.

Additionally, it was discovered that triple negative breast cancers were less likely to be detected through screening and more likely to be diagnosed as interval cancers. According to the Canadian Partnership Against Cancer, “Interval cancers are cancers that are diagnosed after a negative screening test, but before a participant is due to come back for their next screen”.

In a separate study, the same researchers looked at more risk factors among Black women. They found that both breast density and obesity were more strongly associated with TNBC than other subtypes among this group.

Another US study from 2021 compared treatment and mortality rates between Black and white women with breast cancer. According to the study, Black women were:

  • Younger when diagnosed with breast cancer
  • More likely to live in areas with the lowest incomes

Black women were 31% less likely to have surgery, and 11% less likely to have chemotherapy than white women, although triple-negative breast cancers in Black women were:

  • More likely to be advanced
  • More likely to be larger than 5 cm
  • More likely to have spread to the lymph nodes

Taking many demographic, socio-economic, and other factors into account, researchers still found that Black women were 28% more likely to die from triple-negative breast cancer than white women. When adjusted to take the breast cancer characteristics into account, Black women were still 16% more likely to die from triple-negative disease than white women.

It’s important that more Black women participate in clinical trials and other studies for breast cancer, as well as other diseases. A Canadian meta-analysis of 2000 studies done between 2003 and 2018 revealed that only 23 of them focused on Black Canadians. This limited data means that inequalities can’t properly be addressed, which contributes to systemic racism and inequitable care in the Canadian health care system.

While TNBC presents significant challenges, there is reason for hope. Understanding these risk factors is crucial for early detection and intervention. Clinical trials and research are expanding treatment options, offering better outcomes for patients. While limited, emerging research on disparities in TNBC diagnosis and treatment, particularly among Black women, highlights the importance of addressing systemic inequities in healthcare access and participation in clinical trials. Increased awareness, advocacy, and inclusivity in research can lead to improved outcomes and equity in breast cancer care. Regardless of race or socioeconomic status, all Canadians should have equal opportunities for early detection and effective treatment.

The views and experiences expressed through personal stories on Our Voices Blog are those of the authors and their lived experiences. They do not necessarily reflect the position of the Canadian Breast Cancer Network. The information provided has not been medically reviewed and is not intended to be a substitute for professional medical advice. Always seek the guidance of your healthcare team when considering your treatment plans and goals.