Triple-Negative Breast Cancer Has Unique Risk Factors
Compared to breast cancer overall, the risk factors for triple-negative breast cancer are distinct, according to a study. Knowing the risk factors can help women and their doctors take steps to lower that risk and improve detection in women at high risk.
The research was published on March 5, 2024, by the Journal of the National Cancer Institute. Read the abstract of “The unique risk factor profile of triple negative breast cancer: a comprehensive meta-analysis.”
About triple-negative breast cancer
Triple-negative breast cancer is invasive breast cancer that is:
This means it doesn’t have receptors for the hormones estrogen or progesterone and has normal amounts of HER2 proteins. Without hormone receptors or extra HER2 proteins, triple-negative breast cancers won’t respond to hormonal therapy medicines or medicines that target the HER2 protein.
Triple-negative disease makes up 10% of breast cancer cases. Triple-negative breast cancer is more common in women younger than 40, Black women, and women with a BRCA1 mutation. Triple-negative breast cancer also is usually more aggressive and more likely to come back (recur) than cancers that are hormone receptor-positive or HER2-positive.
Why do the study?
Earlier research has suggested that many of the known breast cancer risk factors, such as having a higher BMI and drinking alcohol, were associated with hormone receptor-positive, HER2-negative breast cancer. The links between established risk factors and triple-negative disease haven’t been consistent, partly because triple-negative breast cancer is less common than hormone receptor-positive breast cancer, so the sample sizes in studies have been smaller.
The researchers did this study to look for links between known breast cancer risk factors and triple-negative breast cancer.
About the study
This study was a meta-analysis — a study that combines and analyzes the results of a number of earlier studies. In this case, the researchers analyzed the results of 33 studies on risk factors and triple-negative breast cancer. The studies included nearly 11,000 women diagnosed with triple-negative breast cancer. The risk factors examined in the studies were:
age at first period
age at first live birth
number of births
whether or not a woman breastfed and for how long
family history of breast cancer
whether or not a woman took birth control pills and how long she took them
whether or not a woman received hormone replacement therapy (HRT)
BMI
alcohol consumption
smoking
The researchers found that three risk factors were linked to a higher risk of triple-negative breast cancer:
family history of breast cancer
using birth control pills for more than 10 years
higher breast density
These links were statistically significant, which means the increase in risk was likely due to these factors and not just because of chance.
Two risk factors were linked to a lower risk of triple-negative breast cancer:
having a first period at age 14 or older
breastfeeding a child
These links also were statistically significant.
The researchers also found that being older than 30 when giving birth for the first time lowered the risk of triple-negative breast cancer. This is different from published results on breast cancer overall; studies have found that women who have their first child before age 30 have a lower risk of breast cancer.
The researchers found no statistically significant links between the risk of triple-negative breast cancer and some well-known breast cancer risk factors:
HRT use
alcohol consumption
smoking
BMI
For triple-negative breast cancer overall, the researchers found no link between number of births and higher risk. But for Black women, having more than three children was linked to a higher risk of triple-negative breast cancer.
“Our findings highlight that triple-negative breast cancer has a distinct risk-factor profile compared to overall breast cancer,” the researchers concluded. “This can be the foundational work in identification of actionable triple-negative breast cancer risk factors to improve prevention and early detection of these poor prognosis breast tumors.”
What this means for you
This study found that the risk factors for triple-negative breast cancer are slightly different than the risk factors for breast cancer overall.
The results are important for everyone, but especially if you have a higher risk of triple-negative breast cancer. Previous research suggests that Black women are twice as likely to be diagnosed with triple-negative breast cancer as white women.
While you can’t control how old you are when you have your first period, your family history, or your breast density, you may have some control over the other factors that affect triple-negative breast cancer risk.
For example, if you have been taking birth control for 10 or more years, you may want to talk to your doctor about other types of birth control. A non-hormonal IUD, condoms, non-hormonal vaginal gel, or a diaphragm are some of the options. If you and your partner have decided you don’t want to have any more children, you could consider surgery: tubal ligation for women or vasectomy for men.
Updated on July 18, 2024