Despite a continuous decline in the rate of breast cancer deaths in the United States, the incidence of the disease has increased, especially among younger ages, and significant racial disparities remain, according to a new American Cancer Society report.
The study, published Tuesday in CA: A Cancer Journal for Clinicians, found some good news: The overall breast cancer death rate in the US dropped about 44% between 1989 and 2022, which translates to almost 518,000 fewer breast cancer deaths during that time. This is largely thanks to advances in cancer treatments and in detecting illness early through screening, which is recommended for women at average risk starting at age 40.
But there was also some concerning news: The incidence of the disease itself climbed 1% each year from 2012 to 2021.
“If we look at the last decade or so, we’ve seen breast cancer incidence rise at about a 1% year-over-year increase, and the steepness of that increase does not affect all women in this case equally,” said Karen Knudsen, chief executive officer of the American Cancer Society and the American Cancer Society Cancer Action Network.
“There is a slightly higher increase in the rate of breast cancer diagnosis for women who are under age 50 versus those that are above age 50,” she said. “These are things that we are watching to try to understand.”
A separate study published in January also found that breast cancer incidence rates among women ages 20 to 49 rose over the past 20 years.
The trend follows a pattern seen recently with other cancer types, such as colorectal cancer, in that more people are being diagnosed at younger ages than has traditionally been seen.
Differences by race and region
For the new report, researchers from the American Cancer Society, Weill Cornell Medicine and Harvard Medical School analyzed data on breast cancer incidence and deaths from the National Cancer Institute and registries at the US Centers for Disease Control and Prevention, dating to 1975. They found some significant differences in the data by race and state as well as age.
The researchers found that Black women continue to be more likely to die from the disease, as they had a 38% higher death rate than White women despite being 5% less likely to develop breast cancer.
“If you look actually more carefully at the mortality data, this is really driven by young women particularly,” said Dr. William Dahut, chief scientific officer at the American Cancer Society. “If you look at Black women between the ages of 20 and 29, their chances of dying from breast cancer is two times greater than their White colleagues.”
The data showed that Black women have the highest mortality rate overall. The rate ranged from about 12 deaths per 100,000 women in the Asian American/Pacific Islander community to about 27 deaths per 100,000 in the Black community.
The report notes that Asian American and Pacific Islander women had the fastest increase in breast cancer incidence each year both among those younger than 50, at 2.7% per year, and in women 50 and older, at 2.5% per year.
“The acceleration of breast cancer incidence rates among Asian American and Pacific Islander is particularly disturbing. Emerging data suggest that some gene mutations predisposing to breast cancer may result in greater risk among Asian women compared to White women,” Dr. Ruth Carlos, a professor of radiology and the assistant chair for clinical research at the University of Michigan, who was not involved in the new report, wrote in an email.
“It is disappointing that outcomes appear static for Black/African-American women,” she added. “Several research groups are investigating the biological effects of structural discrimination on the development of breast cancer.”
Some geographic variation also emerged in the data. The researchers found that the incidence of breast cancer ranged from 113 cases out of every 100,000 women in Nevada to about 143 per 100,000 in North Carolina.
Another geographic gap was found for the breast cancer death rate, ranging from about 15 deaths per 100,000 women in Massachusetts to about 23 per 100,000 in Mississippi and 24 per 100,000 in the District of Columbia.
“Differences by state reflect several factors, including demographic characteristics and the prevalence of cancer risk factors, mammography screening, and access to care, which is influenced by public health policy, such as the expansion of Medicaid, and other laws and programs,” the researchers wrote.
They project that this year, nearly 311,000 cases of invasive breast cancer will be diagnosed among US women, affecting about 1 in 8, and more than 42,000 women will die from breast cancer.
The researchers should be “commended” for such a comprehensive analysis of breast cancer trends, Carlos said.
“They have uncovered worrisome trends especially regarding breast cancer in younger women,” she wrote. “Environmental risks, lifestyle risks and genetic risk factors may be contributing to this rise.”
‘We see it in the office every day’
The data in the new report reflects what many oncologists are noticing on the ground, said Dr. Carmen Calfa, a medical oncologist at the University of Miami Health System’s Sylvester Comprehensive Cancer Center and associate director of Sylvester’s community breast cancer outreach program, who was not involved in the new report.
“The alarming increase in incidence overall of breast cancer has been noticed and noted, and we see it in the office every day when we see patients of all ages, but we see more of the young ones than we used to,” Calfa said, adding that her youngest breast cancer patient was diagnosed at 20.
“We’ve been witnessing and seeing patients presenting to us at the higher rate, at the younger age,” she said. “While we’re noticing the increase in incidence of breast cancer in younger patients, the trends have been really significant and consistent throughout other cancer types, and that makes us wonder, it’s not only a breast-specific finding.”
Calfa added that many of the risk factors for breast cancer are common throughout other cancer types as well, which may hold clues as to why the incidence of certain cancers continues to rise among younger ages.
“The common risk factors are all there, and I think that’s where we have a huge opportunity,” she said. “That’s the lifestyle that includes the food, the type of diets, the amount of exercise.”
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Other factors that can raise the risk of breast cancer include having a family history of cancer, increased alcohol consumption, having a high-risk lesion biopsied from the breast or having a certain genetic mutation.
Some ways to reduce the risk of breast cancer include keeping a healthy weight, being physically active, drinking alcohol in moderation or not at all and, for some people, taking medications such as tamoxifen and breastfeeding your children, if possible.
“I would also call to action for every woman and man to try to understand their own, personal risk and to be their best advocates when it comes to prevention, early detection, treatment and ultimately overall outcomes,” Calfa said.