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Despite recent advancements in breast cancer treatments, new breast cancer
cases in women are predicted to rise by a third globally from 2.3 million in
2023 to more than 3.5 million in 2050. Similarly, yearly deaths from the
disease are projected to surge 44%, from around 764,000 to 1.4 million, with
disproportionate impact in countries with limited resources, according to a
major new analysis from the Global Burden of Disease Study Breast Cancer
Collaborators, published in The
Lancet Oncology.
Importantly, the findings suggest that maintaining a healthy lifestyle,
including not smoking, getting sufficient physical activity, lowering red meat
consumption, and having a healthy weight may prevent over a quarter of healthy
years lost to illness and premature death due to breast cancer worldwide.
"Breast cancer continues to take a profound toll on women's lives and
communities," said lead author Kayleigh Bhangdia from the Institute for
Health Metrics and Evaluation (IHME), University of Washington, U.S.
"While those in high-income countries typically benefit from screening and
more timely diagnosis and comprehensive treatment strategies, the mounting
burden of breast cancer is shifting to low- and lower middle-income countries
where individuals often face later-stage diagnosis, more limited access to
quality care, and higher death rates that are threatening to eclipse progress
in women's health."
Using data from population-based cancer registries, vital registration
systems, and interviews with family members or caregivers of women who have
died from breast cancer, the new analysis provides an updated global, regional,
and national analysis of the female breast cancer burden and risk factor
estimates from 1990 to 2023 in 204 countries and territories, with forecasts up
to 2050. Importantly, the study also estimates the number of years of healthy
life that women with breast cancer have lost to illness, disability, and
premature death.
Rates of new cases remain highest in HICs, but growing
fastest in LICs
Breast cancer remains the most common cancer among women worldwide, with an
estimated 2.3 million new breast cancers diagnosed worldwide in women in 2023
(with 73% or 1.67 million cases occurring in high- and upper-middle-income
countries) and 764,000 resulting deaths (with 39% or 300,000 deaths occurring
in low- and lower-middle-income countries).
When global cases and death rates are adjusted to account for
differences in age (to allow comparisons between countries and over time), the
study reveals striking inequalities in the burden of breast cancer. For
example, in 2023, breast cancer age-standardized incidence rates were on
average highest in high-income countries (HICs), including Monaco, Andorra,
France, Germany and Ireland (100 new cases per 100,000 women or higher), and
lower in low- and middle-income countries (LMICs), including Afghanistan,
Somalia, and Mozambique (13 new cases per 100,000 women or lower) in 2023.
However, age-standardized rates of new cases have risen sharply (up 147% on
average) since 1990 in low-income countries (LICs), but remained stable in
HICs, highlighting the disproportionate growth occurring in settings with lower
resources.
Moreover, between 1990 and 2023, age-standardized death rates from breast
cancer in HICs fell on average 30% to 16 deaths per 100,000 women, but almost
doubled in LICs to 24 deaths per 100,000 women, exposing likely disparities in
timely diagnosis and access to quality treatment.
Globally, the number of years of healthy life lost due to poor health and
early death more than doubled from 11.7 million years in 1990 to 24 million
years in 2023. However, although women in low- and
lower-middle-countries account for 27% (around 628,000) of new
cases globally, they contribute to more than 45% of all the ill-health and
early deaths from breast cancer globally (nearly 11 million years of healthy
life lost).
"LMICs are hit hardest by escalating breast cancer burden as many of
these nations grapple with lifestyle and demographic changes alongside health
systems that are less equipped than ideal to respond, with shortages of
radiotherapy machines, chemotherapy drugs, and pathology labs, and standard
treatments that can be quite costly," explained co-author Dr. Olayinka
Ilesanmi, a physician and epidemiologist from Nigeria working for the Africa
CDC.
"Although survival continues to improve in HICs, reflecting success in
breast cancer screening, diagnosis, and treatment, even within HICs, outcomes
can still depend on where a woman lives."
Rise in pre-menopausal breast cancer
Globally, three times as many new breast cancer cases were diagnosed in
women aged 55 or older in 2023 (161 vs. 50 new cases per 100,000 women)
compared to women aged 20–54 years. However, rates of new cases have risen in
women aged 20–54 years old (up 29%) since 1990, with rates in older women not
changing substantially—these differences may reflect changing age patterns as
well as changes in risk factors, which vary between pre- and post-menopausal
women.
Impact of uncontrolled risk
factors
In 2023, 28% of the global breast
cancer burden (6.8 million years of healthy life lost to
disability, illness and early death) was linked to six potentially modifiable
risk factors. High red meat consumption had the biggest impact (linked to
nearly 11% of all healthy life lost), followed by tobacco use (including
second-hand smoke; 8%), high blood sugar (6%), high body mass index (BMI; 4%),
and high alcohol use and low physical activity (both 2%).
Substantial progress has been made in reducing the global breast cancer
burden linked to high alcohol use and tobacco between 1990 and 2023, which
declined by 47% and 28%, respectively, while the breast cancer burden linked to
other risk factors did not indicate the same progress over time.
"With more than a quarter of the global breast cancer burden linked to
six modifiable lifestyle changes, there are tremendous opportunities to alter
the trajectory of breast cancer risk for the next generation," said
co-senior author Dr. Marie Ng, Affiliate Associate Professor at IHME and
Associate Professor at National University of Singapore. "Targeting known
risk factors through public health policies and making healthier choices more
accessible, while working with individuals to take action to reduce obesity and
high blood sugar, is crucial to halting the rise in breast cancers
worldwide."
Ensuring all women have an equal
chance to survive breast cancer
Even with the best prevention policies, millions of women will still
develop breast cancer, which makes closing the care gap an urgent priority. The
authors stress that with fair access to care in low-resource settings,
investment in innovative therapies, and strong political will, there is an
opportunity to ensure that all women have an equal chance to overcome breast
cancer.
As Dr. Lisa Force, co-senior author from IHME, explained,
"Collaborative efforts are needed to ensure well-functioning health
systems capable of early diagnosis and comprehensive treatment of breast cancer
in all countries. Reducing the cost of breast cancer therapies and ensuring
that universal health coverage includes breast cancer care essentials would
also be valuable in protecting patients from catastrophic costs and improving
outcomes."
While the study uses the best available data, the authors note that the
estimates are constrained by a lack of high-quality cancer registry data,
particularly in countries with limited resources, highlighting the need to
increase investments in cancer surveillance systems. They also note that
information on cancer stage at diagnosis and subtype are not included in the
analysis despite their distinct survival patterns and resource implications due
to data limitations, and the analysis does not analyze the impact of the
COVID-19 pandemic or recent conflicts on the disease burden.
Writing in a linked Comment, Professor Yeon Hee Park from Sungkyunkwan University School of Medicine, Seoul, South Korea (who was not involved with the study), noted, "Without ethnic or genetic ancestry data, the study cannot distinguish whether observed regional differences reflect genetic predisposition, environmental exposures, health-care disparities, or combinations thereof… Despite these limitations, this study provides a necessary foundation for global health planning… With appropriate refinements, particularly ethnic and genetic ancestry stratification that acknowledges the distinctive molecular signatures of African, Asian, and other ethnic and genetic ancestry populations, this study can achieve its goal of informing evidence-based cancer control strategies worldwide."
Provided
by Lancet
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