Breast cancer: global growth and disparities between countries, the 6 risk factors to be addressed by 2050

And by 2023, a 'monstrous' figure of some 24 million years of healthy life lost due to disease and premature mortality is estimated.

Using data from population-based cancer registries, registration systems and interviews with family members or caregivers of women who have died of breast cancer, the new analysis provides an updated global, regional and country-level picture of the burden of female breast cancer and estimates of risk factors from 1990 to 2023 in 204 countries and territories, with forecasts up to 2050.

The study also estimates the number of healthy life years that women with breast cancer lost due to illness, disability and premature death.

"Breast cancer is the most common cancer among women worldwide. Almost 1 in 4 cancer cases diagnosed globally among women in 2023 was breast cancer," the researchers point out. If these are the general trends, the researchers also note, the picture changes greatly when looking at different areas of the planet separately.

In fact, while new cases have remained more or less stable in high-income countries, in low-income countries the incidence has more than doubled.

Specularly, mortality dropped by almost 40% in rich countries and doubled in poorer ones.

It is these dynamics, according to the study, that will cause breast cancer cases to grow by about 30% until 2025, reaching 3.56 million cases annually; deaths are estimated to double, reaching 1.37 million.

Also of concern is the growth of breast cancer in young women: since 1990, cases in under-55s have increased by 29 per cent.

In short, breast cancer remains the most common cancer among women worldwide, but 73% of the 2023 cases (1.67 million) occurred in high- and middle-income countries (39% of deaths, or about 300,000, in low- and middle-income countries).

Experts point out that many cases of breast cancer are due to 6 modifiable risk factors, including:
1) high consumption of red meat;
2) tobacco;
3) high blood sugar levels;
4) a high body mass index (BMI);
5) high alcohol consumption;
6) low physical activity,
aspects that offer important opportunities for intervention.

In fact, the results suggest that maintaining a healthy lifestyle - not smoking, sufficient physical activity, reducing red meat consumption, having a healthy weight - could prevent more than a quarter of the years of health lost.

In particular, when analysing the numbers in relation to uncontrolled risk factors, in 2023 high red meat consumption had the greatest impact (linked to almost 11% of all healthy life lost), followed by tobacco consumption (including passive smoking, 8%), high blood sugar (6%), body mass index (4%) and high alcohol consumption and low physical activity (both 2%).

Considerable progress was made between 1990 and 2023 in reducing the overall incidence of breast cancer related to high alcohol and tobacco consumption (it decreased by 47% and 28% respectively), while the incidence of breast cancer related to other risk factors did not show the same progress over time.

"Breast cancer continues to have a profound impact on women's lives and communities," reflects lead author Kayleigh Bhangdia of the Institute for Health Metrics and Evaluation (Ihme) at the University of Washington (USA). "While high-income countries generally benefit from screening, from earlier diagnoses and comprehensive treatment strategies, the increasing burden is now shifting to low- and middle-income countries, where women often face late-stage diagnoses, more limited access to quality care, and higher mortality rates that threaten to overshadow progress in women's health'.