Breast cancer remains the most commonly diagnosed cancer among women worldwide (including Malaysia) and one of the leading causes of cancer-related death, and new global evidence suggests that its burden is set to grow substantially in the coming decades.

A comprehensive international analysis published in The Lancet Oncology paints a stark picture of a disease that is advancing unevenly across the world, shaped as much by social conditions and health systems as by biology.

According to the report, an estimated 2.3 million women were diagnosed with breast cancer globally in 2023, while around 764,000 lost their lives to the disease in the same year. Taken together, this translated into roughly 24 million years of healthy life lost due to illness, disability, or premature death. These figures alone would be sobering.

Yet projections indicate that the situation may worsen. By 2050, annual breast cancer diagnoses are expected to exceed 3.5 million, while deaths could rise to nearly 1.4 million if current trends continue.

The data reveal a troubling paradox. In wealthier nations, long-standing investments in screening, early diagnosis, and modern treatment have begun to pay dividends. Mortality rates have declined steadily, even as case numbers remain high.

In contrast, many low- and lower-middle-income countries are seeing both incidence and mortality rise, a pattern that deepens existing global health inequalities.

Researchers analysing data from 185 countries highlight that almost three-quarters of all breast cancer cases are currently diagnosed in high-income regions. Yet close to 40 per cent of deaths occur in lower-income settings. The imbalance is even more striking when viewed over time. Between 1990 and 2023, age-standardised breast cancer mortality fell by nearly 30 per cent in high-income countries. Over the same period, mortality in low-income countries almost doubled.

Experts describe this as a crisis driven less by differences in tumour biology and more by disparities in access to care. In many resource-limited settings, women are more likely to be diagnosed at a later stage, when the disease is harder to treat. Screening programmes may be limited or absent. Diagnostic tools can be scarce. Treatment options, including surgery, radiotherapy, and targeted drugs, are often unavailable or unaffordable. The result is a much higher chance that a breast cancer diagnosis will prove fatal.

International health initiatives have set ambitious targets to address this gap. The World Health Organization’s Global Breast Cancer Initiative, for example, aims for at least a 2.5 per cent annual reduction in mortality. Some high-income countries are already meeting or exceeding this goal. In contrast, many low-income nations face mortality-to-incidence ratios that are dramatically higher, signalling late diagnosis and inadequate treatment capacity.

While health system strengthening is essential, the new report also draws attention to prevention. Researchers estimate that 28 per cent of the global breast cancer burden is linked to six modifiable risk factors.

These are factors that, at least in theory, can be reduced through changes in behaviour, policy, or environment.

The largest contributor identified was high consumption of red meat, accounting for nearly 11 per cent of healthy life years lost to breast cancer. Tobacco use, including exposure to second-hand smoke, followed at around 8 per cent. High blood sugar levels were linked to about 6 per cent, while excess body weight, defined as a body mass index in the overweight or obese range, contributed roughly 4 per cent. Alcohol consumption and low levels of physical activity each accounted for around 2 per cent.

Progress has been uneven across these areas. Between 1990 and 2023, the impact of tobacco and alcohol on breast cancer burden declined markedly, reflecting decades of public health action, regulation, and shifting social norms. Tobacco-related risk fell by around 28 per cent, while alcohol-related risk dropped by nearly half.

Other factors, however, have shown little improvement. Rates of overweight, obesity, and high blood sugar have increased in many parts of the world, driven by changes in diet, urbanisation, and sedentary lifestyles.

Public health researchers stress that prevention strategies need to be tailored to local contexts. In high-income countries, where more than one-third of breast cancer cases may be preventable through lifestyle changes, policies that promote healthy diets, physical activity, and weight management could have a meaningful impact. These might include food labelling, urban planning that encourages active travel, and restrictions on marketing unhealthy products.

In low- and middle-income countries, the challenge is more complex. Rapid economic and social change is altering lifestyles, often increasing exposure to risk factors such as unhealthy diets and physical inactivity.

At the same time, health systems may lack the capacity to manage a growing cancer burden. Experts argue that prevention efforts must go hand in hand with expanded screening, public awareness campaigns, and investment in diagnostic and treatment services.

Although population-level action is critical, individuals can also take steps to reduce their own risk. Public health guidance consistently emphasises maintaining a healthy weight, engaging in regular physical activity, and limiting alcohol intake.

For women, moderate-intensity exercise for at least 150 minutes a week is often recommended. Alcohol consumption should be kept low, with no more than one drink a day or better not drinking at all. Avoiding smoking, and reducing exposure to second-hand smoke, remains important for overall health as well as cancer prevention.

Reproductive and hormonal factors also play a role. Breastfeeding, where possible, has been shown to lower a mother’s risk of breast and ovarian cancer, as well as offering benefits for infant health. Women who use hormone replacement therapy or oral contraceptives are encouraged to discuss potential risks and benefits with their healthcare providers, as individual circumstances vary. Those with a family history of breast cancer may benefit from tailored advice, genetic counselling, or earlier screening.

The scale of the projected increase in breast cancer cases underscores the urgency of action. Researchers estimate that, without significant intervention, global cases could rise by 38 to 54 per cent by mid-century, while deaths could increase by 68 to 71 per cent. The heaviest toll is expected in countries least equipped to respond.

Health policy specialists argue that this trajectory is not inevitable. The success seen in high-income countries demonstrates what is possible when early detection, timely treatment, and sustained public health efforts are combined. Translating these gains to lower-resource settings will require political commitment, international cooperation, and long-term investment. It will also require addressing broader social determinants of health, including education, poverty, and gender inequality, which influence when and how women access care.

The findings serve as a reminder that breast cancer is not a single story but many intersecting ones. It is a story of scientific progress and lives saved. It is also a story of missed opportunities, preventable risk, and profound inequity. As the global burden continues to rise, the choices made now by governments, health systems, and communities will shape outcomes for millions of women in the decades ahead.

Prevention, early detection, and equitable access to treatment are often discussed separately. The evidence suggests they must move forward together. Reducing exposure to modifiable risk factors can lower future incidence. Strengthening screening can catch disease earlier. Expanding treatment capacity can turn diagnoses into survivorship rather than loss.

The challenge is vast, but the potential gains, measured in lives and healthy years, are greater still.