The number of cancer cases worldwide will increase exponentially in the next 20 years. New diagnoses will grow by 61% to reach 30.5 million in 2050, while annual deaths from this disease will increase by almost 75%, surpassing 18.6 million.
Cases continue to grow and have not stopped. Since 1990, global cases have more than doubled, reaching 18.5 million diagnoses in 2023, while deaths increased by 74% to 10.4 million, according to a new analysis by the Global Burden of Disease Study Cancer Collaborators, published in The Lancet.
Although global cancer death rates (age-adjusted) have decreased, this is not the case in some low- and middle-income countries, where rates and absolute numbers continue to rise.
Cases that could actually be preventable. In fact, more than 40% of cancer deaths worldwide are linked to 44 modifiable risk factors, including tobacco use, an unhealthy diet, and hyperglycemia.
To address the challenge of the growing number of cancer cases and deaths, the authors state that it is imperative for policymakers, governments, and organizations to intensify efforts to prevent, diagnose, and treat cancer at the national, regional, and global levels.
Without urgent action and targeted funding, it is estimated that 30.5 million people will receive a new cancer diagnosis and 18.6 million will die from this disease in 2050, with more than half of new cases and two-thirds of deaths occurring in low- and middle-income countries (LMICs).
One of the reasons for the increase in cases, in addition to risks, is not that the disease is becoming more aggressive, but because there are more people in the world and life expectancy has increased.
When researchers adjust the data to compare people of the same age in different time periods, the rates do not increase: that is, a 60-year-old in 2050 will have more or less the same cancer risk as a 60-year-old today. What changes is that in 2050, there will be many more people aged 60, 70, or 80.
Now, although this may seem like an "improvement," it is far from the goal set by the UN to reduce premature deaths by a third from diseases like cancer by 2030.
"Cancer remains a significant contributor to the global disease burden, and our study highlights how it is expected to grow substantially in the coming decades, with disproportionate growth in countries with limited resources," says lead author Lisa Force, from the Institute for Health Metrics and Evaluation (IHME), University of Washington, USA, in a statement.
"Despite the clear need for action, cancer control policies and their implementation remain a low priority in global health, and there is insufficient funding to address this challenge in many contexts," she denounces, adding: "Ensuring equitable cancer outcomes globally will require greater efforts to reduce disparities in the delivery of health services, such as access to accurate and timely diagnosis, quality treatments, and supportive care."
Notable differences in cancer burden worldwide
In 2023, cancer hit harder than ever: there were 18.5 million new diagnoses and 10.4 million deaths worldwide (excluding non-melanoma skin cancers). That means that since 1990, cases have more than doubled, and deaths have increased by 74%.
But the situation is not the same everywhere. In rich countries, cancer deaths have decreased by 24% in the last three decades, thanks to better healthcare systems and prevention. In contrast, in low-income and lower-middle-income countries, the trend is the opposite: cases continue to grow, with a 24% increase in low-income countries and a 29% increase in lower-middle-income countries, reflecting enormous inequality.
Some countries show extreme changes. Lebanon has recorded the highest increase in incidence and mortality rates since 1990, while United Arab Emirates achieved the greatest reduction in new cases and Kazakhstan the largest drop in deaths.
As for cancer types, breast cancer is the most diagnosed worldwide, while cancers of the trachea, bronchi, and lung are the leading causes of death.
Behavioral risk factors
The study reveals another key fact: 4 out of 10 cancer deaths could be prevented. In 2023, of the 10.4 million deaths, around 4.3 million were related to 44 risk factors that can be prevented or controlled, such as smoking, having an unhealthy diet, or having high blood sugar.
Tobacco remains the major enemy: it was responsible for 21% of all cancer deaths worldwide and tops the list of risk factors in almost all countries. The only exception is low-income countries, where the main risk was unprotected sex, linked to 12.5% of deaths.
Differences between men and women are also notable. In 2023, 46% of cancer deaths in men were related to preventable factors, especially tobacco, poor diet, alcohol, occupational risks, and pollution. In the case of women, the proportion was lower, at 36%, with the most prominent factors being tobacco, unprotected sex, poor diet, obesity, and high blood sugar.
"With four out of ten deaths linked to known risk factors, we have a huge opportunity to act: prevent cancers and save lives, as well as improve early diagnosis and treatments," says co-author Theo Vos, from the Institute for Health Metrics and Evaluation (IHME). "Both individual action and collective policies are needed to reduce exposure to these risks."
Equitable control efforts
Ultimately, the study calls for cancer prevention to be a central component of policies in LMICs and emphasizes the need for equitable control efforts to ensure that all people with cancer receive the care they need, when and where they need it.
"The increase in cancer in LMICs is an imminent disaster," says another co-author Meghnath Dhimal, from the Nepal Health Research Council. "An interdisciplinary approach is urgently needed for evidence generation, as well as multisectoral collaboration and coordination for implementation."
According to Force: "These new estimates and projections can support governments and the global health community in developing data-driven policies and actions to improve cancer control and outcomes worldwide. They can also support monitoring progress towards global and regional cancer control goals."
"Our analysis also highlights the need for more data from sources such as cancer registries and vital records, particularly in resource-limited settings. Strengthening surveillance systems is crucial to improve both local and global understanding of the burden of this disease," she adds.
The authors caution that their calculations have limitations. In many poor countries, there are no good cancer registries, making it difficult to have an accurate picture. In addition, some infections have not been included that are known to cause cancer - such as the bacterium Helicobacter pylori or the parasite Schistosoma - and are common in low-income countries. The impact of the COVID-19 pandemic and recent wars has not been taken into account, factors that could have worsened the situation. And future projections do not consider possible medical advances that could change the course.
In a separate comment, two experts from the University of Sydney point out that, to truly reduce the burden of cancer, governments must invest more money, strengthen healthcare systems, reduce inequalities, and focus on prevention and research. "The future of cancer control depends on collective and decisive action today," they emphasize.