Quitting smoking, vaccinating against HPV, cleaner air and less alcohol could prevent millions of cancer diagnoses every year. Yet these measures remain unevenly applied worldwide, according to a study that examined almost 19 million cases.
Researchers from the International Agency for Research on Cancer, among others, looked at data from 185 countries during this study, which was published in the journal Nature. Of the almost 19 million new cancer diagnoses in 2022, more than 7 million were found to have a direct link to factors that we can already do something about today, such as smoking, alcohol, infections, obesity and air pollution.
A peculiarity of cancer research is that the disease often only develops long after harmful exposure. The researchers therefore linked diagnoses from 2022 to risk factors from approximately ten years earlier. “Cancer typically develops many years after exposure, so including a time delay is essential and biologically plausible,” study co-author Hanna Fink tells Scientias.nl.
The most important risk factors
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Smoking remains the biggest culprit worldwide: approximately one in six cancer cases is related to it. In second place are infections such as the HPV virus and Helicobacter pylori bacteria. Alcohol is responsible for around 700,000 new cases each year. “Together, these three risk factors account for almost 40 percent of new cancer diagnoses worldwide,” Fink said.
Geographic differences
The researchers saw enormous geographical differences. In East Asia, almost 60 percent of cancer cases in men were preventable, mainly due to high smoking rates. In sub-Saharan Africa, infections are the biggest cause, partly because HPV vaccination is hardly available there. In Western countries, in addition to smoking, obesity and UV radiation also play a role.
Men versus women
There is also a striking difference between the sexes. In men, almost half of all cancer diagnoses can be linked to preventable factors; for women it is about three in ten. The explanation: men worldwide smoke more often and drink more on average. In women in poorer countries, infections are the biggest cause, especially HPV, which causes cervical cancer.
“These differences clearly call for gender-sensitive prevention strategies,” says Fink, “such as scaling up HPV vaccination and screening for women, in addition to strict tobacco and alcohol policies that target men.”
Effective prevention
What is still missing in effective prevention? “We are mainly falling short in terms of coverage and equality,” Fink said. “Many countries still lack access to vaccines, screening programs, clean air, safe water and effective regulation of tobacco and alcohol.”
Fortunately, we also know what helps. “The strongest evidence supports tobacco control policies, vaccination against HPV and hepatitis B, reducing harmful alcohol use, and infection control through screening and treatment,” Fink summarizes. “These measures have already reduced the burden of cancer where they have been widely implemented.”
What does ‘preventable’ mean?
But what does it actually mean when scientists say a cancer is ‘preventable’? “This does not mean that individuals are to blame for their cancer, or that each case could have been prevented by personal choices alone. Many risk factors are shaped by social, economic and policy circumstances,” says Fink.
The actual figures are probably even higher the study reports. “Limited data increases uncertainty and can lead to an underestimate of the actual burden,” Fink acknowledges. “For these reasons, it is quite possible that the true potentially preventable cancer burden is higher than what we report, especially in countries with weaker health information systems.”
Collective action
The core message is nevertheless hopeful, although Fink calls for nuance. “The key message is that cancer prevention works. At the same time, people should be careful not to interpret these results as personal blame or as a guarantee of complete prevention. Risk is shaped by broader environments and policies, and prevention requires collective action, not just individual behavior change.”
We have written about this subject before, for example, also read: Drinking for a lifetime significantly increases the risk of rectal cancer (but there is hope) and These ‘treacherous’ brain cells help brain cancer grow (but there may be a cure). Or read this article: ALS turns out to be an autoimmune disease: inflammatory T cells attack nerves.
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date:2026-02-07 12:03:00
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