It's easy to feel powerless against cancer, but research has identified several ways that we can reduce the odds of it occurring.
According to a recent analysis from the World Health Organization (WHO), more than a third of all cancer cases globally are preventable.
Lung, stomach, and cervical cancers make up nearly half of those cases.
This means that millions of deadly cancers every year could be prevented through medical intervention, behavior changes, reducing occupational risks, or tackling environmental pollutants.
Find out more in the video below:
"This landmark study is a comprehensive assessment of preventable cancer worldwide, incorporating for the first time infectious causes of cancer alongside behavioural, environmental, and occupational risks," says Isabelle Soerjomataram, medical epidemiologist at WHO and senior author of the analysis.
"Addressing these preventable causes represents one of the most powerful opportunities to reduce the global cancer burden."
The analysis found that in 2022, there were nearly 19 million new cases of cancer. Roughly 38 percent of those diagnoses were related to 30 changeable risk factors.
These included tobacco smoking, alcohol consumption, high body mass index, insufficient physical activity, smokeless tobacco (like chewing tobacco), a traditional stimulant known as areca nut, suboptimal breastfeeding, air pollution, ultraviolet radiation, infectious agents, and over a dozen occupational exposures.
The number one preventable factor associated with cancer? Smoking tobacco. It was linked to 15 percent of all cancer cases that year.
For men, the risk was particularly high. Smoking contributed to 23 percent of all new cancer cases globally in men that year.
But smoking isn't the only cause; air pollution also plays a role, and its impact varies by region.
In East Asia, for instance, about 15 percent of all lung cancer cases in women were due to air pollution. In Northern Africa and Western Asia, meanwhile, approximately 20 percent of all lung cancer cases in men were due to air pollution.
After tobacco smoking, the runner-up among changeable lifestyle factors was drinking alcohol. It accounted for 3.2 percent of all new cancer cases (approximately 700,000 cases).
According to the researchers' estimates, smoking tobacco and drinking alcohol account for almost half (around 48 percent) of all cases of preventable cancer.
Infections, meanwhile, were linked to roughly 10 percent of new cancer cases. Among women, the largest share of preventable cancers was due to high-risk human papillomavirus (HPV), which can lead to cervical cancer.
Thankfully, we now have a vaccine for HPV that prevents many of these associated diseases, and yet coverage in many parts of the world remains low.
Stomach cancer cases are higher among men and tend to be associated with smoking and infections due to overcrowding, inadequate sanitation, and poor access to clean water.
"This is the first global analysis to show how much cancer risk comes from causes we can prevent," says André Ilbawi, WHO Team Lead for Cancer Control and co-author of the analysis.
"By examining patterns across countries and population groups, we can provide governments and individuals with more specific information to help prevent many cancer cases before they start."
Related: US Cancer Survival Has Reached a Milestone High of 70%
Now it's time to roll up our sleeves, as the research shows there's a huge amount we can do to help lower the risk of people developing numerous forms of cancer.
"In summary, nearly 4 in 10 cancer cases worldwide in 2022 could have been prevented by eliminating exposure to the risk factors considered in this study," the researchers explain in their paper.
"Ultimately, our results reinforce the call for effective cancer prevention, which requires sustained political commitment and investment tailored to the specific risk profiles of populations worldwide."
The study was published in Nature Medicine.
An earlier version of this article was published in February 2026.