A news report in Nature highlighted a large global study suggesting that more than a third of new cancer cases could be prevented by reducing exposure to modifiable risk factors, primarily smoking and alcohol, along with other factors such as carcinogenic infections, air pollution, obesity, and occupational exposure.
The study reported in the Nature report used the Population Attributable Fraction to estimate the number of cancer cases that can be attributed to exposure to modifiable factors.According to the study abstract on PubMed, 36 cancer types across 185 countries were analyzed based on incidence data in 2022, examining 30 modifiable risk factors. The researchers concluded that of the 18.7 million new cancer cases globally in 2022, about 7.1 million (or 37.8%) can be attributed to these modifiable factors.In practice, this ratio means that nearly 4 in 10 new diagnoses are not "purely biological fate" but are linked to environment, behavior and policies that can be changed.
The strength of the study also lies in its breakdown of the biggest "drivers of prevention" globally. Smoking was the most important contributor, linked to about 15.Smoking is the top contributor, associated with about 15.1% of all new cancer cases globally in 2022, followed by carcinogenic infections (such as HPV and others) at 10.2% and alcohol consumption at 3.2%. These figures illustrate why the Nature report and subsequent readings focused on smoking and alcohol: reducing them not only brings individual health gains, but also shifts the incidence curve at the population level.The study also notes that lung, stomach, and cervical cancers account for nearly half of the "preventable" cases, meaning that prevention is not evenly distributed across all cancers, but rather concentrated in specific locations that can be targeted with precise policies.
The most notable medical finding of the study is that smoking remains the largest factor globally. Medically, the relationship between smoking and cancer is not just an "association", but a series of clear biological mechanisms: smoke contains carcinogens that mutate DNA, increase oxidative stress and chronic inflammation, and impair DNA repair mechanisms.Smoking is therefore strongly associated with multiple cancers.
After smoking, cancer-causing infections are a huge medical factor: approximately 10.2% of new cases globally.These are not "transient infections", but viruses and bacteria/parasites capable of pushing cells onto a cancerous path via chronic inflammation or the introduction of viral genes that affect cell cycle regulation.The medical examples are clear: HPV with cervical cancer and some head and neck cancers, Hepatitis B and C with liver cancer, Helicobacter pylori with stomach cancer, and EBV with some lymphomas and other cancers. The medical aspect here is very important because "prevention" does not only mean changing behavior; it also means reducing a specific infection, treating chronic infections, and interrupting a known pathway that leads to cancer.
The third factor highlighted by the study is alcohol, with 3.2% of new cases globally. Medically, the mechanism of alcohol in cancer revolves around its conversion to acetaldehyde, a toxic and carcinogenic compound that can cause DNA damage and increase oxidative stress, in addition to affecting the absorption of certain nutrients and liver function, and interfering with hormones in some cancers.Alcohol interacts with other factors such as smoking to increase the risk of oral, pharyngeal and esophageal cancers exponentially.
There is also an increasingly medically important set of "metabolic" factors: overweight/obesity, physical inactivity, and certain dietary patterns. Air pollution and certain occupational exposures are also important. Air pollution, especially fine particulate matter (PM2.5), is associated with chronic respiratory inflammation and oxidative stress that may increase the risk of lung cancer even in non-smokers. Occupational exposures (such as certain solvents, asbestos, certain chemicals) act via known carcinogenic mechanisms and increase the risk of certain cancers depending on the type and duration of exposure.
"Preventable" does not mean that the risk is reduced to zero. It means that the risk is statistically reduced as the exposure is reduced, and that a number of cases would not have occurred if the exposure did not exist or if it were lower.Also, some cancers occur without obvious risk factors or with factors that cannot be changed (such as age, or genetic predispositions). Therefore, this medical finding complements a very important concept: prevention is not a substitute for treatment and early detection, but it does reduce "upstream" incidence over time.
Reference list:
IARC/WHO Study Group.(2026).Global burden of cancer attributable to modifiable risk factors in 2022.PubMed.
Nature.(2026).News report on global study showing over one-third of cancers are preventable.Nature.
World Health Organization.(2026).Four in ten cancer cases could be prevented globally.WHO News Release.
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