A global analysis released Tuesday, Feb. 3, shows that seven million cancer cases could be prevented every year. WHO scientists report that these avoidable cases make up about 37% of all cancer diagnoses worldwide.
The International Agency for Research on Cancer (IARC), the WHO’s research branch, conducted the study and published it in the journal Nature Medicine. Researchers reached these conclusions by studying 30 different risk factors across 185 countries, comparing health data from 2012 and 2022.
Leading Causes of Cancer
Tobacco use is the top preventable cause of cancer, responsible for 3.3 million cases globally each year. Infections also play a major role, contributing to 2.3 million cases annually. These include viruses like HPV (the leading cause of cervical cancer) and hepatitis (which affects the liver), along with certain types of stomach bacteria.
Alcohol use is linked to about 700,000 cases each year. Looking at all risk factors combined, the study found that just three types of cancer—lung, stomach, and cervical—make up nearly half of all preventable cases. Smoking, air pollution, and various infections are the primary causes of these specific illnesses.
Regional and Gender Differences
Researchers found that men have much higher rates of preventable cancer than women, partly because smoking is more common among men.
For women, the main causes of preventable cancer differ greatly by region. In sub-Saharan Africa, infections cause nearly 80% of preventable cases. However, in Europe, the top three causes for women are smoking, infections, and obesity.
Environmental and Lifestyle Factors
The report explains the different ways these risk factors affect the body. For example, smoking and sunlight (UV rays) can directly damage the body's DNA.
Obesity and a lack of physical activity can change how the body handles inflammation and hormones. Meanwhile, air pollution can increase risk by "waking up" dormant cancer cells that were already present in the body.
By identifying these risks, the agency hopes to help health officials create programs that could save millions of lives in the future.
