40% of Cancer Cases Are Preventable: WHO Study Reveals Key Risk Factors

Nearly 40% of new cancer cases worldwide may be preventable, according to a comprehensive global analysis released by the World Health Organization (WHO) and its International Agency for Research on Cancer (IARC). The study, published in February 3, 2026, estimates that around 7.1 million of the approximately 20 million new cancer diagnoses in 2022 were linked to factors that could be avoided.

The analysis examined 36 cancer types across 185 countries, identifying 30 modifiable risk factors, including tobacco use, alcohol consumption, high body mass index, physical inactivity, air pollution, ultraviolet radiation, and, for the first time, nine cancer-causing infections. This broadened scope provides a more complete picture of cancer prevention opportunities than previous studies.

Tobacco remains the leading preventable cause of cancer globally, accounting for 15% of all new cases. Infections are the second most significant preventable cause, contributing to 10% of cases, while alcohol consumption is linked to 3%. These findings underscore the critical importance of public health interventions focused on reducing exposure to these risk factors.

The impact of these preventable factors varies between sexes. The burden of cancer associated with modifiable risks is notably higher in men, affecting 45% of new diagnoses, compared to 30% in women. Among men, smoking accounts for an estimated 23% of all new cancer cases. In women, infections are more prominent, linked to 11% of cases, followed by tobacco at 6% and high body mass index at 3%.

The study highlights that lung, stomach, and cervical cancers account for nearly half of all preventable cancer cases worldwide. Lung cancer is strongly associated with smoking and air pollution, stomach cancer with Helicobacter pylori infection, and cervical cancer with the human papillomavirus (HPV). These specific links emphasize the potential for targeted prevention strategies.

“This is the first global analysis to show how much cancer risk comes from causes we can prevent,” said Dr. André Ilbawi, WHO Team Lead for Cancer Control and author of the study. “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.”

The researchers emphasize that understanding how these risk factors influence cancer incidence in different countries and populations is crucial for designing effective prevention policies. The inclusion of a broader range of risk factors, including infectious agents, represents a significant advancement in cancer prevention research.

While the study provides compelling evidence for the potential of cancer prevention, it’s important to note that these are estimates based on available data. The complexity of cancer development means that many cases are influenced by a combination of genetic, environmental, and lifestyle factors. However, the findings clearly demonstrate that a substantial proportion of cancer cases are not inevitable and can be avoided through targeted interventions.

The release of this analysis coincides with World Cancer Day, observed annually on February 4th, serving as a reminder of the urgent need for increased investment in cancer prevention and control efforts globally. The WHO and IARC hope that these findings will empower governments and individuals to take proactive steps to reduce the cancer burden and improve public health.

The study’s findings reinforce the importance of established cancer prevention strategies, such as comprehensive tobacco control policies, vaccination programs against HPV and other cancer-causing viruses, and initiatives to promote healthy diets and physical activity. Further research is needed to refine our understanding of the complex interplay between risk factors and cancer development, and to identify new opportunities for prevention.