Up to 40% of Cancers Globally Are Preventable: New WHO Study

Up to four in ten cancer cases worldwide may be preventable, according to a new analysis from the World Health Organization (WHO) and the International Agency for Research on Cancer (IARC). The study examines 30 preventable cancer causes, including well-established risk factors like smoking and alcohol consumption, as well as overweight, physical inactivity, air pollution, and ultraviolet radiation. Significantly, this analysis also incorporates, for the first time, nine infectious agents linked to cancer development.

Published ahead of February 4th, World Cancer Day, the analysis reveals that in 2022, 37% of all new cancer cases – approximately 7.1 million – were attributable to preventable causes. These findings underscore the substantial potential for cancer prevention to reduce the global cancer burden.

The study, based on data from 36 cancer types across 185 countries, identifies smoking as the leading preventable cause of cancer globally, accounting for 15% of new cases. Infections follow closely behind at 10%, and alcohol consumption contributes to 3% of cases.

Lung, stomach, and cervical cancers collectively represent nearly half of all preventable cancer cases worldwide, affecting both men, and women. Lung cancer is primarily linked to smoking and air pollution, stomach cancer is largely attributable to infection with Helicobacter pylori, and the vast majority of cervical cancer cases are caused by the human papillomavirus (HPV).

“Here’s the first global analysis that shows just how much cancer is linked to preventable causes,” said Dr. Ilbawi, Head of the Cancer Control team at the WHO and author of the study. “By examining trends within countries and populations, we can provide more precise information to policymakers and individuals that, in many cases, can contribute to cancer prevention before it even develops.”

Differences Between Men and Women, and Regional Variations

The burden of preventable cancers is notably higher in men than in women (45% of new cases in men versus 30% in women). Among men, smoking accounts for approximately 23% of new cancer cases, followed by infections (9%) and alcohol consumption (4%). For women globally, infections are responsible for 11% of new cancer cases, followed by smoking (6%) and overweight (3%).

“This very important study comprehensively assesses preventable cancers globally, integrating infectious causes for the first time alongside behavioral, environmental, and occupational risks,” stated Dr. Isabelle Soerjomataram, Deputy Head of the Cancer Surveillance Branch at IARC and lead author of the study. “Addressing these preventable causes is one of the most effective ways to alleviate the global cancer burden.”

The burden of preventable cancers varies considerably by region. It ranges from 24% in North Africa and Western Asia to 38% in sub-Saharan Africa among women, and from 57% in Eastern Asia to 28% in Latin America and the Caribbean among men. These differences reflect varying exposures to behavioral, environmental, occupational, and infectious risk factors, as well as disparities in socioeconomic development, national prevention policies, and healthcare system capacity.

The findings emphasize the need for tailored prevention strategies, including stringent tobacco control measures, alcohol regulation, vaccination against cancer-causing infections such as HPV and hepatitis B, improved air quality, safer workplaces, and healthier environments for diet and physical activity.

A coordinated effort across health, education, energy, transportation, and labor sectors can spare millions of families the hardship of a cancer diagnosis. Addressing preventable risk factors not only lowers cancer incidence but also reduces long-term healthcare costs and improves overall population health and well-being.

The study highlights the critical role of public health interventions. For example, widespread HPV vaccination programs have the potential to dramatically reduce the incidence of cervical cancer, a disease strongly linked to HPV infection. Similarly, comprehensive smoking cessation programs and policies aimed at reducing air pollution can significantly lower the risk of lung cancer.

While the study focuses on preventable cancers, it’s important to remember that not all cancers are preventable. Genetic predisposition and other factors also play a role. However, the sheer number of cases linked to modifiable risk factors underscores the importance of prioritizing prevention efforts.

The WHO and IARC are collaborating to strengthen cancer prevention, early detection, treatment, and palliative care worldwide. They provide technical guidance, set global and regional standards, and assist governments in improving access and reducing inequalities. They also promote research, policy development, and global initiatives on cervical cancer, breast cancer, and childhood cancers.

This analysis serves as a powerful call to action for governments, healthcare professionals, and individuals to prioritize cancer prevention. By addressing the modifiable risk factors identified in this study, we can collectively work towards a future with fewer cancer cases and improved health outcomes for all.