Nearly four out of ten cancer cases worldwide could be prevented through targeted prevention efforts, reveals a new joint analysis by the World Health Organization (WHO) and the International Agency for Research on Cancer (IARC), published on World Cancer Day, February 4. According to the study, published in the journal "Nature Medicine," 37% of new cancer cases recorded in 2022, representing approximately 7.1 million people, were linked to preventable risk factors.

The analysis covers 36 types of cancer in 185 countries and examines 30 preventable causes, including smoking, alcohol consumption, being overweight, physical inactivity, air pollution, exposure to ultraviolet rays and, for the first time on this scale, nine infectious agents.

Tobacco remains the leading preventable cause

Globally, smoking remains the leading preventable cause of cancer, responsible for 15% of new cases, ahead of infections (10%) and alcohol consumption (3%). Three cancers alone account for nearly half of all preventable cases: lung cancer, stomach cancer, and cervical cancer. Lung cancer is primarily linked to tobacco use and air pollution, stomach cancer is largely associated with Helicobacter pylori infection, while cervical cancer is caused by the human papillomavirus (HPV) in the vast majority of cases.

“This is the first global analysis to clearly show the extent to which cancer risk is linked to preventable causes,” emphasizes Dr. Rashid Ilbawi, head of the WHO’s Cancer Control Team. “This data provides policymakers and the public with key information to prevent cancers before they occur.”

Significant disparities according to gender and region

The study highlights significant inequalities between men and women. Preventable cancers account for 45% of new cases in men, compared to 30% in women. In men, smoking is responsible for approximately 23% of cancers, followed by infections (9%) and alcohol (4%). In women, infections are the leading cause (11%), followed by smoking (6%) and being overweight (3%). Significant differences also exist between regions. The proportion of preventable cancers in women ranges from 24% in North Africa and West Asia to 38% in sub-Saharan Africa. Among men, it reaches 57% in East Asia, compared to 28% in Latin America and the Caribbean. "This comprehensive analysis shows that tackling preventable causes is one of the most effective ways to reduce the global burden of cancer," explains Dr. Isabelle Soerjomataram, Deputy Director of Cancer Surveillance at IARC.

Focusing on prevention to save millions of lives

The WHO and IARC call for strengthened prevention policies, including strict tobacco control measures, alcohol regulation, HPV and hepatitis B vaccination, improved air quality, workplace safety, and the promotion of environments conducive to healthy eating and physical activity. Coordinated action involving the health, education, transport, energy, and labor sectors could spare millions of families the shock of a cancer diagnosis, while sustainably reducing healthcare costs and improving population well-being.