Nearly 40% of new cancer cases worldwide are potentially preventable, according to a new global analysis released today, , by the World Health Organization (WHO) and its International Agency for Research on Cancer (IARC). The study, published in Nature Medicine, examined data from 185 countries and 36 different cancer types, identifying 30 modifiable risk factors linked to the disease.
Researchers estimate that around 7.1 million cancer diagnoses in 2022 – representing 37% of all new cases – were linked to factors that can be changed, controlled, or managed. “This is the first global analysis to show how much cancer risk comes from causes You can prevent,” said Dr. André Ilbawi, WHO Team Lead for Cancer Control, and author of the study.
Tobacco, Alcohol, and Infections are Key Contributors
The leading preventable cause of cancer globally is tobacco smoking, accounting for 15% of all new cases. Infections are responsible for 10%, and alcohol consumption contributes to 3%. These three factors collectively account for nearly half of all preventable cancer cases in both men and women.
Specifically, lung cancer was primarily linked to smoking and air pollution, stomach cancer to Helicobacter pylori infection, and cervical cancer overwhelmingly to human papillomavirus (HPV). The study highlights the potential of prevention in reducing the global cancer burden.
Disparities Between Men and Women
The burden of preventable cancer is notably higher in men than in women, with 45% of new cancer cases in men linked to modifiable risk factors compared to 30% in women. Among men, smoking accounts for an estimated 23% of all new cancer cases, followed by infections at 9% and alcohol at 4%.
Regional Differences in Preventability
The analysis reveals significant regional variations in cancer preventability. In high-income countries like Australia, the incidence of cervical cancer has been drastically reduced, currently at 5 cases per 100,000 people, largely due to successful HPV vaccination programs. However, in regions like Latin America and sub-Saharan Africa, cervical cancer rates remain high, linked to limited access to vaccination and early treatment.
In Latin America, more than 63,000 cases of cervical cancer were recorded in 2022, resulting in over 30,000 deaths. Epidemiologist Maria Paula Curado, from the A.C. Camargo Cancer Center in São Paulo, Brazil, explained that limited access to HPV vaccination and early treatment contribute to these higher mortality rates. She also noted that in some areas of Brazil, there is hesitancy surrounding vaccination due to misinformation about its impact on sexual activity.
Beyond Traditional Risk Factors
The study expands on previous research by including nine cancer-causing infections as modifiable risk factors, alongside well-established factors like tobacco, alcohol, high body mass index, physical inactivity, air pollution, and ultraviolet radiation. Other modifiable risk factors examined include a high body mass index, insufficient physical activity, smokeless tobacco and areca nut use, certain breastfeeding practices, and exposure to ultraviolet radiation.
The researchers also considered occupational exposure to toxins like asbestos.
The Importance of Targeted Interventions
While the study emphasizes the potential for prevention, researchers stress the need for “interventions specific” to address the diverse factors influencing cancer risk in different populations. The findings underscore that cancer risk is significantly shaped by geographical, social, economic, and cultural factors, but individual actions remain essential in mitigating these effects.
The authors of the study wrote that the increasing cancer burden highlights the “urgent need for effective prevention strategies.” They argue that many cases could be prevented through targeted interventions.
The analysis also revealed differences in the types of cancers most amenable to prevention in men and women. Infections were the largest contributor to preventable cancers in women (29.7%), while behavioral factors, such as smoking, were the dominant risk factor in men (45.4%).
Lung Cancer: A Case Study in Modifiable Risk
A closer examination of lung cancer, one of the most common cancers in both men and women, revealed that the burden of modifiable risk factors was similar in both sexes. Lung cancer was attributed to tobacco, air pollution, and occupational exposure to pollutants in both men and women. However, the number of lung cancer cases was significantly higher in men (1,326,453) compared to women (477,869).
