WHO and IARC Analysis Finds 37% of Cancer Cases Globally Are Linked to Preventable Causes

WHO and IARC Analysis Finds 37% of Cancer Cases Globally Are Linked to Preventable Causes

Up to four in ten cancer cases worldwide could be prevented, according to a new global analysis published by the World Health Organization (WHO) and its International Agency for Research on Cancer (IARC). The study, released ahead of World Cancer Day on 4 February, represents the most comprehensive assessment to date of preventable cancer risk factors globally.

The analysis estimates that 37% of all new cancer cases in 2022 — approximately 7.1 million cases — were linked to preventable causes, according to WHO. Drawing on data from 185 countries and covering 36 cancer types, the study examined 30 known preventable causes of cancer, including tobacco use, alcohol consumption, high body mass index, physical inactivity, air pollution, and ultraviolet radiation. Notably, it also incorporates nine cancer-causing infections for the first time in a study of this scope.

Tobacco Remains the Leading Preventable Cause

The study identifies tobacco as the single largest preventable cause of cancer worldwide, responsible for an estimated 15% of all new cancer cases. Infections ranked second at 10%, followed by alcohol consumption at 3%, according to WHO.

Three cancer types — lung, stomach, and cervical cancer — accounted for nearly half of all preventable cancer cases in both men and women globally. Lung cancer was primarily linked to smoking and air pollution, stomach cancer was largely attributable to Helicobacter pylori infection, and cervical cancer was overwhelmingly caused by human papillomavirus (HPV).

"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 an 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."

Stark Disparities Between Men and Women

The burden of preventable cancer was substantially higher in men than in women, with 45% of new cancer cases in men linked to preventable causes compared with 30% in women. Among men, smoking alone accounted for 23% of all new cancer cases, followed by infections at 9% and alcohol at 4%. Among women, infections were the leading preventable cause at 11%, followed by smoking at 6% and high body mass index at 3%, according to WHO.

Wide Regional Variation

Preventable cancer rates varied widely across regions. Among women, the proportion of preventable cancers ranged from 24% in North Africa and West Asia to 38% in sub-Saharan Africa. Among men, East Asia had the highest burden at 57%, while Latin America and the Caribbean had the lowest at 28%. These differences reflect varying exposures to behavioral, environmental, occupational, and infectious risk factors, as well as differences in socioeconomic development and national prevention strategies.

Dr Isabelle Soerjomataram, Deputy Head of the IARC Cancer Surveillance Unit and senior author of the study, called it "a comprehensive assessment of preventable cancer worldwide" and said that "addressing these preventable causes represents one of the most powerful opportunities to reduce the global cancer burden."

Public Health Implications

The findings carry significant implications for public health policy worldwide, suggesting that targeted interventions addressing tobacco use, infection prevention — including HPV and H. pylori vaccination and treatment programs — and alcohol reduction could avert millions of cancer cases annually. The scale of the preventable burden underscores the potential for governments and health systems to reduce cancer incidence through evidence-based prevention strategies.

Note: This article is based solely on WHO source material. Independent verification of the underlying study data was not available at the time of publication.