Up to 40% of Cancers Preventable, Major WHO–IARC Study Finds

The analysis examined 30 preventable risk factors, including tobacco use, alcohol consumption, high body mass index, physical inactivity, air pollution and ultraviolet radiation.

Up to four in ten cancer cases worldwide could be prevented, according to a major new global analysis by the World Health Organization (WHO) and its International Agency for Research on Cancer (IARC).

Released ahead of World Cancer Day on 4 February, the study estimates that 37 per cent of all new cancer cases in 2022—around 7.1 million cases—were linked to preventable causes, highlighting the enormous potential of prevention to reduce the global cancer burden.

First Global Estimate of Preventable Cancer Causes

The analysis examined 30 preventable risk factors, including tobacco use, alcohol consumption, high body mass index, physical inactivity, air pollution and ultraviolet radiation. For the first time, it also included nine cancer-causing infections, marking a major advance in global cancer surveillance.

Drawing on data from 185 countries and 36 cancer types, the study provides the most comprehensive picture to date of how lifestyle, environmental and infectious risks contribute to cancer worldwide.

“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. “This evidence gives governments and individuals clearer direction on how to stop many cancers before they start.”

Tobacco, Infections and Alcohol Lead the Risk List

The study found that:

• Tobacco is the leading preventable cause, responsible for 15% of all new cancer cases globally

• Infections account for 10%

• Alcohol consumption contributes 3%

Three cancer types—lung, stomach and cervical cancer—accounted for nearly half of all preventable cancers worldwide.

• Lung cancer was mainly linked to smoking and air pollution

• Stomach cancer was largely attributable to Helicobacter pylori infection

• Cervical cancer was overwhelmingly caused by human papillomavirus (HPV)

Sharp Differences Between Men, Women and Regions

The burden of preventable cancer was significantly higher in men (45%) than in women (30%).

Among men:

• Smoking accounted for 23% of all new cancer cases

• Infections contributed 9%

• Alcohol accounted for 4%

Among women globally:

• Infections were the leading cause at 11%

• Smoking accounted for 6%

• High body mass index contributed 3%

Preventable cancer rates also varied widely by region:

• Among women, rates ranged from 24% in North Africa and West Asia to 38% in sub-Saharan Africa

• Among men, the highest burden was in East Asia (57%), with the lowest in Latin America and the Caribbean (28%)

“These differences reflect variations in exposure to risk factors, socioeconomic development, prevention policies and health system capacity,” said Dr Isabelle Soerjomataram, Deputy Head of the IARC Cancer Surveillance Unit and senior author of the study.

Prevention Offers One of the Biggest Gains in Cancer Control

The findings underline the need for context-specific prevention strategies, including:

• Strong tobacco control and alcohol regulation

• Vaccination against cancer-causing infections such as HPV and hepatitis B

• Cleaner air and safer workplaces

• Healthier food environments and more opportunities for physical activity

WHO and IARC say coordinated action across sectors—including health, education, transport, energy and labour—could prevent millions of cancer diagnoses, reduce long-term health-care costs and significantly improve population health.

“Addressing preventable risk factors represents one of the most powerful opportunities to reduce the global cancer burden,” Dr Soerjomataram said.