The study by the UN World Health Organization (WHO) and its International Agency for Research on Cancer (IARC) looks at 30 preventable causes, including tobacco, alcohol, high body mass index, physical inactivity, air pollution and ultraviolet radiation.
Nine cancer-causing infections – such as human papillomavirus (HPV) which can cause cervical cancer – also are included for the first time.
Examining patterns for prevention
Cancer remains a leading cause of morbidity, responsible for nearly 10 million deaths worldwide in 2020, or nearly one in six.
Projections point to a 50 per cent increase in new cases by 2040 if current trends continue, underscoring the urgent need for effective prevention strategies.
The study was released ahead of World Cancer Day, observed annually on 4 February.
The findings draw on data from 185 countries and 36 cancer types. Estimates show that 37 per cent of all new cancer cases in 2022, around 7.1 million, were linked to preventable causes.
“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,” said Dr. André Ilbawi, WHO Team Lead for Cancer Control and author of the study.
Tobacco top cause
Tobacco is the leading preventable cause of cancer, responsible for 15 per cent of all new cases, followed by infections (10 per cent) and alcohol consumption (3 per cent).
Lung, stomach and cervical cancer represented nearly half of all preventable cases in both men and women.
Lung cancer was primarily linked to smoking and air pollution, while stomach cancer was largely attributable to Helicobacter pylori infection. Cervical cancer was overwhelmingly caused by HPV.
Differences among men and women
The burden of preventable cancer was substantially higher in men than in women. Among new cancer cases, 45 per cent occur in men compared with 30 per cent in women.
In men, smoking accounted for an estimated 23 per cent of all new cancer cases, followed by infections (9 per cent) and alcohol (4 per cent).
Among women, infections accounted for 11 per cent of all new cancer cases, followed by smoking at 6 per cent and high body mass index at 3 per cent.
Regional picture, risk factors
Preventable cancers also varied widely between the world’s regions.
Among women, they ranged from 24 per cent in North Africa and West Asia, to 38 per cent in sub-Saharan Africa.
Among men, East Asia accounted for the highest burden at 57 per cent, while the lowest incidence was found in Latin America and the Caribbean at 28 per cent.
These differences are largely due to varying exposure to behavioral, environmental, occupational and infectious risk factors, as well as differences in socioeconomic development, national prevention policies, and health system capacity.
Prevention strategies
The report emphasised the need for “context-specific prevention strategies” such as strong tobacco control measures, alcohol regulation, and vaccination against HPV and other cancer-causing infections such as hepatitis B.
Improved air quality, safer workplaces, healthier food and promoting physical activity are also important.
Furthermore, “coordinated action across sectors, from health and education to energy, transport and labour, can prevent millions of families from experiencing the burden of a cancer diagnosis,” WHO said.
The UN agency stressed that addressing preventable risk factors not only reduces cancer incidence but also lowers long-term healthcare costs and improves population health and well-being.
Listen to an interview with WHO Kenya about the national action plan to eliminate cervical cancer by 2030:
