NEW DELHI: Four in ten cancer cases worldwide could be prevented, according to a latest WHO report.
The new global analysis from the World Health Organization (WHO) and its International Agency for Research on Cancer (IARC) estimates that 37% of all new cancer cases in 2022, around 7.1 million cases, were linked to preventable causes.
The findings highlight the enormous potential of prevention to reduce the global cancer burden, the report published in the journal Nature Medicine said.
Drawing on data from 185 countries and 36 cancer types, the study identifies tobacco as the leading preventable cause of cancer globally responsible for 15% of all new cancer cases, followed by infections (10%) and alcohol consumption (3%).
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).
The study examined 30 preventable causes, including tobacco, alcohol, high body mass index, physical inactivity, air pollution, ultraviolet radiation and – for the first time – nine cancer-causing infections.
“This is the first global analysis to show how much cancer risk comes from causes we can prevent,” said Dr Ilbawi, WHO Team Lead for Cancer Control, and 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.”
In India, it is estimated that one in nine Indians will develop cancer in their lifetime.
In 2024, India reported 1.53 million new cases. It is projected that cancer cases will touch 2.45 million by 2045. In 2022, 0.82 million cancer deaths were reported. It is projected that by 2045, as many as 1.65 million cancer deaths will be reported in the country. The highest incidence is reported among the age group of 40-64 years.
The WHO study said the burden of preventable cancer was substantially higher in men than in women, with 45% of new cancer cases in men compared with 30% in women.
In men, smoking accounted for an estimated 23% of all new cancer cases, followed by infections at 9% and alcohol at 4%. Among women globally, infections accounted for 11% of all new cancer cases, followed by smoking at 6% and high body mass index at 3%.
“This landmark study is a comprehensive assessment of preventable cancer worldwide, incorporating for the first time infectious causes of cancer alongside behavioural, environmental, and occupational risks,” said Dr Isabelle Soerjomataram, Deputy Head of the IARC Cancer Surveillance Unit and senior author of the study.
“Addressing these preventable causes represents one of the most powerful opportunities to reduce the global cancer burden.”
Preventable cancer varied widely between regions.
Among women, preventable cancers ranged from 24% in North Africa and West Asia to 38% in sub-Saharan Africa.
Among men, the highest burden was observed in East Asia at 57%, and the lowest in Latin America and the Caribbean at 28%. These differences reflect varying exposure to behavioural, environmental, occupational and infectious risk factors, as well as differences in socioeconomic development, national prevention policies, and health system capacity.
The findings underscore the need for context-specific prevention strategies that include strong tobacco control measures, alcohol regulation, vaccination against cancer-causing infections such as human papillomavirus (HPV) and hepatitis B, improved air quality, safer workplaces, and healthier food and physical activity environments.
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. Addressing preventable risk factors not only reduces cancer incidence but also lowers long-term health care costs and improves population health and well-being.