Four in ten cancer cases could be prevented globally

Up to four in 10 cancer cases worldwide could be prevented, according to a new global analysis from the World Health Organization and its International Agency for Research on Cancer.

The study examines 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.

Released ahead of World Cancer Day on Feb. 4, the analysis estimates that 37% of all new cancer cases in 2022 — around 7.1 million cases — were linked to preventable causes.

The findings underscore the potential for prevention to reduce the global cancer burden by lowering exposure to known risks before disease develops.

Drawing on data from 185 countries and 36 cancer types, the study identifies tobacco as the leading preventable cause of cancer, responsible for 15% of all new cancer cases globally.

The analysis ranks infections as the second-leading preventable cause at 10% of new cancer cases, followed by alcohol consumption at 3%.

Three cancer types — lung, stomach, and cervical cancer — accounted for nearly half of all preventable cancer cases in both men and women worldwide.

Lung cancer was primarily linked to smoking and air pollution, the analysis said.

Stomach cancer was largely attributable to Helicobacter pylori infection, the study found.

Cervical cancer was overwhelmingly caused by human papillomavirus, according to the analysis.

“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 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.”

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.

In men, smoking accounted for an estimated 23% of all new cancer cases, followed by infections at 9% and alcohol at 4%, the study found.

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, the analysis said.

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%.

The study said these differences reflect varying exposure to behavioral, environmental, occupational, and infectious risk factors, as well as differences in socioeconomic development, national prevention policies, and health system capacity.

The findings call for prevention strategies tailored to local risk patterns, including strong tobacco control measures and alcohol regulation.

The analysis also points to vaccination against cancer-causing infections such as human papillomavirus and hepatitis B as core prevention tools.

The study further highlights environmental and workplace measures, including improved air quality, safer workplaces, and healthier food and physical activity environments.

WHO said coordinated action across sectors — from health and education to energy, transport, and labor — can prevent millions of families from facing the burden of a cancer diagnosis.

The analysis said reducing preventable risk factors can lower cancer incidence, reduce long-term health care costs, and improve population health and well-being.