Breast cancer mammogram
Up to four out of every 10 cancer cases in Kenya could be prevented, a new analysis shows.
About 47,000 Kenyans are diagnosed with cancer each year, according to the National Cancer Institute (NCI).
This means about 18,800 new cases annually could be avoided through measures such as vaccination, screening and reduced exposure to known risks including tobacco and harmful alcohol use.
The analysis was conducted by the World Health Organization (WHO) and the International Agency for Research on Cancer (IARC).
It found that up to 40 per cent of all cancer cases worldwide are linked to preventable causes such as tobacco use, infections including human papillomavirus (HPV), alcohol consumption, high body mass index and air pollution.
Globally, this translated to about 7.1 million new cancer cases in 2022 linked to avoidable risks.
The WHO and IARC examined 30 preventable risk factors and found tobacco caused the largest share of preventable cancer cases worldwide, followed by infection-related cancers and alcohol use.
About three million Kenyans aged between 15 and 65 use tobacco products, which kill about 9,000 people each year, according to the Ministry of Health.
Lung, stomach and cervical cancers together account for nearly half of all preventable cancer cases globally.
NCI data shows Kenya records about 5,845 new cervical cancer cases and 3,591 deaths every year.
Cervical cancer is largely preventable through HPV vaccination and regular screening.
The government has launched the National Cervical Cancer Elimination Action Plan 2026–30 to cut deaths through vaccination, early screening and timely treatment.
The plan aligns with WHO global targets to eliminate cervical cancer as a public health threat by boosting HPV vaccine coverage and expanding screening and treatment services.
“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 give governments and individuals clearer guidance to prevent many cancers before they start,” he said.
The burden of preventable cancer was higher in men than women, accounting for 45 per cent of new cases in men compared with 30 per cent in women.
Among men, smoking caused an estimated 23 per cent of new cancer cases, followed by infections at nine per cent and alcohol at four per cent.
Among women globally, infections accounted for 11 per cent of new cases, followed by smoking at six per cent and high body mass index at three per cent.
“This study offers the most comprehensive review yet of preventable cancer, combining infectious causes with behavioural, environmental and work-related risks,” said Dr Isabelle Soerjomataram, deputy head of the IARC Cancer Surveillance Unit and senior author.
“Addressing these causes offers one of the strongest chances to cut the global cancer burden,” she said.
Radiation oncologist Dr Angela Waweru of Aga Khan Hospital Nairobi said genetics account for only a small share of cancer cases in Kenya.
“In a small number of families we carry out genetic testing to explain strong family histories, but most patients do not have hereditary cancer,” she said.
Preventable cancer rates varied widely by region. Among women, rates ranged from 24 per cent in North Africa and West Asia to 38 per cent in sub-Saharan Africa.
Among men, the highest burden was in East Asia at 57 per cent, and the lowest in Latin America and the Caribbean at 28 per cent.
The differences reflect varied exposure to risk factors, socioeconomic conditions, national prevention policies and health system capacity.
The findings highlight the need for targeted prevention strategies, including strong tobacco control, alcohol regulation, vaccination against HPV and hepatitis B, cleaner air, safer workplaces and healthier diets and physical activity.
The WHO analysis, Global and regional cancer burden attributable to modifiable risk factors to inform prevention, is published in Nature Medicine.