"We now have the information to prevent cancer before it starts," said Isabelle Soerjomataram, a cancer surveillance specialist at the International Agency on Research on Cancer (IARC).
Speaking to the press last week, Soerjomataram and her colleague Andre Ilbawi were presenting the findings of a study involving 36 cancer types in 185 countries. The two co-authored and published their results in the medical journal Nature Medicine on February 3, 2026.
The study leads with a statistic as striking as Soerjomataram's opening claim: 7.1 million new cases of cancer were linked to what's known as modifiable risk factors (MRFs) — such as consuming tobacco or alcohol, as well as various infections. That's 37.8% of a total of 18.7 million new cancer cases in 2022.
Research into MRFs is not strictly new. We have long known that MRFs, which also include overweight and obesity, air pollution, and other environmental toxins, can be carcinogenic. And the claim to be able to "prevent cancer before it starts" depends on many other factors, as well, like access to healthcare resources — which is not a given everywhere in the world.
But the details of this study do offer some insight into the effects of MRFs, which can vary by region and by sex.
The authors considered 30 MRFs, including tobacco, alcohol, air pollution, and occupational exposure to toxins such as asbestos, as well as:
- Insufficient physical activity
- Smokeless tobacco and areca nut
- Certain breastfeeding practices
And, for the first time in a study involving MRFs, the researchers also included infectious agents, such as hepatitis B and human papillomavirus (HPV).
HPV-caused cancers account for the highest share of preventable cancers in women, globally — despite the availability of HPV vaccines, which have shown themselves to be highly effective in protecting against cervical cancer. But "vaccine hesitancy is very real," said Ilbawi in answer to questions from DW.
"[In] higher income countries — Australia is one of them — cervical cancer is almost eradicated [at its current] level of 5 cases per 100,000, [people]," said Soerjomataram.
"Yet when we look at the burden in Latin America, but also in Sub-Saharan Africa, that's where the issues remain. HPV-related cancer, especially cervical cancer, is still very high there," Soerjomataram added.
In Latin America, for example, the Global Cancer Observatory recorded more than 63,000 cases of cervical cancer in 2022 [the most recent data], and more than 30,000 deaths from cervical cancer.
Maria Paula Curado, a leading cancer epidemiologist at the A.C. Carmargo Cancer Center in Sao Paulo, Brazil, told DW that mortality rates from cervical cancer were high in Latin America where women had poor access to prevention through HPV vaccination and early treatment.
There may also be some vaccine hesitancy, "due to a lack of knowledge about how aggressive cervical cancer can be," said Curado, who was not involved in the WHO/IARC study and commented via email.
"But in some areas of southern Brazil, some families think that if they have the HPV vaccination, they can start early sexual activity, and for some [other people] that is not acceptable."
Curado said that while in some regions of Brazil vaccine coverage was about 67%, this was changing as the vaccine had only recently been adopted. But the "ideal coverage" would be about 80%.
New insights into preventable cancers among women and men
The inclusion of infectious agents in the study has revealed new information about cancers among women — but, equally, variations compared to men. And the researchers say they hope this will help improve cancer prevention measures.
Infections were found to have caused the highest number of preventable cancers among women — a total of 2.7 million cases (29.7%). Among men, it was behavioral risk factors like smoking tobacco — a total of 4.3 million cases (45.4%).
Diving deeper into the data on lung cancer, which is one of the most frequently diagnosed cancers in both women and men (aside from breast, colorectal, and prostate cancers), uncovers how the burden of MRFs is similar, but the effect is different: Among both sexes, tobacco, air pollution and occupational exposures were attributed to lung cancer cases in almost equal measures.
But while there were 1,326,453 lung cancer cases among men, the number was significantly lower, at 477,869, among women.
Preventable cancers require 'targeted interventions'
With the Global Cancer Observatory predicting cancer cases to rise by more than 50% by 2045, the researchers wrote in their paper that "this growing burden underscores the urgent need for effective prevention strategies," arguing that "many cases could be prevented through targeted interventions."
Little is said in the study of the 62.2% of cancer cases which could not be attributed to preventable MRFs.
"We are an ageing population," said Curado, "and, therefore, rare cancers are emerging with no standards for diagnosis or treatments, and unknown risk factors."
But Suzette Delaloge, a specialist in breast cancer and cancer prevention at the French research hospital Gustave Roussy, told DW the study represented "a pivotal contribution to shaping a global, data-informed approach to cancer prevention."
Delaloge, who was not involved in the study, said that while the study highlighted how cancers were "largely shaped by geographical, social, economic, and cultural determinants, [...] individual-level actions remain essential to mitigating their profound effects."
The researchers said themselves that future cancer prevention measures will increasingly have to address various effects among women and men, as well as respond to differing social and economic contexts across countries and regions.
Edited by: Maren Sass, Carla Bleiker
