World Cancer Day: "Prevent it before it starts"

"We now have the information to prevent cancer before it starts," said Isabel Sorjomataram of the International Agency for Research on Cancer (IARC).

Speaking to reporters last week, she and her colleague Andre Ilbavi presented the findings of a study that included 36 types of cancer in 185 countries. The two co-authored the study, which was published in the medical journal Nature Medicine on February 3, 2026.

At the beginning of the study is a statistic, and it is as striking as Sorjo Mataram’s opening claim: 7,1 million new cancer cases are linked to what are known as “modifiable risk factors” (MRFs) – things we can influence, or change, such as tobacco or alcohol consumption. That’s 37,8 percent of the total 18,7 million new cancer cases in 2022.

Research into the effects of MRF is not new. We have long known that carcinogens can include overweight and obesity, air pollution, and the presence of various toxins in the environment, and the claim that cancer can be “prevented before it starts” also depends on many other factors, such as access to health resources – which is not possible everywhere in the world.

The details of this new study, however, provide insight into the effects of modifiable risk factors that may differ by region and gender.

The authors considered 30 such factors, including tobacco, alcohol, air pollution and exposure to toxins such as asbestos at work, as well as:

• high body mass index (BMI), • insufficient physical activity, • smokeless tobacco and betel nut (which is consumed by chewing), • certain breastfeeding methods, and • ultraviolet radiation (UVR).

And, for the first time in a study involving modifiable risk factors, the researchers also included infectious agents, such as hepatitis B and human papillomavirus (HPV).

The level of preventable HPV-related cancers in certain regions “remains high,” the study said.

HPV accounts for the largest proportion of preventable cancers in women globally – despite the availability of HPV vaccines, which have been shown to be highly effective in protecting against cervical cancer. But “vaccine hesitancy is very prevalent,” says study co-author Andre Ilbavi.

“In higher-income countries – Australia is one of them – cervical cancer has been almost eradicated and is currently at a rate of five cases per 100.000 [people],” says Isabel Sorjomataram.

"However, when we look at Latin America, but also sub-Saharan Africa, the problems remain. HPV-related cancer, especially cervical cancer, is still very present there," the scientist adds.

New insight into cancer prevention in women and men

The study's inclusion of infectious agents has revealed new information about cancers in women - but also about variations compared to men. Researchers hope this will help improve cancer prevention measures.

It was found that in women, the largest number of preventable cancers were caused by infections – a total of 2,7 million cases (29,7 percent). In men, it was behavioral risk factors, such as tobacco smoking – a total of 4,3 million cases (45,4 percent).

A deeper exploration of data on lung cancer, which is one of the most commonly diagnosed cancers in both women and men (alongside breast, colon and prostate cancer), reveals how the influence of MRF factors is similar, but their effect is different.

In both sexes, tobacco, air pollution and occupational exposure were attributed to lung cancer cases in almost equal proportions. But while there were 1.326.453 cases of lung cancer in men, the number was significantly lower in women – 477.869.

Preventable cancers require “targeted interventions”

Given that the Global Cancer Observatory predicts that the number of cancer cases will increase by more than 50 percent by 2045, the researchers write in their paper that "this growing burden highlights the urgent need for effective prevention strategies," but also that "many cases can be prevented with targeted interventions."

The study makes little mention of the 62,2 percent of cancer cases that could not be attributed to preventable MRFs.

However, Suzet Delaloz, a specialist in breast cancer and cancer prevention at the French research hospital "Gistav Rusi", told DW that this new study represents "a key contribution to shaping a global, data-based approach to cancer prevention."

Delalogèze, who was not involved in the study, explains that while the study highlighted that cancer cases are “largely shaped by geographic, social, economic and cultural determinants, […] actions at the individual level remain essential to mitigate their profound effects.”

As for the study authors themselves, they emphasize that future cancer prevention measures will increasingly need to address the different effects on women and men, as well as adapt, or respond, to different social and economic contexts in different countries and regions.