More than one-third of cancer cases are preventable, massive study finds

Nearly 40% of new cancer cases worldwide are potentially preventable, according to one of the first investigations¹ of its kind, which analysed dozens of cancer types in almost 200 countries.

The study found that in 2022, roughly seven million cancer diagnoses were linked to modifiable risk factors — those that can be changed, controlled or managed to reduce the likelihood of developing the disease. Overall, tobacco smoking was the leading contributor to worldwide cancer cases, followed by infections and drinking alcohol. The findings suggest that avoiding such risk factors is “one of the most powerful ways that we can potentially reduce the future cancer burden”, says study co-author Hanna Fink, a cancer epidemiologist at the World Health Organization’s International Agency for Research on Cancer in Lyon, France.

The study was published today in Nature Medicine.

Troubling trend

Cancer continues to be a leading cause of illness and death worldwide, with cases expected to rise over the next decades if current trends continue. Previous studies² have estimated that around 44% of global cancer deaths can be attributed to avoidable or controllable causes. Estimates of preventability have mainly focused on the number of deaths rather than cases and have mostly investigated a single risk factor, says Fink.

To address this gap, Fink and her colleagues examined global case data from 2022 for 36 different cancers across 185 countries. The study included 30 modifiable risk factors that are well-established causes of cancer — such as tobacco smoking, alcohol consumption and infections.

The researchers combined this information with data from 2012 that captured people’s exposure to each risk factor. Fink and her colleagues then estimated the proportion of cases that were directly linked to each risk factor.

Drinking and smoking

In 2022, there were a total of 18.7 million new cancer cases worldwide. Roughly 38% — or 7.1 million — of these cases could be attributed to avoidable causes. Globally, tobacco smoking was the leading contributor, accounting for around 15% of preventable cases. This was followed by infections (10%) and drinking alcohol (3%). Lung, stomach and cervical cancers made up nearly half of all preventable cancer cases.