Almost four in ten cancer cases in the Netherlands are linked to lifestyle and other preventable factors, according to a major international study published this week. Smoking is by far the leading cause, followed by unprotected sun exposure, high body mass index and alcohol consumption.
The research, published in Nature Medicine by the International Agency for Research on Cancer (IARC), part of the World Health Organization, analysed data on 36 types of cancer across 185 countries. It examined the impact of 30 modifiable risk factors, including tobacco use, alcohol consumption, infections such as HPV and hepatitis, air pollution, physical inactivity and occupational exposures.
In the Netherlands, smoking accounted for more than 16% of cancer cases in women and over 23% in men. Globally, tobacco was responsible for 15% of all new cancer cases in 2022, followed by infections at 10% and alcohol consumption at 3%.
7.1 million preventable cases worldwide
Of the 18.7 million new cancer cases diagnosed globally in 2022, the study estimates that 7.1 million, or 37.8%, were attributable to preventable causes. Among men, 45% of cancers were linked to modifiable factors, compared to 30% among women.
Three cancer types alone, lung, stomach and cervical, accounted for nearly half of all preventable cases. Lung cancer is primarily linked to smoking and air pollution, stomach cancer to the bacterial infection H. pylori, and cervical cancer overwhelmingly to HPV.
"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."
Photo Credits: National Cancer Institute
Dutch smoking rates still high
While smoking rates in the Netherlands have gradually declined, from 25.7% in 2014 to around 20% today, the country still has work to do. Approximately one in five Dutch adults still smokes, with prevalence significantly higher among those with lower incomes and education levels.
The Dutch National Cancer Control Programme has set an ambitious target: reduce smoking prevalence to no more than 5% of adults and 0% of minors by 2032. A separate study by the Netherlands Comprehensive Cancer Organisation (IKNL) estimated that achieving these targets could prevent more than 120,000 cancer cases between 2024 and 2045, including approximately 89,000 cases of lung cancer, 16,000 of bladder cancer and 15,000 of oesophageal cancer.
Lung cancer remains among the most common cancer types in the Netherlands, including among women. This is partly a delayed effect of increased smoking rates among Dutch women in the 1960s and 1970s. Tobacco was responsible for an estimated 81.7% of all lung cancer deaths in the Netherlands in 2021.
Model-based estimates
Lead researcher Hanna Fink explained that the findings are model-based estimates rather than counts of specific patients. "For example, insufficient physical activity is a risk factor for colorectal, breast and uterine cancer. Around 2012, 13.7% of Dutch adults were not active enough. Using models, we estimate that 1,091 cases in 2022 could have been avoided if everyone had met activity recommendations."
Bart Kiemeney, professor of cancer epidemiology at Radboudumc, called the research extensive and carefully conducted, though he noted inherent uncertainties in the underlying data. "These results are not natural constants, but they align with previous studies. In Dutch and US research using other methods, roughly two-thirds of cancer cases are due to chance or genetics, and one-third are linked to preventable factors."
The study used exposure data from around 2012 to account for the time lag between exposure to risk factors and the development of cancer.
