Several cancer types are becoming more common in people under 50, according to a report by the World Cancer Research Fund that examined two decades of data from England, the United States and the Netherlands.
The report covered 12 cancer types, and Prof Devi Sridhar, chair of global public health at the University of Edinburgh, wrote in a Guardian opinion column that while results differed slightly between the three countries, the broader patterns were consistent. Cancers rising in younger age groups are commonly described as “early onset cancer”.
Among women under 50 in England, incidence increased for breast, bowel, uterine, kidney, liver, pancreatic and stomach cancers. Among men of the same age in England, increases were recorded for bowel, kidney, liver, pancreatic and prostate cancers.
Cancer has long been treated as a disease of old age, and most cancers still occur in elderly people. Sridhar noted that global health experts have long described each generation as living longer and healthier lives than the one before, citing gains in life expectancy, a sharp fall in child mortality and the near elimination of many vaccine-preventable diseases. Since the turn of the century, she said, that progress has stalled, and in some cases several health metrics have gone backwards.
Sridhar said the rise in younger people cannot be put down solely to better diagnostic tools or more testing. Those factors explain part of the increase, she wrote, but not all of it. The data indicates that younger generations are developing some cancers at a higher rate than previous generations did at the same age — in effect, people today face a greater chance of cancer at a younger age than their parents did.
Search for a cause
Scientists are trying to establish what changed between generations, concentrating on exposures during childhood or adolescence in the 1990s that would not have occurred in the 1950s.
Among the possible explanations Sridhar sets out is a substantial change in diet over the past 50 years, including the growth of ultra-processed food, fast food and sugary drinks, alongside a more sedentary population. Both shifts are linked to rising levels of excess weight and obesity, she wrote.
Body fat, particularly around the vital organs and the waist, is a risk factor for chronic inflammation, insulin resistance and metabolic dysfunction, all of which are linked to higher cancer incidence. Globally, obesity rates have more than doubled among adults and quadrupled among adolescents since 1990, and data collected in 2024 found that about 66% of adults in England were either overweight or living with obesity.
Diet, physical activity and excess body weight do not fully account for the rise of certain cancers in young people, such as breast cancer, according to the column. Studies have shown that among women before menopause, a higher BMI is linked to a slightly lower risk of cancer — a contrast with older women, for whom a higher BMI significantly increases the risk of developing breast cancer.
Researchers are also looking at the health impact of sustained exposure to environmental toxins such as air and water pollution, chemicals and plastics, which have become widespread and almost impossible to avoid over the past 50 years.
Pinning the global increase on a single toxin has proved scientifically difficult, Sridhar wrote. Cancer can develop long after exposure to a toxic chemical, and people encounter a range of chemicals and pollutants over their lifetimes, making it hard to say which one is responsible or whether exposure occurred in childhood, in utero or in adulthood.
One area where progress has been made among young people is lung cancer, largely driven by anti-smoking campaigns and widespread awareness of the links between smoking and lung cancer, she noted.
No blame for patients
Sridhar warned against attaching blame to patients. One of the first human impulses after a diagnosis is to ask what caused it, and then what the patient themselves did, she wrote, and that is not helpful.
Scientists estimate that only 40% of cancers at a population level are due to an “individually modifiable” behaviour such as smoking, alcohol consumption, diet, physical activity or weight. The remaining 60% is a mix of ageing, genetic susceptibility, infection, possible environmental factors and sometimes just bad luck.
Research and investment into the subject continue, and the factors driving the rise in cancer among younger people will eventually be learned. For now, Sridhar wrote, that mystery is still to be uncovered.
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