Cancer rates among people under 50 have increased for several cancer types in England, the United States and the Netherlands over the past 20 years. Most cancers still occur in older people, but the rise in early-onset cases challenges the long-standing view that cancer is primarily linked to old age.
In England, women under 50 saw increases in breast, bowel, uterine, kidney, liver, pancreatic and stomach cancers. The precise timing of the changes—whether they began in childhood, before birth or during adulthood—is difficult to establish, and patterns varied slightly across the three countries.
Lung cancer was an exception among younger people, with progress largely linked to anti-smoking campaigns and greater awareness of smoking’s connection to the disease. The broader causes of the increase in early-onset cancers remain unresolved, with possible influences including lifestyle, genetic susceptibility, infections, environmental factors, ageing and chance.
At the population level, scientists estimate that about 40% of cancers are associated with individually modifiable behaviours such as smoking, alcohol use, diet, physical activity or weight. The remaining 60% reflects other factors, meaning the figures do not support assigning responsibility to individual patients. The evidence identifies a clear rise in several cancers among younger adults, but not yet the specific reason for it.