Overview
- The Annals of Internal Medicine analysis examined incidence trends for 13 cancers in adults aged 20–49 and 50+ across 42 countries using IARC’s GLOBOCAN data from 2003 to 2017.
- Incidence rose in younger adults for leukemia, thyroid, breast, colorectal, kidney, and endometrial cancers in at least three quarters of countries, and all but colorectal also increased in older adults.
- Colorectal cancer climbed in younger adults in 88% of countries versus 55% for older adults, with faster increases in the young in 69% of countries, which authors suggest may reflect widespread screening in older populations.
- Cancers with parallel rises in both age groups were obesity-related, with endometrial and kidney cancers showing the strongest associations, while liver, oral, esophageal, and stomach cancer rates declined among younger adults in many countries.
- Study leaders and commentators call for age-inclusive research, prevention and screening policies, noting limitations such as data ending in 2017 and unresolved questions about the roles of obesity, detection, and potential novel carcinogens.