The surge in early-onset cancer is mostly present in industrialized countries, though researchers have no explanation for it.

Data from the University of Washington School of Medicine show that between 1990 and 2019, cancer rates in 25- to 29-year-olds in G20 nations rose by 22 percent, faster than any other age group. Young people in upper-middle-income countries saw the fastest cancer growth rates overall—over 50 percent since 1990.