Cancer is typically a disease of older people. In the United States, about 88 percent of cancer cases are among those over 50. Of the roughly 2 million people in the country diagnosed with cancer annually, less than 100,000 people are between 15 and 39. But since the 1990s, rates of early onset cancer — diagnosed before the age of 50 — have been rapidly increasing globally.

One major study found that the global incidence of early onset cancer increased by 79 percent between 1990 and 2019, while deaths rose by 28 percent. Another study, published in the Lancet Public Health last year, found that the incidence of 17 cancers in the United States has risen steadily among young men and women, particularly among those born after 1990. The steepest rises were seen in cancers of the small intestine and pancreas, says study coauthor Hyuna Sung, a cancer epidemiologist at the American Cancer Society in Atlanta.