Colorectal Cancer Is Now the Leading Cause of Cancer Death Under Age 50

Colorectal cancer has become the leading cause of cancer death for Americans younger than 50, according to a research letter published online Thursday in the Journal of the American Medical Association. Researchers at the American Cancer Society, led by Rebecca Siegel, analyzed U.S. death data from 1990 through 2023. Neither NBC News nor the ASCO Post, which summarized the letter, names a funder for the work.

The analysis used National Cancer Institute data and counted about 1.27 million cancer deaths among people under 50 over the period, ASCO Post reported. Overall cancer mortality in that age group fell 44 percent, from 25.5 deaths per 100,000 people in 1990 to 14.2 per 100,000 in 2023, according to the same summary. The sources reviewed did not give a death rate for colorectal cancer by itself.

Within that overall decline, colorectal cancer went the other way. It ranked fifth among cancer deaths in this age group in 1990 and was first in 2023, NBC News reported. Its death rate has risen about 1 percent a year since 2005, or 1.1 percent a year in the figure ASCO Post cited, and it was the only one of the five most common causes of cancer death in this group to increase. Siegel told NBC News the shift came seven years earlier than a 2030 projection and called it “absolutely an outlier.”

Other cancers moved down the list. Lung cancer fell from first to fourth, with deaths declining nearly 6 percent a year from 2014 to 2023, and leukemia fell from third to fifth, according to NBC News. Breast cancer remained the second-leading cause overall and the leading cause among women, with deaths down 1.4 percent a year over the same stretch.

The research letter reports deaths, not new diagnoses, and does not establish why colorectal deaths are climbing. NBC News said possible contributors under study include rising obesity, less physical activity, changes in the gut microbiome and diets heavy in ultraprocessed foods, and Siegel said other factors are likely involved.

Screening is the main tool doctors point to. The U.S. Preventive Services Task Force recommends that colorectal cancer screening begin at age 45 for people at average risk, and earlier for those at high risk. Siegel noted that half of people diagnosed before age 50 are 45 to 49, which means they are already old enough to be screened, NBC News reported. A 2025 American Cancer Society report found about 20 percent of colorectal cancer diagnoses are now in people 54 or younger, double the 1995 share.

Researchers not involved in the study offered mixed readings. Dr. Andrew Chan of Massachusetts General Brigham told NBC News that the rise in colorectal deaths “really outpace[s]” the declines in other cancer deaths. Dr. Folasade May of UCLA called the findings “a good-news, bad-news story,” a reference to steep drops in deaths from other cancers.

ASCO Post quoted Ahmedin Jemal, the senior author, saying colorectal cancer “can no longer be called an old person’s disease.” Lisa Lacasse of the American Cancer Society Cancer Action Network, the society’s advocacy arm, said progress against other cancers shows the value of prevention and access to screening, and warned that premium increases and program cuts threaten those gains.