January 22, 2026
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A new report from the American Cancer Society shows that colorectal cancer deaths in people under 50 have risen 1.1% per year since 2005, making it the leading cause of cancer death among young adults.
Colorectal cancer has become the leading cause of cancer death among people under 50 in the United States – and the reasons why are still murky, a new report says.
In the early 1990s, colorectal cancer was the fifth most deadly cancer for young adults, but its death rate among young people has been climbing by about 1% per year since 2005, an American Cancer Society study published Thursday found.
At the same time, mortality rates among people under 50 from all other cancers are on the decline.
"It is only colorectal cancer mortality that is increasing, but we really don't know fully what contributes to this rising burden," Dr. Ahmedin Jemal, senior vice president of surveillance, prevention and health services research at the American Cancer Society and senior author of the new study, told CNN.
The researchers examined data from 1.3 million people under 50 who died of cancer between 1990 and 2023. Overall cancer deaths in young adults fell 44% during that time frame, dropping from 25.5 per 100,000 people in 1990 to 14.2 in 2023.
Mortality rates for breast cancer, lung cancer, brain cancer and leukemia all went down — although breast cancer remained the second leading overall cause of cancer death and first cause of cancer deaths in women.
Between 2014 and 2023, the average annual decline for brain cancer was 0.3%. It was 1.4% for breast cancer, 2.3% for leukemia and 5.7% for lung cancer.
Increased prevention and screening have contributed to the overall decline in cancer deaths, the researchers said.
But environmental factors, as well as lifestyle factors including smoking, obesity, lack of exercise and diets high in processed foods, may be contributing to the rise in colorectal cancer rates in people under 50, though the precise causes are still unknown, Yale Medicine says.
"We weren't expecting colorectal cancer to rise to this level so quickly, but now it is clear that this can no longer be called an old person's disease. We must double down on research to pinpoint what is driving this tsunami of cancer in generations born since 1950," Jemal said in a news release. "In the meantime, people 45-49 years make up 50% of diagnoses under 50, so increased screening uptake will prevent disease as well as death."
