New reporting on an American Cancer Society study published in the Journal of the American Medical Association described a stark shift in cancer mortality among younger Americans: colorectal cancer had become the leading cause of cancer-related death for people under 50 in the United States.
The finding marked a reversal from the pattern seen in 1990, when colorectal cancer ranked fifth among cancer causes of death in that age group. By 2023, according to the study described by NBC News and USA Today, it had risen to first place. Researchers examined national cancer death data covering more than 1 million people under 50 who died of cancer from 1990 through 2023 across the United States.
The change stands out because overall cancer mortality among people younger than 50 has improved substantially over the same period. NBC News reported that cancer death rates in the group fell by 44% since 1990. Among the five leading causes of cancer death in people under 50, colorectal cancer was the only one for which deaths increased. Its death rate in that age group rose by 1% annually since 2005.
Other major cancer categories moved in the opposite direction. Lung cancer, which had been the leading cancer killer for younger people in 1990, fell to fourth place. Leukemia moved from third to fifth. Breast cancer remained second overall and continued to be the leading cause of cancer death among women, while its death rate declined in recent years.
Rebecca Siegel, senior scientific director of surveillance research at the American Cancer Society and the study’s lead author, characterized colorectal cancer as an outlier in the NBC News account. USA Today quoted senior author Dr. Ahmedin Jemal as saying the findings showed the disease could no longer be treated as only an illness of older adults.
The causes of the rise remain uncertain. Experts cited in the reports said researchers have not identified a single driver. Possible contributors discussed include obesity, lower levels of physical activity, changes in the gut microbiome, diets high in ultraprocessed foods, smoking and alcohol use, excess body weight, high consumption of red and processed meats, and low intake of calcium, whole grains and fiber. The study authors and outside specialists said more research is needed.
The reports also noted that rising diagnoses alone do not fully explain the mortality trend. NBC News cited Dr. Andrew Chan of Massachusetts General Brigham, who was not involved in the study, as saying the pace of increase in colorectal cancer deaths among younger people remains notable even when declines in other cancer deaths are considered.
Public health attention is likely to focus on earlier detection. The U.S. Preventive Services Task Force recommends routine colorectal cancer screening starting at age 45, with earlier screening for people at higher risk. Siegel said young adults should take symptoms seriously, including blood in the stool or abdominal cramping. USA Today also reported that the study authors urged greater awareness among clinicians and the public so that symptoms are recognized sooner and treatment can begin earlier.
