A new study reveals that early-onset cancer—defined as cancer diagnosed in people under the age of 50—is on the rise in the United States. While cancer in this age group was once considered rare, the research paints a very different picture.
Conducted by scientists at the U.S. National Cancer Institute, the study analyzed more than 2 million cancer cases diagnosed between 2010 and 2019 in individuals aged 15 to 49. Of the 33 cancer types reviewed, 14 showed an increase in at least one younger age group. The cancers with the largest increases included breast, colorectal, kidney, and uterine cancers.
Breast cancer accounted for the largest portion of the increase, with approximately 4,800 more cases than predicted based on 2010 rates.
Colorectal cancer followed with 2,000 additional cases,
Kidney cancer with 1,800, and
Uterine cancer with 1,200 additional cases.
Although cancer diagnoses are rising, mortality rates have remained stable for most types among younger adults. However, deaths from colorectal, uterine, and testicular cancers are trending upward.
Researchers have proposed several hypotheses to explain the rise, including the increasing prevalence of obesity, a known risk factor for many of the cancers studied. Obesity is considered a major contributor to the growing cancer burden in this age group.
Additionally, advances in cancer detection and changes in screening guidelines may also be responsible for identifying cancers at earlier stages than in the past.
In the case of breast cancer, scientists suggest that delayed childbearing could be a contributing factor, as pregnancy and breastfeeding are known to lower breast cancer risk.
However, not all cancers are increasing. Some are declining among younger adults:
Lung cancer rates have dropped, likely due to decades of reduced smoking rates.
Prostate cancer incidence has also declined, possibly due to new PSA screening guidelines that recommend against early testing in younger men to avoid overdiagnosis and overtreatment. Experts agree that further research is urgently needed to understand the root causes of early-onset cancer. A major conference on this issue is scheduled to take place later this year.
