Cancer rates are climbing in younger adults and researchers want to know why

Cancer is on the rise in people under 50, but not all types and not all age groups. This comprehensive study uncovers where and why cancer rates are climbing, laying the groundwork for earlier prevention and smarter detection.

Study: Trends in Cancer Incidence and Mortality Rates in Early-Onset and Older-Onset Age Groups in the United States, 2010–2019. Image Credit: CI Photos / Shutterstock

Researchers at the National Institutes of Health (NIH) have completed a comprehensive analysis of cancer statistics for different age groups in the United States and found that from 2010 through 2019, the incidence of 14 cancer types increased among people under age 50. Of these cancer types, nine, including several common cancers, such as breast cancer and colorectal cancer, also increased in some groups of people aged 50 and older. However, the incidence of 19 other cancer types, including lung cancer and prostate cancer, decreased among people under age 50, so the total rate of all cancers diagnosed in both younger and older age groups did not increase, nor did the rate of cancer death.

Among 2,020,829 early-onset cancers diagnosed during this period, 63.2% were in females. The most common early-onset cancers were breast, thyroid, and melanoma in women, and colorectal, testicular, and melanoma in men.

"This study provides a starting point for understanding which cancers are increasing among individuals under age 50," said lead investigator Meredith Shiels, Ph.D., of NIH's National Cancer Institute. "The causes of these increases are likely to be cancer specific, including cancer risk factors becoming more common at younger ages, changes in cancer screening or detection, and updates to clinical diagnosis or coding of cancers."

The study appeared May 8, 2025, in the journal Cancer Discovery.

Researchers examined incidence and mortality trends for 33 cancer types, including incidence data for 2010–2019 from the CDC's United States Cancer Statistics database, including cancer registry data representing the entire U.S. population, and mortality data for 2010–2022 from national death certificate data. Data were analyzed in six age groups: three early-onset (15–29 years, 30–39 years, and 40–49 years) and three older-onset (50–59 years, 60–69 years, and 70–79 years).

The incidence of 14 of the 33 cancer types increased in at least one of the younger age groups. Incidence of nine of these 14 types has also risen in at least one of the older age groups: female breast, colorectal, kidney, testicular, uterine, pancreatic, precursor B-cell non-Hodgkin lymphoma, diffuse large B-cell lymphoma, and mycosis fungoides/Sézary syndrome.

Although death rates did not increase in early-onset age groups for most of these cancers, researchers did observe concerning increases in rates of colorectal and uterine cancer deaths at younger ages. In addition, testicular cancer and cancer of the bones and joints also showed increased mortality in at least one age group.

Only five cancer types increased in incidence among one of the younger age groups but not among any of the older age groups: melanoma, cervical cancer, stomach cancer, plasma cell neoplasms (including myeloma), and cancers of the bones and joints.

To understand the magnitude of the increases in terms of absolute numbers, the researchers estimated how many additional people were diagnosed with early-onset cancers in 2019 compared with expected diagnoses based on rates in 2010. The largest absolute increases were seen for female breast cancer, with about 4,800 additional cases in 2019, followed by colorectal (2,100), kidney (1,800), uterine (1,200), and pancreatic cancers (500). Female breast, colorectal, kidney, and uterine cancers contributed to more than 80% of the additional early-onset cancers in 2019.

These descriptive data may inform future research and cancer control strategies. For example, recent screening guidelines for breast and colorectal cancer have been updated to begin at younger ages, in part due to these increasing trends.

The researchers speculated that risk factors such as increasing obesity may have contributed to some of the increases in early-onset cancer incidence in recent years. Changes in cancer screening guidelines, advances in imaging technologies, and increased surveillance of high-risk individuals may also have led to earlier cancer diagnoses, potentially contributing to rising rates among younger age groups.

To more fully understand and address these increasing rates, the authors said that future studies should examine trends in early-onset cancers across demographics and geography in the U.S. and internationally. Additional research is also needed to understand better the risk factors that are particularly relevant to younger people.

A notable strength of the study was the use of national-level incidence and mortality data, along with estimates of excess cases in 2019, which provided context that has been missing in previous analyses. However, a limitation was the absence of individual-level data on risk factors, screening behaviors, or healthcare access, which limits the ability to identify causes of increasing incidence directly.

The study was funded by the Intramural Research Program of the National Cancer Institute and the Institute of Cancer Research. Shiels declared no conflicts of interest.