It’s been widely reported that breast cancer rates are up in Americans under the age of 50. New research shows that’s far from the only type of cancer with such increases.

The National Institutes of Health recently analyzed cancer statistics based on six different age groups: 15-29, 30-39, 40-49, 50-59, 60-69, and 70-79. The researchers looked specifically at the incidence rates of 33 types of cancer between 2010 and 2019, along with cancer death rates between 2010 and 2022.

According to the findings, published in the journal Cancer Discovery, 14 types of cancer had increased rates in at least one of the under 50 age groups, including female breast, colorectal, kidney, testicular, uterine, pancreatic, and three types of lymphoma. All of these also saw increases in at least one of the older groups, though. Five, however, only went up in the younger cohort: cancers of the cervix, stomach, and bones and joints, as well as melanoma and myeloma.

There was some good news, though. Nineteen types of cancer had decreased rates in the under 50s, including lung and prostate. Additionally, most of the cancers with increased incidence did not have increased mortality rates in younger people, but uterine and colorectal did.

To put case rates to percentage increases, researchers also estimated how many more under 50s were diagnosed with cancer in 2019, compared with expected numbers based on 2010 rates. Female breast at 4,800 cases, colorectal at 2,100 cases, kidney at 1,800 cases, and uterine at 1,200 cases were responsible for more than 80% of the increases. There were also about 500 more pancreatic cancer cases.

What’s behind the increase? The team has a few theories.

Dr. Meredith Shiels, lead researcher from NIH’s National Cancer Institute, says, “This study provides a starting point for understanding which cancers are increasing among individuals under age 50. 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 researchers say in order to better understand these trends, more research is needed on early-onset cancer incidence based on demographics, as well as location both in the U.S. and globally. Specific risk factors should also be studied.

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