Cancer death rates are decreasing for younger adults, according to a new study, except for 1 type. Here’s what to know.

A new study from the American Cancer Society is shedding light on cancer mortality rates among young people — and the one type of cancer that is sounding the alarm.

The study, published today in JAMA, analyzed national mortality data from the National Center for Health Statistics. It found that between 1990 and 2023, cancer death rates in the U.S. for people under 50 fell by 44% overall. Death rates from breast cancer and leukemia declined even as cases have risen in recent years, while lung cancer has shown the steepest drop in mortality. Meanwhile, death rates from brain cancer, pancreatic cancer, non-Hodgkin lymphoma and cervical cancer also declined over the past three decades.

Death rates from colorectal cancer, however, have continued to rise in younger adults, becoming the leading cause of cancer death among people under 50 in 2023. The disease was the fifth-leading cause of death from cancer in the early 1990s.

Nikita Wagle, co-author of the study and the principal scientist of surveillance research at the American Cancer Society, told Yahoo News in an email that researchers have been tracking colorectal cancer (CRC) mortality trends specifically because cases have increased among people born since 1950. “While there has also been the suggestion by some in the scientific literature recently that the rise in CRC incidence is mostly because of increased diagnostic scrutiny through imaging and incidental detection, the steady increase in the number of deaths since 1990 and in the death rate since 2005 contradicts that hypothesis,” she said.

Timothy Rebbeck, professor of cancer prevention at the Dana-Farber Cancer Institute, who did not work on the study, told Yahoo News over the phone that the data presented here shows colorectal cancer in young people remains a “critically important problem.”

While the exact cause of the rise in colorectal cancer cases and deaths is not known, Rebbeck pointed to dietary changes that include more processed foods, more environmental and chemical exposures and an increase in obesity rates as potential theories.

What can we do to prevent colorectal cancer? 

Colonoscopies, which use a camera to examine the large intestine, can help detect colon cancer. During a colonoscopy, a doctor can also remove cancerous or precancerous polyps, meaning that the test can both find and prevent what can be a deadly disease.

The American Cancer Society currently recommends people start getting regular colonoscopies every 10 years beginning at age 45. Those with a family history of this type of cancer, or who have symptoms such as rectal bleeding or abdominal pain, can be screened earlier or more often.

But while it may seem like getting colonoscopies early and more often is a solution for preventing deaths from colorectal cancer, Rebbeck says it’s not ideal because, despite rising rates, colorectal cancer in young people is still rare. “A lot of colonoscopies are not going to detect a lot more cancers,” he explained, noting the cost, inconvenience and potential risks of the procedure that come with the screening. “So one of the things we’re trying to figure out is, are there risk factors? Are there people who are at particularly high risk for early-onset cancer that should have colonoscopies earlier?”

Wagle said that “we must double down on research that can pinpoint us to what is driving early-onset colorectal cancer.” But until more research pinpoints what’s causing the rise in colon cancer cases and deaths, it is important to stay on top of screenings for those in the appropriate age window. “Screening uptake among those aged 45 to 49 years, who account for 50% of diagnoses, can prevent disease and death,” she said.