Sung and her colleagues used cancer diagnosis and mortality data from two databases –– the North American Association of Central Cancer Registries and the U.S. National Center for Health Statistics –– to analyze cancer trends in people born between 1920 and 1990, who were diagnosed with cancer between 2000 and 2019.
The data included 34 types of cancer, nearly 24 million diagnoses and more than 7 million deaths. To get a better view of how cancer diagnoses and mortality rates changed in groups of people born around the same year — called a birth cohort —the researchers grouped people by birth year in five-year intervals. For example, people born in 1920 through 1924 were all one birth cohort.
Seventeen of the 34 cancers had increasing incidence in younger people. The risk was two to three times higher in people born in 1990 for pancreatic, kidney and small intestine cancers, compared to people born in 1955. Liver cancer diagnoses in women followed the same pattern.
“The most important thing it tells us is there is something that changed for the group of individuals born after this period of time. They have been exposed to some environmental or lifestyle factor that is leading to this shift,” said Dr. Andrea Cercek, a gastrointestinal medical oncologist at the Memorial Sloan Kettering Cancer Center, who was not involved with the research.
After declining for decades, these types of cancers have begun to climb again:
- Colorectal
- Endometrial
- Non-cardia gastric
- Gallbladder
- Ovarian
- Testicular
- Anal
- Estrogen-receptor positive breast cancers
- HIV-linked cancer called Kaposi sarcoma
While the study found that mortality declined or was stable in younger generations for most cancers, mortality rate increased among younger age groups for endometrial, intrahepatic bile duct, gallbladder, colorectal and testicular cancers, as well as liver cancer among women.
Endometrial cancer was the fastest growing for both diagnoses and mortality.
“That was a sobering finding,” said Sung. “Although many cancer rates are rising, we don’t necessarily see this increase in mortality because we are treating them a lot better than before.”
Many of the cancers found to be on the rise are still rare in young people and, while rates have increased, the overall number of cases is comparatively low.
“It is clearly happening. Almost all the oncologists I know of can say they see it,” Brawley said, adding that despite the alarming increases, it’s important to keep in mind that most cancer diagnoses still happen in people older than 50 years.
“In the 1990s, 10% of people diagnosed with colon cancer were under age 50. Now it’s 20%, but we should not forget the 80% that are still over the age of 50,” he said.
Looking at people born within a specific time period can give important clues into why certain types of cancer are rising among younger generations.
“All of these cancers are linked to the obesity epidemic. We know that’s the second-leading cause of cancer right now, behind tobacco use,” said Dr. Otis Brawley, Bloomberg Distinguished Professor of Oncology and Epidemiology Johns Hopkins University, who was not involved with the new study.
About 20% of cancer diagnoses in the U.S. are linked to excess body weight, according to the American Cancer Society. Obesity rates in the nation changed little in the 1960s and 1970s but increased sharply after that. About 13% of adults had obesity in 1980, compared to 34% in 2008, according to data from the Surgeon General.
Among children, obesity rates grew from 5% to 17% in the same period. Today, more than 40% of American adults and about 20% of children and adolescents are obese, the Centers for Disease Control and Prevention reports.
If obesity is a culprit, it’s likely one of several lifestyle and environmental factors that is leading to the rise. Other factors could be more sedentary behavior or something in the food or the water, common medications or chemical exposures or chemical agents, the experts said.
The overuse of antibiotics is another possible link under scrutiny. Antibiotics are known to change the gut microbiome, which has been linked to colorectal cancer. While antibiotics are needed to treat many bacterial infections, they’re often misused and taken for issues that are not bacterial, or that do not require antibiotics.
“The list of things we are potentially investigating is very long,” Cercek said. “Antibiotics are one of the top culprits on the list.”
Researchers still don’t understand what’s behind the rise in certain types of cancers among younger generations. Although obesity and antibiotics are primary suspects, “we can’t rule out other chemical exposures or chemical agents,” Brawley said.
Kaitlin Sullivan
Kaitlin Sullivan is a contributor for NBCNews.com who has worked with NBC News Investigations.She reports on health, science and the environment andis a graduate of theCraig Newmark Graduate School of Journalism at City University of New York.
FAQs
A study led by the American Cancer Society reveals that Generation X and Millennials face a significantly higher risk of developing 17 types of cancer compared to older generations. This trend includes a rise in cancers such as breast, pancreatic, colorectal, and liver cancer.
Do Millennials face higher risk of 17 cancers than older generations? ›
People born between 1981 and 1996 are called Millennials. Researchers found that 17 out of 34 cancer types are on the rise in these two groups when compared to older generations. Cancers of the kidney, pancreas, and small intestine are a few of the cancers becoming more common in younger people.
Are Gen X people at higher risk for cancer? ›
Younger generations have a heightened risk of some cancers, new research found. A study published Wednesday in Lancet Public Health found that Gen X and millennials are more likely to be diagnosed with 17 types of cancer, including nine that had been declining in older adults.
Why do millennials have higher cancer rates? ›
Several factors – including changes in diet, decreased physical activity levels, rising childhood obesity rates and the increased use of more advanced diagnostic tests – are probably behind the rising cancer incidence among younger age groups, said Dr.
What are the 17 cancers on the rise? ›
The cancers on the rise included two types of stomach cancer, small intestine cancer, estrogen receptor (ER) positive breast cancer, ovarian, liver, bile duct and colorectal cancer, uterine and testicular cancer, gall bladder, kidney and pancreatic cancer, and two types of blood cancer: myeloma and leukemia.
What cancers skip a generation? ›
Cancer gene variants cannot skip or miss a generation. If one of your parents has a gene variant, there is a 1 in 2 (50%) chance it has passed to you. You either inherit it or you do not. If you do not inherit the variant, you cannot pass it to your children.
What generation has the highest life expectancy? ›
It is a known fact that lifespan increases with each generation. For baby boomers, the average life expectancy is 70 years, for Gen X its 85, and newer generations like Gen Z and Alpha will likely exceed the 100-year mark.
Why is cancer risk higher with age? ›
But sometimes the damage in a cell builds up, and the cell starts to behave differently. This is when it can grow out of control and develop into a cancer. As we age, there's more time for damage in our cells to build up, making cancer more likely. Further information on what cancer is and how it starts.
Why is Gen X the greatest generation? ›
Generation X is known as the “middle child” generation because of its small size in comparison with the baby boomer and millennial generations. Gen Xers are typically described as resourceful, independent, and good at maintaining work-life balance. They were the first generation to grow up with personal computers.
Are you more Gen X or Millennial? ›
Generation X (circa 1965 to 1980) Millennial Generation (circa 1981 to 1996) Generation Z (circa 1997 to 2012)
With the two-pronged rise of the Western diet and antibiotic use, the gut microbiome has been severely impacted . Although scientists do not fully understand the role of gut bacteria in cancer, the authors write that specific microbes and dietary patterns have now been linked to oral and gastrointestinal tract cancers.
Why do millennials worry so much? ›
In her book, she argued another factor was the disconnect between expectations and reality – young people were told: “You can be anything you want to be”, and then found that reality was not quite so easy. Mackay says Western society's “me” culture encourages anxiety-inducing individualism and materialism.
Why are millennials so healthy? ›
Millennials are more proactive and health conscious than their parents and grandparents. They're more willing to spend money on fitness, healthy food, and self-care. But as health care costs become more and more unpredictable, millennials have learned to do their research beforehand.
Why are cancers on the rise? ›
Genetic clues
The prominence of gastrointestinal cancers and the coincidence with dietary changes in many countries point to the rising rates of obesity and diets rich in processed foods as likely culprits in contributing to rising case rates.
What are 90% of all cancers? ›
Carcinoma refers to a malignant neoplasm of epithelial origin, also referred to as cancer of the internal or external lining of the body. Carcinomas account for 80 to 90 percent of all cancer cases.
Which cancers are increasing the most? ›
This trend is largely affected by the aging and growth of the population and by a rise in diagnoses of 6 of the 10 most common cancers—breast, prostate, endometrial, pancreatic, kidney, and melanoma. (The other 4 top 10 cancers are lung, colon and rectum, bladder, and non-Hodgkin lymphoma.)
Which age group is most affected by childhood cancers? ›
The most common types of cancer diagnosed in children ages 0 to 14 years are leukemias, brain and other central nervous system (CNS) tumors, and lymphomas. NCI's Cancer Stat Facts include detailed cancer rate and trend information for certain types of childhood cancer.
Do Gen Xers have higher reported stress levels than Millennials? ›
More recent information from 2021 shows this trend is still in progress, as 22% of Gen Xers confess to struggling with stress daily, compared to 17% for Millennials, 14% for Gen Zs, and 8% for Baby Boomers.
What cancers are common in younger people? ›
In 15 to 19 year olds: thyroid cancer, Hodgkin lymphoma, brain and central nervous system tumors, and non-Hodgkin lymphoma are the most common cancer types. In 20 to 29 year olds: thyroid cancer, testicular cancer, melanoma, and Hodgkin lymphoma are the most common cancer types.
Why are cancers more likely to develop as a person ages? ›
Often our body repairs the damage, or damaged cells self-destruct. But sometimes the damage in a cell builds up, and the cell starts to behave differently. This is when it can grow out of control and develop into a cancer. As we age, there's more time for damage in our cells to build up, making cancer more likely.
