Gen X, millennials more likely to develop 17 types of cancer than older generations, study finds

The risk of developing many types of cancer — including breast, pancreatic, ovarian and colorectal — has become higher among millennials and generation X than among older generations, a new study from American Cancer Society researchers suggests.

An analysis of data from more than 23 million patients diagnosed with 34 common types of cancer revealed that the rates of 17 different kinds of cancer were as much as three times higher among the younger generation compared to baby boomers, according to the report published in The Lancet Public Health.

Other studies have linked many of those cancers to obesity, which has risen sharply over the past several decades, Dr. William Dahut, chief scientific officer at the ACS, tells TODAY.com. And because cancers take a long time to develop, it’s likely that environmental and lifestyle factors, such as carrying excess pounds, came into play when these individuals were teenagers and children, Dahut says, adding that the increased rates may “undo all of the progress we’ve made in treating cancer.”

RELATED: Cancer is rising in young people. This little-known syndrome may be one reason why

Dahut suspects that other factors, including lack of exercise and the consumption of unhealthy foods, such as sugary drinks, may have played a role in the rising rates of these cancers.

To explore whether cancer was on the rise in gen X and millennials compared to baby boomers, the researchers analyzed data from North American cancer registries. They found age-adjusted rates of certain cancers, such as those in the small intestine, the kidneys and the pancreas, were two to three times higher in the younger generation than in boomers.

They found smaller, but still substantial, increases in other cancers in the younger generation compared to the older one: an increase of 12% for ovarian cancer and an increase of 169% for uterine cancer. Nine of the 17 types of cancer had previously been declining in older generations.

Dahut hopes that the study will spark more awareness among the younger generation. “It’s a reminder that young folks can get cancer,” he says. “If you have abnormal vaginal bleeding, persistent abdominal pain, weight loss or swollen lymph nodes, you shouldn’t take a doctor’s word that you are too young to get cancer as the truth. Go find another doctor. Be an advocate for yourself.”

People should also talk to their families to learn whether any relatives had cancer, Dahut says.

The new findings are “alarming and surprising,” adds Jiyoung Ahn, Ph.D., associate director of population sciences at the NYU Langone Perlmutter Cancer Center in New York City.

There’s been discussion among cancer specialists about the possibility that cancer rates were rising among people under age 50, Ahn tells TODAY.com. “Over the last couple of years, specialists noticed that colorectal cancer was rapidly increasing in younger people. This study gives concrete evidence that the increasing rates of early onset cancers is real.”

No one knows exactly what the cause is, but “I think it’s got to be environmental factors,” Ahn says. “Obesity rates have been increasing for decades, and it’s a known risk factor for multiple cancers.”

Changes in the microbiome associated with antibiotic use may also play a role, Ahn says. “Antibiotic use in this country has changed since the 50s,” she explains.

The new findings are “stunning,” Dr. Deborah Doroshow, a cancer specialist and an associate professor of medicine at the Icahn School of Medicine at Mount Sinai in New York City, tells TODAY.com “This is showing that numerous types of cancer are increasing in younger cohorts, even cancer types that were getting less common in older cohorts.”

“One thing that’s really worrisome is that several of these cancer types are much harder to treat,” Doroshow adds. Also worrisome, per Doroshow, is that “there is no way to screen for some of these cancers, such as uterine and pancreatic cancer. If we don’t have a screening test, patients are more likely to be further along when we find their cancer.”

The study is telling us that we need to make lifestyle changes, Dr. Alfred Neugut, a professor of medicine and epidemiology at Columbia University’s Mailman School of Public Health, streses.

And those changes should start happening early in life, Neugut said. “It’s telling us we have to focus on teenagers, people who are in high school or college.

“It’s telling us that we need to put recess back in the curriculum for younger kids. These days kids are sitting around playing video games and not exercising. We can’t wait until people are middle-aged.”

This article was originally published on TODAY.com