The Connection Between Accelerated Aging in New Generations and Cancer – Men’s Health

July 8, 2026

Yasu & Junko / Trunk Archive

Doctors Discover What’s Behind the Disturbing Rise of Cancer Cases in Millennials and Gen Z

Cancer keeps striking younger and younger. We now know why.

By Sarah Elizabeth Richards, Published: Jul 07, 2026 4:07 PM EDT

WHEN ANDREW CHAN, MD, became a gastroenterologist two decades ago, he began noticing a gradual shift in the patients calling for appointments. These weren’t the usual people over 65. Instead, they were young adults who, at first glance, check the boxes for “healthy.” Yet each had been diagnosed with colorectal cancer.

Most weren’t obese. Some were marathoners. Some were vegetarians. Some didn’t even take a sip of alcohol. Since Dr. Chan specializes in high-risk cancer genetics, he also checked to see if there was a family history of disease. Negative.

Dr. Chan’s situation is not an outlier. In fact, it’s becoming more of the norm. According to the 2026 report by the American Cancer Society, the overall rate of colorectal cancer has gone down since the mid-1980s. But if you look at it by age, the rate has increased by 2.9 percent each year in people under 50. Plus, these cancers tend to be more aggressive than those diagnosed at an older age.

“Early onset” patients used to make up less than 10 percent of Dr. Chan’s caseload. Today it’s more than double—a trend he calls “truly stunning” because they’re his age or even 20 years younger. (Dr. Chan, professor of medicine at Harvard Medical School, is in his 50s.)

It’s become one of the decade’s most disturbing medical mysteries: Why are more younger adults getting diagnosed with cancers historically linked to old age? There’s a lot of opinions and not enough answers—until now.

Microplastics, Alcohol, Deli Meat—What’s the Cause?

THERE ARE A lot of trails to chase: Did we eat too many processed foods as kids and mess up our microbiomes? Ingest too many microplastics or absorb too many “forever chemicals”? Was it too many years of binge drinking or burning the midnight oil? Or something else entirely?

These questions are what prompted Dr. Chan to step up to be a leader of Team Prospect, a $25 million project funded by the National Cancer Institute along with research groups in the UK, France, Italy and India. The initiative enlists epidemiologists, clinicians, chemists, computational scientists and microbiome experts to investigate all these factors.

Already, Chan’s co-leader, cancer epidemiologist Yin Cao, is creating buzz with work she published in Nature Medicine. Her team at Washington University School of Medicine in St. Louis found evidence that younger people with cancer were somehow aging faster than their peers. They crunched the so-called biological age of over 150,000 people’s blood samples in the U.K. Biobank database.

By looking at nine blood biomarkers, including creatinine, C-reactive protein, glucose and white blood cell count, they calculated that people who were born after 1965 had a 23 percent higher likelihood of accelerated aging than those born between 1950 and 1954.

The evidence that their bodies were getting old faster was linked with the dramatic increase in lung, gastrointestinal, and uterine cancers. Her team’s research has teed up the urgent question: If we could hold back abnormal cellular aging, could we hold back cancer, too?

Cancer has traditionally been seen as a disease of aging. That’s because as we add years, our bodies experience more oxidative stress and DNA damage, which can alter cells and lead to the growth of tumors. Also with age, the body gets less efficient at clearing out old “senescent” cells that can be inflammatory and fuel those tumors. Ultimately, our immune system’s ability to fight those tumors weakens.

Can Aging Clocks Help Us?

THIS NEWS OF cancer in rapidly aging younger bodies comes at a time when aging science is exploding. That’s a good thing, since aging starts earlier than you think: Research by Vadim Gladyshev, PhD, professor of medicine at Harvard Medical School who studies aging clocks, lifespan control and age reversal, suggests that the aging process starts after our third week in the womb. From there, people will naturally age at different rates throughout their lifetimes. While we still don’t fully understand why, we’ve found ways to measure it.

In 2013, geneticist Steve Horvath, PhD, invented the breakthrough that made this conversation even possible: the epigenetic clock. While at UCLA, he published a landmark paper explaining that the so-called “Horvath clock” could estimate someone’s age by using DNA methylation from any tissue and cell type in the human body. (Methylation refers to chemical changes that happen to DNA and are influenced by genetics, lifestyle and environment; there are 28 million locations in the human body where this can happen, and a quarter change with age.) His clock looks at several hundred of them to come up with someone’s biological age estimate.

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