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Why gastrointestinal cancer is increasing among young adults

cancer treatment

Gastrointestinal cancers — including colorectal, pancreatic, and bile duct — are being diagnosed more often and at a faster rate in younger adults than they were a decade ago, according to a new report.

The study, published in JAMA Network Open, compared cancer incidence rates in people younger than 50 between 2010 and 2019. Over a decade, the rates of early-onset cancer increased by 0.74%.

During that time, early-onset gastrointestinal cancers had the greatest increase in new cases, rising from 6,431 cases in 2010 to 7,383 cases in 2019 — a 14.8% increase. This supports other recent research on the rise of gastrointestinal cancers in younger populations.

“Many in the medical community have known about the increase in GI and specifically colorectal cancer in younger patients for some time,” said Jake Stein, MD, MPH, assistant professor of oncology at the University of North Carolina School of Medicine. “But this study gives clear data to show those trends are real.”

It’s not just gastrointestinal cancers on the rise; the study also identified increases in breast, urinary system, and reproductive system cancers.

Understanding the data

The study used data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program, covering about 26% of Americans. Researchers examined reported cases of cancer in people under 50 and matched them with individuals’ self-reported gender and race.

In total, 562,145 patients were diagnosed with early-onset cancer between 2010 and 2019. The majority were women between the ages of 40 and 49. The study cataloged 56,051 new early-onset cancer cases in 2010, and 56,468 in 2019, marking a 0.74% increase over the decade.

Gastrointestinal cancers, particularly colon, rectal, stomach, and pancreatic cancer, were the most commonly reported. However, appendix, intrahepatic bile duct, and pancreas cancers grew the fastest.

Demographic disparities

Women saw a 4.35% increase in early-onset cancer cases over the 2010s, while men saw a 4.91% decrease. Racial disparities were also evident: Asian or Pacific Islander and Hispanic individuals saw increases of 32.3% and 27.6%, respectively. Indigenous Americans saw a 2.3% increase, while rates decreased for both White and Black Americans.

People aged 30 to 39 saw the greatest increase in early-onset cancer rates, while rates remained stagnant for those aged 40 to 49 and declined for those over 50.

Possible causes and prevention

The reasons for the increase remain poorly understood. Risk factors such as obesity, diabetes, and lack of physical exercise may play a role. Diet, particularly high consumption of alcohol, processed foods, and red meat, could also be a factor.

“The pandemic exacerbated many social determinants to health,” Stein explained. “Many people skipped out on preventive health care, including mammograms and colonoscopies, during the pandemic. We have seen an increase in later-stage cancers as well, which is a distinct and troubling trend.”

To mitigate risk, individuals should maintain a healthy weight, avoid smoking, and protect their skin from the sun. While these strategies aren’t foolproof, having awareness of risk factors is the first step to catching cancer early.

“Eating healthier, drinking less alcohol, losing weight, staying active — these are habits that can keep us healthy even in our 30s,” Stein said.