Colorectal cancer has gained attention for rising rates among younger adults, but a new study shows it’s not the only gastrointestinal cancer increasingly affecting this age group.
Researchers came to that conclusion after reviewing the scientific literature on newly diagnosed early-onset gastrointestinal (GI) cancers, which they defined as those occurring in people under 50.
“There has been a lot of attention on early-onset colorectal cancer” said Sara Char, MD, the study’s co-first author and a medical oncology fellow at the Dana-Farber Cancer Institute. “But importantly, the rates of pancreatic, esophageal, gastric, biliary, appendiceal, and neuroendocrine cancers are also rising in adults under 50.”
Here’s what to know about the new findings, which were published in the British Journal of Surgery—and why researchers think more younger adults are being diagnosed with these cancers.
Colorectal cancer is the GI cancer most frequently diagnosed in younger people, accounting for about 54% of early-onset cases. In the United States, incidence has increased from 5.9 per 100,000 people in 2000 to 8.4 per 100,000 in 2017.
Awareness of early-onset colorectal cancer is also higher, said Cleveland Clinic gastrointestinal oncologist Suneel D. Kamath, MD, in part because it’s the only GI cancer with routine screening recommended starting at age 45.
But other gastrointestinal cancers are rising in the young right alongside colorectal cancer, the new review found. Appendix cancer, though still exceedingly rare, showed the sharpest increase, with diagnoses jumping by 15% between 2010 and 2019.
Pancreatic cancer, which is particularly deadly, increased across all younger adult age groups, but the most pronounced rise—more than 4%—occurred in people aged 25 to 29.
Esophageal cancer, neuroendocrine tumors, biliary tract cancer, and gastric cancer—the second most frequently diagnosed early-onset GI malignancy—have also become more prevalent among adults under 50.
These cancers don’t appear to affect all groups equally: Women, Black, Hispanic, and Indigenous people are disproportionately impacted. “Significant racial disparities have been reported,” Char told Health.
Survival outcomes can also be worse, she added. For example, Black patients with early-onset colorectal and esophagogastric cancers have lower survival rates and are also less likely to receive guidance-based care for colorectal cancer specifically.
“It is critical that we continue to study the drivers of these disparities, particularly among young individuals,” Char said.
While genetics play a role in 15% to 30% of early-onset GI cancers, experts say shifting lifestyle habits are likely driving the increase.
One likely culprit, Kamath told Health, is the rise in overweight and obesity rates over the past 50 years, including among younger adults. For example, the obesity rate among girls and women aged 15 to 24 nearly doubled between 1990 and 2021.
The Western diet, which tends to be high in red meats and processed foods, is another probable factor, he said. These foods are believed to drive up inflammation in the body, which can interfere with the cells’ ability to repair DNA mutations that may lead to cancer.
Other potential drivers include excessive alcohol intake, frequent consumption of sugar-sweetened beverages, and a sedentary lifestyle. Additionally, “research into the gut microbiome has identified specific species of bacteria associated with colorectal cancer development,” Char said.
Not only are more younger adults being diagnosed with gastrointestinal cancers, but they’re also more likely to be diagnosed at advanced stages, Char said.
This likely comes down to two factors: “Patients and physicians have a low suspicion for cancer in young adults,” she explained. Compounding the issue is that many symptoms of gastrointestinal cancers, such as stomach pain, bloating, indigestion, and acid reflux, can mimic more common gut issues like irritable bowel syndrome, inflammatory bowel disease, or Crohn’s disease.
Because of this, younger adults should be vigilant about speaking to a doctor if they notice changes in their bowel habits or digestive health, Char said. “Many people also feel it is taboo to discuss topics surrounding bowels and digestion. It’s time to change that,” she added.
Continuing to analyze these trends may help improve outcomes, Kamath added. Greater awareness that cancer is increasingly showing up in younger people could hopefully lead to “earlier diagnoses and better outcomes,” he said.
