Gastrointestinal (GI) cancers, which affect the stomach, colon, pancreas, and other digestive organs, are rising at an alarming rate in younger adults, especially those under 50. Experts are calling it one of the most concerning trends in cancer today.
A new medical review published in the journal JAMA this week has revealed that GI cancers are now the fastest-growing group of cancers among adults under 50 in the US. The review examined over 115 research papers and major global and American cancer databases, making it one of the most detailed reports yet on this topic.
While the exact reason behind the spike still remains unclear, doctors believe a mix of modern lifestyle factors, genetics, and possibly even gut health could be the reason behind the rise.
Sharp rise in GI cancers among the young
Colorectal cancer (which includes colon and rectal cancer) is leading this rise. According to the American Cancer Society, diagnoses of colorectal cancer in Americans under 50 have been increasing by about 2 per cent every year since 2011. Globally, there were around 185,000 early-onset colorectal cancer cases reported in 2022, 21,000 of those in the US alone.
“This really points to the importance of improving screening and early detection,” said Dr. Kimmie Ng, co-author of the review and director of the Young-Onset Colorectal Cancer Center at Dana-Farber Cancer Institute.
Until recently, colon cancer was mostly seen in older adults. But now, even people in their 20s, 30s, and 40s are being diagnosed. One well-known example is actor Chadwick Boseman, who died from colon cancer in 2020 at just 43.
The new review also found rising rates of pancreatic, stomach, and oesophageal cancers in young adults. These cancers are especially dangerous because they’re often caught late, when they’re harder to treat.
What could be causing this?
Doctors still don’t fully understand why GI cancers are increasing in younger people, but they do have some theories.
“The leading theory is that there is no single leading theory,” said Dr. Scott Kopetz, a GI cancer expert from MD Anderson Cancer Center.
Many researchers believe lifestyle choices play a major role. Obesity, lack of exercise, unhealthy diets, smoking, and alcohol use are all known risk factors. One study included in the JAMA review found that women who drank a lot of sugary beverages during their teenage years had a higher risk of developing early-onset colon cancer.
“It’s really what people were doing or exposed to when they were infants, children, or teens that’s probably contributing to their cancer risk as young adults,” said Dr. Ng.
The role of gut health and microbiome
Some experts also suspect that changes in our gut microbiome—the bacteria and organisms that live in our digestive tract—might be connected. The modern diet, increased use of antibiotics, exposure to chemicals, and even microplastics may be affecting gut health in ways scientists are only beginning to understand.
“We don’t yet know what a healthy microbiome truly looks like,” said Dr. John Marshall, chief medical consultant at the Colorectal Cancer Alliance. “But something has clearly changed over the past few decades.”
Genetics may also play a role
The review found that 15 per cent to 30 per cent of young adults with GI cancer carry genetic mutations that may have made them more likely to get cancer early. Because of this, Dr. Ng recommends that anyone under 50 who is diagnosed with a GI cancer should be tested for hereditary conditions.
Still, the majority of young adults who develop these cancers don’t have a strong family history, which suggests that environmental or lifestyle factors are also heavily involved.
Screening is the key
Doctors stress that early detection can save lives. In fact, improved screening is one reason survival rates have gone up in recent years.
For colorectal cancer, screening is recommended starting at age 45 for people at average risk. This usually involves a colonoscopy or a stool test. But for pancreatic, stomach, and oesophageal cancers, there are currently no routine screenings in the US, which makes early detection much harder.
“This is why we need new tools to screen people for these other cancers,” Dr. Ng said.
Younger patients often have worse outcomes
Surprisingly, the review found that younger patients with GI cancers tend to have worse outcomes, even though they often receive more aggressive treatments, including surgery, radiation, and chemotherapy.
One reason may be that doctors don’t usually suspect cancer in younger patients. Common symptoms like stomach pain, constipation, reflux, or fatigue are often brushed off or misdiagnosed.
“My feeling is that we’re catching these cancers later because no one thinks of GI cancers when a young person complains of vague symptoms,” said Dr. Howard Hochster, director of gastrointestinal oncology at Rutgers Cancer Institute.
Even when these cancers are caught early, younger people still seem to have a lower survival rate.
“That makes us wonder—are the cancers that appear in younger people more aggressive or somehow different biologically?” Dr. Ng said.
What you can do
While researchers continue to search for clearer answers, there are a few things young adults can do to reduce their risk:
- Follow a healthy diet rich in fruits, vegetables, and fibre
- Limit processed foods, red meat, alcohol, and sugary drinks
- Stay physically active
- Avoid smoking
- Get screened for colon cancer starting at age 45, or earlier if you have risk factors
- Talk to your doctor about any persistent digestive symptoms, no matter your age
“This isn’t something you can ignore anymore,” said Dr. Ng. “GI cancers are no longer just a concern for older adults. We need to pay attention, ask questions, and take steps to protect ourselves.”