Gastrointestinal cancers are on the rise among young Americans, and no one knows for sure why
Younger people appear to be more susceptible to digestive system cancers, but researchers aren't entirely sure why this surge is occurring.
In a new study published this week, scientists led by the Dana-Farber Cancer Institute found that rates of early-onset digestive system cancers—those that affect people under 50—are rising faster than other types of cancer. In particular, colorectal cancer cases have increased significantly, while rates of other forms of the disease, such as stomach cancer, are also on the rise. While the study doesn't reach definitive conclusions about the reason for the increased incidence, researchers point to risk factors such as obesity, poor nutrition, and lack of exercise.
"Colorectal cancer is the most common early-onset gastrointestinal cancer worldwide, accounting for more than half of all cases, but it's not the only gastrointestinal cancer on the rise among young people," Kimi Ng, senior author of the study and director of the Early Colorectal Cancer Center at Dana-Farber, said in a statement. "Unfortunately, pancreatic, stomach, and esophageal cancers are also on the rise among young people."
Ng and her colleagues reviewed data collected from 100 studies, as well as previous scientific reviews and cancer guidelines. They also analyzed three publicly available statistical databases on cancer.
Researchers found that since 2010, the incidence of early-onset gastrointestinal cancers has increased globally, particularly in high-income countries like the United States. Between 2010 and 2019, the age-adjusted incidence rate in the United States rose by 2.16% per year, the largest increase for any early-onset cancer during that period. In 2022, at least 25,000 Americans under the age of 50 developed gastrointestinal cancer. The team's findings were published Thursday in JAMA.
A separate previous review of data—conducted by some of the same authors—over a similar period found that the incidence of gastrointestinal cancer tripled in young adults aged 15 to 19 and nearly doubled in those aged 20 to 24.
"The rising incidence of early-onset gastrointestinal cancers is alarming and underscores the need for improved prevention strategies and early detection methods," Ng said.
As rates of these cancers have risen, so have some of their associated risk factors, including obesity and prolonged sedentary time. Ultra-processed foods are also becoming more common, especially in Western diets. However, researchers estimate that up to 30% of early-onset gastrointestinal cancers may be linked to genetic mutations. Other scientists have argued that other factors, such as common stomach infections, may also be contributing to the increased cancer rates.
Even though the causes remain unclear, it's clear that more work is needed to help detect these cancers early, before they become untreatable, according to researchers. In 2020, public health experts recommended routine colorectal cancer screening for people aged 45 and older, but researchers noted that a year later, less than 20% of people aged 45 to 49 were screened. Another question remains: Are early gastrointestinal cancers different from those detected later in life? And if so, should they be treated differently?
“We need to think not only about the risk factors for these diseases but also about how we screen, diagnose, and treat young people with these cancers,” Ng said.