Researchers have identified a focal point for the forces they suspect of driving up cancer cases in young people: the gut. They are searching people’s bodies and childhood histories for culprits.
Rates of gastrointestinal cancers among people under 50 are increasing across the globe. In the U.S., colorectal cancer is the leading cause of cancer death in men under 50 and second for women behind breast cancer. Each generation born since the 1950s has had higher risk than the one before.
“Everything you can think of that has been introduced in our society since really the 1960s, the post-World War II era, is a potential culprit,” said Dr. Marios Giannakis, a gastrointestinal oncologist at the Dana-Farber Cancer Institute in Boston.
Robert F. Kennedy Jr., President-elect Donald Trump’s pick for Health and Human Services secretary, has pointed to ultra-processed foods and chemicals in medicines and the environment.
Cancer doctors share some of his suspicions about diet and exposure to contaminants such as microplastics, shards that make their way from packaging or clothing into our bodies through water and food. They are scrutinizing those and other potential hazards including “forever chemicals” and even light.
“We’re all concerned and want to do something quickly and act quickly, but we want to do so based on sound science,” said Dr. Andrew Chan, director of epidemiology at Mass General Cancer Center in Boston.
His team has found connections between early-onset colorectal cancer risk and obesity, consuming a lot of sugar-sweetened beverages and physical inactivity. But those studies don’t prove a direct cause.
Chan’s team is expanding its work to incorporate studies that track more people and analyze blood, tumor and stool samples. They will scour the results for potential carcinogens, then expose mice to them and see if cancers develop.
They plan to first focus on obesity and alcohol, said Yin Cao, a cancer epidemiologist from Washington University School of Medicine in St. Louis, who co-leads the work with Chan.
Excessive alcohol use is linked with risk for early colorectal cancer, studies show, along with diets high in fat and added sugars. One study found people who ate more ultra-processed foods had a greater risk of precursors to colon cancer.
The group plans to test ways to lower risks, including whether prescribing weight-loss drugs including Ozempic can help prevent colorectal cancer. Another trial will assign some participants a healthier diet and study whether changes in the bacteria and pathogens in the gut, called the microbiome, affect their risk.
