What is behind the rising incidence of colorectal cancer in young adults?

andreas kaiserProfessor, MD, Chief of the Division of Colorectal Surgery in the Department of Surgery, reviewed the scans of an anxious young woman sitting in his office. When he said, “Your cancer will be cured,” she held his hand and burst into tears.

Kaiser's office involves many conversations, both fun and difficult, with patients and their families. But what he didn't expect was to have such conversations with patients so young.

colorectal cancer, the disease that claimed the life of “Black Panther” actor Chadwick Boseman at age 43 (he was diagnosed at age 39) was once considered an “old man's” disease. Not so anymore.

“We see an incredible number of young patients,” Kaiser said. He acknowledges that this may be due to “referral bias”. That means the most difficult cases are sent to City of Hope. Still, “On some days we only see young people. I have treated five young mothers who were diagnosed with metastatic disease during pregnancy.'' Is it? I just don't see it.'' Kaiser said he has also treated teenagers with colorectal cancer.

What Kaiser has seen in his clinic is backed up by national numbers. While overall cancer incidence is decreasing, with colorectal cancer in older people declining steadily since its peak in 1985, so-called “early-onset” colorectal cancer affecting younger people is on the rise. There is a trend. In 2002, the average age at which people were diagnosed with colorectal cancer was 72 years old, but in 2019 this has fallen to 66 years old. This is because new cases among people under 55 have doubled from 11% to 20%. The National Cancer Institute has announced that early-onset colorectal cancer is now the leading cause of cancer death for people ages 20 to 49.

becomes terrible. Research shows that cancers that occur in younger people tend to be more aggressive.

what happened? Why are Gen

Possible causes of increasing rates of colorectal cancer

No one can point to a single factor as the cause of this disturbing trend. But there are a lot of theories out there. These range from genes to diet, weight and lack of exercise, to pollutants in the air, soil, and water.

If there's one condition that raises more red flags than others, it's obesity. Overweight, often accompanied by chronic inflammation, insulin resistance, and diabetes, appears to be part of a “perfect storm” that increases the incidence of colorectal cancer. And the under-50 generation came of age at a time when Americans' diets were fundamentally changing and obesity became an epidemic.

“Colorectal cancer is a disease of obesity'' declared Victoria L. SeewaldMD, Chair and Professor Department of Population Scienceadded, “Young patients have appeared in the era of fast food.”

“Nutrition and calories used to be tied together,” she continued. “But now we have high-calorie foods with very little nutritional content. That's what our younger generation is eating.” Add to this a sedentary lifestyle, and millions of Too many people consume excess calories, which are not absorbed by the muscles and are stored as fat. This leads to insulin resistance, which causes the body to produce too much insulin, “a powerful hormone that drives all the pathways that make cancer more aggressive.”

2017 study published in Oncology annual report It also revealed that some of the foods and habits that lead to obesity are associated with a risk of colorectal cancer. “High intakes of red meat, processed meat, and alcohol increase the risk of colorectal cancer.” The same study showed a reduction in colorectal cancer correlated with a healthy diet of fruits, vegetables, and whole grains.

Again, the numbers bear that out.

'Patients with a BMI greater than 30 have twice the risk of colorectal cancer,' says gastrointestinal cancer specialist Afsaneh Bulge, Associate Professor in the Department of Medical Oncology and Therapeutic Research, MD. “This trend started in his 1990s and has become even more pronounced.”

Environmental factors and colorectal cancer

What changed during that period other than people getting heavier? Bulge points to environmental factors that may have altered our “microbiome,” or gut bacteria. She said: January 2024 Survey A paper published by the American Association for Cancer Research found that “many of the lifestyle factors that promote colorectal cancer can also affect the gut microbiome, which may be associated with colorectal cancer risk. It has been suggested that there may be. Furthermore, this association was age-dependent, meaning that “tumor pathway-microbe interactions are stronger in younger versus older colorectal cancer patients.”

Bulge is particularly concerned about a chemical called triclosan, which was introduced in the late 1960s as an antibacterial agent in household products such as soap and toothpaste. Some studies have linked triclosan to increased cancer risk, but the data are inconclusive. Still, although the Food and Drug Administration banned the substance for household use in 2016, the substance is still found in commercial pesticides.

Other things we ingest can also harm us.a June 2023 Survey The National Institutes of Health has investigated how so-called “microplastics,” tiny particles that seep from plastic products such as water bottles and food containers, get into our food and water and from there enter our bodies. did. This increase in the prevalence of microplastics has roughly coincided with an increase in colorectal cancer among young people.

Where you live may also have an impact.

“Look at San Francisco,” he said. Yuman Fung Doctor of Medicine, San Giacomo Family Chairman of Surgical Oncology. “All the new urban spaces that are built in shipyards, garbage dumps, and places that were once filled with asbestos, oil, and toxic spills. All the pollution on the ground and in the air. People don’t think about that.’ Or maybe they don’t know.

Professor Seewald points out that colorectal cancer can now be considered in some sense a 'disease of poverty', with colorectal cancer being more prevalent in the most socio-economically disadvantaged areas. Pointed out. These areas often have the highest levels of pollution and are often referred to as “food deserts'' due to the lack of nutrients. Improving access to healthy food options. “Colorectal cancer rates are highest in the Lower Mississippi River region of Arkansas, Tennessee, and Mississippi, which have heavily polluted areas, high levels of obesity and poverty, and a shortage of doctors. “There is,” she said.

Lack of symptom recognition of colorectal cancer

Finally, poor judgment on both sides of the examination table may also be a factor. It is believed that many young people delay seeking medical attention when experiencing bleeding or some type of digestive disorder. They never realize that they may be experiencing early symptoms of colorectal cancer. When it comes to the doctors who treat them, too many doctors still discount the tummy troubles of young people.

“Young people don't go to the doctor because they think they're invincible, which delays diagnosis,” Fung said. “What’s worse is that no one believes you when something goes wrong.”

“Young people are being ignored,” Kaiser agreed. And when diagnosis is delayed, it is the ultimate tragedy. ”

A small number of early-onset colorectal cancer cases may have a genetic component. People who inherit various syndromes, such as familial polyposis, which causes hundreds of polyps in the colon, may be at greater risk. Lynch syndrome is known to cause tumors to develop on the right side of the colon. There are also spontaneous changes called BRAF mutations that tell cells to keep growing without telling them to stop. This mutation is present in 10% of colorectal cancer patients.

However, there is no overwhelming genetic “smoking gun” like BRCA mutations that create a high risk of breast cancer.

“Most young people with colon cancer don't have a genetic component; they don't have a history of it in their families,” Fung said. “Then is there something hidden that we haven't found yet?”

Prevention is difficult when the cause is unclear. But nearly everyone agrees that changing individual behavior can make a big difference.

“Each of us has the power to change our destiny,” Bulge said. “That means changing what we eat: healthier foods, cutting back on processed foods, etc. And we need to create an environment that encourages physical activity. This means that our direct It's under control.”

And if something feels off, pay attention.

“Don't minimize your symptoms,” Kaiser warns. “If you're bleeding from your rectum, for example, don't assume it's nothing. Get it checked out!” I want to educate people about colorectal cancer.

The gold standard for “getting tested” is a colonoscopy. Unfortunately, current guidelines do not recommend this surgery for people under age 45 with average risk, and insurance companies will not pay for it. Many would like to see a policy change that would see more practitioners trained to perform colonoscopies on more people. Research is also underway to develop more non-invasive tests.

But the ultimate silver lining message here is that stage 4 colorectal cancer, even the aggressive type more common in younger patients, no longer carries the grim prognosis it once did. That means no.

Thanks to today's advanced treatment options, “there are now many young patients who don't have cancer,” Fung said.

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Main image: Milton Liu was diagnosed with inoperable stage 4 colon cancer in his 40s before coming to City of Hope for a second opinion. He credits Dr. Yuman Fung for his work. save his life.