Gut toxins and 50,000 deaths: The truth behind the rise in colon cancer and the signs to look for

Independent

24-04-2025

Colorectal cancer rates are rising among younger Americans - the reason behind the jump has become hard for scientists to identify, but the symptoms to watch out are known.
Colorectal cancer, which encompasses colon and rectal cancer, is the second leading cause of all cancer-related deaths in the U.S. Last year saw a slight increase in deaths, with just over 53,000 reported. There were also nearly 153,000 new cases of colorectal cancer, the majority of which were in men. While survival rates have improved among older Americans, the incidence rate for people under the age of 55 continues to rise by between 1 and 2 percent, according to the Colorectal Cancer Alliance. The trend has been reported since the mid-1990s.
The mortality rate has also increased by about 1 percentage point each year since the mid-2000s. If current trends continue, colorectal cancer is slated to become the leading cause of cancer-related death among young adults in the next five years.
Now, a new study has identified a potential link between a toxin in the gut and the sharp rise of disease in younger people. Colibactin, which is produced by harmful species of gut bacteria, can inflict DNA damage on colon cells that can lead to the development of cancer.
Researchers say that damage is prominent in people who developed colorectal cancer at a younger age. Previous research had identified the DNA mutations in approximately 10 to 15 percent of all colorectal cancer cases.
'These mutation patterns are a kind of historical record in the genome, and they point to early-life exposure to colibactin as a driving force behind early-onset disease,' UC San Diego professor Ludmil Alexandrov explained in a statement.
So, what should Americans know about this toxin?
E. coli — yes, the foodborne illness E. coli — is a vital part of a healthy gut microbiome. However, some strains can produce the toxin called colibactin, which is capable of altering a person's DNA.
The toxin has been previously been linked to some cases of colorectal cancers, and 20 percent of people are thought to contain strains that can produce it.
But, colibactin-producing microbes are not the only bacteria linked to colorectal cancers. Another gut microbe called F. nucleatum has been implicated in the development of the disease.
It may contribute to disease development by enabling the tumor to proliferate and evade the immune system, Alexandrov told NBC News.
When should people look out for impacts from colibactin?
Colibactin's damaging effects begin early on. Alexandrov and the study's authors found such mutations occur within the first 10 years of life.
Furthermore, the study revealed that DNA mutations account for approximately 15 percent of mutations found in the tumor-suppressing APC gene in colorectal cancer, which are some of the earliest genetic changes that can directly promote cancer development.
'If someone acquires one of these driver mutations by the time they're 10 years old,' Alexandrov said, 'they could be decades ahead of schedule for developing colorectal cancer, getting it at age 40 instead of 60.'
What are the symptoms to be aware of?
Although some people could have colon cancer and not know it, others may experience blood in their stool, diarrhea, fatigue, rectal bleeding, constipation, abdominal pain, a change in bowel habits and unexplained weight loss.
Colorectal polyps that grow in the colon or rectum can turn into cancer if not removed.
If you are experiencing a symptom, it does not mean you have colorectal cancer. But, you should see a doctor.
'If anyone has any change in their bowel habits, if they have any bleeding — even if they think it's a hemorrhoid, and it doesn't go away — just get a colonoscopy,' Yale Medicine colorectal. surgeon Dr. Vikram Reddy advised.
Why are colorectal cancer rates rising in young people?
Young people are often diagnosed with more advanced cancers due to delays in detection.
'If you're 39 and you're having these symptoms, you're not thinking, 'I have colon cancer,'' Dr. Sonia Ramamoorthy, chief of colorectal surgery at UC San Diego said. 'You're thinking, 'I ate something. I'm working too hard.' If you're tired and you're stressed out, you're thinking, 'It'll go away.' People are presenting later because they're just not attributing their symptoms to something that could be serious.'
But, doctors have also singled out other contributing factors, including excess body weight, a sedentary lifestyle, smoking, a high intake of red or processed meat, and other environmental factors.
A family history of colorectal cancer or polyps, and conditions such as inflammatory bowel disease, are also risk factors, according to Yale Medicine.
How do I protect myself?
People may reduce their risk of colorectal cancer by limiting their alcohol consumption, keeping a healthy diet and increasing their physical activity.
Screenings also play an important role in finding any precancerous polyps before they turn into cancer.
Federal health officials say people should get screened starting at age 45, although there are questions about whether it should be lowered to 40. Those with a family history of colorectal cancer may need to get checked even earlier. Although, screening comes with its own risks as some medical machines have been linked to higher cancer rates.
There are some disparities to be aware of - Black Americans are 15 percent more likely to develop colorectal cancer and 35 percent more likely to die from it than white Americans.
But, there's still a lot to learn.
'We don't understand a lot about the causes, the biology, or how to prevent early onset of the disease,' Phil Daschner, a program director in NCI's Division of Cancer Biology said. 'And that's important to learn more about because it may affect [approaches for] the treatment and survivorship of early-onset colon cancer.'