Is THIS why so many young people are getting colorectal cancer? A fungus could be to blame

Doctors may be one step closer to revealing why colon cancer rates are rising among younger adults.

A mysterious rise in cases among 55-year-olds has raised concerns in medical circles, especially as the cancer is being spotted among healthy young people who “run marathons” and watch their diet.

Now doctors at Georgetown University in Washington DC say the uptick may be related to changes in young people’s gut microbiomes.

They found that tumors from younger patients were more likely to contain the fungus Cladosporium sp. compared to older patients.

The fungus is only occasionally found in the human gut, where it is suspected to be an invader that does not aid in digestion. The fungus is also known to cause infections of the skin and nails.

Colorectal cancer is the third most common cancer diagnosed in the United States, according to the National Cancer Institute. And it is increasing in young people.

Each year, approximately 153,000 Americans are diagnosed with colon cancer, with 19,550 under the age of 50.

The number of people under the age of 55 has doubled since the 1990s, raising concerns among health professionals.

A 2023 report from the American Cancer Societystates, for example, that the rate of colon cancer in Americans under age 55 increased from 11 percent of all cases in 1995 to 20 percent in 2019.

Dr. Benjamin Weinberg, an expert on gastrointestinal cancer, shared AXIOS: ‘Many people blame obesity and diabetes.

“But we have these patients who run marathons and eat them.” [healthy diets] and they have very advanced colon cancer.’

For the study, scientists looked at tissue samples from 63 patients who were younger than 45 or older than 65.

They checked the DNA of microorganisms in the tumors for differences in the gut microbiome.

This showed that Cladosporium sp. was more common in tumors of young patients than in older subjects.

The researchers also evaluated bacterial factors that could play a role.

There was no difference for most bacteria, such as Fusobacterium nucleatum, which was found in both groups about 30 percent of the time.

Other bacteria were also found to be more common in the tumors of older patients.

It is still unclear how Cladosporium sp. could lead to this increase in cases, but the researchers think it could damage cell DNA. This can turn them into cancer cells.

The results will be presented next week at the annual meeting of the American Society of Clinical Oncology in Chicago, Illinois.

The researchers say their paper may have brought doctors one step closer to understanding the cause of the rise in colon cancer cases.

Dr. Weinberger added, “We think there was some kind of exposure in the 1970s or 1980s — maybe everyone started taking antibiotics for ear infections or stopped breastfeeding.”

“Something happened where this cohort is seeing this increase and we don’t know why.”

Previous theories have suggested that unhealthy diets, alcohol consumption and the rise of sedentary lifestyles could be behind the uptick.

But scientists say this doesn’t explain why other cancers have remained flat or continued to tumble at the same time in those under age 55.

All tumors contain bacteria and may also contain fungi, although they are usually not present.

Part of the increase could be that people are also more likely to have their colorectal cancer discovered at a later stage, when it is more difficult to treat.

A 2017 study in the journal Clinical gastroenterology and hepatology found that people under 50 tended to wait two months longer to seek medical attention after first noticing symptoms than people over 50.

Amid concerns about the rising rate among younger adults, the US Preventive Services Taskforce lowered the screening age from 50 to 45 in 2021.