People in their 30s had the greatest rise in late-stage colon cancers over time, at 49 percent. Meanwhile, those in their twenties saw the greatest increase in advanced rectal cancer, up 133 percent.

The findings add to mounting evidence of an alarming, and as yet unfathomable, rise in early-onset colon cancer.

While the absolute numbers remain low, the National Cancer Institute of the United States reports that the rate of colon cancer among Americans younger than 50 has more than doubled during the 1990s.

According to the current study, Americans in their 20s and 30s are experiencing the greatest increase in advanced-stage colon cancer, which refers to cancers that have spread to other parts of the body.

Their rates increased from 57 percent to 66 percent between 2000 and 2016: Late-stage cases increased from 0.21 per 100,000 to 0.33 per 100,000 in individuals in their 20s, and from 1.14 per 100,000 to 1.9 per 100,000 in adults in their 30s.

According to lead researcher Dr. Jordan Karlitz, chief of the gastrointestinal division at Denver Health Medical Center, delayed detection definitely plays a large part in why young people are commonly diagnosed with severe disease.

For one thing, he said, most people under the age of 45 aren’t eligible for regular screenings, which can help find cancer early and even prevent it. 

Dr. Robin Mendelsohn, who co-directs Memorial Sloan Kettering’s Center for Young Onset Colorectal and Gastrointestinal Cancer in New York City, noted that young adults with colon cancer generally “present late,” after they have had symptoms for a while.

Changes in bowel habits, blood in the stool, chronic stomach cramps, and unexplained weight loss are all symptoms of colon cancer.

Young individuals sometimes ignore those signs at first, according to Mendelsohn. However, clinicians may overlook colon cancer as a probable reason.

“Patients may have to see multiple providers before they get a diagnosis,” Mendelsohn added.

According to a 2019 study, two-thirds of 1,200 colon cancer patients under the age of 50 waited three months to a year to consult a doctor about their symptoms. After that, individuals usually had to see at least two doctors before receiving a proper diagnosis.

In fact, other disorders, such as IBS or hemorrhoids, are more likely to be the cause of problems in a healthy young person, according to Mendelsohn’s research.

“But it’s important to have [colon cancer] on the radar,” she said.

Rectal bleeding, in particular, should never be overlooked, according to Karlitz.

The new findings, which were published in the journal Cancer Epidemiology, Biomarkers & Prevention recently, are based on data from a federal cancer registry in the United States. Between 2000 and 2016, almost 104,000 Americans aged 20 to 54 acquired colorectal cancer.

When it comes to colon cancer, those in their 30s saw the largest increase in late-stage tumors, with a rate of 49 percent. Meanwhile, those in their twenties experienced the greatest increase in advanced rectal cancer, with a 133 percent increase.

There were also hints of disparities: Black and Hispanic Americans in their 20s had a disproportionately high rate of late-stage cancer, which deteriorated over time. Between 2000 and 2016, the proportion of late-stage rectal malignancies among young Black individuals increased from zero to 46 percent.

Researchers are still attempting to figure out why young people are developing colon cancer.

“Some data suggest that obesity and diabetes are playing a role, but that’s not the whole story,” Mendelsohn said. “The majority of our patients are not obese and do not have diabetes.”

Diet and its impact on the gut microbiome — the enormous collection of bacteria that live in the gut and help maintain normal physiological processes — is one suspect under investigation, she said. According to some laboratory tests, an unhealthy balance of those bacteria can contribute to inflammation and tumor growth.

For the time being, both specialists advised anyone with symptoms of colon cancer to contact their doctor and begin screening as soon as they are eligible.

Image Credit: Getty

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