More Younger Adults Being Diagnosed With Colorectal Cancer, Scientists Warn

More adults below the age of 50 are being diagnosed with colorectal cancer compared with five decades ago, scientists say. And when younger patients are diagnosed, the disease is more likely to be picked up in the advanced three or four stages, at 51.6 percent versus 40 percent of those above 50.

Between 2004 to 2015, the last year when figures were available,130,165 people under the age of 50 were diagnosed with colorectal cancer, compared with 1,055,598 over that age. Of the total, under 50s made up 12 percent of colorectal patients, spiking to 13.9 percent among African Americans and 18.9 percent among Hispanic populations.

On average, those in urban areas were more likely to be diagnosed with the disease at a younger age, as were those with the highest incomes.

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A stock image of a man holding his stomach. Scientists have examined the rates of people under the age of 50 with colorectal cancer. Getty

The figures for the study published in the journal Cancer came from the National Cancer Database registry. As the study was observational, the authors couldn't find a cause for the rise.

"Because of the lack of screening, younger patients are more likely to present with and die of advanced disease. These data should be considered in the ongoing discussion of screening guidelines," the authors wrote.

Last year, concerns around climbing levels of colorectal cancer in those under 50 led the American Cancer Society to update their guidelines to start screenings for the disease at 45 years old.

Dr. Boone Goodgame, study co-author from The University of Texas at Austin, commented in a statement: "Several studies have shown that the rates of colorectal cancer in younger adults have risen slowly in the US since the 1970s, but for practicing physicians, it feels like we are seeing more and more young people with colorectal cancer now than we were even 10 years ago.

"Until just last year, guidelines recommended colon cancer screening beginning at 50. Now many guidelines do recommend screening at age 45, but most physicians and patients don't appear to be following those recommendations."

Dr. Chyke Doubeni of the University of Pennsylvania commented in a statement: "Because the number of colorectal cancer cases from inherited causes are much higher in younger individuals, it is unknown whether screening for sporadic cases in a group with such low disease rate can result in a favorable balance of harms and benefits.

"It is therefore imperative that the various hypotheses for increasing colorectal cancer incidence among people younger than 50 be rigorously tested to determine if changing the current screening age in people who are not at increased familial risk represents the most appropriate public health response."

Goodgame told Newsweek: "Colorectal cancer takes 10 to 20 years to develop, so the cause of the increase in cancer rates in the 2000s started in the 1980s and 1990s.

"In addition to the rising rates of excess weight and obesity, the frequent use of broad-spectrum antibiotics increased in the 1980s and 1990s. Many researchers believe that changes in the 'microbiome,' the bacterial flora of the colon that are essential to healthy digestion, have led to the increase in colorectal cancer in younger adults."

At first, colorectal cancer may not cause any symptoms, but as the disease progresses a person may find blood in their feces, experience stomach pains and cramps that don't pass as well as unexplained weight loss.

This form of cancer usually starts out as a precancerous polyp, or growth, in the colon or rectum. The CDC recommends a diet low in animal fat and rich in fruit and vegetables, as well as whole grains to potentially cut the risk of developing the condition.

This article has been updated with comment from Dr. Boone Goodgame.