No easy explanation for rising cancer rates in young people

Cancer experts are clamoring to find an explanation for the grim growing trend of rising cancer rates among young people.

A study published in JAMA Network Open last year found that cancer diagnosis rates in thirtysomethings jumped almost 20% between 2010 and 2019, with most of the increase occurring in women.

Gastrointestinal cancers — including bowel, colon, colorectal, appendix, bile duct and pancreatic cancers — increased a startling 15% during the study period, making them the fastest-rising types of cancer.

And according to the American Cancer Society, 20% of new colorectal cancer cases in 2019 were in people younger than 55, up from 11% in 1995.

Some experts and studies suggest the uptick in bowel cancer diagnoses is due in part to a fiber-deficient Western diet that prioritizes ultra-processed foods (UPFs).

Research has proposed that a high intake of dietary fiber can lower the risk of several types of cancer, including esophageal, gastric, colon and rectal cancer.

But what about young, fit folks who already follow a healthy diet?

Speaking to the Daily Mail this week, UK cancer specialist Karol Sikora acknowledged that junk food and UPFs could be factors but said citing them as the sole source for rising cancer rates is overly “simplistic.”

Sikora says the true reason remains elusive and is likely multifaceted, “It doesn’t seem to be particularly associated with obesity. There’s no difference in vegetarians’ increasing early-onset cancer rate either, which is part of the puzzle.”

Sikora suspects a shift in the younger generation’s gut bacteria and other microorganisms that live in the intestines could be to blame.

“A healthy microbiome is critical for preventing bowel cancer. Gut cells bathe in the products produced by the bacteria 24/7,” he explained to the Daily Mail. “So it wouldn’t be surprising if some changes resulted in a higher or lower incidence of colon cancer.”

However, as Sikora notes, establishing that correlation is difficult, “The trouble when analyzing is there are so many factors that affect the microbiome: diet, alcohol, how you cook food.”

London oncologist Hendrik-Tobias Arkenau said the most concerning consequence of this youthful cancer surge is that many patients are diagnosed in the late or even final stages of the disease.

He asks, “Who thinks a 35- or 42-year-old has bowel cancer if they have tummy ache, weight loss, some blood (in stool)?”

Arkenau supports the microbiome theory while also mentioning childhood antibiotic use, diet changes, vitamin intake and failing breastfeeding rates as possible contributing factors.

“There is no clear-cut one thing,” he told the Daily Mail. “I think it is multi-factorial and there are other aspects like dropping vitamin D levels.”

Nearly 35% of US adults have a vitamin D deficiency, with some studies suggesting a link between low vitamin D levels and an increased risk for several cancers.

Arkenau maintains that while there is no clear answer for why cancer is occurring at such alarming rates in young people, health care providers can be on the lookout for concerning symptoms.

“If someone comes and says, ‘I’ve lost weight, had a bit of blood, a bit of a tummy ache,’ it’s not always irritable bowel syndrome, it’s not always appropriate to say, ‘Come back in three months and be checked,’” he said.