Charts show a sharp rise in the rate of young adults getting cancer before age 50

• Data analyzed by Business Insider shows a sharp rise in young people being diagnosed with cancer.

• Meanwhile, rates of cancer diagnosis and death is dropping in older people.

• Experts say healthy young people are presenting with advanced-stage cancers.

The rate of young adults being diagnosed with cancer has risen sharply in the past 30 years, particularly in high-income countries. Researchers aren't sure why.

Take this chart, for instance:

In the US, the rate of cancer diagnosed in those under 40 increased a staggering 35.4% from 1975 to 2019, according to a Business Insider analysis of federal data.

It's a global trend. UK-specific data shows a 22% increase in under-50s getting cancer since the early 1990s. A recent study published in the BMJ showed a steady rise in millennials being diagnosed with cancer worldwide, with the sharpest rates seen in high-income countries, including the US and Western Europe.

Business Insider's analysis of young adult cancer rates in G20 countries shows a fast, uniform increase:

While cancer screening has dramatically increased, helping to prevent cancer deaths, the rise in young cancer cases can't be accounted for by increased screening.

"We're seeing more higher stage tumors and more aggressive tumors in younger people, much higher compared to older patients," Shuji Ogino, an epidemiologist and cancer researcher at Harvard Medical School, told Business Insider.

If it were the result of screening, Ogino said, we would expect to be finding more early stage cancers. That's not the case; young people who seem relatively healthy are being diagnosed with advanced-stage cancers.

This includes people like Chadwick Boseman, who died at 43. Boseman was diagnosed with stage-three colon cancer at age 39, at the peak of his career. He continued to perform in major movies, including Black Panther, until he died. Kate Middleton, who just turned 42, announced on March 22 that she was diagnosed with cancer after abdominal surgery, though she will not be disclosing the type or stage of cancer.

Dr. David Liska, a colorectal cancer surgeon at the Cleveland Clinic, told Business Insider he and his colleagues are struggling to understand the trend.

"As clinicians, almost daily, we see young people have cancer where they're healthy, they're obviously young, they eat well, they do not have a genetic condition. And then we are left scratching our heads," he said.

Many researchers, including Ogino, point to Western lifestyles, which have radically reshaped how we live compared to previous generations.

Liska said the proliferation of fast food, unhealthy diets, sedentary lifestyles, and poor sleep schedules likely don't help.

"But we also see these individual cases, which are becoming more and more common, that are exceptions; that you can't explain. There's something else at play here as well that we need to understand better," he said.

There's a rise in young cancers of the digestive system with aggressive features

Ogino is the coauthor of a recent study published in Nature that made a huge splash in the field of cancer research.

In it, Ogino and his research team showed that millennials, particularly those born after 1990, are developing early-onset cancer at such a high rate that he dubbed it "an epidemic."

The study identified 14 cancers detected more frequently in young people: breast, colorectum, endometrium, esophagus, bile duct, gallbladder, head and neck, kidney, liver, bone marrow, pancreas, prostate, stomach, and thyroid.

Among the 14 cancer types on the rise, eight are related to the digestive system.

The team also found that these early-onset cancers have more aggressive clinical features.

Oncologists studying this trend say colorectal cancer cases provided the first warning sign. This was the statistic that started spiking first, and prompted investigations that showed more cancers were increasing among young people.

Per a recent JAMA study, colorectal cancer is now the most common for people under the age of 50. One in five new cases of colorectal cancer in the United States occurs in people younger than 55. In the early 90s, it was one in 10, according to a recent report from the American Cancer Society.

A young cancer diagnosis is especially difficult, doctors say

A cancer diagnosis in your 30s and 40s comes with unique challenges.

This age group often has young families and may be caring for parents or trying to buy a house. They are less likely to have the time and savings to focus on treatment.

In recent years, medical centers like Yale and Cleveland Clinic have launched programs that are specifically dedicated to young adults with cancer. A significant amount of that care is psychological support.

"These are people who are in the most productive times of their life and have busy careers," Liska told BI. "So you have people here who are thinking of themselves as caregivers. They're giving care to their children, to their parents, and all of a sudden they become people who need care to be given to them because they're going through a diagnosis and treatment of cancer. The psychological implications are immense."

Read the original article on Business Insider