The number of people under 50 being diagnosed with cancer in the UK has risen by 24% in the past 20 years – faster than any other age group – and experts say the rise is likely linked to rising obesity rates, cheap junk food and lack of exercise.
Data analysis showed that early-onset rates increased from 132.9 per 100,000 people in 1995 to 164.6 in 2019. Research shows that around 35,000 people under the age of 50 now develop cancer every year, with almost 100 young women and men developing the disease every day.
Meanwhile, concerns are growing that a global cancer epidemic may be occurring among young people. The surge in cancer cases was a major focus of discussion at the world’s largest cancer conference, the American Society of Clinical Oncology (ASCO), which kicked off this weekend.
Experts are in the early stages of understanding the reasons for the rise in cases, but most believe that unhealthy diets, lack of exercise and obesity are likely factors behind the sharp rise in cancer rates among young people in the UK.
Incidence rates have increased in all age groups over the past two decades, but the 24% increase in those under 50 years is much higher than the increase seen in other age groups.
Professor Charles Swanton, chief clinical officer at Cancer Research UK, said: “The incidence of cancer among younger adults in the UK has clearly been rising in recent decades, and the evidence suggests that cancer rates in adults under 50 may be higher than ever before.”
The second largest increase in infections occurred among people under 25 years old. Their infection rate increased by 16%, from 16.6 cases per 100,000 in 1995 to 19.2 cases per 100,000 in 2019.
According to analysis by Cancer Research UK, the incidence of cancer across all age groups has increased from 539 cases per 100,000 people in 1995 to 611.5 in 2019 – a 13% increase, almost half the rate of increase in those under 50.
The incidence rate for people aged 50 to 74 increased 14%, from 955.1 to 1,092 per 100,000. For people aged 75 and over, it increased 10%, from 2,259.7 to 2,482.7 per 100,000. In other words, the incidence rate for people under 50 is more than twice as high as that for people aged 75 and over.
Early-onset cancers are still rare: About 90% of all cancers occur in people over the age of 50.
But Swanton said the trend remains “alarming,” with the analysis showing 34,945 cases in 2019. That’s a 34% increase from 26,176 cases in 1995. The reason the percentage change is greater than the 24% increase is likely due to population growth.
“Although these cases represent a small percentage of the overall population and are still relatively rare, the trend is important and warrants further investigation,” Swanton said.
Researchers are in the early stages of understanding why cancer is becoming a disease of younger people, but clues are already emerging, he said.
“Increased exposure to known and unknown cancer risk factors, long-term lifestyle and dietary changes, and increased obesity may all be contributing to the increase in early-onset cancers,” Swanton said.
The UK has one of the highest obesity rates in Europe, with two in three British adults being overweight or obese.
“Genetics, improved diagnosis and screening, and the microbiome may also play a role,” Swanton said. “We’re seeing these cases in the clinic, and it’s disturbing. We don’t have a clear answer for why this is happening. This is really a scientific puzzle that we need to solve quickly.”
The surge in early-onset cases is a global issue: The Guardian reported last year that there has been an 80% surge in infections among people under 50 worldwide.
Recent Reviews A review of registry records from 44 countries found that early-onset rates of bowel cancer and 13 other types of cancer, many of which affect the digestive system, are rising rapidly.
Dr. Aparna Parikh, an associate professor of medicine at Harvard Medical School and an oncologist at Massachusetts General Hospital, is part of Team Prospect, an international research group funded by Cancer Research UK that is investigating the sudden increase in cases.
“We want to get a deeper understanding of the mechanisms of biological processes and environmental causes, and to do that we’re looking at diverse data and patients from around the world,” she said at the ASCO meeting.
Parikh added that the spike in infections is complex but “likely driven by a variety of factors, including diet, environment and microbiome characteristics.”
A study presented at the ASCO meeting added to evidence suggesting that unhealthy diets are contributing to the rise in cases of colorectal cancer in people under 50.
The balance of bacteria and inflammation in the gut, both of which are affected by what a person eats, could lead to “accelerated aging” of the colon, Ohio State University said.
Swanton said while researchers are racing to find more answers, there are ways people can reduce their risk.
“Around 40 per cent of cancers are preventable and there are steps people can take to reduce their risk of cancer,” he said. “Not smoking, maintaining a healthy weight, safe sun exposure and limiting alcohol all make a big difference.”
