WHY IS THERE SUCH A BIG RISE IN CANCER CASES AMONG YOUNG PEOPLE AROUND THE WORLD?

THERE are rising cases of breast, colorectal and other cancers in people in their 20s, 30s and 40 around the world.

What is really going on?

Over the past 10 years, rates of colorectal cancer among 25 to 49-year olds have increased in 24 different countries, including the UK, US, France, Australia, Canada, Norway and Argentina.

The investigation’s early findings, presented by an international team at the Union for International Cancer Control (UICC) congress in Geneva last month, were as eye-catching as they are concerning.

The researchers, from the American Cancer Society (ACS) and the World Health Organization’s (WHO’s) International Agency for Research on Cancer, surveyed data from 50 countries to understand the trend.

In 14 of these countries, the rising trend was only seen in younger adults, with older adult rates remaining stable.

The results are the latest in a host of studies detailing a similar rise of a range of different cancers in the young.

Breast cancer is one form of cancer where the trend is apparent.

A new report from the ACS found that while deaths from breast cancer in women have dropped by around 10% in the past decade, incidence rates are rising by 1% per year overall — and 1.4% per year for women under the age of 50.

Based on epidemiological investigations, it seems that this trend first began in the 1990s.

One study found that the global incidence of early onset cancer has increased by 79% between 1990 and 2019, with the number of cancer-related deaths in younger people rising by 29%.

The issue of early-onset cancers has become such a matter of concern that major organisations such as the UICC are keen to raise awareness of the trend among general practitioners to ensure that warning signs are being picked up among younger patients.

“A doctor listening to somebody above 60 who’s talking about difficulty passing stool, feeling tired and bloated, is going to take those symptoms a lot more seriously than a young person in their 30s who’s active and doesn’t fit the typical profile of a person with cancer,” says Sonali Johnson, head of advocacy at the UICC.

“They might put it down to irritable bowel syndrome or work stress, so there’s plenty of cases where people’s symptoms are dismissed instead of being referred for blood work or a colonoscopy.”

Cancer specialists say that patients presenting with diseases like pancreatic cancer, an illness where most people are diagnosed in the early 70s, are sometimes decades younger than would usually be expected.

“It’s not uncommon for me to see someone under the age of 40 with pancreatic cancer,” says Eileen O’Reilly, a gastrointestinal medical oncologist at Memorial Sloan Kettering Cancer Centre in New York.

“It’s almost every week, which is a scary thought. These are people in the prime of life, who are starting families and have everything to live for. The implications for society are profound.”

While oncologists have typically thought of cancers in younger people as being primarily a consequence of heritable risk factors, such as the BRCA1 and BRCA2 gene mutations in the case of breast cancer, more and more patients have no obvious genetic predisposition.

O’Reilly says that in the majority of the young-onset cases she sees, there is no obvious genetic explanation, and when studied in the lab, the tumours carried by patients in their 20s, 30s or 40s appear to be more aggressive compared with a typical pancreatic cancer patient in their 70s.

Cancer specialists say that patients presenting with diseases like pancreatic cancer, an illness where most people are diagnosed in their early 70s, are sometimes decades younger than would usually be expected.

“It’s not uncommon for me to see someone under the age of 40 with pancreatic cancer,” says Eileen O’Reilly, a gastrointestinal medical oncologist at Memorial Sloan Kettering Cancer Centre in New York.

“It’s almost every week, which is a scary thought. These are people in the prime of life, who are starting families and have everything to live for. The implications for society are profound.”

Perhaps the most obvious explanation points to the role of obesity and metabolic syndrome, conditions which have been associated with driving cancer risk through increasing inflammation throughout the body and causing the dysregulation of key hormonal pathways.

The overall evidence points to lifestyle change,” says Shuji Ogino, professor of pathology and epidemiology at Harvard University who has been investigating the rise of early-onset cancers.

“We know that eating too much sugar and processed food, having consistently high blood glucose and becoming insulin resistant not only raises your risk of diabetes but also cancer.”

But obesity alone doesn’t represent the full story.

O’Reilly says that many of the younger pancreatic cancer patients she sees are fit and apparently healthy, with no clear explanations for why they should have fallen unwell.

While epidemiologists have long focused on the link between smoking and cancer, smoking prevalence has declined markedly in recent decades with the WHO finding that globally just one-in-five adults consume tobacco products now, compared with one-in-three in 2000.

Instead, Ogino feels that a heavily overlooked connection is the marked change in sleep patterns around the world which has occurred in 50-100 years.

Some scientists have even argued that our near permanent exposure to artificial light, either through streetlights or mobile phones and tablets, represents a novel carcinogen through triggering disruptions in the body’s biological clock, something that has been linked to breast, colon, ovarian and prostate cancer. — BBC.