Early-onset cancer has been steadily rising. The younger you are, the greater the risk. But the really worrying part? Scientists have no clue why this is happening.
Tell me again what is ‘early-onset’ cancer?
Cancer is supposed to be an old person’s disease. So the medical phrase to describe cancer that affects anyone under the age of 50 is “early-onset”. The big picture is that since the 1990s, the number of cancer patients under the age of 50 has been steadily increasing. And it is rising with each generation:
For instance, people born in 1960 experienced higher cancer risk before they turn 50 than people born in 1950, and we predict that this risk level will continue to climb in successive generations.
One study found they increased with each decade:
Ogino’s review found something called a cohort effect, meaning the risk of an early-onset cancer has increased for each successive group of people born at a later time. Those born in the 1990s have a higher risk of developing an early-onset cancer in their lifetime than those born in the 1980s, for example.
In fact, models based on global data predict that the number of early-onset cancer cases will increase by around 30% between 2019 and 2030.
WTF? Surely this can’t be true…
It is indeed true. And it has been reaffirmed by multiple studies—both in the US and around the world. Here is a quick rundown of the latest research:
The BMJ study: A 2023 British Medical Journal study found a nearly 80% increase in the early onset of breast, stomach and colorectal cancers—between 1990 and 2019—worldwide. The number of deaths caused by early-onset increased 27.7%—even though cancer treatments improved vastly in this period. The study looked at the early-onset of 29 different cancers in 204 countries. The fastest rising cases were early-onset windpipe and prostate cancer. Breast cancer accounted for the highest number of new early-onset cases in 2019.
The JAMA study: Another 2023 study, published in the JAMA Network Open, showed that cancer cases in people above 50 had actually declined in the US—between 2010 and 2019. But the number of cancer cases for people below 50 was ticking upwards. The biggest jump was in gastrointestinal cancer cases—which spiked by 15%.
The most notable bit: The increase was driven by women and people in their 30s. The number of cases of people between the ages of 30 and 39 jumped by 19%. Also this:
The change seemed to be driven by rates of cancer in younger women, which went up an average of 0.67% each year; at the same time, rates decreased in men by 0.37% each year.
Overall, the number of early-onset cancers in women increased by 4.4% during this decade—while the number for men declined by nearly 5%. One likely reason for this gender gap: Breast cancer once again accounted for the highest number of cases.
Cancer registry review: In 2022, researchers looked at cancer registry records from 44 countries. They found that the numbers of 14 types of early-onset cancers were increasing—eight of them were related to the digestive system:
Ogino’s review found that across the years of the study, the average yearly climb in colorectal cancer in young adults was about 2% in the US, Australia, Canada, France and Japan. In the UK, it’s almost 3% per year in England, Scotland and Wales. In Korea and Ecuador, it is roughly 5% per year. “It doesn’t seem big, but you can think about inflation: If it’s 2% every year, it’s going to be a big change in 10 years or 20 years, you know?” Ogino said. “It’s not trivial.”
As for India: We couldn’t find a lot of data but according to a Deccan Herald op-ed penned by a doctor:
An estimated 6-7 lakh deaths in India are caused by cancer in a year. This figure is close to the mortality burden seen in high-income countries. About a lakh young adults aged 20-39 years are diagnosed with cancer each year. About five per cent of all cancers are diagnosed in this age range. Cancer is the fourth leading cause of death in this age group.
Some studies show a similar surge in colorectal cancers among young people.
What’s with colorectal cancer?
Much of the attention on early-onset cancers has focused on colorectal—because its numbers are surging at an alarming rate. In the US, one in five new colorectal patients is under the age of 55. Reminder: ‘Black Panther’ star Chadwick Boseman died of colon cancer at the age of 43.
Shocking stat to consider: A study “found that people born in the 1990s are at double the risk for early-onset colon cancer and four times the risk for rectal cancer, compared with people born around 1950.”
The death rates: for colorectal cancers are also alarming. While the numbers among patients over 65 are going down, they are going up for those under 50. One reason is that they are not caught early—since young people don’t go in for routine cancer screenings. But an NIH study found that young people who got colorectal cancer had far worse outcomes—even if they were diagnosed at Stage I. It may be there is a biological difference between the cancer that affects young people—and the one that attacks the elderly.
This is about our diet, isn’t it?
Actually, scientists don’t know why early-onset cases are rising. There are a lot of hypotheses—but none of them have been proven. Some of the proposed links for colorectal cancers can sound a bit kooky:
Researchers are scrutinising possible causes ranging from inactive lifestyles to microplastics. Oncologists have found a greater risk of developing colorectal cancer at a young age among women who spent a lot of time sitting in front of the TV. Drinking sugary drinks in high school correlated with higher risk, too. Even being born via caesarean section seemed to link another group of women with higher risk of getting colorectal cancer early.
But in general, doctors think it has to do with what we eat—and how much we weigh:
Deep-fried and highly processed foods have been implicated in other studies of early onset colorectal cancer, while diets with fiber, fruits and vegetables likely lower risks. Cancers including colorectal, breast and pancreatic have been tied to obesity, and studies support a link between excess weight and some early onset cancers.
But, but, but: There are many cases where this doesn’t hold true. As we said, there is no hard evidence—just a lot of theories.
Theory of early exposure: is related to this lifestyle argument. It may have to do with bacteria in our digestive tract. The microbes found in the gut tissue of younger patients are different from that of older ones. And this may be due to something we are exposed to at a very young age: “Some doctors suspect that cancer-causing exposures might have started during patients’ childhoods, something that is difficult to trace.”
Is it about ‘when’? The generational difference seems to point the finger to changes to our food—and/or environment. One possible culprit is microplastic pollution—which has dramatically increased in the past three decades. And it would make sense that generations are exposed to these risks at a younger age—“whether in utero, early childhood, or early adulthood”—could make them more susceptible to cancer.
Point to note: Researchers around the world are teaming up on a $25 million project to study early-onset cancers. They will gather evidence on the ground in the US, Mexico, the UK, France, Italy, and India. While the surge in early-onset cancers is the highest in the affluent West, middle income countries like India are not far behind. One Indian oncologist predicts: “This is going to be a problem that is going to be facing us as our economy gets stronger.”
The bottomline: Dylan Scott asks: “How do we feed a world of 8 billion people a diet that lowers the risk of more people dying too young?” If the culprit lies in our very lives—how we eat, work, sleep—tackling early-onset cancer will be a truly herculean task.
Reading list
Vox has the best, in-depth overview of new research into early-onset cancer. Wall Street Journal (splainer gift link) looks specifically at colorectal cancer. The Hill lays out the many, many theories about the cause for this trend. CNN has more on the JAMA study and the global study of registries. Deccan Herald has a decent op-ed on the situation in India.
