The number of cases of breast cancer, colon cancer and other forms of this serious disease is increasing in people in their 20s, 30s and 40s. What's going on?
Over the past 10 years, rates of colon cancer in people aged 25 to 49 have increased in 24 different countries, including the United Kingdom (UK), the United States (US), France, Australia, Canada, Norway, and Argentina.
The early findings of the research, presented by an international team at the Congress of the Union for International Cancer Control in the Swiss city of Geneva in September 2024, were very striking and worrying.
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Researchers from the American Cancer Society and the World Health Organization's (WHO) International Agency for Research on Cancer examined data from 50 countries to understand the reasons for this trend.
In the 14 countries surveyed, an upward trend was observed only among younger people, while rates among the elderly remained unchanged.
These are the latest results of a large number of studies detailing similar increases in various types of cancer in younger people.
Breast cancer is one form of cancer where growth is obvious.
A new report from the American Cancer Society shows that although breast cancer deaths have declined by about 10 percent in the past decade, overall incidence rates are increasing by 1,4 percent per year, and 50 percent per year among women under XNUMX.
Based on epidemiological studies, this increase appears to have started during the 1990s.
One study revealed that between 1990 and 2019 the frequency of cancer in people younger than 50 in the world increased by 79 percent, while the number of cancer deaths in the same age group increased by 29 percent.
Another study published in Medical Science of the Lancet magazine (The Lancet) reports that rates of 17 different types of cancer in the US have risen steadily with each successive generation, particularly among members of Generation X (born from the mid-1960s to the late 1970s) and millennials (born between the early 1980s and the late 1990s - them).
The issue of cancer occurring in people under 50 has become such a concern that major organisations, such as the Union for International Cancer Control, are directing GPs to look out for warning signs in younger patients.
"A doctor who listens to someone over 60 who complains of difficulty passing stools, fatigue and bloating will take those symptoms much more seriously than someone in their 30s who is active and doesn't fit the typical profile of a person with cancer," says Sonali Johnson of the Union for International Cancer Control.
"Doctors can attribute those symptoms to irritable bowel syndrome or stress at work, so there are a lot of cases where people ignore their symptoms instead of going for a blood test or a colonoscopy."
Cancer specialists say that patients who have, say, pancreatic cancer are the ones most people are diagnosed with in the early 70s, sometimes decades younger than one would expect.
"It's not unusual for me to have patients under the age of 40 with pancreatic cancer," says Eileen O'Reilly, a gastroenterologist-oncologist at Sloan Kettering Cancer Center in New York.
"I have such patients almost every week, which is scary.
"These are people in their prime, who are starting families and have many reasons to live.
"The consequences for society are profound".
While oncologists usually believe that cancer in younger people is primarily due to hereditary risk factors, such as mutations in the BRCA1 and BRCA2 genes for breast cancer, there are more and more patients who do not have an obvious genetic predisposition.
O'Reilly says that in most cases of cancer in the under-50s, there is no obvious genetic explanation, and when studied in the laboratory, tumors in patients in their 20s, 30s and 40s appear more aggressive compared to those in a typical patient with pancreatic cancer in their 70s.
He says that because of this, the prognosis for them is often very poor, even though these patients are often in good general health.
"They are younger, in better physical condition and can often tolerate the intensity of treatment better, but some have this very aggressive form of pancreatic cancer, which causes an accelerated decline in the overall state of the organism," she explains.
"For them and for us, it is often incomprehensible, because who could imagine that a healthy 40-year-old would develop this type of malignancy?".
In addition to observing this growing trend, cancer specialists believe that it is urgently necessary to get to the bottom of the factors that trigger the disease.
Authors of the Lancet study have said that if this pattern continues, it could ultimately increase the burden of disease in the future and thereby halt or even reverse decades of public health progress in the fight against cancer.
What is actually happening?
Perhaps the most obvious explanation points to the role of obesity and metabolic syndrome, conditions that are associated with an increased risk of cancer, because they promote inflammatory processes throughout the body and cause hormonal disturbances.
A recent study found that accumulating excess body weight between the ages of 18 and 40 was associated with a higher risk of up to 18 different cancers, and a Lancet report found that 10 of the 17 cancers that are increasing in young people in the US are obesity-related malignancies , such as kidney, ovarian, liver, pancreatic, and gallbladder cancer, as well as myeloma (plasma cell cancer).
"The overall evidence points to a change in lifestyle," says Shuji Ogino, a professor of pathology and epidemiology at Harvard University who studies the rise in the number of cancer patients under the age of 50.
"Each of us has thousands of genetic variants, some of which confer a very small increased risk of cancer, which increases when combined with certain changes in the environment.
"We know that consuming too much sugar and processed food, consistently high blood glucose levels and insulin resistance not only increase the risk of diabetes but also cancer."
But obesity is not the answer to all questions.
O'Reilly says that many younger patients with pancreatic cancer are in good physical shape and apparently healthy, and there are no clear explanations for why they got the disease.
"I certainly always think that the traditional causes that we think about generally don't apply to these people," she says.
"They often look healthy, lively and in excellent physical condition".
Ogino believes that this may mean that it is some other carcinogens (any substance, radioisotope or radiation that directly participates in causing cancer) that have previously received less attention.
Watch the video: Twelve symptoms of breast cancer
While epidemiologists have long focused their attention on the link between smoking and cancer, the number of smokers in the world has decreased significantly in recent decades.
According to WHO data, now every fifth person in the world uses tobacco products, while in 2000, every third smoked.
Ogino believes that the connection between the onset of cancer and the noticeable changes in sleep patterns around the world that have occurred in the last 50 to 100 years has been largely overlooked.
One study showed that between 1905 and 2008, the average sleep duration of children and adolescents decreased by 60 minutes per night, while shift work in recent decades became more and more popular in Australia, China, Japan, Europe, and North and South America.
A 2021 study using data from the English Longitudinal Study of Aging, a database containing data on more than 10.000 people over the age of 50, found a link between poor sleep quality and a higher risk of cancer.
Some scientists even claim that our almost constant exposure to artificial light, whether it's street lighting or mobile phones and tablets, is a new carcinogen because it causes disturbances in the body's biological clock, which is linked to breast, colon, ovarian, and prostate cancer.
Studies even indicate that constant exposure to light during night shift work can facilitate the growth of cancer by lowering the level of the hormone melatonin.
"At night we are exposed to a lot of artificial light, even when we are babies," says Ogino.
"And in Japan, for example, a significant part of the population stays up until midnight every night.
"Shift work has become more common because of things like 24-hour stores."
Ogino says it is unlikely that there is a single risk factor in many of these cancers in people under 50, but that there is a complex of factors that work together to cause the disease.
Many cancer scientists believe that the key cause of cancer is actually the consequences of various toxic changes in the intestines that are accompanied by lifestyle changes.
In June 2023, Frank Fricele, a colorectal surgeon at the hospital Christchurch Hospital in New Zealand, has issued something of a "call to battle" to colon cancer experts around the world, asking them to investigate in more detail possible links between the ingestion of large amounts of microplastics and the development of colon cancer in people under 50.
His work called "Could microplastics be a trigger for colon cancer in people under 50?", claims that the appearance of this type of cancer, as an increasingly problematic disease in people under the age of 50, coincides with the time frame in which microplastics became exponentially more present in the environment.
His work indicates that the presence of these tiny plastic particles can disrupt the mucus layer of the large intestine, which protects the intestinal mucosa from various pathogens and toxins from the food we eat.
"Micro and nanoplastics can lead to a kind of penetration through the mucus layer, like when a condom is punctured with a needle," he explains.
"If we can prove this to be true, it could be related to size, as in the relationship between carbon particle size and lung disease."
Currently, this is still at the level of conjecture, but Fritzel is not the only scientist who has linked toxic changes in the intestines to possible carcinogens.
Other researchers suggest that certain components in ultra-processed foods may play a role in triggering inflammation and DNA damage in the colon, from food coloring do emulsifier, although, as with microplastics, the evidence remains relatively limited.
Since the colon is connected to the stomach and the digestive system, as well as to the immune system, pronounced changes in the intestines are not only associated with colon cancer, but also with various solid tumors, including breast cancer, including blood cancer.
Researchers are investigating whether the use of antibiotics can be a factor influencing the development of cancer.
Regarding exposure to microplastics, the use of antibiotics worldwide has increased in recent decades.
It is especially noted increase in the amount of antibiotics taken by children under the age of five - from 9,8 per 1.000 people in 2000 to 14,3 in 2018.
Overall, per capita consumption of antibiotics worldwide across all age groups increased between 2000 and 2015, which O'Reilly says is a key cause for concern.
Given the ability of antibiotics to remove large amounts of bacterial species and thus drastically alter the gut microbiome in potentially harmful ways, higher exposure to antibiotics has previously been linked to lung cancer, lymphomas, pancreatic and renal cell cancers, and multiple myeloma.
"The bacteria that live in the gut have been selected by a kind of Darwinian process and are part of the immune surveillance that allows our immune system to recognize abnormal cells, foreign particles and above all to prevent malignancy," says O'Reilly.
"It's not yet known, but it's hypothesized that higher exposure to antibiotics may mean immune surveillance isn't working as effectively as it should."
One of the possible consequences of the excessive use of antibiotics is that by destroying the so-called commensal bacteria, species originating from the intestine, space is created that can then be filled by malignant microbes.
Over the past 10 years, Ogino and his colleagues around the world have published numerous studies on certain opportunistic pathogens that appear to be able to invade the gut and cause changes in cells that increase the risk of cancer.
In particular, Ogino and other scientists discovered that a bacterium called Fusobacterium nucleatum probably capable of initiating precancerous intestinal growths, as well as the development of more aggressive tumors.
Other studies have shown that certain types of Escherichia coli bacteria are capable of triggering the development of cancer while weakening the body's immune response.
As with sleep deprivation and obesity, Ogino says there are multiple factors from childhood to adulthood that trigger cancer in people under 50, and that their effects likely combine to gradually increase the risk of developing the disease in early adulthood.
He points out that although most of us have some type of Escherichia coli, his research has shown that these bacteria tend to flourish the most when we eat a so-called "Western diet" high in ultra-processed foods, indicating that diet also plays a role.
We are still a long way from knowing exactly why different groups of people under the age of 50 get cancer.
But O'Reilly says it is essential that scientists try to examine them in more detail to try to avoid a global health catastrophe in the coming years.
"There is a huge need for research to try to understand what happens and what drives these diseases much earlier in life," she says.
"I think it's an incredibly frightening observation that the incidence of pancreatic cancer and other solid organ cancers is increasing in young people.
"I believe it threatens to cause a public health crisis."
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