British women under 50 are around 70 per cent more likely to develop cancer than men of the same age, worrying data reveals.
A similar pattern has emerged in the United States, where women under 50 are now 82 percent taller than men of the same age, compared with a difference of 51 percent two decades ago.
The gender discrepancy comes amid a skyrocketing of illnesses among young people on both sides of the Atlantic, with overall cancer cases in those under 50 rising by 79 percent since the 1990s.
In the UK, cases of some forms such as breast and bowel cancer in some younger age groups have increased by 17 per cent and 63 per cent respectively.
Now, American experts have explored the trend and suggested why the gender difference may exist.
One reason is falling rates of some cancers that affect men.
These include cases of melanoma, non-Hodgkin lymphoma, a blood cancer, and prostate cancer.
At the same time, cancer cases affecting women have increased among younger women, American Cancer Society experts explain in CA: A Cancer Journal for Clinicians.
Working-age women are now almost twice as likely to suffer from cancer as men, a worrying new report reveals following a rise in breast and thyroid cancers.
Almost half of all cancer cases affecting young women under 50 are currently breast or thyroid.
Breast cancer in young women in the UK has increased by 17 per cent since the 1990s, while thyroid cancer, which affects the small butterfly-shaped gland in the neck, has soared by 256 per cent. .
The researchers added that changes in cancer screening practices may also have led to an increase in diagnoses in younger women.
Data from Cancer Research UK (CRUK) suggests that the gap in cancer risk for men and women under 50 in Britain peaks in the early 40s.
Cancer rates among women of this age reach almost 270 cases per 100,000 women, more than double those of men of the same age (130 cases per 100,000 men).
Experts say the exact cause driving the rise in breast cancer is unknown, but they suggest several factors could be involved.
One theory is greater exposure to lifestyle factors such as smoking and drinking compared to historical levels.
While only one in 10 women are now smokers, rates were as high as one in four in the 1990s, which could have contributed to diagnoses a decade or two later.
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Constant, regular drinking can cause the buildup of a carcinogenic chemical in the body called acetaldehyde, which can increase the risk of some types of breast cancer.
The rise of “wine o’clock” culture has also been blamed for the increase in alcohol consumption among women; Some studies show that heavy drinking has increased by 57 percent among British women since 2019.
Obesity is another known risk factor for breast cancer, as fat cells can produce estrogen and higher levels of this female sex hormone are linked to the development of breast cancer.
Government data shows the proportion of women in England who are obese almost doubled between 1993 and 2019, from 16 per cent to 29 per cent.
And it is estimated that eight per cent of breast cancer cases in England are caused by obesity and a further eight per cent are suspected to be caused by alcohol consumption.
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Thyroid cancer cases have exploded even further in Britain, with rates in women aged 25 to 49 rising by 256 per cent in the same period.
While diagnoses in men of the same age have also increased, many more women suffer from the disease than men.
There are around 3,000 cases of thyroid cancer in British women each year, compared to just 1,000 cases diagnosed in men.
Experts are still trying to unravel the reasons why women are more vulnerable, but some suspect that fluctuations in female sex hormones that occur throughout a woman’s life are involved.
CRUK also said women under 50 have seen significant increases in small bowel (119 per cent) and kidney (96 per cent) cancers since the 1990s.
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However, they added that because the total number of cases of these cancers, including thyroid cancer, diagnosed each year is low, such increases should be interpreted with caution.
The overall risk of cancer is known to increase greatly with age as damage to cells, which can lead to the disease, accumulates over time.
However, an explosion of so-called early-onset cancer, medically defined as cases of the disease in adults under 50, has sparked alarm among experts.
Part of the concern is that it is happening globally. A 2023 study published in the British medical journal It found that cases of early-onset cancer overall increased globally by 79 percent between 1990 and 2019.
Experts also predicted that cancer cases among young people will rise even further, by an additional 31 percent by 2030.
World Health Organization data shows Australia had the highest number of early-onset cancer diagnoses in the world, with a rate of 135 per 100,000 people in 2022.
New Zealand came in second, with 119 cases per 100,000 people among young people.
In comparison, the UK and US were well below but still up in the global rankings, ranking 28th and 6th respectively.
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Much concern has focused on juvenile bowel cancer, with victims such as Dame Deborah James, who died from the disease aged 40.
A report last month warned that disease rates among young people are rising by 3.6 per cent each year in England, one of the fastest growth rates of the disease seen in the world.
Scientists are still trying to explore the factors behind the rise in early-onset cancers, with some suggesting that modern diets and exposure to substances such as microplastics, or a combination of several triggers, could be to blame.
Katrina Brown, senior cancer intelligence manager at CRUK, said finding out why this was happening and why younger women appeared to be at higher risk was an area that needed more research.
“We know that risk factors such as diet, obesity, alcohol and smoking could explain the increase in cancer in some age groups,” he said.
“Improvements in screening, meaning people are diagnosed at a younger age, could also play a key role in higher rates of early-onset cancers.”
Although early-onset cancer is increasing, it still represents only a fraction of total recorded cases of the disease.
More than half of cancer cases in the UK are diagnosed among people over 50, and one in three cases specifically among people over 75.
CRUK data also shows that the risk of an individual being diagnosed with cancer peaks between the ages of 85 and 89.
On average, around 25,000 cases of cancer are diagnosed each year among British women under the age of 50, accounting for just 13 per cent of all cancers among women.
Although men have lower cancer incidence rates among those under 50 years of age, this trend reverses after age 60.
In general, men have a cancer rate of approximately 690 cases per 100,000 people, while for women the figure is 550 cases per 100,000.