British women under 50 are around 70 per cent more likely to develop cancer than men of a similar age, worrying data has revealed.
A similar pattern has emerged in the US, with women under 50 now 82 per cent higher than men of the same age — compared to a difference of 51 per cent two decades a go.
The gender discrepancy comes amid a soaring rise in disease among young people on both sides of the atlantic, with global cases of cancer in the under 50s rising by 79 per cent since the 1990s.
In the UK, cases of some forms like breast and bowel cancer in some younger age groups have risen 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 the falling rates of some cancers that affect men.
These include cases of melanoma, the blood cancer non-Hodgkin lymphoma, and prostate cancer.
Simultaneously, cases of cancers that affect women have risen in younger women, experts from the American Cancer Society, explain in the journal CA: A Cancer Journal for Clinicians.
Working-age women are now more nearly twice as likely to get cancer than men, a worrying new report reveals after rises in breast and thyroid cancers
Almost half of all cancer cases that affect young women aged under 50 are now breast or thyroid.
Breast cancer in young, UK women has risen by 17 per cent since the 90s, while thyroid cancer — which affects the tiny butterfly-shaped gland in the neck — has soared 256 per cent.
The researchers added that changes in cancer screening practises could also have led to increased diagnoses in younger women.
Data from Cancer Research UK (CRUK) suggests the cancer risk gap for men and women under 50 in Britain peaks in the early 40s.
Cancer rates for women this age reach almost 270 cases per 100,000 women, more than double the figure for men of the same age (130 cases per 100,000 men).
Experts say the exact cause driving the increase in breast cancer is unknown but suggest several factors could be involved.
One theory is increased exposure to lifestyle factors like 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 90s, which could have contributed to diagnoses a decade or two later.
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Consistent, regular drinking can lead to a build-up of a cancer-causing chemical in the body called acetaldehyde which can drive up the risk of some types of breast cancer.
The rise of ‘wine-o-clock’ culture has also been blamed for increased alcohol consumption in women with some studies showing binge drinking has increased 57 per cent among British women since 2019.
Obesity is another known risk factor for breast cancer as fat cells can produce oestrogen 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 nearly doubled between 1993 and 2019 — from 16 per cent to 29 per cent.
And estimated eight per cent of breast cancer cases in England are thought to be caused by obesity with an additional eight per cent suspected to be caused by drinking alcohol.
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Cases of thyroid cancer have undergone an even greater explosion in Britain with rates in women aged 25 to 49 rising 256 per cent in the same period.
While diagnoses in men of the same age have also risen, far more women suffer the disease than men.
About 3,000 cases of thyroid cancer are recorded in British women each year, compared to just 1,000 cases diagnosed in men.
Experts are still trying to unpick the reasons why women are more vulnerable, but some suspect the fluctuations in female sex hormones that occur during a woman’s life are involved.
CRUK also said women under 50 have seen significant increases in cancers of the small intestine (119 per cent) and the kidney (96 per cent) since the 90s.
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However, they added that as the overall number of cases of these cancers, including thyroid, diagnosed each year is low, such increases should be interpreted with caution.
Overall cancer risk is known to broadly increase with age as damage in cells, which can spark the disease, accumulate over time.
However, an explosion in what is called early onset cancer, medically defined as cases of the disease in adults under the age of 50, has sparked alarm among experts.
Part of the concern is that it’s happening globally. A 2023 study published in the British Medical Journal found cases of early onset of cancer increased overall globally by 79 per cent between 1990 and 2019.
The experts also predicted cases of cancer in the young are set to rise further, by an additional 31 per cent by 2030.
World Health Organisation 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 second, with 119 cases in per 100,000 people among the young.
In comparison the UK and the US were far lower but still high in the global rankings, coming 28th and 6th, respectively.
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Many of the worries have centred around young bowel cancer with victims including the likes of Dame Deborah James who was killed by the disease aged 40.
A report last month warned rates of disease among young people are rising 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 modern diets and exposure to substances like microplastics, or a combination of several triggers, could be to blame.
Katrina Brown, senior cancer intelligence manager at CRUK, said uncovering the why this was happening, and why young women seemed to have a greater risk, was an area needing further research.
‘We know that risk factors like diet, obesity, alcohol, and smoking, could explain the rise of cancer in some age groups,’ she said.
‘Improvements to detection, meaning that people are diagnosed at a younger age, could also be playing a key role in higher rates of early onset cancers.’
While early onset cancer is on the rise it still accounts for only a fraction of cases of the disease recorded in total.
More than half of cancer cases in the UK are diagnosed among the over 50s, with one in three cases specifically among the over 75s.
CRUK data also shows an individual’s risk of being diagnosed with cancer peaks between the ages of 85 to 89.
On average about 25,000 cancer cases are diagnosed among British women under the age of 50 each year, which accounts for just 13 per cent of all cancers among women.
While men have lower cancer incidence rates in the under 50s, this trend reverses from the age of 60 onward.
Overall, men have a cancer rate of about 690 cases per 100,000 people, for women the figure is 550 cases per 100,000.
