11 loại ung thư đang gia tăng ở người dưới 50 tuổi tại Anh – những yếu tố này có thể giải thích xu hướng đó

Rising cancer rates in younger adults are real, worrying and still partly unexplained.

A new analysis adds important detail for England, suggesting that 11 cancers are becoming more common in people under 50, highlighting a broader shift in who gets cancer and when.

For a generation that expects to be building their lives, cancer is arriving unexpectedly early, and health services are only just beginning to adapt.

The new analysis found that rates of breast, bowel, melanoma, thyroid, multiple myeloma, liver, kidney, gallbladder, pancreatic, womb, mouth and ovarian cancer are all rising in under-50s. They also found that diagnosis rates of many of the same cancers are stable or even falling in older age groups.

This pattern isn’t unique to England. International data shows that early–onset cancers – those diagnosed before age 50 – have been increasing in many countries over the last few decades.

In the UK, the overall number of cancers in people aged roughly 25 to 49 has risen by around a quarter since the early 1990s, even after accounting for population growth.

Globally, the steepest rises in younger adults have been seen in cancers of the bowel, breast, uterus, kidney and several digestive organs, as well as melanoma of the skin.

The new English data fits this broader picture and highlights that the trend cuts across both sexes – though the exact cancers and rates differ between men and women.

Modelling studies also suggest that, without changes, early‑onset cancer rates and deaths could increase by more than 12% by 2050.

One possible explanation for this finding is that we’re simply getting better at finding cancers. This means tumours that might previously have been missed are being picked up earlier.

Earlier diagnosis is, of course, a good thing. But it cannot explain the whole story. Some of the cancers the study showed are rising in younger adults are being found at more advanced stages. This suggests they’re genuinely occurring more often rather than merely being detected earlier.

Lifestyle and cancer risk

So what else is going on?

The clearest suspect is excess body weight and the metabolic changes that accompany it.

Being overweight or obese is now the second biggest preventable cause of cancer in the UK after smoking. Excess weight is linked to more than a dozen cancers, including bowel, breast (after menopause) , womb and kidney cancers.

Crucially, obesity is starting earlier in life and has become more common in children, teenagers and young adults over the last 30 to 40 years. So younger generations may have had longer exposure to the hormonal and inflammatory effects of excess body fat.

But obesity does not exist in isolation. It’s part of a wider shift in our lifestyles.

Diets higher in alcohol and ultra‑processed foods, red and processed meat and sugar‑sweetened drinks, and lower in fibre, are linked to higher risks of bowel and other digestive cancers.

Many of us also spend long hours sitting each day and aren’t physically active enough. This worsens weight gain and inflammation – processes thought to influence cancer risk.

Irregular sleep patterns and night‑shift work may also disrupt our body clocks and hormones (including melatonin) , which might affect how cancers develop – although this research is still emerging.

Scientists are also looking beyond lifestyle to factors we are only beginning to understand.

There’s growing interest in how environmental pollutants and carcinogens might contribute to rising cancer rates – especially if younger generations have been exposed to these factors for longer or at higher levels than their parents.

Changes in the gut microbiome, the vast community of bacteria that live in our intestines, are another candidate. Diet, antibiotic use and modern hygiene all influence which microbes we carry. This in turn can affect inflammation, immunity and how we process potential carcinogens.

Earlier puberty and hormonal changes, possibly related to nutrition and environment, may also play a part by increasing the number of years breast and reproductive tissues are exposed to hormones.

Together, these ideas point to an unsettling conclusion: cancer risk may begin much earlier than we think.

No single factor is proven to be the cause. It’s likely that multiple factors – lifestyle, environment, infections, hormones and genetics – influence risk over time. That makes prevention more complicated – but it also offers opportunity to act.

What this means for young people

For any person in their 20s, 30s or 40s, the absolute risk of developing cancer still remains relatively low. And, when cancers are diagnosed in younger people, their bodies often tolerate treatment better and survival can be higher. Nonetheless, the rise matters.

The trend also challenges assumptions in both patients and professionals. Doctors may not immediately think of cancer when a 30‑year‑old patient reports symptoms such as persistent bloating, rectal bleeding, a breast lump or unexplained weight loss. This can delay investigation and diagnosis.

Younger people themselves may dismiss or ignore symptoms because they think they’re too young to have cancer. Changing this mindset is one of the key tasks ahead.

Policies that support healthier food environments, active transport, reduced smoking and alcohol use and cleaner air are likely to pay dividends for overall population health, too.

On an individual level, steps such as not smoking, maintaining a healthy weight, being physically active, limiting alcohol, protecting skin from intense sun, keeping up to date with vaccines (such as HPV) can all lower risk of cancer.

Perhaps the most important message for younger adults is not one of fear, but of awareness. Cancer is still uncommon at a young age, but it’s no longer as rare as it once was. Seeking medical advice for persistent or unexplained symptoms can help cancers be found earlier.

Justin Stebbing does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.