A cancer survivor has issued an urgent warning after new research revealed that younger adults are ageing faster than the generations before them, and this makes them more prone to the disease.

A new study published in academic journal Nature Medicine this week examined the rise of early-onset cancers diagnosed in the under-55 age group.

Funded by Cancer Research UK, the global study of more than 160,000 UK and US participants found that younger generations are ageing faster internally.

Those born between 1965 and 1974 showed signs of ageing faster at a cellular level than those born two decades earlier.

The research raised the possibility that this accelerated internal ageing could be contributing to the growing incidence of cancer among younger adults.

'In Australia, Canada, the UK and the US, people born in the 1990s face at least a fourfold higher risk of early-onset colorectal cancer compared with those born in the 1960s,' the study states.

Sydney mother-of-two Kylie Swords knew that something wasn't right when she started suffering gastrointestinal symptoms in 2024.

She sought advice from her GP, who brushed off her concerns and told her she was too young to worry. 

She eventually sought a second opinion and months later, was diagnosed with stage three bowel cancer.

'I was 37. I had two really young kids. I was working full time. It was a huge shock, a huge surprise,' she told Seven News.

Following several major surgeries to remove what doctors had called a 'very curable' cancer and months of gruelling chemotherapy, she has now been in remission for almost a year.

'Get a second opinion if you're not happy with the answers. You're the expert on your body. Nobody's too young for this stuff,' Ms Swords warned.

The study published in Nature Medicine has prompted interest from Aussie researchers. 

'The key gap now is trying to understand what's driving that lifestyle changes, the obesity, the microplastics - they're all things that could be conduits for that acceleration in ageing,' Dr Lochlan Fennell from the University of the Sunshine Coast said.

Researchers on the original study compared blood samples and other health data across different age groups.

They noted any presence of 'wear and tear' markers – such as damaged DNA and inflammation are typically caused by unhealthy lifestyles and exposure to pollutants.

The study found that adults who had a biological age that was higher than their actual age faced an increased risk of developing cancer before 55.

'Biological ageing isn't just about the number of birthdays you've had,' co-author Yin Cao of Washington University School of Medicine wrote.

'It also reflects wear and tear happening inside the body at a cellular and molecular level,' he said.

'This can include changes that affect how cells and tissues function, such as chronic inflammation, weakening of the immune system and damage building up in cells over time.'

They also stressed that the results were observational and do not prove that accelerated biological ageing directly causes cancer.

The researchers said further study is needed to confirm the findings and understand what may indeed be driving the link.