Cancer incidence increases among young adults in England
Cases of several cancers are rising faster in England among younger adults than older adults, with rates of bowel and ovarian cancer increasing only among younger adults, a new study finds.
The study, which was published in the open-access journal BMJ Oncology, included analysis of cancer incidence trends in England from the National Disease Registry Service for the period 2001 to 2019
The researchers from the Institute of Cancer Research and Imperial College London compared patterns in cancer incidence by sex in two age groups – adults aged 20–49 years and adults aged over 50 years – for more than 20 different cancer types and assessed whether changes in behavioural risk factors could explain differences.
Commenting of the study, professor of cancer epidemiology at Cedars-Sinai Health Sciences University in Los Angeles, USA, Professor Paul Pharoah, said: ‘[The researchers] noted that most cancers that are rising in incidence in young adults are also rising in incidence in older adults. They also found that established risk factors are unlikely to account for the rising trends.’
Analysis of the data showed that new cases in 16 out of 22 types of cancer in younger women, and 11 out of 21 types of cancer in younger men, increased significantly in England between 2001 and 2019.
The study found that there was a significant rise in 11 cancers with known behavioural risk factors – such as excess weight, smoking, alcohol use, red meat consumption, physical inactivity, and fibre intake – among the under 50s. These were: thyroid, multiple myeloma, liver, kidney, gallbladder, bowel, pancreatic, womb lining (endometrial), mouth, breast, and ovarian cancers.
Notably, five cancers – endometrial, kidney, pancreatic, multiple myeloma and thyroid cancer – increased significantly faster among younger women than in older women, while multiple myeloma increased faster in younger men than in older men.
Rates of all 11 of these cancers also rose significantly among those aged over 50, with the notable exceptions of bowel and ovarian cancers.
According to the researchers, the rising incidence of several cancers among younger adults isn’t unique to England, and it’s not clear if changes in behavioural risk factors explain current trends.
Professor Pharoah said that rises in incidence rates of some cancers in young adults have been reported ‘many times’ in recent years and the way this study was set up meant that it was more useful for hypothesis generating rather than hypothesis testing.
‘It is likely that different factors explain the trends for different cancers and, as noted by the authors, carefully-conducted, large-scale studies in individuals will be needed to identify the specific causes for different cancers.’
Behavioural risk factors
Excess weight emerged as a key contributor to changes in cancer incidence, with all 11 cancers that saw increases in younger adults – except for mouth cancer – being associated with obesity.
Although, excess weight was the risk factor associated with most cancers in 2019, ranging from 5% for ovarian cancer to 37% for endometrial cancers, the researchers say it is unlikely to fully explain this trend.
In addition to excess weight, six cancers – liver, bowel, mouth, pancreas, kidney, and ovary – were linked to smoking; four – liver, bowel, mouth, and breast – were associated with alcohol intake; three – bowel, breast, and endometrial – were linked to physical inactivity; and just one – bowel – was associated with dietary factors.
Established behavioural risk factors accounted for a substantial share of cancer cases. In 2019 these contributed 68% and 65% of mouth cancers for younger and older men, respectively; 42% and 48% of liver cancers; 49% and 53% of bowel cancers, 29% and 33% of kidney cancers and 36% and 34% of pancreatic cancers.
With the exception of excess weight, trends in these risk factors have been stable or improving for younger adults over the past one to two decades.
The researchers said: ‘The observed increasing cancer incidence despite declining trends in several behavioural risk factors may reflect the net effect of multiple influences operating in different directions.
‘Other contributing factors not evaluated here, for example, reproductive history, early-life or prenatal risk factors, and changes in cancer diagnosis and detection practices, may also play a role.’
Bowel cancers, for example, was a notable exception to the trends seen in the study, increasing only in younger adults, pointing to possible generational or early-life exposures.
Bowel cancer screening programmes
The authors highlight that the NHS bowel cancer screening programme, which was introduced for older adults in the mid-2000s, likely contributed to declines in that group.
However, they concede that this screening programme is unlikely to fully explain the differences by age groups given that rates have been different since the early 2000s
The study comes as the NHS announced that they have detected tens of thousands of bowel cancers thanks to their bowel screening programme.
According to the NHS, since bowel screening started two decades ago, 70,000 cancers have been caught in England and almost 85 million people have been screened.
A further 270,000 people have benefited from regular surveillance after screening highlighted that they may be vulnerable to developing the disease.
Almost 7 million people have had bowel screening from the NHS during 2024/25, compared with around 4.7 million in 2014/15.
Minister for Public Health, Minister Sharon Hodgson said: ‘Bowel cancer screening prevents thousands of unnecessary deaths every single year, and this progress shows what can be achieved when the NHS focuses on catching cancer earlier.’
Cancer burden
In light of their findings, the researchers highlight that, ‘Although increases in cancer in younger adults are concerning, the absolute burden remains far higher in older adults, underscoring the public health and clinical importance of studying risk factors across all ages.’
The authors, therefore, call for more studies to investigate emerging risk factors influencing cancer incidence and the strengthening of prevention efforts, such as NHS bowel cancer screening programme, targeting known factors across all ages.
