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 age groups, a new study finds.
Published in the BMJ Oncology, the study included analysis of cancer incidence trends in England from the National Disease Registry Service for the period 2001 to 2019.
Led by researchers from the Institute of Cancer Research and Imperial College London, it 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 any differences.
Their 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.
There was also 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, 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, but 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.
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 cancer, the researchers say it is unlikely to fully explain this trend.
In addition to excess weight, liver, bowel, mouth, pancreas, kidney and ovarian cancers were linked to smoking. Liver, bowel, mouth and breast cancers were associated with alcohol intake; bowel, breast and endometrial cancers were linked to physical inactivity; and bowel was associated with dietary factors.
The researchers noted that 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 highlighted 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 conceded 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 shared the successes of its bowel screening programme, with almost 85 million people being screened and 70,000 cancers having been caught in England since bowel screening started two decades ago.
A further 270,000 people have benefitted from regular surveillance after screening highlighted that they may be vulnerable to developing the disease.
Almost seven million people have had bowel screening from the NHS during 2024/25, compared with around 4.7 million in 2014/15.
Commenting on these results, minister for public health, 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 the most recent findings, the researchers said: ‘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.’
They are therefore calling 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.
In March, Cancer Research UK revealed that cancer death rates have dropped to their lowest level on record but continued action on prevention is key to keep progress from stalling.
This article was originally published by our sister publication The Pharmacist.