Plans to lower the bowel cancer screening age to 50 could do more harm than good, experts have warned.
At present, screening is offered to men and women in England and Wales between 60 and 74, using home testing kits every two years.
Health Secretary Matt Hancock announced in August 2018 the screening threshold would be lowered to 50, bringing it in line with Scotland.
Those plans are yet to be implemented – but details of a roll-out are expected to be announced next week.
Figures released by medical journal The Lancet claim that an NHS bowel cancer test fails to detect about one third of abnormal growths and potentially fatal tumours
They received a blow, however, when a group of international experts writing in the British Medical Journal said mass screening in this age group is not beneficial.
British charities and doctors hit back – stressing that age-based screening is the best system they have at their disposal, and lowering the age threshold will save lives.
But the BMJ’s experts, led by scientists from Norway, Canada and the US, said those who are at low risk of the disease, but whose home tests raise red flags, could be harmed by the resulting colonoscopies.
The panel said at the age of 50 most people have a one to two per cent risk of developing bowel cancer in the next 15 years.
They calculated that people should only be tested if their 15-year cancer risk reaches three per cent – at which point the risk of cancer overtakes the risk of side effects.
The scientists wrote: ‘After age 50, colorectal cancer risk increases by 0.5 to 1.5 per cent every five years for most people.’
They said that instead of screening based on age alone, everyone’s individual risk should be assessed and a test offered.
‘People need balanced information to decide whether they wish to screen for colorectal cancer, and public health efforts should focus on shared decision making for individuals who are eligible for screening,’ the scientists wrote.
‘As many well informed individuals will choose to forego screening, discussion and information sharing on screening for colorectal cancer would be a better marker of care rather than uptake.’
British experts criticised the findings, saying there is no accurate way at present to determine individual risk.
Dr Lisa Wilde, director of research and external affairs at Bowel Cancer UK, said: ‘Inviting people to take part in bowel cancer screening based on their individual risk of developing the disease is absolutely something we would like to see in the future.
‘However, at the moment we’re a long way off this being possible and as the research highlights, there is more work needed in this area to make this a reality.
‘We know that the current bowel cancer screening programme saves lives.
‘The new screening test, the faecal immunochemical test, is a game changer as it can detect twice as many cancers and four times as many adenomas (pre-cancerous growths) than the previous screening test and is much easier for people to use.
‘We welcome studies that look at ways to improve the current screening programme as early detection of bowel cancer gives people the best possible chance of survival.’
Bowel cancer is the second deadliest cancer in the UK, claiming 16,000 lives a year, and about one in 20 are diagnosed with it in their lifetime.
Currently only 10 per cent of bowel cancer cases are diagnosed through screening, with roughly a fifth of diagnoses not made until the patient is in an emergency department.
By this time, the cancer has often spread around the body and cannot be cured.
Stephen Duffy, professor of cancer screening at Queen Mary University of London, said a move to separate patients based on their risk was ‘premature’.
He said: ‘As the panel notes, we already screen based on the most important risk factor of all – age.
‘How much the other risk factors would add to this is unclear.
‘This also means that it is not certain what the total numbers of lives saved would be in the UK under the panel’s recommended regimen compared to the current bowel screening programme.’
But Professor Anne Mackie, director of screening at Public Health England, said the National Screening Committee will take the new recommendations into account as it looks to improve the screening programme.