Is preventing disease before it happens the future for NHS?

Earlier this week, researchers unveiled the results of a pilot study evaluating a potential new test for prostate cancer - the most common form of the disease among men in Scotland, but for which there is currently no routine screening tool.

Like most cancers, the number of cases diagnosed each year in Scotland has been rising rapidly as people live longer.

In 1996, there were just over 2,200 cases of prostate cancer detected in Scotland; by 2019 - the last full year before Covid disrupted the health service - that had climbed to 3,780, an increase of around 70 per cent in 23 years.

It is inevitable that incidence will increase as the population ages: living into old age is the single biggest risk factor for cancer.

READ MORE: 'Shocking north-south divide' in prostate cancer diagnoses 

If you are a man in Scotland, for example, your chances of developing prostate cancer are more than 12-fold higher if you are in your 80s compared to being aged 50 to 54.

However, recent analysis by Prostate Cancer UK also found that 35% of men in Scotland were being diagnosed with the disease at stage four - by which time it had spread and become incurable - compared to just 12.5% of men in London.

Detecting prostate cancer at a very early stage is tricky because there are often little or no symptoms, and the current PSA blood test which checks for a protein biomarker associated with the disease is too unreliable for routine use (only around a quarter of people who have a prostate biopsy due to an elevated PSA level are actually found to have prostate cancer).

The alternative blood test - known as a PSE test, and devised by Oxford BioDynamics in collaboration with scientists at Imperial College London and the University of East Anglia - was 94% accurate in detecting prostate cancer when tested on 147 men known to have the disease.

The next step will be to trial it in a sample of men whose cancer status is unknown. If successful, however, this could pave the way to much faster diagnoses of prostate cancer at an earlier, treatable stage - potentially even through routine screening programmes, similar to those already used for breast, bowel, and cervical cancers.

The real “Holy Grail” of cancer medicine, however, is the long-touted idea of a universal blood test: a one-stop-shop capable of picking up one of a number of cancers long before any symptoms emerge.

It may sound like science fiction, but one possible candidate - the Galleri test - is already being assessed via the NHS in England and Wales in what is the world’s largest clinical trial to date of the technology.

READ MORE: Why are Scotland's cancer deaths lower in 2022 than before the pandemic - and will it last?

The NHS-Galleri trial, which launched in September 2021, has been recruiting 140,000 asymptomatic volunteers aged 50 to 77 with no recent history of cancer treatment or diagnosis.

Participants are split into two groups - half receiving the Galleri blood test and half having their blood samples stored for the future.

The Galleri test looks for traces of abnormal DNA in patients’ blood - a signal that they might be developing cancer. Early research in the US suggested that Galleri was able to accurately detect over 50 types of cancer, including pancreatic and oesophageal cancers which tend to be diagnosed late.

The much larger NHS trial will provide much more robust evidence of its success rate.

The Galleri test is seen as a potential 'Holy Grail' in cancer detection, but results from the trial will not be known until 2025 (Image: Grail)

Its manufacturers, Grail, say that it could enable the NHS to diagnose three quarters of all cancer cases at stages one or two by 2028 (compared to around half now), but final results from the trial are not expected until 2025.

If they meet required thresholds, however, the plan is for an almost immediate population-wide rollout of Galleri as a routine screening tool for all eligible age groups.

Along with early detection, however, it also carries the risk of false positives for participants whose blood tests throw up a worrying result only for subsequent scans and investigations (which themselves may carry a risk of unnecessary exposure to radiation, for example through CT scans) to rule out the disease.

The key will be weighing up whether the benefits outweigh the harms.

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The peril of the ageing population is not unique to the NHS, of course.

A panel discussion at the recent Davos summit entitled ‘The Economy of a Super-Ageing Society’ noted that the proportion of the world’s population aged 60-plus is set to nearly double, from 12% in 2015 to 22% by 2050.

This “silver tsunami”, as one panellist put it, has huge implications for healthcare costs globally.

The imperative is to find ways of keeping people well much longer into old age, partly so that they can continue to work (and thus generate taxes) but also because it will become increasingly unaffordable to spend millions keeping people alive in poor health for 15-20 years or longer at the end of their lives when money could be better invested in solutions to prevent people falling ill in the first place.

This goes beyond early cancer detection.

One of the mobile clinics being used as part of the Our Future Health clinical trial (Image: Twitter/@ukfuturehealth)

One trial already underway in the UK - Our Future Health - aims to recruit five million volunteers over five years through its mobile clinics located in supermarket car parks.

Participants’ blood samples will be analysed for genetic, protein, and metabolic clues that indicate they are either in the early stages of disease or at risk, with the goal that everything from cancers to hearts attacks and strokes could be averted through pre-emptive lifestyle or medical interventions.

No one knows yet whether it will work - saving the NHS money and keeping out of hospital - or be counterproductive, resulting in too many misdiagnoses.

That is what the trial will find out.

Its lead researcher, Dr Raghib Ali, expects to have the answers within five years.

The current system - more people requiring ever-more expensive medicines for longer - is “not sustainable”, he said.

Health systems of the future must pivot to preventing illness and keeping people well - not waiting until they are sick.