Health
Breaking down barriers to cervical screening – the evidence for HPV self-sampling – Cancer Research UK
The Alliance – which has now morphed into two separate entities, North East London, and North Central London – agreed to fund a large self-sampling study, YouScreen, to build on the findings of ALOHA.
“Essentially, in YouScreen, we did what we did in ALOHA but with a key difference,” says Sasieni. “We persuaded England’s national screening programme that if study participants returned a sample, it formally counted as having been screened.”
This was important for two reasons. First, if GPs knew participating would count towards their screening reimbursement, they’d be much more likely to offer a test kit. And second, it benefited participants too. “During ALOHA, participants would occasionally get annoyed – they go ‘hang on a minute, four months ago, I got a letter to say my test result was negative and everything’s fine. And now I’ve got a letter saying I missed my last appointment, so I need to come for screening’. So, it was vital that we made the trial screening count as part of the national programme.”
YouScreen launched in 2021, and its findings were published three years later: nearly two-thirds of around 9,000 non-attenders returned a sample after being offered a kit by their GP, along with 12% of some 17,500 who received one in the post. Overall, this represented a significant increase in coverage among non-attenders: self-sampling was indeed feasible and could help boost rates.
And, even more positively, 6 in 10 people who took part were from deprived backgrounds, and around 6 in 10 were from ethnic minority groups. This showed self-sampling had huge potential to minimise inequities in cervical screening.
Sasieni’s team also led a parallel economic analysis, in collaboration with colleagues in Australia, based on the YouScreen data – which rigorously modelled how cost-effective self-sampling might be under a range of different conditions.
Together, these were vital pieces of the puzzle. But YouScreen’s primary aim was to determine whether participants would, in practice, return their kits. It was less concerned with how accurate the tests were, nor whether they’d work on standard NHS equipment.
For self-sampling to be scaled up across the UK’s diverse patchwork of healthcare systems, these questions needed answers, and Matejka Rebolj’s team, working closely with Jo Waller and her colleagues, set out to find them.
Validation
A HPV test has two components.
On the one hand, there are the kits used to take vaginal samples – and there now are scores of such devices on the market.
On the other, there are the laboratory machines used to analyse these samples. And by 2019, with cervical screening across the NHS now reliant on HPV testing rather than cytology, two separate, equally effective laboratory technologies had been approved: one that relied on testing for viral DNA, the other analysed levels of viral mRNA. That means, says Rebolj, “half of the country’s labs now use DNA and the other half use mRNA.”
With attention turning to self-sampling, that meant that any home test kits the NHS procured would need to be compatible with both platforms. QMUL experts Cuzick and the late Louise Cadman had begun to investigate this issue in the late 2010s, testing a range of self-sampling devices in the Predictors studies.
But with momentum building, and recognising the need to pin this down before self-sampling could be rolled out, Public Health England commissioned a large study to test five combinations of three different kits and two analysis machines, within existing NHS HPV testing laboratories. The study, called HPValidate, launched in 2021 and ran across five regions of England.
