Women may only need three cervical screens in their lifetime if they have been given the human papillomavirus (HPV) vaccine, a UK study has found. The Cancer Research UK-funded team from Queen Mary University of London (QMUL), found that three screens at 30, 40 and 55 would offer the same benefit to vaccinated women as the 12 lifetime screens currently offered in England.
The results are based on how the HPV vaccine and the improved cervical screening programme will work best together. The new programme called HPV primary testing is set to be introduced in England by December 2019. It means that cervical samples are tested for HPV but only checked for abnormal cells if the virus is found. The current test checks for abnormalities first, which is less efficient.
Scotland and Wales are also preparing their own plans to introduce this new HPV test.
Since 2008, the HPV vaccine has been offered to schoolgirls aged 11-13 across the UK. This group is now reaching the age for their first cervical screening invitation. This new research shows that these women can still be effectively protected from cervical cancer with fewer screens, which could also save the NHS resources.
Professor Peter Sasieni, Cancer Research UK's screening expert and lead author based at QMUL, said: "The NHS should benefit from the investment that it's made by introducing the vaccination programme. These women are far less likely to develop cervical cancer so they don't need such stringent routine checking as those at a higher risk. This decision would free up resources for where they are needed most. The change in the screening system is a unique opportunity to reassess how often women are invited for cervical screens during their lifetimes."
HPV infects most people at some point. Most infections go away on their own, but if an infection is not cleared it can go on to cause cervical cancer. Without HPV infection there would be almost no cervical cancer.
The current HPV vaccine protects women against the most dangerous forms of HPV significantly reducing the chance of developing cervical cancer. As the risk of cervical cancer is considerably reduced, the study suggests that the number of screens should be decreased accordingly, avoiding unnecessary procedures for women.
The study also suggests that unvaccinated women should only need seven lifetime screens when the new screening test comes in, five fewer than is currently standard.
Dr Julie Sharp, head of health information at Cancer Research UK said: "This is great news for women. The cervical screening programme is already very successful, and has led to a dramatic fall in deaths from the disease since its introduction. While we hope to see these improvements to the screening programme in the future, it's important that women continue to take up invitations for cervical screening. So if you're all set for your next screen, keep that appointment."
Women vaccinated against HPV16/18 are approaching the age for cervical screening; however, an updated screening algorithm has not been agreed. We use a microsimulation model calibrated to real published data to determine the appropriate screening intensity for vaccinated women. Natural histories in the absence of vaccination were simulated for 300,000 women using 10,000 sets of transition probabilities. Vaccination with (i) 100% efficacy against HPV16/18, (ii) 15% cross-protection, (iii) 22% cross-protection, (iv) waning vaccine efficacy and (v) 100% efficacy against HPV16/18/31/33/45/52/58 was added, as were a range of screening scenarios appropriate to the UK. To benchmark cost-benefits of screening for vaccinated women, we evaluated the proportion of cancers prevented per additional screen (incremental benefit) of current cytology and likely HPV screening scenarios in unvaccinated women. Slightly more cancers are prevented through vaccination with no screening (70.3%, 95% CR: 65.1–75.5) than realistic compliance to the current UK screening programme in the absence of vaccination (64.3%, 95% CR: 61.3–66.8). In unvaccinated women, when switching to HPV primary testing, there is no loss in effectiveness when doubling the screening interval. Benchmarking supports screening scenarios with incremental benefits of ≥2.0%, and rejects scenarios with incremental benefits ≤0.9%. In HPV16/18-vaccinated women, the incremental benefit of offering a third lifetime screen was at most 3.3% (95% CR: 2.2–4.5), with an incremental benefit of 1.3% (−0.3–2.8) for a fourth screen. For HPV16/18/31/33/45/52/58-vaccinated women, two lifetime screens are supported. It is important to know women's vaccination status; in these simulations, HPV16/18-vaccinated women require three lifetime screens, HPV16/18/31/33/45/52/58-vaccinated women require two lifetime screens, yet unvaccinated women require seven lifetime screens.
Rebecca Landy, Peter Windridge, Matthew S Gillman, Peter D Sasieni
[link url="https://www.sciencedaily.com/releases/2017/11/171109224038.htm"]Cancer Research UK material[/link]
[link url="http://onlinelibrary.wiley.com/doi/10.1002/ijc.31094/abstract;jsessionid=ADC1667DD247821A0DDA8794D822B817.f02t01"]International Journal of Cancer abstract[/link]