Every single case of cancer that can be prevented, should be and we are passionate about HPV vaccination and cervical screening. We want to every person eligible to feel assured to attend vaccination and cervical screening and to understand what their screening results mean. Here we try to better explain the changes to the programme in Wales and why they have been introduced.
In 2019, the UK National Screening Committee (UK NSC) looked at evidence to consider intervals between screening. Currently in women and people with a cervix aged 50-64, this is every five years. The Committee recommended that this should change to five years for those aged 25-49 but with clear guidance that this would only apply to those with low risk – not everyone. This is an important point and one that was not made as clear as it could have been in the reporting of the interval changes in Wales yesterday.
Why the Changes?
In 2019, the UK NSC changed the primary screening test from cytology (this is where cervical cells are examined under a microscope to find those which might develop into cancer) – to testing for high-risk human papillomavirus (HPV). This was a very important change as our understanding of risks for developing cervical cancer have grown since the screening programme was first introduced in England in 1964 – nearly 50 years ago.
A number of European studies demonstrated that primary HPV screening offers much greater sensitivity, 20% more, compared with cytology. This means that HPV primary testing will be picking up more women and people with cervixes who are at a higher risk of cervical cancer than the previous cytology testing method. One of these large-scale studies was conducted in England, the ARTISTIC trial. This showed since HPV screening offered much greater sensitivity, compared with cytology to detect underlying disease, women who are negative for HPV could have a longer screening interval. This would not apply to women with high-risk HPV.
Our understanding of the causative role of HPV was confirmed in the early 1990’s. This has led to prevention in two ways:
- Primary Prevention: Prophylactic vaccination – girls and boys aged 12 to 13 (born after 1 September 2006) are offered the HPV vaccine – this is part of the NHS vaccination programme
- Secondary Prevention: HPV testing in cervical screening. This is based on greater sensitivity to detecting Cervical Intraepithelial Neoplasia (CIN)* – pre-cancerous cells
*CIN: there are three stages. CIN1 is probably best regarded as a chronic infection and is not treated, CIN2 is treated as is CIN3 a cancer precursor lesion. People do not necessarily go ‘up the scale’ from CIN 1 to CIN 3. Sadly, a small number of women develop CIN3 spontaneously.
Being HPV negative places someone at very low risk, lower than negative cytology. Whereas if you are high-risk (HR) positive, you will be selected for appropriate onward investigation or early recall – you would not fall into screening every five years.
We are exposed to HPV as soon as we become sexually active. Usually, people acquire the infection within 6 months. In the majority of cases our immune system kicks in and the infection is cleared. However, in some cases, specific viral persistence remains. It is this viral persistence which is responsible for cellular changes resulting in CIN. It usually takes a long time for this persistent HPV to develop into abnormal cells, often five years or more. And even longer to then develop into a cancer. This is why some women and people with cervixes are found to have abnormal cells or a cancer may occur many years or even decades after they last had any sexual activity, or sex with a new partner.
Why is Primary and Secondary Prevention Important?
Primary vaccination will have a large impact on the incidence of high-risk HPV infection.
The ‘catch-up’ programme for 14-18 year olds who were vaccinated between 2008-2010 will also be seen, reducing the prevalence of high-risk HPV amongst 25-year-olds being screened from 2015 onwards – so we should now be starting to see these importance changes. The ARTISTIC trial suggests that vaccination could reduce the prevalence of high-risk HPV by around 50% – this is great progress.
Secondary prevention through screening to pick up HPV is not only important for those who have had the vaccine (as the vaccine protects against 4 high-risk viruses, not all HPV viruses as there about 200 of these) is also very important for older women who would not have received the vaccine.
Will I be adversely affected by screening changing from 3 to 5 years?
The changes have come about based on a review of evidence – several large, randomised trials, appraised by the National Screening Committee. Women and people with a cervix who have a high-risk HPV will keep being monitored regularly and CIN 2 and 3 will always be treated. This is in line with worldwide practice. The positive benefits of vaccination are becoming clear – data is continuously being collected which shows this. But vaccination does not cover every strain of HPV and so cervical screening must continue.
With the introduction of an HPV based programme, the evidence states people with cervixes can be safely screened less frequently – ordinarily in a lifetime a woman might receive 12-13 invitations every 3 years until 50, but with HPV testing, this could essentially be halved, reducing the number of screens required and therefore reducing the burden of psychological distress which many women and people with cervixes experience when undergoing screening.
Athena Lamnisos, CEO of Eve Appeal said: “Cervical screening is not a ‘one size fits all’ programme – the evidence shapes the current guidance and makes sure that we treat those at low risk and high risk appropriately. There are many positive benefits to good risk stratification based on clinical evidence. We have made progress with HPV primary testing due to its higher sensitivity in reducing the likely burden of developing cervical cancers.
Our understanding of the causes which may lead to cervical cancer has increased significantly over the last 30 years. The new guidance is good news for those at low risk in Wales, they will no longer be required to attend screening so frequently – women and people with cervixes with high-risk HPV or persistent HPV infection will always be treated and seen at much shorter intervals. The challenge we face is to ensure that everyone attends screening when they are called and need to. Education and information around HPV and screening needs to be so much better.”
If you have any further worries or concerns our gynae specialist nurse is always happy to help guide you. You can contact her on nurse@eveappeal.org.uk or 0808 802 0019 for free and confidential advice.