Prof Nóirín Russell has been practicing as a colposcopist since 2002 and joined CervicalCheck as Clinical Director in August 2020, the same year we changed to primary HPV cervical screening. Here, Prof Russell reflects on this change, why it provides better outcomes for women, and what we have learned in the past five years to further improve the programme.
By Prof Nóirín Russell, Clinical Director, CervicalCheck
Ireland was an early adopter of primary HPV cervical screening in Europe. In 2020, we made the switch from cytology (the traditional smear test) to primary HPV testing. While we were later than some other countries in establishing a population-based cervical screening programme in 2008, we then jumped ahead, becoming one of the first countries to adopt this more advanced screening method.
The evidence for change
The decision to change was based on strong evidence. Research published in 2014 showed that HPV screening was better at detecting cervical abnormalities before they developed into cancer. We did a Health Technology Assessment (HTA) in Ireland and it confirmed that HPV screening was more effective for women as well as being cost-efficient. The HTA also recommended that screening women up to the age of 65 could save more lives. Alongside this, we changed the screening interval to every three years for women aged 25 to 29, and every five years for women aged 30 to 65.
Roll-out of HPV-based screening
The change to HPV screening was a major undertaking, requiring extensive stakeholder engagement - including women, sample takers, colposcopy and histology services, and laboratories. Quality assurance, training and communications were key priorities. This all happened alongside the challenges of the CervicalCheck crisis and maintaining routine screening services for women.
The official switch happened on 30 March 2020, and on that same day we also had to pause screening due to COVID-19. Colposcopy clinics remained open and changed to HPV screening in their follow-up care. When we started inviting women for screening again in July 2020, there were questions about the change. We worked hard on our messaging to reassure women that HPV screening is a more sensitive test and that a negative HPV test is highly predictive of low risk, meaning women can safely wait five years for their next screening.
A better test for women
HPV causes most cervical cancers. It is responsible for around 92% of all cases and 99% of squamous cancers, the most common type. Compared to cytology, which has a sensitivity of about 75%, HPV testing is superior, with a sensitivity of around 90%. In simple terms, cytology picked up about 15 out of 20 abnormalities in every 1,000 women screened. HPV testing detects 18 out of those 20. The chance of a false negative test is lower with HPV testing.
Seeing this in practice over the last five years has reaffirmed the benefits of HPV screening. It’s better at identifying women with high-grade abnormalities. In population-based screening, we’re trying to find the 20 women in every 1,000 screened who have high-grade abnormal cells and treat them to prevent cervical cancer. Without screening and treatment, women with high-grade abnormalities would have a 31% chance of developing cancer. With treatment, that risk drops to 0.5% (1 in 200). It’s an incredible reduction, demonstrating the effectiveness of cervical screening.
What the data tells us
Data published by the National Cancer Registry of Ireland confirms that screening helps detect cervical cancer earlier, making it easier to treat, and has contributed to a reduced number of deaths from cervical cancer. It’s reassuring to know that CervicalCheck is doing what it was set up to do. Since the programme began in 2008, the incidence of cervical cancer has dropped from 15.8 per 100,000 women to 10.1 per 100,000. Our goal is to reach the global target of 4 per 100,000 to eliminate cervical cancer.
HPV vaccination has also been a game-changer. Our research combining CervicalCheck and National Immunisation Office data shows that girls vaccinated in school have a 60% lower rate of high-grade disease at age 25. The combination of HPV vaccination, cervical screening and treatment will reduce cervical cancer incidence further.
Impact on services
The move to HPV screening has led to an increase in referrals to colposcopy. Initial modelling predicted a 40% increase in referrals in the second year, followed by a decline. In practice, referrals have remained high. Our triage process invites a woman back for another HPV test in a year if she tests positive for HPV with normal cells, to see if the virus has cleared itself. We’re seeing more women staying HPV-positive than the models predicted, resulting in more referrals to colposcopy. One of the challenges is ensuring we continue to have enough capacity in our colposcopy and histology services to offer follow-up to all women who need this.
The future of HPV cervical screening
Other countries, like the UK, allow 24 months for a woman’s body to clear HPV before referring women to colposcopy, a model we may consider.
The prevalence of HPV among the screened population is just over 11%, and not all of these women need colposcopy. We need to explore ways to refine triage to reduce unnecessary referrals to colposcopy, while at the same time ensuring the women who are most likely to benefit from colposcopy and/or treatment get referred. Additional tests such as HPV genotyping or methylation markers could help assess risk more effectively and reduce unnecessary anxiety for women.
The positive impact of the HPV vaccination means the long-term screening needs of vaccinated women may be different, with potentially longer intervals between screenings - perhaps just two or three screens over a lifetime.
HPV self-sampling is also being explored. While it is a less sensitive test, it could play a role for women who don’t come for screening or don’t attend regularly. We need to carefully assess how it fits into our programme and a well-designed pilot could help determine its value and effectiveness in the Irish context. We’re keen to learn from other countries providing a self-sampling option to see the impact, particularly on coverage and participation rates.
Increasing participation
Understanding why Ireland’s coverage continues to grow while other countries are seeing declines will be an important area for future analysis. We invite about 270,000 women and people with a cervix for screening every year, out of an eligible population of 1.3 million. Our coverage in 2022 was 73%, the third highest in the EU and well above the EU average of 55%. We’re seeing this coverage increase. High participation in the screening programme is crucial because nearly half of cervical cancers are diagnosed in women who have never been screened.
Community engagement is playing an important role in improving equity and supporting women to come for screening. Certain groups including migrant women, women in socially deprived areas, Traveller women, and LGBT+ individuals, are less likely to attend for screening. Our community champions project works with these communities to understand the barriers to screening, address them and improve access.
Caring for women beyond screening
HPV cervical screening is the best test that we have to prevent cervical cancer. It’s not perfect. We tell women about the symptoms of cervical cancer because screening will not prevent every case.
A small number of women who have regular cervical screening will still develop cervical cancer, even after a normal screening result or after a normal colposcopy. I’m proud that we developed a personal review process for women who are affected by this and who may want to know more about why this happened. Personal cervical screening reviews offer a person-centred, caring and human approach to restoring trust in an open and transparent way.
A call to action
When a woman turns up for cervical screening, that’s her vote of confidence in the CervicalCheck programme. Having over 4,000 sample takers across the country to choose from is a positive part of the programme for women.
Cervical screening can save lives. It takes just 10 minutes with a GP or practice nurse to provide a sample for an HPV test - 10 minutes that could make all the difference. While we continue to look at the best evidence to improve outcomes for women, the most important message remains the same: screening works.
If you’re eligible, choose screening and book your test when it’s due.