Screen saver: How new cervical screening tests look for HPV
Picture: iStock
The new HPV cervical screening was due to start last March. Covid hit and it was put on pause until early July when CervicalCheck resumed screening. “Covid affected everything. We were cautious about sending out lots of screening invitations that might be ignored,” says Dr John Price, colposcopy adviser with CervicalCheck.
By end of 2020, CervicalCheck had caught up with screening invites – in a typical year, they send out 270,000 and get an 80% response. “We got 20% below that due to Covid, which we expected,” says Dr Price. In the 2020 Covid period (March-December) 117,000 HPV screening tests were carried out in primary care.
HPV causes over 90% of cervical cancers. This link was discovered by German virologist Harald zur Hausen in the 1970s/early '80s – he later won a Nobel Prize for his work. International evidence finds HPV screening the best way of carrying out cervical screening. The programme took three years to develop in Ireland, and Dr Price says we learned from the experience of countries like Wales, Australia and the Netherlands.
Irish Family Planning Association medical director Dr Caitríona Henchion says – like anything new – HPV cervical screening takes explaining. “Although women get an information sheet prior to coming for screening, quite often they arrive with no information. It can take quite a while to explain.”
The big change is: HPV is now the primary test in cervical screening – the woman is checked first for any of the high-risk types of HPV. The big players are HPV 16 and 18 – Irish College of General Practitioners (ICGP) says about 4.3% of women in the general population are estimated to have these strains at any given time – plus an additional panel of cervical cancer-causing strains. If HPV is found, the same sample is checked for abnormal cells.
And if these are found, the woman’s referred to hospital for colposcopy - a procedure to check for abnormal cervical cells - and treatment if deemed necessary.
If no HPV’s found, there’s no check for abnormal cells – because, without HPV, the risk of developing cervical cancer is very low.
With the new HPV test, if the woman’s HPV-positive but doesn’t have abnormal cell changes, she’ll be called back for a further test the following year. “If they’d only looked for abnormal cells, as in the past, the woman would’ve been put on a routine call-back interval of three to five years. But with the new screening, knowing she has HPV, which puts her at slightly higher risk of developing abnormal cell changes, she’ll be called back in a year,” explains Dr Henchion.
But what of the woman who says ‘I don’t know how long I’ve had HPV. Can I afford to wait a year – should I see a gynaecologist immediately?’. ICGP director of women’s health Dr Noirín O’Herlihy says it takes a long time for cervical cancer to develop following initial HPV infection: “In most cases, it takes 10 to 15 years for it to develop.” And, points out Dr Henchion, if a woman still has no abnormal cell changes the following year – but is HPV-positive – she’ll then be referred for colposcopy.
In the old system (pre-March 2020), the smear test looked first for abnormal cells in the cervix. If found, the woman usually had colposcopy and treatment to remove these cells – followed by HPV screening to check treatment had worked. However, most abnormal cells return to normal by themselves – there’s very little risk they’ll develop into cancer if the woman doesn’t have HPV, which meant some people had colposcopy and treatment when they mightn’t have needed it.
Dr Henchion says HPV screening’s a very welcome development. “Cytology [smear testing] is a manual test – technicians look at all the slides. The chance of human error’s always going to be there. The HPV test is a more automated system with less scope for error.” Also, being HPV-negative, she says, is a better predictor of your risk of developing cervical cancer than detecting mildly abnormal cells.
Like most screening tests it’s not perfect – some women will still develop cervical cancer despite regular screening. But HPV screening will detect 15% more cases of cervical cancer than smear testing did. With 20 women in every 1,000 screened having abnormal (pre-cancerous) cervical cells, HPV screening will pick up 18 of these 20, compared to 15 caught by smear testing. “Traditional screening picked up 75% of cervical cancers. With HPV testing, we’re picking up 90%. It’s not 100% – but it’s better,” says Dr Price.
For women, the actual experience of HPV screening will feel no different to the traditional smear test. But women aged 30-44 will now be screened every five years, instead of every three. The same interval applies for women aged 45-65, while 25 to 29-year-old women will be screened every three years.
Because HPV’s a skin-to-skin virus, acquired during sexual contact, the peak time for new infections is the 20s,when most people start being sexually active. “As people change partners in later life, it may also be detected then,” says Dr Henchion.
Dr Price says at least 40% of women aged 25 and under will at some stage have HPV infection. One in four women up to the age of 25 is HPV-positive, while the proportion drops to 10% for women aged 35-50. “For the vast majority of these women their own immune system clears it – they become HPV-negative within 18 months to two years.”
In general, 14,000 women are referred annually for colposcopy – about 4,000 need treatment. HPV-positive women with abnormal cell changes will be assessed in the colposcopy clinic to see if changes are mild, moderate or severe. Mild changes may clear by themselves – the woman will be checked again after six to 12 months. If changes are moderate or severe, she’ll have treatment to remove the abnormal cells.
“Six months after treating these cells, we re-test to see if the HPV has cleared – once it’s gone the likelihood of it returning is under five per cent,” says Dr Price.
A HPV self-sampling study – women test themselves at home for HPV – started on a pilot basis in January in some areas of London. It might seem a good option for women too busy or embarrassed to visit their GP for screening, but a CervicalCheck spokesperson points out the sample can only be used to check for HPV – if the woman’s HPV-positive, she’ll need further screening by her doctor to check for abnormal cells. “And the evidence isn’t there yet that [self-sampling] is an accurate or cost-effective method.”
CervicalCheck’s screening programme has reached close to 80% of eligible women in recent years, whereas international programmes currently using self-testing have target coverage of 60% or lower. “The best study’s from the Netherlands, where they tried to reach women who hadn’t responded to their routine test invitations. They delivered home-testing kits and got 35% take-up,” says Dr Price, adding that home-test kits haven’t yet been evaluated or recommended for use internationally.
When Dr Henchion phones women with news they’re HPV-positive – and particularly if they’ve abnormal cell changes – they’re understandably a bit upset. “Most people assume their test’s going to be negative. They almost feel they’re finished once they’ve been screened.”
Her job, she says, is to change something that seems bad into something positive. “We explain it’s a really good thing they came. They could have gone on and not had the test, but instead this has been detected at a really early, easy-to-treat stage. And we explain if they need to go to hospital/clinic they may not even need treatment. And if they do, treatment’s done as an out-patient and is very successful at preventing cervical cancer.”
Dr Mairead O’Connor is a research fellow at the School of Public Health, UCC, and a researcher with CERVIVA Consortium, which investigates HPV-associated diseases. In 2012/’13 – along with Professor Linda Sharp – she conducted in-depth, face-to-face interviews with 27 women in a colposcopy clinic at a Dublin maternity hospital. A pilot study (exa.mn/ImpactHPVtesting) looked at the emotional impact on women of undergoing HPV testing in the context of post-treatment for abnormal cell changes.
“We found women’s concerns about their abnormal cell change and their fears of developing cancer far outweighed concerns around HPV,” says Dr O’Connor.
She recalls one woman saying: ‘I don’t care whether it’s HPV or ABC, I just want to know if I have cancer’. But some women did experience worry, fear and anxiety about being HPV-positive. “A few were concerned about possible infidelity in the relationship – may be their partner had been unfaithful and that’s how they caught HPV. Some felt shame and stigma – they hadn’t told anyone about the diagnosis because they didn’t want people to think less of them.”
It gives insight into how best to communicate a positive HPV diagnosis to women, says Dr O’Connor, citing also a 2007 UK study (exa.mn/HPVStigma) that found women who know there’s a high prevalence of HPV in the population feel lower levels of stigma, shame or anxiety – while those who don’t know it’s highly-prevalent, but do know it’s sexually-transmitted, are more likely to score high for stigma and shame.
Pointing out that CervicalCheck has done lots of training of GPs/practice nurses around discussing HPV with women, Dr O’Connor says it’s about normalising HPV infection – most people get it at some point in their lives. “It’s also important to talk about HPV screening in the context of cervical screening, not in the context of STI. This minimises anxiety and worry around possibility of having a HPV infection.”
Dr Price says when cervical cancer’s picked up through screening it’s almost always caught early, making it easier to treat, more curable. Unfortunately in Ireland, only half of cervical cancers are picked up through screening. With 80% of women attending for screening, Dr Price says the 50% of cervical cancers not caught by screening are in the 20% group that don’t attend for testing. “They’re waiting ‘til they have symptoms so their outcome’s less good.”
“We hope by changing to HPV screening it’ll come down even further,” says Dr Price, adding that the Netherlands, which began HPV cervical screening in 2017, expects incidence of cervical cancer to reduce by 15% within five years.
Kim Hanly, founder of Cervical Cancer Awareness Ireland, has had cervical cancer. She’s pleased HPV cervical screening is now happening in Ireland. “It’s going to catch more pre-cancers and cancers. I would urge women to go.”
While the third wave of Covid-19 means some GP practices/community clinics aren’t able to offer cervical screening appointments or are operating at reduced capacity, CervicalCheck recommends women keep in contact with their GP/clinic and re-book as soon as possible. Anyone worried about symptoms – for example, bleeding after sex or after menopause – should contact their GP immediately.
- Visit exa.mn/HSEcervicalscreening
- Cervical Cancer Awareness Ireland runs online support network online for women experiencing cervical abnormalities on Facebook, Twitter and Instagram
- International HPV Awareness Day is on March 4: exa.mn/International-HPV-Awareness-Day
Offaly-based Niamh*, 25, had her first screening test with CervicalCheck last August. Mum to a five-year-old son, the care assistant tested HPV positive – and had abnormal glandular cells.
“I was confused. I’d had the HPV vaccine at school, so I thought I’d be protected – but of course when I got the vaccine 10 years ago it didn’t protect against as many HPV strains.”
She went for colposcopy to investigate the abnormal cells. “They took a biopsy and referred me for hysteroscopy [looks inside uterus]. I was sent to a multi-disciplinary team to see how best to treat the abnormal glandular cells.”
Abnormal glandular cells arise inside the cervical canal and, for that reason, may not show up on a cytology sample. They are a pre-cancerous change and not cancer.
“It was seven o’clock of a December evening – I was Christmas shopping – when they rang to say they’d decided I should have LLETZ treatment [procedure to remove cervical tissue]. I had it five weeks ago and I’m waiting for the results.
“I didn’t feel embarrassed about having HPV. Nearly everyone has it at some stage. I had no issue telling my partner. The abnormal cells worried me more. If HPV hadn’t shown up, they’d have told me to come back in three to five years, so I’m lucky. It’s rare enough for abnormal glandular cells to come up in a screening. They said it was lucky it was picked up because it isn’t always.”
*Name changed.
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