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Screening currently involves looking at cells down a microscope

Cervical screening is never far from the headlines – just look at this week’s stories on possible ways of increasing the number of women taking part. And recently there’s been much debate about the ages when women are screened.

But is it all about age? Or are there other areas where new evidence points to potential changes to the programme?

To mark cervical screening awareness week, in this post we’ll explore the latest evidence about cervical screening – including the evidence about screening age – and how we think the programme could be improved to help save even more lives in future.

Science isn’t static

It’s not surprising that debates about issues like screening age keep cropping up. The very nature of science and medicine means that researchers constantly publish new evidence and data that could improve things such as screening programmes.

So it’s important that the Government keeps abreast of this evidence, so that screening can do what it’s designed to – prevent more cancers and save more lives.

In the field of cancer screening, hundreds of scientific papers are published every month, and we keep on top of the lot, distilling them down to what we think is really useful.

This is how Cancer Research UK decides what to recommend the Government to do or change. And it’s how we can be sure that the information we provide is accurate and clear.

So what’s the evidence on age? And does it match up with how the current programme works?

20 or 25?

In England, the cervical screening programme is offered to women after their 25th birthday.

But after the tragic death of 19 year old Sophie Jones in March, a huge online petition reached the Government, asking them to offer screening to women under 25.

This is clearly a very sad and emotive subject, but based on the balance of evidence at the moment we think that inviting healthy women under 25 for cervical screening would be likely to do more overall harm than good.

But first, it’s vital to clear up one very important thing. If women have symptoms, at any age, they should tell their doctor, even if they’ve recently been for screening.

Doctors can then offer appropriate diagnostic tests (which aren’t the same as cervical screening), no matter how old the patient. It’s important that women get these diagnostic tests promptly, as well as any subsequent treatment they need.

But cervical screening isn’t designed to spot women who already have cancer (although it occasionally does) – instead it aims to find subtle changes to the cells lining the cervix that could go on to become cancer in the future.

These abnormal cells can be removed, preventing cervical cancer from developing in the first place.

Here’s the important bit. In younger women, these abnormal cell changes develop more often but, crucially, are much more likely to clear up by themselves. Research has shown that, compared to older women:

  • Younger women are more likely to receive an abnormal test result
  • Cell changes found in younger women are less likely to develop into cancer
  • Younger women are therefore more likely to have unnecessary further investigations and treatments

How does this translate into actual numbers? A recent study compared data from England – where screening starts at 25 – with data from Wales, during a period when screening started at age 20. This allowed researchers to estimate that, for every 100,000 women invited for screening from age 20 rather than 25, the programme would:

  • Prevent between 3 and 9 cancers
  • Lead to 8,000 extra unnecessary referrals for further tests (colposcopy)
  • Lead to 3,000 extra women receiving unnecessary treatment for abnormal cell changes

This treatment can lead to side effects – including severe bleeding – and it could also raise the risk of premature birth in later pregnancies.

Who decides?

Decisions on screening programmes are based on recommendations from the UK National Screening Committee, which brings together leading experts to review all the evidence.

They then consult with the public to make recommendations. They last looked at the cervical screening age range in 2012, and decided to keep the lower age limit at 25. We agree with this assessment.

What about older women?

It’s not just the lower age range where new evidence has come out recently – researchers have also been investigating what happens to older women.

In England, Wales and Northern Ireland, women continue to be invited for screening every five years between the ages of 50 and 64. And in Scotland women receive an invitation every three years up to the age of 60.

But a study a few months ago showed that being screened after their 60th birthday protected women from cervical cancer even into their eighties, though the level of protection dropped over time.

So what’s the take home message from this? It’s still important to take up screening when you’re in your sixties. But also, in future, as our life expectancy increases, we may need to start reconsidering the upper age limit for screening.

Improving the cervical screening programme

The human papillomavirus

The human papillomavirus causes cervical cancer

All this may sound as though we think the cervical screening programme is perfect just the way it is. It’s certainly very effective, saving around 5,000 lives a year in the UK, but there are also improvements that could make it even better.

One change that we’d like to see is HPV testing as the main type of cervical screening test, rather than the existing Liquid Based Cytology (LBC) test.

The former looks for DNA from the human papillomavirus (HPV) that causes cervical cancer, while the latter looks for signs of abnormal cells down a microscope.

HPV testing is used as a ‘secondary’ test and, since 2008, women with a borderline result or ‘mild abnormalities’ from LBC have their samples tested for the virus to see whether they need further follow up.

Research has shown that HPV testing is better at preventing cervical cancer than the current test, and could prevent an additional 600 cases of cervical cancer a year if the tests were swapped around.

As a result, the screening programme has begun rolling this out with a small proof-of-concept programme – women in certain areas will first have their sample tested for HPV and it will only be checked for abnormal cells if HPV is found in their sample.

This won’t change how screening works from a woman’s point of view – the way the sample is collected will stay the same. And because HPV testing works better than LBC, women who test negative for the virus can also safely wait longer before their next appointment – maybe up to five or six years instead of three.

This would reduce the number of tests they need and potentially save the NHS money as well as saving lives.

The pilots are happening in six areas of England. But there seems to be a lack of information about what happens next – we’d like to see plans in place now to extend and roll out HPV testing as the ’main’ test as soon as the pilots are over.

These sorts of changes can only be made by looking at the evidence from research. The evidence shows that attempts to improve the cervical screening programme by lowering the age range won’t help. But making the switch to HPV testing could.

By planning for this now, more lives will be saved, sooner.

The future of cervical screening?

Cervical screening is an effective, evidence-based way to prevent cervical cancer, but it isn’t the only option.

Infection with HPV is behind almost all cervical cancers, and a vaccine against the virus is now offered to young women, which is a very effective way of preventing infections.

So it’s likely that, in future, there will need to be more changes to how cervical screening works, to take account of the fact that more and more women of screening age will have been vaccinated.

They’ll still benefit from screening (as the vaccine doesn’t prevent 100 per cent of cases), but we need research to tell us how best to screen vaccinated women, and whether this will vary over a woman’s lifetime.

In the meantime, it’s important that vaccinated women still go for screening.

It’s critical that we and others continue to monitor and study existing screening programmes, to ensure they are working as they should be, now and into the future.

And so that they save as many lives as possible.

Jess Kirby is a senior health information manager at Cancer Research UK

Image of researchers and microscope from Wikimedia Commons

 

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Comments

Gemma S June 17, 2014

At 26 years old i was diagnosed with stage 2 cervical cancer. After being told i had a tumour the size of a small marble this could have easily been noticed before if i had been told to go for a smear earlier. No symptoms and no referral for a smear. It needs to be lowered young girls are dying andf not even realising there is anything wrong with them. 9 months later im on the mend after convincing my GP there was definately something wrong with me… but if this hadnt been caught when it was i most certainly wouldnt have been here. Something needs to be done before we are all just statistics….

Sue Oliver June 14, 2014

My friend’s daughter – age 25 has just had her first smear. She has severe dyskariosis and has to have extensive treatment. I think the age for the first smear should be lowered.

Henry Scowcroft June 13, 2014

There is. Younger women are less likely to have had an HPV infection – so the vaccine is much more effective in this age group. As people get older, they’re much more likely to have already had an infection with HPV, or currently be carrying the virus – so they’re less likely to benefit from the vaccine.

Henry
Cancer Research UK

H June 13, 2014

Is there any reason why older women aren’t also given the vaccine?

Madge June 11, 2014

I had my last screening at age 58. I was told by my practice nurse that I may or may not be asked to attend as I would be 60 next time around. I wasn’t called. I am now 65 and if possible I would like to be given the choice of attending cervical screening. I am a happy active lady and like many others do not feel my age. If we, elder ladies, are being asked to work longer and contribute to the economy surely our health is important to everyone, ourselves, our family, our employer and our local health service who will be responsible for treating us if we developed cervical cancer.

Diane Gray June 11, 2014

I asked my doctor for a cervical smear 18 months ago and was told it was not done at my age. I was 70 in November 2013.

Nick Peel June 11, 2014

Thanks for your comments everyone.

Gill – The Joint Committee on Vaccination and Immunisation (JCVI) – who make decisions on vaccination programmes – are considering whether to extend HPV vaccination to boys, and this includes assessing whether or not this will be cost effective. Infection with HPV is also linked to other types of cancer, including cancers of the anus, vagina, mouth and penis, so extending the vaccination programme may also provide benefits in reducing the risk of these cancers too. We wrote about the discussions around extending HPV vaccination to all boys, and also men who have sex with men (MSM) in a recent blog post about anal cancer, which you may find interesting.

Anne – the policy on screening age is the same across the country, so both areas should be offering the same follow-up. If you think you should still be offered screening in your new area then the best thing you can do is to contact your GP.

Nick Peel, Cancer Research UK

Julie Martin June 11, 2014

I had an abnormal smear test at 37. My result was CIN3 and required colposcopy and LLETZ treatment. I then went on to have yearly testing which this year showed I was still carrying HPV and another colposcopy was required. Luckily this is shown to be dormant but had I not had regular testing the outcome could have been very different! My 25 year old daughter was tested for the first time this year and was abnormal CIN3 and had to have colposcopy and LLETZ and whilst she was worried she had lots of help and advice available from my experience. I think creating more awareness is needed which eliminates the fear of a poor result

Michelle June 11, 2014

I am now 35 and I remember having the cervical smear test done at aged 18. It came back with abnormalities. This scared and worried me. When I changed doctors through starting university in a different town, the new doctor said I was too young and not to worry as most women my age would show a normalises. I don’t think its a good idea to routinely test too young as it causes unnecessary worry.

Anne Hills June 11, 2014

I follow this debate with interest as a 68 year old woman with previous history of pre-cervical cancerous cells. I had my last smear test a year ago, last, as in Avon NHS Trust do not as a policy offer the smear test to women over 64. I had just moved from Surrey NHS Trust area where I was not only offered yearly testing because of my history of abnormal cell activity, they wrote to me at my new address to find out why I hadn’t attended the Surrey based screening. Why do postcodes make such a difference?

Gill June 11, 2014

What puzzles me is why it is only girls who are offered the HPV vaccine – if they are catching the virus from sex with boys who have it, why don’t we vaccinate the boys as well to protect the girls even more? Would this not be cheaper than screening women and treating those who are unfortunate enough to have contracted cervical cancer?

Gayle Higgott June 11, 2014

This is another excellent well communicated article from Cancer Research UK. This is the only info source I consult to get the facts about Cancer and research.

I can understand the reasoning for keeping the testing lower age at 25. Weighing up the benefits versus the risks (and unnecessary burden on the NHS no doubt) and taking the ‘greater good’ ethical approach. However everyone will still be thinking ‘what about those 3 to 9 undetected cervical cancer patients?’. Its a tough call and emphasises how vital it is to make every screening appointment as soon as you are old enough. If you were in the very unlucky few youngsters developing cancer, hopefully at 25 the chances are it would still be in the early stages due to the fact it takes years to develop.

Angela kirk June 10, 2014

I think more women would come forward to have the test done if the way in which the test was carried out was maybe through a blood test.I know the test is a small price to protect you from cancer but it puts a lot of people off and it’s a massive risk to take.