A new research study has confirmed that testing first for HPV infection during cervical screening predicts more accurately who is at risk of developing cervical cancer than traditional screening by examining cervical cells under a microscope (cytology).
The latest findings, combined with previous research, suggest that screening using HPV primary testing may provide many women and people with a cervix with longer term reassurance about their risk of cervical cancer, and safely extend the interval between each invitation for cervical screening.
What is HPV?
Human papillomavirus or HPV is a very common infection from a group of viruses that are transmitted from skin to skin contact. It is often harmless. Most people who are infected with HPV don’t realise that they have it. In most cases the body’s immune system can clear the infection within two years.
Since the 1990s, higher risk strains (types) of HPV have been known to be linked to cervical cancer. Almost all cervical cancers are now thought to be caused by high-risk HPV. Even these higher-risk strains of HPV infection can often be cleared by the body’s immune system, but if high-risk HPV remains in the body over a period of many years, it can cause dangerous changes to the cells in the cervix. Untreated, these cell changes can cause cervical cancer, but this process can take as long as 10 or 15 years. HPV testing during cervical screening helps identify people with high-risk HPV, so that they can be monitored for early signs of changes in their cells.
It is very rare for people who do not have HPV infection to develop cervical cancer. Where it develops, this may be because the type of cervical cancer is very rare, or because screening tests failed to detect or follow up signs of HPV infection.
In any event, anyone who thinks they may have symptoms of cervical cancer should seek advice from their GP immediately and not wait for their next screening invitation.
Why is HPV primary testing now used for cervical screening?
Cervical screening used to be carried out by examining cervical cells from the smear test sample under a microscope to look for any unusual changes. This method of screening is known as cytology. However, HPV infection will be present in the body before the cells become abnormal, so cervical screening by HPV primary testing identifies people with high-risk HPV, and their risk of developing cervical cancer, at an earlier stage. This means that HPV primary testing is a more accurate way of predicting who is at higher risk of developing cervical cancer than the traditional method of screening with cytology.
HPV primary testing is now used across most of the UK to test the samples taken during cervical screening. It is also used in some other countries, such as the Netherlands and Australia.
Cervical screening with HPV primary testing involves a practice nurse or other health professional taking a smear test sample from the patient’s cervix. The sample is then sent to a laboratory where it is checked for high-risk HPV.
If the test is positive and high-risk HPV is found, the laboratory then examines the same sample for any abnormal cell changes. If abnormal cells are found, the patient should be notified and invited to undergo a colposcopy to take a closer look at the cervix and decide whether further treatment is needed.
If the patient has HPV but there are no cervical cell changes, they should be invited back in one year for further cervical screening.
What did the latest research study find?
The study, which was funded by Cancer Research UK and carried out by researchers from King’s College London, involved 1,341,584 people, aged from 24 to 64, who participated in an HPV primary testing pilot run by NHS England. These women were initially screened in 2013 to 2016 and were followed up until the end of 2019. During the pilot, several screening facilities changed their cervical screening from cytology to HPV primary testing. This allowed the researchers to compare the efficacy of HPV primary testing in the converted tests with the standard cytology test which was being used at the time.
The research compared the number of patients who developed high grade cell changes (CIN3) and cervical cancer within the two different methods of cervical screening. In accordance with standard screening intervals, all patients aged 24 to 49 with a negative result were invited for a second screening test three years later. All aged 50 to 64 with negative results were invited back in five years.
Those who were screened using cytology were referred for further testing if abnormal cells were found. Those who had HPV primary testing and were positive for HPV had their samples analysed to look for cell changes. If abnormal cells were found, they were referred for further testing. If no abnormal cells were found they were asked to return in 12 months for another test.
The study found that:
- HPV primary testing was significantly better at picking up abnormal cell changes than cytology, in all age groups.
- The number of patients aged 24 to 49 who were diagnosed with CIN3 or worse on their second screening after testing negative with HPV testing was significantly (74%) lower than those who had a negative cytology result.
- The same differences were not seen for people aged between 50 and 64, possibly because people over 50 are less likely to develop cervical cancer.
The study showed that HPV testing is a more sensitive test for detecting people with abnormal cells, and that the risk of developing abnormal cells is significantly lower in people who had a negative HPV test compared with a negative cytology test.
The results of this study, combined with previous research, suggest that the time interval between cervical screening tests may be safely extended from every three years to every five years for those who test negative for HPV. It is thought that, overall, cervical screening every five years with HPV primary testing will save more lives from cervical cancer than screening with the previous test every three years. By reducing the frequency of cervical screening tests it is also hoped that the additional risks from invasive cervical screening will be reduced and the potential benefits of cervical screening increased.
What happens now?
In 2015, the UK National Screening Committee recommended that all countries within the UK should bring in HPV primary testing. HPV primary screening has been used in Wales since 2018, in England since 2019, and in Scotland since 2020. Northern Ireland still hasn’t implemented the recommendations.
In 2019, the UK National Screening Committee then recommended implementation of five yearly screening intervals for people who test negative for HPV. Scotland changed their cervical screening programme to extend the interval between cervical screening tests in 2020. Wales followed in January 2022. To date, England has not yet announced any changes to the standard cervical screening intervals.
Leading cancer charity, Cancer Research UK, welcomed the findings of the new research which, if implemented, could mean less frequent cervical screening tests for most women and people with a cervix. The charity also emphasised that screening is for people who are not currently experiencing symptoms. Anyone who notices any unusual symptoms which could mean cervical cancer should not wait for a screening invitation, but must speak to their doctor.
Delays in diagnosis and treatment of early signs of cervical cancer can cause severe and often devastating injury. If negligent treatment leads to radical treatment, severe physical or psychological injury or death, the injured patient or their family may be entitled to substantial compensation.
If you have suffered severe injury or bereavement as a result of medical negligence, you can talk to one of our experienced solicitors to find out more about making a claim by contacting us here.