As 2017 drew to a close, so too did the era of the traditional Pap test. From 1 December 2017, Australia became just the second country in the world, behind the Netherlands, to incorporate a 5-yearly human papilloma virus (HPV) test into its National Cervical Screening Program.
How is HPV linked to cervical cancer?
HPV is perhaps most often recognised as the sexually transmitted infection (STI) responsible for causing genital warts. While this is certainly the case, there are actually more than 40 different types of genital HPV that can be spread through sexual contact. HPV affects both men and women, and it’s surprisingly common, even in young women who have had just one sexual partner.
In fact, nearly half of all women will be infected with HPV within three years of becoming sexually active. In most cases, HPV is cleared by the immune system within one or two years without causing any symptoms or lasting effects.
However, in a small number of women, an ongoing HPV infection can lead to cellular changes in the cervix, known as cervical intraepithelial neoplasia (CIN). If left untreated, CIN can lead to cervical cancer, but this usually occurs slowly over 10 to 15 years. A cervical screening program exists to detect any cellular changes early.
What parts of testing are the same?
To check for changes and abnormalities – such as CIN – your gynaecologist (or other specialised healthcare professional) will conduct a vaginal examination to collect cells from your cervix. Under the new screening program, this internal examination will be the same as it was at your previous Pap test appointments.
The main difference is that your cells will be placed into a container of liquid, rather than being ‘smeared’ onto a slide. This will allow the pathology lab to conduct all standard screening tests on a single sample of your cells.
What parts of testing have changed?
More than 99% of cervical cancers are caused by HPV. Out of the 40-plus different types of genital HPV, there are two particular types that cause around 70% of all cervical cancers. These two types are HPV 16 and 18.
Based on this known link between HPV and cancer, you will now be screened for HPV infection using a method that tests for DNA from the virus itself. This method accurately confirms whether your cells are positive or negative for the HPV virus, so it’s more reliable than the traditional Pap test.
In comparison, your previous Pap tests would have involved a pathologist looking closely at your cells under a microscope for any changes or abnormalities. Also known as cytology, this test relied on a visual assessment alone, and it didn’t test for HPV infection.
From now on, testing for HPV infection will now also be supported by what is known as partial genotyping. This method is used to check if you have a ‘high-risk’ type of HPV that is more likely to cause cervical cancer. In particular, partial genotyping is used to test for HPV 16 and 18.
For reference, there are two HPV vaccines approved for use in Australia (Gardasil and Cervarix), and both protect against HPV 16 and 18. However, these vaccines don’t protect against all types of HPV that can cause cervical cancer, so it’s important to continue having regular screening tests, even if you’ve been vaccinated.
If you test positive for HPV infection, the pathology lab will conduct another test called liquid-based cytology (LBC) on your initial cell sample. LBC is similar to a Pap test in that it involves examination of your cells under a microscope for any changes or abnormalities.
Although HPV infection is common among young women, there’s a very low rate of cervical cancer in women under 25 years old. If HPV infection does progress to cervical cancer, it usually takes place over decades, with most cases occurring between 35 and 55 years old.
Additionally, there is no evidence to suggest that screening women under 25 is effective or that it reduces deaths from cervical cancer. In fact, screening women under 25 may lead to unnecessary treatments, some of which can increase the risk of pregnancy complications later in life.
For these reasons, the starting age for cervical screening has increased from 18 to 25 years old. Between the age of 70 and 74 years old, you will be invited to have your final screening test, at which time you will exit the program if you return a negative result.
Under the new program, you will receive all invitations and reminder letters from a new National Cancer Screening Register (NCSR), rather than from your local State or Territory service (such as the Victorian Cytology Service).
More than 80% of women with cervical cancer are at least six months overdue for a cervical screening test or have been never been screened at the time of diagnosis. To help improve screening rates, there is now a self-collection option available to women aged 30 years and over who also: have never participated in screening, or; are at least two years overdue for screening.
If you fit into one of these categories, your gynaecologist will be able to provide you with a self-collection kit and instructions for use. However, you will still need to perform the collection at your medical or healthcare clinic.
What if my test is negative for HPV infection?
Low-risk result – next test in 5 years
If you return a negative result (i.e. HPV infection is not detected), you’re considered to be at ‘low risk’. Your next cervical screening test will be due in five years, rather than in two years, as was previously the case with a Pap test.
What if my test is positive for HPV infection?
Intermediate risk – next test in 12 months
If partial genotyping shows that your infection is not caused by HPV 16 or 18, but your LBC test shows negative or low-grade changes, you’re considered to be at ‘intermediate risk’. You will be invited to attend a follow-up cervical screening test in 12 months.
Higher risk – attend a colposcopy
If you’re considered to be at a ‘higher risk’ of developing cervical cancer, you will be asked to arrange another appointment to have a colposcopy. This group includes the following test results:
- Partial genotyping shows that your infection is caused by HPV 16 or 18
- Partial genotyping shows that your infection is not caused by HPV 16 or 18, but your LBC test shows possible or confirmed high-grade changes.
During a colposcopy, your gynaecologist will insert a speculum into your vagina and then apply iodine and acetic acid solutions to your cervix to highlight any abnormal areas. A close examination of your cervix will follow using a specialised microscope, known as a colposcope.
Summary of changes
|New HPV test||Previous Pap test|
DNA test, with:
|Cytology (i.e. examination of your cells under a microscope)|
|Standard screening frequency||Every five years||Every two years|
|Start||From 25 years old||From 18-20 years old|
|Finish||At 70-74 years old||At 69 years old|
Where do you fit into the new cervical screening program?
To find out how changes to the cervical cancer screening program affect you – or to arrange your next HPV screening test or a colposcopy – please feel free to call my rooms on (03) 9418 8299 or book an appointment online.