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Mention the word ‘Pap smear’, and most women will reflexly cross their legs and shudder.
It’s become something of a modern rite of passage for young women; receiving your invitation to join the cervical cancer screening program, and submitting yourself to the dubious pleasure of being prised open like a recalcitrant car door and probed with a glorified toothbrush.
Despite the brief discomfort of his procedure, Dr Georgios Papanikolaou’s nearly 100-year legacy can be measured in millions of female lives saved from cervical cancer.
But the era of the Pap smear is drawing to a close, and from 2017 there will be a new testing regime.
We now know that the vast majority of cervical cancers are caused by a virus – the human papillomavirus, or HPV – and in the absence of this virus, cervical cancer is extremely rare.
This understanding, and the deployment of a vaccine against HPV, has led to what will be the biggest overhaul of Australia’s cervical cancer screening program since it first began in 1991.
An expert committee tasked with this overhaul has recommended that instead of undergoing trial by Pap every two years, women will instead have an HPV test – which still involves a speculum – every five years between age 25 to 74 years, even if they have received the HPV vaccine.
The HPV test will look for particular sub-types of the virus that are known to cause cervical cancer. If any of these cancer-causing subtypes are found, further testing is done on the same sample to look for evidence of the abnormal cells that can be a precursor to cervical cancer.
This is done in the same way that a Pap smear used to be analysed, although the technology has changed.
If HPV subtypes 16 or 18 are found, which are responsible for around 70 perCent of cervical cancers, then the woman is automatically referred for a colposcopy. (This involves examining the cervix directly with a special microscope to look for those same abnormalities.)
If there is no sign of abnormal cells, these women will most likely to be asked to return for another test in 12 months.
But if no evidence of HPV infection is found, then the woman has another five years before she needs to have another HPV test.
Common in young women
All these changes have come about because of major advances in our understanding of how HPV behaves in our population and how it causes cervical cancer, says renewal steering committee chair Professor Ian Hammond.
"The first thing is that HPV is prevalent in young women … one in four girls under 25 will have HPV if you test them," says Hammond. However this HPV infection is also very transient: 80 per cent of HPV infections in young women clear spontaneously within a year, and 95 per cent are gone within two years, he says.
"The other thing is that under 25, cervical cancer is actually very rare, so each year somewhere between four and 17 women will get cervical cancer under 25."
Unfortunately, these cancers tend to be particularly malignant, and so far, no cervical cancer screening program has been able to make a dent in the rates of cervical cancers in women under 25.
Given all of these factors, the biggest concern from a screening perspective is therefore persistent HPV infection, because HPV that hangs on – particularly the cancer-causing varieties – is what leads to cervical cancer.
So while women will now undergo just nine or ten screening tests in their lifetime, instead of 26, the new screening program is expected to lead to a 15 per cent reduction in the number of cases and deaths from cervical cancer in Australia.
One not-so-positive side effect of the new program is that it will dramatically impact the pathology workforce. The cytotechnicians who currently process around 2.4 million Pap test results a year will face a three-quarter drop in their workload.
One hoped-for gain with this new screening program is that it might finally pick up the small numbers of women who have never had a Pap smear. Unfortunately, 80 per cent of cervical cancers happen in women who have never been screened, or not been screened for many years.
The committee has therefore recommended use of self-testing for HPV for women who, for one reason or another, don't want someone else to perform the swab. It would still be done in a health-care setting, perhaps under the supervision of a nurse.
Hammond says the self-test would simply involve putting a swab into the vagina, much the same as is done for STD tests. Then if the result is positive for HPV, the woman would be asked to have the follow-up tests done to look for abnormal cells.
"What's been interesting, in all the trials that have been done of this, women may or may not agree to stick a swab inside them, but once they've done it and had a positive test, they nearly all agree to go on, because now they know something's wrong," he says.
However, if a woman experiences any kind of symptoms that might suggest a problem, such as pain or bleeding, then she should go to the doctor, irrespective of her age, screening history or anything else.
Until the new regime is implemented in 2017, Hammond stresses women should continue with their regular two-yearly Pap smears.
Impact of HPV vaccine
What impact will the HPV vaccine have on this shiny new screening program? This Australian-invented vaccine protects women and men against four HPV subtypes; the two that cause most cervical cancers, (HPV16 and 18), and the two responsible for genital warts (HPV6 and 11).
Dr Julia Brotherton, director of National HPV Vaccination Program Register, says the national immunisation program is tracking well; in 2013, 71 per cent of girls aged 15 years were immunised against HPV, with no major safety issues emerging from the nearly 200 million doses of the vaccine given worldwide.
The benefit of the vaccine is already clear in the rapid decline in the incidence of genital warts among not just women but also men, but the most telling results come from the changes in the HPV subtypes being found during Pap smears.
"When we have started to look at measuring how much HPV we can find at the cervix of young women who are coming in to have their pap test and again, there are absolutely dramatic declines," Brotherton says.
"It almost looks like HPV16, which is the nastiest type, is virtually disappearing in young women, which is just wonderful news".
Research is also showing that the rate of cervical pre-cancers has almost halved in young women, and this is now showing up in the 20-24 years old group as those who were first vaccinated get older.
An HPV vaccine that protects against nine HPV subtypes has recently been approved by the US Food and Drug Administration, which could further reduce the incidence of cervical pre-cancers and cancer as it targets some of the other cancer-causing subtypes of the virus.
But can the vaccine completely eradicate HPV and do away with the need for cervical cancer screening altogether? Brotherton says this is unlikely because HPV is a silent infection that can hide in the cells. Unless 100 per cent worldwide vaccine coverage is achieved, screening will always be around in one form or another.
"We certainly are going to rely on our disease modellers to look at this and work out what the most efficient system would be for less harm if we do have a heavily vaccinated population," she says.
"But we will have to change, pull it right back, and hopefully have even better protection without the need for all that treatment that we currently do for those lesions we find on pap screenings."
"It's a very exciting era to be grappling with these as problems, it's a fantastic opportunity."
This article was originally published on the ABC. Read the original article.
How have your experiences with Pap smears been? Would you prefer to DIY or do you like going to the doctors?