DIY smear tests could be a 'game changer'
A DIY smear test could be a “game changer”, experts say.
Cervical screening looks for abnormal cells in the lining of the cervix, which may develop into cancer.
Women aged between 25 and 64 who are registered with a GP in the UK are invited for a test every few years.
However, around a quarter fail to attend, with uptake at its lowest in England for 19 years, according to Jo’s Cervical Cancer Trust.
With many reluctant women citing embarrassment or pain for putting the appointment off, a non-invasive at-home test could be a “promising” solution.
READ MORE: Thousands of women admit to skipping their smear tests
Scientists from Queen Mary University in London have developed a test that looks for signs of cervical abnormalities in a urine sample or vaginal swab.
The test, called S5, detects genetic changes to four strains of the human papilloma virus (HPV) that are most associated with cancer.
HPV is responsible for up to 99.7% of all cervical tumours, according to Jo’s Cervical Cancer Trust.
The “extremely common virus” is carried by around four in five (80%) people at some point in their life.
Primarily spread via skin-to-skin contact of the genitals, HPV is usually cleared up by the immune system.
However, persistent, high-risk infections can trigger cervical abnormalities, which may develop into cancer.
Based on the genetic changes S5 picks up on, a woman is given a “risk score” for cervical cancer.
To put it to the test, the scientists looked at more than 1,000 women who had either an abnormal cervical screening result or were HIV positive.
Of which, 620 provided vaginal swabs, while 503 gave a urine sample.
READ MORE: Urine test could mark the end of smear tests
“We found the S5 classifier with or without HPV testing worked well in both urine and vaginal samples,” researcher Dr Belinda Nedjai said.
“It distinguished between women who had no pre-cancerous lesions and those who had CIN3 or higher lesions.”
“Pre-cancer” can occur if abnormal cells crop up on the surface of the cervix, which often develop into the disease.
CIN3 is the most advanced stage of pre-cancer.
Results suggest the urine S5 identified CIN3 96% of the time, compared to 73% with a standard HPV test.
When done as a standalone test, without first checking for HPV, S5 got it right “at least” 85% of the time.
The results will be presented at the NCRI cancer conference in Glasgow.
“We are working on new markers to try to improve the accuracy of the classifier even further, but these findings represent an advance in cervical cancer screening, especially for women who do not attend the clinic, such as older women, or who find the smear test too painful,” Dr Nedjai said.
“We think it’s promising.
“In the longer term, self sampling could become the standard method for all screening tests.
“The study indicated women much preferred doing a test at home than attending a doctor’s surgery.”
While samples are currently sent off to the laboratory for analysis, results could one day be generated at home, the scientists claim.
Dr Nedjai admits, however, S5 is not as accurate as traditional smear tests.
“It will be soon,” she told BBC Radio 4’s Today programme. “With improvement we'll get there.”
While larger trials are required, the scientists estimate the test could be available on the NHS in just five years.
READ MORE: Why people are calling to ditch the term 'smear test'
Dr Manuel Rodriguez-Justo, from Imperial College London, added: “This is exciting research that shows it’s possible to detect cervical pre-cancer that is at high risk of developing into invasive cancer in urine and vaginal samples collected by women in the comfort and privacy of their own homes.
“This has the potential to revolutionise the way a positive HPV test is followed up.
“The cervical screening programme in the UK has been very successful but there has been also a decline in its uptake.
“If the results of this study are validated by other groups, the implementation of urine-based testing and self-sampled vaginal samples will, potentially, increase uptake and reduce costs for the screening programmes whilst achieving high sensitivity to detect pre-malignant lesions.”
Robert Music, chief executive of Jo's Cervical Cancer Trust, agreed more research is needed but added the test could be a “game changer”.
“For women who find the current methods of cervical screening difficult, including those with a physical disability or who have experienced trauma, it could mean they can access screening in a far more acceptable and accessible way,” he told the BBC.
“It could mean those requiring treatment are identified faster and reduce the number of women having to go for potentially unnecessary investigations”.
What is a smear test?
Women aged between 25 and 49 are invited for a cervical screening every three years in the UK.
With the risk of cervical cancer falling with age, those aged 50-to-64 are called up every five years.
The test should not be painful, however, some report finding it uncomfortable.
This does not last long and a woman has the right to ask the nurse to stop at any time, Jo’s Cervical Cancer Trust states.
The NHS is moving towards HPV testing.
The experience is the same as a smear test, but a woman’s cervical sample is tested for HPV, rather than looking for cell changes.
This is said to be a more accurate way of identifying who may be at risk of cervical changes or cancer.
After the screening, you should get the results within two weeks, depending on where you live.
If abnormal, a woman may be invited for a colposcopy, which allows for closer examination of the cervix.
Some may also have a biopsy taken of their cervical tissue.
Around 40% of colposcopy results come back clear, according to Jo’s Cervical Cancer Trust.
In very rare cases, colposcopies reveal a woman has cancer.
Most of the time, they show up abnormalities on the cervix’s surface.
This is usually treated via large loop excision of the transformation zone (LLETZ).
LLETZ involves using a thin wire loop with an electrical current to remove the area of the cervix with cell changes.
The removed area is then sent off for tests to determine the extent of the cell abnormalities.
If cell changes are higher up the cervical canal, a thin straight wire is used rather than a loop.
Alternatively, a cone biopsy may be carried out to remove a funnel-shaped piece of tissue from the cervix.
If abnormal cells remain, lasers or heat may be used to “burn” away the affected tissue.
Extreme cold cryotherapy could also help.
Nine in 10 women do not have abnormal cell changes again after the above treatments, according to Jo’s Cervical Cancer Trust.
Without screening, a woman’s risk of cervical cancer rises.
The disease affected 3,192 women in the UK between 2014 and 2016, Cancer Research UK statistics show.
Around 13,170 are expected to be diagnosed in the US by the end of this year, according to the American Cancer Society.