Someone’s cervical cancer risk could be gauged non-invasively by collecting and analysing samples of their urine
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Urine tests seem to detect strains of the human papillomavirus (HPV) that are particularly associated with cervical cancer with the same level of accuracy as vaginal swabs that people carry out themselves.
Cervical cancer screening has historically been performed by a medical professional collecting cell samples from the cervix, either to test for abnormal cells or for the presence of HPV strains that are responsible for most cases, like HPV 16 and 18.
In countries like the US and Canada, people now have the option of using self-collected vaginal swabs, which don’t need to touch the cervix. The UK is also moving towards this approach. Such swabs have been linked to increased screening uptake, but are still invasive and may be uncomfortable for some.
Previous research suggests that the DNA of HPV can be detected in urine. To better understand its screening potential, Julia Lynch at the International Vaccine Institute in Seoul, South Korea, and her colleagues asked 753 sexually active women, aged 18 to 25, to collect a urine sample at any time of day and to carry out a vaginal swab while in a clinical setting in Bangladesh, Pakistan or Nepal.
The researchers found that the tests’ ability to detect seven high-risk HPV strains was highly similar for both sample types, with 5.3 per cent of the self-collected swabs positive for one or more of the seven strains, compared with 5 per cent for the urine sample. For HPV 16 and 18, the results were nearly identical, at 2.3 per cent for the swabs and 2.4 per cent for the urine test.
Urine samples also seemed to be preferred by some. “We are working in countries with a lot of different social contexts, and [a] vaginal swab was less acceptable for some ages in some countries,” says Lynch.
The World Health Organization set a goal to eliminate cervical cancer in 2018, based largely on the success of HPV vaccines. But it can take years for the effects of vaccine initiatives to be seen at the population level, so screening uptake is still needed, says Lynch.
There are several types of HPV vaccines, which all protect against strains 16 and 18. But HPV risk is typically based on data from North America and Europe, says Lynch, so studies like this may also help determine which strains are circulating in other parts of the world to guide vaccine decision making, she says.
The study included only young women, so the findings may not be generalisable to everyone, says Beverly Green at Kaiser Permanente Washington Health Research Institute. Lynch says the study was performed as part of a larger project to determine HPV prevalence among eight low- and middle-income countries in South Asia and Africa, and that other studies within this project will test samples from older women.
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