It could be possible to screen for cervical cancer with urine, US scientists believe.
Screening can detect early cancer
Cancer could be picked up by looking for specific gene patterns in urine samples, they told the American Association for Cancer Research.
In trials, the method accurately picked up many cases of early and invasive cervical cancers.
It would be ideal for the developing world where smears are unaffordable, the Washington University team said.
Cheap and non-invasive
Lead researcher Dr Nancy Kiviat said: "More studies involving a much larger group of women need to be done, but we are hopeful about the potential of urine testing as a cost-effective and less invasive way to screen for cervical cancer."
Cervical screening, in the form of Pap smear tests and liquid based cytology, now saves approximately 1,300 lives per year and prevents up to 3,900 cases of cervical cancer per year in the UK.
But of the estimated 471,000 new cases of cervical cancer diagnosed each year in the world, 80% occur in the less developed world.
Developing countries often cannot finance cervical screening, which costs about £37.50 per woman screened in England.
This means women present late with disease and many die as a result.
Dr Kiviat and colleagues believe urine screening could be the answer for such countries.
They took urine samples from 143 women from Senegal, West Africa, who had cervical cancer.
Of these women, 41 had non-invasive early stage tumours of the cervix, 30 had non-invasive high-grade cancers and 72 had invasive cervical cancer.
They tested the urine samples for the presence of four genes.
Dr Kiviat's team had already shown that these genes could be detected in swabs and tissue samples from the cervix when a tumour was present.
Three of the genes were frequently detected in the samples from women with invasive cancers but rarely found in the samples from the women with non-invasive cancers.
The researchers were able to detect non-invasive cancers with 53% accuracy (sensitivity) and invasive tumours with 90% accuracy.
They are continuing their studies to see whether checking for other genes will improve the accuracy of the urine test.
Dr Nick Coleman, from the Medical Research Council Cancer Cell Unit in Cambridge working with Cancer Research UK, said: "This is very interesting.
"They are addressing a key issue in cervical screening.
"The developing world can't afford to adopt the kind of tests that we have in the West.
"We need something that can be done very cheaply.
"Whether or not the final test we want to use is this particular one remains to be seen."
He pointed out that the screening methods used in the developed world were more accurate than the urine test and should continue to be used in those countries that could afford them.