"What our study shows is that by using HPV testing, we detect precancerous lesions earlier", says lead author Dr. Gina Ogilvie.
"Whether it's co-testing or choosing one test over another, it's really important to think about the system in which cervical cancer screening is introduced, and that women are called back and followed-up for an abnormal test, whether it be a Pap smear or an HPV test", Ogilvie said.
The HPV test also seemed better at predicting who'd stay cancer-free, the investigators found. Women whose HPV test showed they didn't have the infection were less apt to develop a pre-cancerous lesion over the next four years, compared to women who'd gotten the Pap test alone.
Many women who have HPV (usually acquired via sexual contact) eliminate it from their bodies within a year or two.
There's a vaccine that prevents most cancer-causing strains of HPV, but once a person has become sexually active, it's too late to get it.
It was funded by the Canadian Institutes of Health Research and published in the peer-reviewed Journal of the American Medical Association on an open-access basis, so it is free to read online. She explained that according to the new draft guideline from the U.S. Preventive Services Task Force, HPV test may soon replace the Pap test.
Tuesday's report detailed the "exit" results of the study 48 months after the women were enrolled and first screened.
Human papillomavirus (HPV) is a DNA virus from the papillomavirus family. They recommend that women between 21 and 65 should have a Pap smear every three years, but that women aged 30 to 65 may choose to have both the Pap smear and HPV testing together every five years.
A new study conducted by a team of researchers has revealed a yet simpler method to examine any condition of cervical cancer.
HPV testing was approved as a cervical cancer screening method by the FDA in 2014. The Pap smear has been around for 50 years, so co-testing remains a viable option, Wright said.
They also cautioned that more work needs to be done to assess the economic consequences of changing the screening model. The final round of co-testing found additional abnormal cells in some women who originally tested negative in both groups.
Pap smears involve scraping cells from the cervix and examining them for cancerous changes, also known as "cytology" testing. The other group was tested using the Pap test and returned after two years and four years for rechecks.
Whether they receive a Pap test or an HPV test, the experience for patients is the same in their doctor's or nurse practitioners' office. Fewer cases of precancer were found in the HPV group, since that group had already had more precancerous signs identified and treated. "This has been building for decades", he said, adding that the Pap smear is "crude and inaccurate" while the HPV test is much more precise, operates on the molecular level and can provide information on the specific type of HPV causing the problem. So while the HPV test is more sensitive of a test, it isn't flawless and missed some women with early signs of cervical cancer.
Experts say the new method will save the lives of hundreds of British women when it is rolled out on the NHS by the end of next year.
Of note, the Canadian Task Force on Preventative Health Care differs from the US task force - it recommends Pap smear screening every three years between ages 30 and 69, citing weak evidence for screening women ages 25 to 29. Partly because of that, he said, "we're a long way away from replacing the Pap smear".