From the participants, 9,552 women were screened using HPV test and those who were negative for the test came back after four years for a check if they had a pre-cancerous or cancerous lesion. Pap smear tests and HPV tests are designed in such a way that they help in early detection of precancerous and cancerous processes of cervical cancers so as to avoid contracting those cancers.
Several experts predicted the results would spur efforts to entirely replace the Pap test with the HPV test.
He said co-testing with both Pap smear and HPV remains and effective approach for cervical cancer screening.
The HPV infection is the most common sexually transmitted infection and is usually eliminated by the immune system within a year or two.
The virus is now known to be the main cause of cervical cancer.
Cervical cancer screening is essential because almost 13,000 women in the USA are diagnosed with cervical cancer annually. About 4,200 women will die of the disease.More news: Eleven killed, at least 45 missing as torrential rain pounds Japan
"But we will gradually move to more HPV testing for primary screening", he said. However, the U.S. Preventive Services Task Force, which creates guidelines for the diseases people should be screened for and when, still recommends Pap smears every three years for most women with uteruses ages 30 to 65, NPR reports. Where it is hard to apply HPV tests over pap smear for U.S. as there hasn't been head to head comparison until now.
Major driving factors for the growth of this market include, increasing prevalence of cervical cancers, increasing demand for advanced cancer diagnostics, increasing awareness about technological advancements in cancer testing and aging population. "It's fantastic", she said.
The smear tests were carried out using liquid-based cytology (the standard method used in the NHS). Cervical cells for both the Pap and HPV tests can be collected at the same time, during a pelvic exam.
The study is titled "Effect of Screening With Primary Cervical HPV Testing vs Cytology Testing on High-grade Cervical Intraepithelial Neoplasia at 48 Months - The HPV FOCAL Randomized Clinical Trial".
The Canadian researchers explain that nearly all cases of cervical cancer are associated with a HPV infection.
While co-testing catches more precancerous cells, it also raises the incidence of false positives, points out Dr. Diane Harper, a professor of medicine who researches HPV at the University of MI. The Pap smear has been around for 50 years, so co-testing remains a viable option, Wright said.More news: Sweden aiming to upset an England team on the verge of history
This study was funded by grant MCT82072 from the Canadian Institutes of Health Research (CIHR).
"This supports the small, but significant benefit of co-testing".
Now that we have the results of such a large study, scientists are better able to understand the long-term accuracy of HPV test results. The researchers also noted concerns over lower CIN2+ specificity with HPV testing, leading to higher screen positive rates and therefore more colonoscopies and biopsies, which could cause unintended harms for women and increased costs if the tests prove unnecessary. They also found that women with negative HPV test were more likely to not have cancer for the next four years, compared to the ones that had a negative Pap test. Women who originally had the Pap smear were more than twice as likely to have abnormal cells.
It also causes head and neck cancer, anal cancer and cancer of the penis.
That's why doctors strongly recommend that children and young adults be vaccinated against HPV; a vaccine was approved by the Food and Drug Administration in 2006.
The United States Preventive Services Task Force, an independent panel that reviews the evidence of effectiveness for preventive services, now recommends the "co-testing" for signs of cervical cancer that other groups advocate.
In most provinces, Pap tests are recommended every three years. But there were still no final guidelines issued on this and that's why the new study might be important in helping with the decision.More news: Scott Pruitt resigns as chief of United States Environmental Protection Agency
Most cervical cancers are caused by a particular strains of the Human papillomavirus, or HPV.