Adding HPV (human papillomavirus) screening to conventional Pap tests appears to significantly improve the early detection of precancerous cervical abnormalities and reduce the rate of subsequent cervical cancer, according to a new study in The Lancet Oncology.
Researchers in the Netherlands provided over 30,000 women aged 29 to 56 with either a Pap smear alone, or a Pap smear plus a test for HPV DNA. In this initial phase, there was no difference between the two groups in the number of women who had precancerous lesions (neoplasia) of grade 3 or worse. However, in the Pap smear plus HPV test group, more cases of low-grade neoplasias (grade 2 or worse) were detected.
The most impressive results occurred after a five-year follow-up, at which point the women were retested for neoplasias and cervical cancer. In the group that had received HPV testing plus Pap smear in the first phase, there were significantly fewer cases of high-grade neoplasias and cervical cancer. This suggests that, by detecting more low-grade lesions early on those that were caused by infection with HPV 16 the HPV test allowed for early treatment of these precancerous lesions, and thus prevented the development of cervical cancer.
This is an important study, notes ACSH's Dr. Gilbert Ross. Grade 2 precancerous lesions are very amenable to treatment, so detecting them early is important to preventing cervical cancer.
The study authors concluded that the results provide overwhelming evidence of the benefits of inclusion of HPV testing in screening programs. Dr. Ross notes that adding an HPV test to the screening procedure did not increase the rate of overtreatment or false positives, which suggests that this test is very specific.
As ACSH s Dr. Josh Bloom explains, Advances in molecular biology have made it possible to accurately measure minute quantities of viral DNA or RNA, which reflect the number of viral particles. In general, it s better to assay a virus directly, such as with the HPV DNA test, rather than just to look for the effects of the virus which is what the conventional Pap smear does. It makes perfect sense that adding the HPV test to Pap screening would allow us to detect more cases of precancerous lesions.