Human papillomavirus testing as a stand-alone screen appears to be significantly more effective than Pap smears in identifying women at high risk for cervical cancer and those with cancer, according to an article in the October 18 issue of the New England Journal of Medicine.

The study, the first randomized, controlled study in North America, concluded that virus testing is almost 40 percent more accurate than traditional cytology (Pap smears) in identifying women with advanced cervical disease. The study, which involved more than 10,000 Canadian women age 30-69 years, found that the virus test's sensitivity was 94.6 percent compared with 55.4 percent for Pap smears.

The study used QIAGEN's Hybrid Capture(R) 2 High-Risk HPV DNA test.
"We already knew before conducting this study that the sensitivity of the Pap left a lot to be desired," stated one of the study's authors, Eduardo Franco, DrPH, of Montreal's McGill University.

Participants in the Canadian Cervical Cancer Screening Trial (CCCaST) were randomly assigned to a "focus on Pap" or "focus on HPV" screening group, although for ethical reasons, both groups received both tests. In this study, conventional cytology was used. Recent analyses have found that the newer "liquid-based" cytology does not significantly improve the ability to detect disease. All CCCaST participants who tested positive on either the Pap or HPV test were referred for a follow-up biopsy. In addition to the HPV test's greater sensitivity, the study found that its specificity was only slightly less than the Pap's (94.1 percent versus 96.8 percent).

HPV testing for routine cervical cancer prevention is currently most widely practiced in the United States, where it is approved for use along with a Pap smear in women age 30 and over. Under the currently recommended guidelines, screening that includes HPV testing may be performed at longer intervals than when the Pap is used alone. However, the authors of the current report concluded that co-testing "only marginally improved sensitivity compared with HPV testing alone."

"We believe that a shift from cellular to viral (screening) tests, coupled with education and vaccination, will contribute to more efficient control of cervical cancer," the authors concluded.