Stand Alone-HPV Test Is More Accurate Than Cytology

A randomized, controlled study of human papillomavirus (HPV) testing as a stand-alone screen concluded that it is almost 40% more accurate than traditional cytology (the Pap "smear”) in identifying women with advanced cervical disease.

The study, which involved more than 10,000 Canadian women age 30-69, found that the HPV test's sensitivity--its ability to accurately identify women with pre-cancerous cervical cells or cancer-- was 94.6%, compared to 55.4% for the Pap. HPV is the primary cause of cervical cancer. The study was published in the October 2007 issue of The New England Journal of Medicine.

Qiagen's (Hamburg, Germany) hybrid capture 2 high-risk HPV DNA test that is both CE-marked in Europe and approved by the U.S. Food and Drug Administration (Rockville, MD, USA) was used in the study. The molecular diagnostic test was developed by Digene Corp., now part of Qiagen. The performance of Qiagen's HPV test has been validated in studies that included more than 300,000 women.

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. 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--the likelihood that women with positive results actually have disease--was only slightly less than the Pap's (94.1 percent vs. 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 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 NEJM report concluded that co-testing "only marginally improved sensitivity compared with HPV testing alone”.

Cervical cancer affects more than 400,000 women annually worldwide and, after breast cancer, is the second-most-common malignancy found in women. Cervical cancer is caused by "high-risk” types of the HPV, which are sexually transmitted. It's estimated that 80% of women will get an HPV infection at some point in their lives. However, in most cases, the infection goes away or is suppressed by the body without causing problems. It is only infections that persist that can cause abnormal cells to form that may develop into cervical cancer if not detected and treated early.


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