Home Forums Obstetrics & Gynaecology 1* HPV Screening Not Ready For Prime Time!

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    Primary HPV Screening Not Ready for Primetime
    An Interview With David Chelmow, MD Laura A. Stokowski, RN, MS, David Chelmow, MD Laura A. Stokowski, RN, MS Freelance writer
    David Chelmow, MD Leo J. Dunn Professor and Chair, Virginia Commonwealth University School of Medicine; Chair, Department of Obstetrics and Gynecology, Virginia Commonwealth University Medical Center, Richmond, Virginia May 22, 2014

    Editor’s Note: One hundred years ago, Dr. George Papanicolaou first put vaginal smears under the microscope to study human vaginal cytology, using samples supplied by his wife.[1] Dr. Papanicolaou then discovered that cytologic examination of vaginal smears could identify cancerous lesions. Since that time, Dr. Papanicolaou’s technique (the “Pap smear”), followed by the liquid Pap test, have been the only practical methods to screen women for cervical cancer.

    Enter the cobas® human papillomavirus (HPV) test, a qualitative in vitro test that uses polymerase chain reaction (PCR) and nucleic acid hybridization for the detection of 14 high-risk HPV types in a single analysis. It provides genotyping for HPV-16 and HPV-18, while concurrently detecting 12 other high-risk types in a pooled analysis. The cobas HPV test was originally approved in 2011 for use in conjunction with a Pap test in women aged 30 years and older or as a follow-up for certain Pap abnormalities. On April 24, however, a US Food and Drug Administration (FDA) panel approved the cobas test for primary cervical cancer screening in women aged 25 years or older . This approval gives clinicians another option for screening women for cervical cancer, but it has also left many puzzled about how it should be used, if at all, in younger women.

    To get answers, Medscape spoke with David Chelmow, MD, Leo J. Dunn Distinguished Professor of Obstetrics and Gynecology, Virginia Commonwealth University School of Medicine, and Chair of the Department of Obstetrics and Gynecology, Virginia Commonwealth University Medical Center, Richmond, Virginia. Dr. Chelmow attended the FDA Advisory Committee meeting last month at which the new indication for the cobas test was discussed, where he spoke on behalf of the American Congress of Obstetricians and Gynecologists.

    Medscape: What is the advantage of adopting the HPV DNA test for primary screening?

    Dr. Chelmow: What has been lost in this whole controversy over the approval of this new screening method is the fact that screening by any method greatly reduces cervical cancer risk. One half of the cervical cancers now diagnosed in the United States are in women who never underwent any screening at all, so anything that we do that opens screening to more women is going to save lives.

    With respect to the advantages, it is a mixed bag, and that is what makes it so complex. However, the best news is that a negative HPV DNA test is an even better predictor of low risk than a normal Pap test. A woman with a negative cobas test can be even more reassured that the chance of developing cancer or a significant precancer over the next several years is tremendously small.

    The bad part is the other half, which is that the test picks up a lot of women with HPV who don’t have a precancerous problem and don’t benefit from additional testing, but could end up having procedures performed on them. When HPV tests were first approved, they weren’t used for primary screening, largely because no one knew how to sort out the positives. The ATHENA trial[2] used to approve the cobas test has a triage algorithm that works pretty well.

    The fear is partly about an increased rate of colposcopies, but even more about more women getting a loop electrosurgical excision procedure (LEEP) procedure, which many think is a risk factor for preterm delivery.

    Medscape: HPV testing for screening women aged 30 years or older is currently performed in conjunction with the Pap test. It’s believed that only about 40% of women in this age group are being co-tested, and 60% are still being screened with cytology alone.[3] Will the new indication change the screening routine for the 30-and-over population?

    Dr. Chelmow: Several unanswered questions, particularly how often the HPV test should be repeated, make this question hard to answer right now. In co-testing, both the Pap and HPV test provide important information. Of the 2 tests, the HPV test is probably contributing most of the information. Compared with HPV testing alone, a small number of patients will have abnormalities detected by Pap that would be missed by HPV testing alone.

    To some degree, this is going to be a public health question, as we ask whether the small increment in cancers prevented by co-testing compared with HPV testing alone is balanced by what will probably be an increased cost. This equation will depend on the costs of the tests and the frequency with which guidelines recommend repeating the HPV test, neither of which is known yet. There are some longer-term issues that will come into play as well, for instance whether cytology will work as well if we ever get to a point where most women have been vaccinated against HPV.

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