Pap vs HPV Testing: Any Screening Is Better Than None

Beth Skwarecki

June 10, 2014

Does a standalone HPV screening test for cervical cancer carry any benefit over cotesting with a Papanicolaou (Pap) test or a Pap test alone? All 3 approaches are adequate for testing, Rebecca B. Perkins, MD, and Elizabeth A. Stier, MD, from Boston University School of Medicine, Massachusetts, write in an article published online June 10 in the Annals of Internal Medicine.

"Although the relative merits of screening tests and screening intervals warrant additional discussion, we cannot lose sight of the fact that most cervical cancer occurs in women who have not had any recent screening," they write. They emphasize that efforts to decrease cervical cancer should focus on increasing screening rates, regardless of which test is used.

The US Food and Drug Administration approved HPV testing in 2011; it was originally used alongside Pap testing for women aged 30 years and older and as a follow-up test for younger women who have an abnormal Pap test result.

The Cobas HPV test, 1 of 4 HPV tests on the market, was approved in April 2014 as a standalone screening test for cervical cancer. The test can recognize DNA from 14 high-risk types of the human papillomavirus, including types 16 and 18, which are responsible for 70% of cervical cancers.

Women who test positive for types 16 or 18 should then have a colposcopy; those who test positive for the other types should have a Pap test to determine whether a colposcopy is needed.

Despite its approval, providers are not entirely sold on using the HPV test alone, in part because Pap tests work so well and because recommendations have not yet been written to guide the use of HPV-only tests.

The HPV-only test has both higher sensitivity and specificity than a Pap test alone, write Dr. Perkins and Dr. Stier. "A single screening with HPV testing (either Cobas or other commercially available HPV test) detects 95% of precancerous lesions, compared with 40% to 70% for Pap testing alone; the corresponding specificities are 94% for HPV testing and 97% for Pap testing," they note.

Cotesting detects more disease than either test alone, they write — twice as many cases as a Pap alone, or 12% to 16% more than HPV testing alone. Current guidelines recommend screening intervals of 5 years for cotesting or 3 years for Pap testing alone.

Guidelines do not yet exist for how often to screen with the HPV-only test. The most recent cervical cancer screening guidelines were published before its approval, in 2012: a set from the US Preventive Services Task Force and a similar set of guidelines issued jointly by the American Cancer Society, the American Society for Colposcopy and Cervical Pathology, and the American Society for Clinical Pathology. A panel convened by the Society of Gynecologic Oncology and the American Society for Colposcopy and Cervical Pathology intends to publish interim guidelines on the use of the new test.

The overall cost of the HPV test cannot be determined without a screening schedule, Dr. Perkins and Dr. Stier write, but by other metrics, the 3 approaches are similar. Both Pap and HPV tests require speculum examination and identical collection techniques, so the patient experience is the same for both.

HPV testing alone "is at least equal to Pap testing alone," they conclude, in women aged 30 years and older who are screened every 3 years. Primary HPV testing would have higher false-positive rates in younger women. It is approved for women aged 25 years and older, and women younger 30 years frequently have transient HPV infections that do not cause cervical dysplasia. Increasing coverage with any screening test, and increasing coverage of the HPV vaccine, they write, are more important than the choice of test in efforts to decrease rates of cervical cancer.

The study was supported by an American Cancer Society Mentored Research Scholar Grant. Dr. Stier reports receiving grants from the National Institutes of Health/National Cancer Institute outside the work. Dr. Perkins has disclosed no relevant financial relationships.

Ann Intern Med. Published online June 9, 2014. Abstract

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