A woman's 3-year risk of cervical cancer after a negative HPV test was roughly half that of women who'd had a negative Pap test, according to research from the NCI. Future guidelines based on primary HPV testing could reduce the number of cervical cancer screening tests a woman needs.

Pap tests have long been the cornerstone of cervical cancer screening in the United States, but a negative test for human papillomavirus (HPV) may better predict a woman's risk for cervical cancer than a negative Pap test, according to a study by NCI researchers published in July (J Natl Cancer Inst 2014;106:dju153).

The researchers analyzed data from more than a million women between ages 30 and 64 in the Kaiser Permanente Northern California health care system. Every 3 years between 2003 and 2012, the women were screened for cervical cancer with Pap and HPV tests. After analyzing the outcomes, the researchers concluded that a woman's 3-year risk of developing cervical cancer following a negative HPV test was just 11 per 100,000, roughly half the 20 per 100,000 for women who'd had a negative Pap test.

The researchers weren't particularly surprised by the results. “We expected to find that HPV testing was superior [to Pap testing] because we know that a persistent infection of cancer-causing types of HPV is the causal agent of cervical cancer,” says Julia Gage, PhD, MPH, first author of the study. “In the absence of HPV, a woman's risk of cervical cancer is extremely low.”

Currently, the U.S. Preventive Services Task Force and many professional societies recommend two strategies for cervical cancer screening: either Pap tests every 3 years or both HPV and Pap tests every 5 years. Although the optimal screening interval for primary HPV testing has not been determined, based on current screening guidelines, a negative HPV test might provide reassurance against cancer for 5 years, compared to 3 years for a Pap test. Using those intervals, the researchers estimated that in a hypothetical population of 1 million women, changing from giving Pap tests every 3 years to giving HPV tests every 5 years would result in nearly 2 million fewer tests over a 15-year period.

If the interval for primary HPV testing is set at every 3 years, it “might provide as much, if not more, reassurance against precancer and cancer, compared to primary Pap testing every 3 years,” the researchers note. Determining the ideal screening interval is a critical next step, they say.

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