An NCI study found that a negative HPV screening test result is a better predictor of low cervical cancer risk than a negative Pap test.
The study, which included more than 1 million women, was published in the Journal of the National Cancer Institute.
Since 2003, women between the ages of 30 and 64 enrolled in Kaiser Permanente Northern California’s health care system have had cervical cancer screening with concurrent HPV and Pap testing (called cotesting). This group of women is the largest known in the U.S. with the longest history of HPV testing in routine clinical practice.
In a 2011 study, researchers and their colleagues published findings on screening outcomes for about 300,000 of the women in this group. Those data were used to inform current U.S. cervical screening and management guidelines, including those of the U.S. Preventive Services Task Force, which recommends Pap testing every three years between the ages 21 and 65, or cotesting every five years between the ages 30 and 65 for women with normal screening results.
In this study, the researchers extended their 2011 analysis to more than 1 million women who were screened through December 31, 2012. They estimated cervical cancer risks among women who tested HPV-negative alone, Pap-negative alone, and cotest-negative. They compared risk estimates based on USPSTF guidelines of pap testing every three years and cotesting every five years.
Researchers found that the risk of developing cervical cancer within three years following a negative HPV test result was about half of the already low risk following a negative Pap test.
Cervical cancer risk within three years of a negative HPV test was similar to the risk of developing cancer within five years following a negative cotest. The researchers estimated that the following number of women would go on to develop cervical cancer after a negative test:
- Pap-negative: 20 per 100,000 women over three years
- HPV-negative: 11 per 100,000 women over three years
- Cotest-negative: 14 per 100,000 women over five years
“Our findings provide evidence to support the currently recommended cotesting guidelines, as well as the possibility of primary HPV testing as another alternative for cervical screening,” said Julia Gage, first author of the study report and a research fellow in the Clinical Genetics Branch of the NCI Division of Cancer Epidemiology and Genetics.
