Study: HPV Test Better Than Pap Test for Cervical Cancer Screening
More women develop disease after negative Pap test
Based on a study that included more than 1 million women, investigators at the National Institutes of Health (NIH) have determined that a negative test for human papillomavirus (HPV) infection, compared with a negative Pap test, provides greater safety, or assurance, against the future risk of cervical cancer. That is, women who tested negative on the HPV test had an extremely low risk of developing cervical cancer.
This finding, by researchers at the National Cancer Institute (NCI), part of the NIH, was published online July 18 in the Journal of the National Cancer Institute.
HPV tests detect the DNA or RNA of the HPV types that cause nearly all cervical cancers. The Pap test detects abnormal cell changes associated with the development of cervical cancer. Both types of test are performed on a sample of cells collected from the cervix.
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 co-testing). This group of women is the largest known in the U.S. with the longest history of HPV testing in routine clinical practice.
In 2011, NCI researchers and their colleagues published findings on screening outcomes for approximately 300,000 women in this group. These data were used to inform current U.S. cervical screening and management guidelines, including those of the U.S. Preventive Services Task Force (USPSTF), which recommend Pap testing every 3 years (between the ages of 21 to 65) or co-testing every 5 years (between the ages of 30 to 65) for women with normal screening results.
In the new 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 co-test–negative. In addition, they compared risk estimates based on the USPSTF guidelines of pap testing every 3 years and co-testing every 5 years.
The researchers found that the risk of developing cervical cancer within 3 years after a negative HPV test result was about half of the already low risk after a negative Pap test. The risk of cervical cancer within 3 years of a negative HPV test was similar to the risk of developing cancer within 5 years following a negative co-test.
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 3 years
- HPV-negative: 11 per 100,000 women over 3 years
- Co-test–negative: 14 per 100,000 women over 5 years
“Our results demonstrate the superior predictive value of a negative HPV test compared with a negative Pap test. Our findings provide evidence to support the currently recommended co-testing guidelines, as well as the possibility of primary HPV testing as another alternative for cervical screening,” said lead author Julia Gage, PhD.
Source: NCI; July 18, 2014.