HPV Test Could Lower Need for Pap Smears
Test Helps Identify Women at Risk for Cervical Cancer
Dec. 31, 2002 -- Annual Pap smears to screen for cervical cancer are still recommended for most women, but a new study from the National Cancer Institute suggests that yearly testing may not be necessarily if a women has a negative Pap test along with a negative test for cervical cancer-causing forms of human papilloma virus (HPV).
NCI researchers followed almost 21,000 women for 10 years and found that those who had a negative Pap test and a negative test for HPV had almost no risk of developing cervical cancer within three or four years of screening. The findings are reported in the Jan. 1, 2003, issue of the Journal of the National Cancer Institute.
Approximately 13,000 women in the United States will develop invasive cervical cancer this year and 4,100 women will die of the disease. Pap screening checks for changes in the cells of the cervix, which may indicate infection, abnormal cells, or cancer. HPV testing specifically looks for the infections that cause cervical cancer.
NCI investigator Mark E. Sherman, MD, says direct screening for HPV can help identify women who have a low risk for cervical cancer and those who are at increased risk. He writes that a negative screen should provide reassurance for lengthening the screening interval among low-risk women while a positive test identifies a group that requires more frequent screening.
"Infection with HPV is extremely common, and most women who become infected clear the virus through an immune response," he tells WebMD. "But even when there is progression to cancer it usually takes a decade or more. This means that women who are not infected are at very low risk."
Sherman and NCI colleagues reported that over a 10 year period, 123 women out of the 171 (almost 72%) who developed cervical cancer or a precursor to the disease known as cervical intraepithelial neoplasia 3 (CIN3 ) had abnormal Pap results and/or a positive HPV test. Among these women, 102 were diagnosed with cervical cancer within the first three to four years.
Overall, the number of new cases of cervical cancer occurring over the first three to four years was three times higher in women with an abnormal Pap smear and/or a positive HPV test compared with women who had both a negative Pap and a negative HPV test.
The HPV test is not approved for cervical cancer screening in women under the age of 30, but the NCI authors conclude that it could help target women who need the closest surveillance while sparing others the inconvenience, cost, and emotional pain associated with a false-positive Pap tests.
Gynecologic oncology specialist Carmel Cohen, MD, tells WebMD there are about 6,000 cervical cancers found each year among the 5 million women who end up having abnormal Pap smears.