Aug. 22, 2011 -- DNA tests that detect the most virulent strains of human papillomavirus, or HPV, may find more advanced precancerous cells that can lead to cervical cancer than traditional Pap smears, a new study shows.
The study, which is published in The Lancet Oncology, suggests that testing for HPV strains 16 and 18, which cause about 70% of all cervical cancer, could replace Pap tests as the primary screening tool for the disease.
“We’re not there yet, but this trial gives us more data that shows that it is reasonable to consider HPV as a standalone test,” says Therese Bevers, MD, medical director of the Cancer Prevention Center at the University of Texas M.D. Anderson Cancer Center in Houston.
The study of more than 40,000 healthy women over age 25 found that HPV testing correctly detected nearly 40% more advanced precancers than Pap smears did.
“There are still points to be worked out, but clearly this study is providing more data to say that this may be a strategy that’s reasonable to consider,” says Bevers, who was not involved in the research.
Importantly, the study also found that combining HPV and Pap testing, as many doctors do, only found about 5% more advanced precancers and cancers, but it increased the number of women who falsely tested positive by more than one-third.
“You get a 5% gain for a 35% over-referral,” says study researcher Mark H. Stoler, MD, professor of pathology and clinical gynecology at the University of Virginia Health System in Charlottesville, Va.
Those false-positive tests lead to more frequent or invasive testing to rule out cancer, more anxiety for patients, and more expense for individuals and insurance companies.
“The study suggests that if you’re really concerned about efficiency with very little penalty, then HPV testing should be the first test,” Stoler tells WebMD.