, according to a new study.
The study, which analyzed data from Mexico’s population-based hrHPV screening program over 6 years, confirms the importance of HPV screening for catching high-grade cervical lesions early.
“Our results provide evidence that hrHPV testing is the best strategy for a timely diagnosis of CIN2+ lesions while avoiding overtreatment of young women,” the study authors write. “Many countries now use hrHPV testing as the primary screening method, given it has higher sensitivity and detects more cervical cancer precursor lesions, such as CIN2+.”
According to Erik Jansen, MSc, the analysis supports recent updates to U.S. screening standards and confirms findings from previous trials, which show that HPV testing significantly improves prevention of cervical cancer.
“The significance of this paper is that the data reported is from a long follow-up in a country that implemented HPV screening on a large scale,” Mr. Jansen, PhD candidate in the Department of Public Health, Erasmus University Medical Center, Rotterdam, the Netherlands, told this news organization.
The study, conducted by Mexico’s National Institute of Public Health, analyzed screening data from the country’s public cervical cancer prevention program from 2010 to 2015. More than 2 million women aged 34 to 65 who had hrHPV-based screening tests followed by cytologic triage if they were HPV positive were included, as were 2.8 million women of the same age who received cytologic testing alone.
In the hrHPV group, 1.2% of women (n = 24,276) received referrals to colposcopy versus 3.1% of women (n = 90,980) in the cytology group. And among all women, only 0.8% who had abnormal results (n = 16,459) in the HPV went for a colposcopy versus 1.5% (n = 43,638) in the cytology group.
Overall, the authors found that 13.3 colposcopies were required to detect a single CIN2+ case in the cytology group compared to 5.7 colposcopies in the hrHPV with cytologic triage group.
The authors also note that the cost of colposcopies was three times lower in the HPV testing group and that the positive predictive value of hrHPV testing with cytologic triage was 17.5% versus 7.5% for cytology alone.
“The positive predictive value did not change for either screening strategy whether or not women lost to follow-up were taken into account,” the authors write.
Although Mr. Jansen noted that the findings are important, he also pointed to several limitations – namely, the significant loss to follow-up in the HPV group.
The HPV testing and cytologic triage happened in separate visits, and under the two-visit protocol, more than 50% of women who tested positive for HPV didn’t return for cytology. Such a significant loss to follow-up may call some of the findings into question, Mr. Jansen noted.
For instance, the rate of colposcopy referrals does not account for HPV-positive women who skipped their cytology screening. Assuming the same HPV risk for women who received cytology and those who did not, Mr. Jansen calculated that without any loss to follow-up, the colposcopy referral rate would have increased from the reported 1.2% to 2.6%, which is much closer to the 3.1% of the women referred in the cytology arm.
The lower colposcopy costs in the HPV group were also likely due, in part, to the loss to follow-up, which is not necessarily a good thing, Mr. Jansen said.
Still, “this study does confirm the finding that a primary HPV screening program is more effective than cytology [alone],” Mr. Jansen said.
Co-author Eduardo Franco reported receiving grants and personal fees from MSD and has a pending patent, “Methylation Markers in Cervical Cancer.” All other authors reported no conflicts of interest.
A version of this article first appeared on Medscape.com.