Age and cohort patterns seen in recent data showed that declines in high-grade cervical lesions among young women are likely driven by HPV vaccination, not changes in screening or risk behaviors, according to findings published in Clinical Infectious Diseases.
“Cervical lesions are clinically important outcomes to monitor because they are most closely related to the development of cervical cancer and because they are diagnoses that incur substantial morbidity, psychological distress and treatment cost,” Linda M. Niccolai, PhD, from the Connecticut emerging infections program at Yale School of Public Health, and colleagues wrote. “Though evidence of the impact of HPV vaccines on cervical infections and genital warts is growing, less is known about trends in precancerous high-grade cervical lesions.”
In their study, researchers examined whether HPV vaccination coverage, changes in screening for cervical cancer and risk behaviors for acquiring HPV affected trends in high-grade cervical lesions among women aged 21 to 39 years in Connecticut from 2008 to 2015. Using negative binomial regression and change-point methods, they modeled trends of cervical intraepithelial neoplasia grades 2/3 and adenocarcinoma in situ (CIN2+) by age and birth cohort. These trends were then compared with changes in HPV coverage, cervical cancer screening, an antecedent event to detection of a high-grade lesions and changes in sexual behaviors and Chlamydia trachomatis.
Of 15,218 CIN2+ cases reported among young women in Connecticut during 2008-2015, the number declined from 2,163 in 2008 to 1,540 in 2015. During the study period, the rates of CIN2+ dropped from 30% to 74% among women aged 21 to 26 years, with greater declines observed in younger women. Primary analysis showed a significant drop in CIN2+ among women aged 21 years, then successive declines in women aged 22 to 26 years during 2011-2012. All birth cohorts between 1985 and 1994 saw significant declines, ranging from 22% in 1985 to 82% in 1994, during the surveillance period. Ecological comparisons showed significant increases in HPV vaccine, with HPV coverage with at least one dose increasing 6.7% per year among adolescents aged 13 to 17 years in Connecticut during the study period and 18% per year among those aged 19 to 26 years in the U.S. during 2010-2014. Comparisons also showed modest reductions in cervical cancer screening and sexual risk behaviors.
“Our results add to the small but growing body of literature about trends in CIN2+, an important clinical outcome, since the introduction of HPV vaccines,” Niccolai and colleagues wrote. “Though it is encouraging that declines in [Connecticut] have been achieved with only moderate vaccine coverage, these results should promote renewed efforts [to] increase vaccination coverage to achieve their full prevention potential.” – by Savannah Demko
Niccolai reports no relevant financial disclosures.