High-Grade Vulvar, Vaginal, and Anal Precancers Among U.S. Adolescents and Young Adults After Human Papillomavirus Vaccine Introduction

Abstract

Since human papillomavirus vaccine introduction, incidence rates of cervical precancers have decreased; however, the vaccine's impact on noncervical anogenital precancers has not been shown. These precancers are identified opportunistically and are not collected routinely by most cancer registries. This study examined the incidence rates of high-grade (intraepithelial lesions grade 3) vulvar, vaginal, and anal precancers among persons aged 15-39 years using 2000-2017 data from select cancer registries covering 27.8% of the U.S. population that required reporting of these precancers. Trends in incidence rates were evaluated with Joinpoint regression. Analyses were conducted in 2020. High-grade vulvar precancer rates declined by 21.0% per year after human papillomavirus vaccine introduction among females aged 15-19 years. In addition, high-grade vaginal precancer rates declined by 19.1% per year among females aged 15-29 years after human papillomavirus vaccine introduction. Compared with that in the prevaccine period when high-grade anal precancer rates were increasing, anal precancer rates after human papillomavirus vaccine introduction were stable among females aged 15-29 years and among males aged 30-39 years. Among males aged 15-29 years, the rates increased over the entire period but less so after human papillomavirus vaccine introduction. Opportunistically-detected high-grade vulvar and vaginal precancers among females aged 15-29 years decreased and anal precancers stabilized in years after the introduction of the human papillomavirus vaccine, which is suggestive of the impact of the vaccine on noncervical human papillomavirus cancers.