Introduction: Since human papillomavirus vaccine introduction, incidence rates of cervical pre-cancers 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.

Methods: 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 pre-cancers. Trends in incidence rates were evaluated with Joinpoint regression. Analyses were conducted in 2020.

Results: 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.

Conclusions: 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.