Vulvar Cancer Incidence in the United States and its Relationship to Human Papillomavirus Vaccinations, 2001-2018

The human papillomavirus (HPV) vaccine was indicated for the prevention of vulvovaginal cancers in 2008, but its impact on the incidence of vulvar cancers within the US is unknown. To determine this, we conducted a secondary analysis of 88,942 vulvar cancer cases among women 20+ years old using the US Cancer Statistics 2001-2018 databases. Data were stratified by tumor behavior (in situ or invasive), age (20-44, 45-64, 65+ years old), race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic), and US census region (Northeast, South, Midwest, West), and incidence rates and average annual percentage changes (AAPC) were calculated by group. Reversing previous trends, the incidence of vulvar carcinoma in situ significantly decreased between 2001 and 2018 among women from all age groups, races/ethnicities, and regions (combined AAPC, -4.3; 95% confidence interval (CI), -4.7 to -3.8). The incidence of invasive vulvar squamous cell carcinoma decreased significantly among 20- to 44-year-old women (AAPC, -0.8; 95% CI, -1.3 to -0.3), but significantly increased among those 45 to 64 (AAPC, 2.3; 95% CI, 1.8-2.8) and 65+ years old (AAPC, 1.2; 95% CI, 1.1-1.4). Regardless of tumor behavior, incidence was highest among non-Hispanic Whites and the Midwest region. Overall, the significant declines in vulvar carcinoma in situ among all ages, as well as invasive vulvar cancer among younger women, are encouraging and complement other recent data suggesting HPV vaccinations are already reducing anal and cervical cancer incidence. Over time, further declines in vulvar carcinoma incidence are likely as uptake and completion rates of the HPV vaccine increase in the US. We found evidence that HPV vaccinations likely contributed to a decrease in the incidences of vulvar carcinoma in situ and invasive vulvar carcinoma among 20- to 44-year-old women between 2001 and 2018. Our data add to the growing evidence that HPV vaccinations are reducing the incidence of HPV-related anogenital cancers.