Human Papillomavirus (HPV) Vaccine Effect on Incidence of in Situ and Invasive Squamous Cell Cancer of the Vulva, 2001-2018 [A322

Abstract

INTRODUCTION: A recent study found that the incidence of invasive squamous cell carcinoma of the vulva (VSCC) is increasing among U.S. women, but rates of VSCC in situ (VIS) have not been reported since 2000. In 2008, indications for the human papillomavirus (HPV) vaccine were extended to include prevention of vulvar cancers. To examine its impact, we compared 2001–2018 incidence trends of VIS and VSCC among different populations of U.S. women. METHODS: This study was a secondary analysis of 88,942 vulvar cancer cases among adults aged 20 years and older reported in the U.S. Cancer Statistics 2001-2018 databases. We stratified data by tumor behavior (in situ/invasive) and age (20-44, 45-64, 65+ years old), race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic), and U.S. census region (Northeast, South, Midwest, West). Incidence rates and annual percentage changes (APC) were calculated by group. RESULTS: VIS incidence significantly decreased from 2001 to 2018 (APC –4.3, 95% CI –4.7 to −3.8) among all groups. Invasive VSCC decreased among 20- to 44-year old women (APC –0.8, 95% CI –1.3 to −0.3), but increased among older women. Regardless of tumor behavior, incidence was highest among non-Hispanic White women and those living in the Midwest. CONCLUSION: Rates of VIS are decreasing in women of all ages over 20 years old as well as in invasive VSCC among vaccine-eligible 20- to 44-year-old women. Since the trend began before the vaccine was available, this is probably due to multiple factors. Additional time is needed to fully realize the benefit of HPV vaccination on this cancer.