Abstract
Vulvar cancer incidence has been rising in recent years, possibly due to increasing exposure to human papillomavirus (HPV). We assessed incidence rates of HPV-associated and non-HPV-associated vulvar cancers diagnosed from 2001 to 2017 in the United States (US). Using population-based cancer registry data covering 99% of the US population, incidence rates were calculated and stratified by age, race/ethnicity, stage, geographic region, and histology. The average annual percent change in incidence per year were calculated using joinpoint regression. From 2001 to 2017, the incidence of HPV-associated vulvar cancers increased by 1.2% per year, most notably among women who were aged 50-59 years (2.6%), 60-69 years (2.4%), and ≥ 70 years (0.9%); of White (1.5%) and Black (1.1%) race; diagnosed at an early (1.3%) and late (1.8%) stage; and living in the Midwest (1.9%), Northeast (1.4%), and South (1.2%). Incidence increased each year for HPV-associated histologic subtypes including keratinizing (4.7%), non-keratinizing (6.0%), and basaloid (3.1%) squamous cell carcinomas (SCCs), while decreases were found in warty (2.7%) and microinvasive (5.5%) SCCs. HPV-associated vulvar cancer incidence increased overall and among women aged over 50 years while remaining stable among women younger than 50 years. The overall incidence for non-HPV-associated cancers was stable. Continued surveillance of HPV-associated cancers will allow us to monitor future trends as HPV vaccination coverage increases in the US.