Incidence Trends of Vulvar Cancer in the United States: A 20-Year Population-Based Study

BackgroundDespite being uncommon, vulvar cancer is a serious health concern with a 5-year relative survival rate of 71%.AimsThe objective was to investigate the incidence rates of this disease across different racial, ethnic, and histological subgroups in the United States, as well as the effects of the COVID-19 pandemic on this cancer.MethodsWe used the Surveillance, Epidemiology, and End Results (SEER) 22 database. The International Classification of Diseases for Oncology Version 3 topologic code C51 was assigned for vulvar cancer. Average annual percent change (AAPC) and the pairwise comparison with the parallelism and coincidence were reported. Counts and age-adjusted incidence rates per 100 000 individuals with their corresponding 95% confidence intervals (CIs) were reported.ResultsThe age-adjusted incidence rate of vulvar cancer was 2.40 (95% CI, 2.38-2.43) over the period 2000-2019, with an AAPC of 0.80 (95% CI, 0.63-0.99). By race/ethnicity, only non-Hispanic Whites had an increasing trend over 2000-2019 (AAPC: 1.30; 95% CI, 1.07-1.54). The highest age-adjusted incidence rate of vulvar cancer in the United States was for squamous cell carcinoma (SCC). There was a significant decrease in the age-standardized incidence rate of vulvar cancer in all races/ethnicities in all age groups (AAPC: -10.15; 95% CI, -15.35 to -4.94) over 2019-2020. Also, the incidence rates and incident numbers of vulvar cancer increased with aging and peaked at the 85+ age group.ConclusionThere was an increase in the incidence rate of vulvar cancer in all races, with a significantly increased trend in non-Hispanic White women from 2000 to 2019. SCC displayed the highest incidence rate among vulvar cancer histological types. It is recommended to conduct further research to identify the relevant risk factors of vulvar cancer in the United States.