Vulvar cancer incidence: An analysis of SEER data by race and ethnicity

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Objective: Vulvar cancer is among a minority of cancers with increasing incidence over the past 3 decades. The purpose of this study was to determine if recent population trends occurred equally among various racial and ethnic groups and to further analyze clincopathologic differences at presentation between groups.
 >Methods: Incidence and clinicopathologic data for invasive vulvar carcinoma was gathered from the Surveillance, Epidemiology, and End Results Program for the years 1992 -2004. Racial / ethnic groups analyzed included non-Hispanic Whites (W), non-Hispanic Blacks (B), Hispanic Whites (H), and Asian / Pacific Islanders (API). Age-adjusted incidence rates and 95% confidence intervals were calculated using SEER*Stat.
 >Results: 4,707 cases of invasive vulvar carcinoma were registered during the study period including 3,818 W, 403 B, 367 H, and 119 API. The age-adjusted incidence per 100,000 women was 1.70. W had the highest age-adjusted incidence at 2.47 followed by B (1.84), H (1.72), and API (0.77). While incidence rose sharply after age 60 in W and H, the increase remained nearly linear in B and API. Stage at presentation varied slightly between racial / ethnic groups with W and API presenting more often with localized disease (68% and 70% compared to 60% and 65% in H and B respectively) and less often with distant disease (4% and 3% compared to 6% and 4% in H and B) (p = 0.03). API, B, and H were more likely to present with high grade or undifferentiated cancer but the difference was not significant (5%, 3%, and 2% respectively compared to W at 2%) (p = 0.41). In the 12 years studied, overall vulvar cancer incidence was stable with minimal racial / ethnic variance. Furthermore, there were no clinically relevant differences when temporal trends were adjusted by racial / ethnic group and stage.
 >Conclusion: In contrast to prior trends in both vulvar cancer and dysplasia, vulvar cancer incidence stabilized from 1992 -2004. Racial disparities in age related incidence, stage and grade at presentation suggest both societal and biologic differences. Further investigation may point to exploitable differences for prevention, diagnosis and treatment.