Descriptive epidemiology of vaginal cancer incidence and survival by race, ethnicity, and age in the United States.

BACKGROUND

Vaginal cancer is a rare malignancy. It has many of the same risk factors as cervical cancer, including a strong association with persistent human papillomavirus infection. Descriptive studies of the epidemiology of vaginal cancer are scarce in the literature.

METHODS

The 1998 through 2003 incidence data from 39 population-based cancer registries were used, covering up to 83% of the US population. The 1996 through 2003 data from 17 cancer registries were used for survival analysis. Incidence rates, disease stage, and 5-year relative survival rates were calculated by race, ethnicity, and age group. Data analysis focused mainly on squamous cell carcinoma (SCC).

RESULTS

Incidence rates for all vaginal cancers combined were 0.18 per 100,000 female population for in situ cases and 0.69 for invasive cases. The median age of invasive cases was older than that of in situ cases (aged 68 years vs 58 years). SCC was the most common histologic type (71% of in situ cases and 66% of invasive cases). Compared with the rate for white women, the age-adjusted incidence rate of invasive SCC was 72% higher (P < .05) among black women, whereas the rate among Asian/Pacific Islander (API) women was 34% lower (P < .05). Hispanic women had a 38% higher rate than non-Hispanic women (P < .05) of invasive SCC. The rates for in situ SCC peaked at age 70 years and then declined, whereas the rates of invasive SCC increased continuously with advancing age. Black, API, and Hispanic women as well as older women were more likely to be diagnosed with late-stage disease, and these groups had lower 5-year relative survival rates than their white, non-Hispanic, and younger counterparts.

CONCLUSIONS

Incidence rates of vaginal SCC varied significantly by race, ethnicity, and age group. Black, API, and Hispanic women as well as older women had a high proportion of late-stage disease and a low 5-year survival rate.