Racial variation in the incidence of squamous cell carcinoma of the bladder in the United States.

Abstract

Racial differences in the incidence of squamous cell carcinoma of the bladder may provide insight into the pathogenesis of this disease. We determined the incidence of squamous cell carcinoma of the bladder according to race in the United States. Data obtained from the Surveillance, Epidemiology and End Results program from 1973 to 1997 were analyzed to determine the incidence of squamous cell carcinoma of the bladder in individuals 35 to 84 years old. Incidence rates by race and gender were then adjusted to the age distribution of the 1970 American population. The average annual incidence of squamous cell carcinoma of the bladder was 1.20/100,000 in black and 0.60/100,000 in white Americans (relative risk 2.0, 95% CI 1.74 to 2.29). Black men were at increased risk compared with white men and black women were at increased risk compared with white women. The higher incidence in black versus white individuals existed in all age groups beyond 45 years and was present throughout the study period. Squamous cell carcinoma of the bladder appears to be twice as common in black as in white individuals in the United States.