Cooper GS Yuan Z, Rimm AA.
Racial disparity in the incidence and case-fatality of colorectal
cancer: analysis of 329 United States counties.
Cancer Epidemiol Biomarkers Prev 1997;6(4):283-5.
It is possible that there are differences in the quality of care between
regions that have a large proportion of black patients and regions that
have a small proportion of black patients. These regional differences
may account for the previously reported racial variation in long term
survival for colorectal cancer in large-scale studies. Alternatively,
if racial disparities in survival occur within regions, other factors
would be responsible. The goal of this study was to determine whether
race was associated with county-level differences in the incidence rate
and survival of patients with colorectal cancer in a Medicare sample of
beneficiaries aged 65 years and older between 1989 and 1991.
The data were divided into four quartiles with 3.5%, 6.9%, 12.3%, and
28.2% of the population being adult blacks. The incidence of colorectal
cancer was consistently higher in whites, and the 2-year case fatality
rate was consistently higher for blacks. The disparities were highest
in areas with more blacks; and, for both races, the fatality rates were
also highest in areas with more blacks. The data were also stratified
by geographic area: incidence rates were higher for whites than blacks
in the Northeast and South, but equal in the Midwest/West (where the proportion
of blacks in the population is lowest). However, the case fatality rates
were, again, consistently higher for blacks.
The authors conclude that "although race is a frequently used surrogate
for SES, the data suggest that race may be associated with colon cancer
incidence and survival, independent of social class." The following
potential explanations for the differences in survival were offered: confounding
by more severe comorbid diseases in black patients, diet and lifestyle
differences, patient preferences in surgery and follow-up care, and differences
in access and quality of care.
