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Race and Location Play Strong Role in Cancer
Survival
Roxanne Nelson
July 18, 2008 — There are large global variations in cancer
survival, and within the United States, survival rates vary among
geographic locations and racial groups. Direct comparisons of cancer
survival in high- and low-income countries have not been easy, but a
new study published online July 17 in Lancet Oncology
provides directly comparable data on cancer survival from 31
countries.
Overall, the international team of researchers found that the
5-year relative survival rates for breast, colorectal, and prostate
cancer were higher in North America, Australia, Japan, and northern,
western, and southern Europe, but lower in Algeria, Brazil, and
eastern Europe. The data also show distinct racial disparities in
the United States, with cancer survival 7% to 14% higher among white
patients than black patients.
"To some extent, the results were as expected," said lead author
Michel Coleman, BM, BCh, MSc, MFPHM, professor of epidemiology and
vital statistics at the London School of Hygiene and Tropical
Medicine, in the United Kingdom. "But the range was wider than I
imagined and the study provides some fairly hard data."
The authors noted that most of the international variation in
survival can probably be attributed to differences in access to
diagnostic and treatment services, and part of the variation can
likely be attributed to underinvestment in health resources.
The CONCORD study, which began in 1999 as an extension of the
EUROCARE-3 study, was originally designed to assess survival of
adults who were diagnosed with breast, colorectal, or prostate
cancers from 1990 to 1994 in Europe and the United States. For the
current analysis, data from 1.9 million cancer patients from
101 population-based registries in 31 countries on 5 continents were
used to compare 5-year survival for first, primary, invasive cancers
of the breast (women only), colon, rectum, and prostate. In the
United States, data were obtained from 22 registries, covering 16
states and 6 metropolitan areas.
The survey results show that the United States had the highest
survival rates for breast and prostate cancers, Japan had the
highest survival rates for colon and rectal cancers in men, and
France had the highest survival rates for colon and rectal cancer in
women.
Variations in survival among the provinces of Canada and among
the states and territories of Australia were generally small, with
overall high survival rates suggesting a high level of healthcare in
most areas, the authors note. The variations in survival among
European countries were much wider. For example, the 5-year relative
survival for breast cancer ranged from 57.9% in Slovakia to 82.0% in
Sweden.
Disparities in the United States
Within the United States, variations in survival were observed in
different geographic locations. The lowest overall survival rates
were in New York, except for rectal cancer in women, and the best
survival rates for almost all cancers were in Hawaii. The state of
Idaho had the highest survival rates for rectal cancer in men, and
the city of Seattle, in Washington, had the best survival rates for
prostate cancer.
Cancer survival has been shown to vary with race, but
unfortunately, racial data were only available from the United
States, explained Dr. Coleman, where individual tumor records are
coded as white, black, or other. "We would have liked to have
included Singapore — Chinese, Malay, Indian — but that proved
impossible at this stage," he said.
In all 16 states and 6 metropolitan areas that were included in
the survey, the rates of cancer survival among black people were
systematically and substantially lower than that in white
people.
"The disparities between blacks and whites are well documented in
the United States, but thus far only in data from the SEER
[Surveillance, Epidemiology and End Results] program, which until
recently included 10% of the American population," said Dr. Coleman.
"We have shown that these disparities are wide and consistent across
42% of the American population, even where blacks comprise over 25%
of the population, such as Atlanta or Louisiana."
Variation by Race and Geography
For breast cancer, the age-adjusted pooled estimate of 5-year
survival was 84.7% for whites and 70.9% for blacks. The absolute
differences in survival between the 2 groups ranged from a low of 2%
in Rhode Island and Nebraska, to 25% to 27% in Iowa and Seattle. The
researchers observed that survival for black women was 8% to 14%
below the lowest estimate for white women, even in regions where
blacks comprised at least a quarter of the total population.
The relative 5-year survival rates for breast cancer ranged from
80% or higher in North America, Sweden, Japan, Finland, and
Australia, to less than 60% in Brazil and Slovakia; a low of 38.8%
was seen in Algeria. Of the 24 European countries that contributed
data to the study, survival rates were primarily in the range of 70%
to 79%.
For colon cancer, the relative 5-year survival was approximately
60% in North America, Japan, Australia, and some western European
countries, but dipped to 40% or lower in Algeria, Brazil, and
eastern European countries. In Europe, rates ranged from a low of
28.5% for men in Poland to 54% to 57% in Spain, Finland, Austria,
and France.
Racial disparities were noted between white and black patients in
the United States. Estimated colon cancer survival rate was 61% for
white people and 51% to 52% for black people.
The 5-year survival rates for rectal cancer were similar to those
for colon cancer, ranging from about 20% to 60%; Japan, Canada, the
United States, France, the Netherlands, Sweden, and Australia were
at the upper end of the range, and Algeria, Estonia, Poland, and
Slovakia were at the lower end. In the United States, survival was
generally lower among blacks than whites for both sexes. The
estimated 5-year survival for black men was 47.4% and for white men
was 57.3%, and for black women was 49.4% and for white women was
60.4%.
Finally, the highest rates of survival for prostate cancer were
seen in the United States (92%), with rates of 80% or higher in
Austria and Canada, but less than 40% in Denmark, Poland, and
Algeria. As with other cancer sites, the 5-year relative survival
for prostate cancer in blacks was lower than for whites in all
American populations for which racial differences could be assessed.
Overall estimated 5-year survival was 85.8% for blacks and 92.4% for
whites, with a difference of 6.6%. Differences in survival varied
according to geographic location; the highest survival for black men
was in Seattle (89.6%) and the lowest was in New York City
(74%).
"We also corrected for black–white differences in background
mortality within each state or metropolitan area, and in each
calendar year, neither of which the SEER estimates have done," Dr.
Coleman told Medscape Oncology. "In other words, even with
the tightest control on background mortality, the most stiffly
conservative estimates of black and white differences in survival
are wide and robust."
Dr. Coleman added that they intend to expand the study to other
countries and other cancers. "The interest is already beginning to
come in from other registries around the world, and we will seek
funding on the basis of the interest."
The study was funded by the CDC, the UK Department of Health,
and Cancer Research UK. The researchers have disclosed no relevant
financial relationships.
Lancet Oncol. Published online before print July 17,
2008.
Roxanne
Nelson is a staff journalist for Medscape
Hematology-Oncology.
Medscape Medical News 2008. © 2008 Medscape
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