Prostate cancer survival in North Carolina: evaluating the race-specific differences

              INTRODUCTION
In October 1 992, the Cancer Committee ofthe
North Carolina Medical Society established a pros-tate
cancer task force. This group was charged with
developing recommendations to increase the rate of
early detection ofprostate cancers in North Carolin-ians.
To help accomplish this mission, the task force
requested the North Carolina Central Cancer Reg-istry
(NC-CCR) to conduct a study of prostate
cancer and the stage-at-diagnosis difference be-tween
the races in North Carolina. At the Spring
1 993 meeting a preliminary report was presented to
the membership. Based on that presentation, the
NC-CCRwas directed to extend its study to include
an analysis of survival differences for prostate can-cer.
This is the report of that study.
BACKGROUND
American men have a 10 percent lifetime risk
of developing clinically confirmed prostate cancer,
making prostate cancer the most commonly diag-nosed
malignancy in U.S. males. 1 In 1993, an esti-mated
1 65,000 American men were diagnosed with
prostate cancer, while the disease killed approxi-mately
35,000. 2 Prostate cancer is the second lead-ing
cause of cancer-related death among men in the
United States. 3
For black men, prostate cancer poses even more
of a threat. American blacks have the highest rate of
prostate cancer in the world.4,5 Furthermore, in some
areas of the country, the mortality rate among blacks
is more that twice that observed in whites.6 North
Carolina is one such area. When 5-year mortality data
(1986-1 990) are adjusted to the age composition ofthe
total state population, the death rate for black males is
almost two and a half times that for whites (57.0/
100,000 versus 23.2/1 00,000).
7'8 North Carolina has
the highestprostate cancermortality rateamongblacks
in the nation. 7 In 1 990, there were 320 prostate cancer
deaths to blacks in North Carolina (who comprise 23
percent of the male population), compared to 643
deaths to whites.
Stage-at-diagnosis appears to be a key factor
contributing to the mortality differences between
races. Several reports including some from North
Carolina indicate that blacks tend to have more
advanced cancer at the time ofdiagnosis. 8-9^ -"- 12 in
1990, about 25 percent of North Carolina blacks
were diagnosed with distant disease compared with
only 12 percent of whites. 8 Survival rates were
substantially lower in men diagnosed with prostate
cancer at distant versus localized stages. 13 - 14
However, survival rates depend not only on
stage-at-diagnosis, but also on treatment and re-sponses
to treatment. A handful ofstudies suggests
that although stage-at-diagnosis is an important
factor contributing to survival differences between
blacks and whites, other factors that may influence
survival include: 1) access to medical care and
behavioral patterns that delay seeking treatment, 2)
treatment preferences, 3) inherited tendency and 4)
socioeconomic status. 11,14' 15' 16 A recent assessment
has been completed on the attitudes and behavioral
characteristics ofmen responding to prostate cancer
screening programs in North Carolina. 17 These re-sults
describe considerable reluctance to have pros-tate
cancer screening tests, as well as substantial
misunderstanding about the disease process. Also,
there is variation in these findings by racial group. 17
The present report explores the discrepancy in
prostate cancer-related survival between blacks and
whites in North Carolina.
METHODS
This study analyzes survival patterns through
1992, of prostate cancer cases diagnosed in 1988.
Because the NC-CCR does not actively follow
cancer patients reported to it, survival information
is obtained by matching the cancer incidence files
with successive annual death files.
18 Since the NC-CCRpopulation-
based coverage began in 1990, for
this special study of prostate cancer survival the
NC-CCR worked with cooperating hospital-based