Health Care Use May Account for Colorectal Cancer Disparities
Posted Apr 26 2010 7:55am
Higher rates of colorectal cancer incidence and death among
African-Americans may be driven less by biology and more by differences
in health care use, according to a new study.
Image of a human colon cancer cell. Image by Annie
Cavanagh. All rights reserved by Wellcome Images.
Colorectal cancer disproportionally affects African-Americans
in the United States. From 2002 to 2006, the average annual incidence
rate for colorectal cancer was about 49 per 100,000 for white
men and women, compared to 60 per 100,000 for black men and women.
The annual death rates were about 18 and 25 per 100,000, respectively.
Some researchers have suggested these differences may be related
to health care access. However, studies have found that black
people tend to develop colorectal cancer at an earlier age. They
are also more likely to be diagnosed with advanced colorectal
cancer, which is more difficult to treat and has worse survival
A team led by Dr. Adeyinka O. Laiyemo and Dr. Christine Berg
of NIHs National Cancer Institute (NCI) examined the issue more
closely. Their study involved more than 60,000 people who participated
in the ongoing NCI-funded Prostate, Lung, Colorectal and Ovarian
Cancer Screening Trial—a multi-center effort designed to
evaluate the effect of screening on cancer mortality.
At the start of the study, participants were offered a screening
flexible sigmoidoscopy, which is used to examine the lower, or
sigmoid, part of the colon. People who had polyps or lesions
detected during the sigmoidoscopy were referred to their personal
physician for follow-up colonoscopy, in which the entire colon
is examined. The costs of the colonoscopies weren't covered by
In the April 21, 2010, Journal of the National Cancer Institute,
the team reported that black and white people were equally likely
to need a follow-up colonoscopy after a screening sigmoidoscopy,
but black people were less likely to actually receive the follow-up.
The groups didnt differ significantly in the presence of pre-cancerous
lesions or cancer. About 24% of the white participants and
26% of the black participants had abnormal results from the
screening sigmoidoscopy, such as polyps or lesions. However,
72% of the white but only 63% of the black people received
a follow-up colonoscopy. Lower rates of follow-up could lead
to delayed diagnosis and treatment, and higher mortality.
The reasons behind lower follow-up rates among black people
in the study are unknown. The cost of follow-up care may have
been a factor, but the authors didnt have direct information
on socioeconomic status. One sign that socioeconomics may have
played a role is that the overall education level among black
participants was lower.
"Our research suggests that the biology of colorectal cancer
may not differ by race, at least in the early stages of tumor
development," Laiyemo says. "Instead, health care utilization
differences among races may play a more important role in colorectal
"This research suggests that targeting interventions toward
increasing the use of screening among minority populations might
go a long way toward reducing disparities in colorectal cancer," Berg