VIDEO:
BIRMINGHAM, Ala. – A new study by University of Alabama
at Birmingham (UAB) researchers shows that body-mass index (BMI)
and co-existing medical conditions (co-morbidity) do not explain
the decreased survival observed among African-Americans compared to
Caucasians who also have colon cancer. The study is published
online Nov. 23 in Cancer, a journal of the American Cancer
Society.
The finding indicates that although BMI and co-morbidity are
independent predictors of poor survival for all patients, these
factors do not explain the increased risk of death associated with
African-Americans. "Therefore, more research is needed to gain a
fuller understanding of how race and ethnicity are involved in
colon cancer survival following surgery," says Upender Manne,
Ph.D., an associate professor in the UAB Department of Pathology
and the lead study author.
For many cancers, including colon cancer, African-Americans
have lower survival rates than whites; possible reasons behind this
disparity – including genetic variation, tumor
characteristics, access to health care and other factors –
are being examined extensively, Manne says. There was a belief that
racial disparity in survival following surgery for colon cancer was
related to a high BMI and co-morbidity. BMI is a numerical value of
weight in relation to height; obesity is defined as a BMI of 30 or
more.
The UAB researchers analyzed data from 496 patients who
underwent surgery for colon cancer at UAB Hospital between 1981 and
2002. Until the end of the study in 2008, the researchers looked at
factors such as BMI, co-morbidity, demographics and tumor
properties as they relate to survival rates.
The analysis revealed that African-Americans were 34 percent
more likely to have died by the end of the study than Caucasians.
Among patients with advanced stages of cancer, being underweight
increased the risk of death by 87 percent. Being overweight or
obese was protective in patients with Stage IV disease and
decreased the risk of death by 42 percent.
"That was the surprising finding for us – that a high
BMI was actually protective in patients with advanced-stage
disease," Manne says. "Co-morbidity in cancer can have an important
role, we know, because it impacts everything from the timing of
diagnosis to treatment decisions. Obviously, BMI and co-morbidity
are not the answers we need to explain the survival disparity in
colon cancer. Something else is going on."
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