(08-12-11) Colon Cancer Prognosis Worse for the Obese, Type 2 Diabetics Cancer and heart-disease deaths higher, studies find

By Serena Gordon
HealthDay Reporter

FRIDAY, Dec. 2 (HealthDay News) -- People who have been diagnosed with colon
cancer have a poorer prognosis if they're obese or have type 2 diabetes, new
research suggests.

Two new studies that looked at the impact that body-mass index (BMI) and a
diagnosis of type 2 diabetes had on survival rates after a colon cancer
diagnosis found that both factors influence whether or not someone survives
colorectal cancer. In addition, both studies found that deaths from any cause,
including heart disease, were also increased in those who were obese or had
type 2 diabetes.

Results of the studies were published online in the Journal of Clinical
Oncology.

"The message here is to avoid obesity and type 2 diabetes because they have
negative health outcomes. We don't know for sure that losing weight or
increasing physical activity will help, but we know they're good for trying to
avoid other diseases, like cardiovascular disease, that can come up down the
road," said Dr. Jeffrey Meyerhardt, author of an accompanying editorial in the
same journal, and an associate professor of medicine at the Dana-Farber Cancer
Institute and Harvard Medical School in Boston.

There are more than 1 million people who've survived a colon cancer diagnosis
living in the United States, and mortality from colorectal cancer has gone down
over the past two decades, according to background information in the studies.

And, while previous research has linked a higher BMI and type 2 diabetes to
the development of colorectal cancer in the first place, it hasn't been clear
how these factors influence the course of colorectal cancer once someone has
been diagnosed.

The first study included 2,303 people involved in an ongoing study that began
in 1992. Between that time and 2007, the study participants had been diagnosed
with colorectal cancer. Follow-up continued through December 2008.

During the study, 851 people with colorectal cancer died. Of those, 380 died
as a result of colorectal cancer, while 153 died of heart disease, according to
the study. The remaining 318 people died of other causes.

The risk of all-cause mortality was 30 percent higher for people who were
considered obese at the start of the study vs. those of a normal weight. The
risk of dying from colorectal cancer was 35 percent higher, and the risk of
dying from heart disease was 68 percent higher.

Meyerhardt explained that the researchers tried to adjust the data for
important factors, such as physical activity, red meat intake (a known risk
factor for colorectal cancer), family history and blood pressure levels. Even
after adjusting the data, obesity increased the risk of dying.

"In and of itself, obesity does seem to have some effect," Meyerhardt said.

In the second study, researchers recruited 2,278 people who'd been diagnosed
with non-metastatic colon or rectal cancer between 1992 and 2007. In this
group, there were 842 deaths. Of those, 377 were from colorectal cancer and 152
were from heart disease, according to the study.

People with type 2 diabetes had a 53 percent higher risk of dying from any
cause and a 29 percent higher risk of dying from colorectal cancer compared to
people without type 2 diabetes. The risk of dying from heart disease was 2.16
times higher in people with type 2 diabetes and nearly four times higher in
people with type 2 diabetes who used insulin, compared with people without type
2 diabetes, the study found.

"Insulin use in type 2 diabetes usually indicates longer-standing diabetes,
which is usually associated with worse outcomes," Meyerhardt noted.

Obesity, elevated body-mass index and diabetes are associated with worse
disease states across the board," said Dr. David Bernstein, chief of
gastroenterology at North Shore University Hospital in Manhasset, N.Y. "But, we
don't know if you lose weight if that risk will go down. I don't counsel
patients who've been diagnosed with colorectal cancer to lose weight, because
weight loss tends to be a worry in people undergoing cancer treatment anyway. I
do counsel my patients that haven't been diagnosed with cancer to lose weight.
The medical community needs to spend more time counseling prevention."

Meyerhardt added that it's also not clear from these studies whether or not
obese people or those with type 2 diabetes would benefit from changes in the
treatment they receive for colorectal cancer.

More information

Learn more about preventing colorectal cancer from the American Cancer
Society.

Source: U.S.News & World Report LP

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In evidenza

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