Obesity Raises Risk of Aggressive Prostate Cancer

Roman Bystrianyk · medicine forum Guru Joined: 02 May 2005 Posts: 454

http://www.healthsentinel.com/news.php?event=news_print_list_item&id=846

"Obesity Raises Risk of Aggressive Prostate Cancer", Medical News
Today, May 23, 2005,
Link: http://www.medicalnewstoday.com/medicalnews.php?newsid=24963

Obesity appears to increase the risk of prostate cancer, particularly
aggressive disease, and may make it harder to find, researchers say.

Smaller prostates also increase the risk of aggressive disease, they
say.

Both findings are being presented at the annual meeting of the American
Urological Association May 21-26 in San Antonio.

The obesity study examined the association between body mass index -
weight to height ratio - and prostate cancer in 787 men undergoing
biopsy due to an elevated tumor marker in the blood or an abnormal
physical exam at a Veterans Affairs hospital in California between 1998
and 2002.

It indicated that obesity increases the risk of prostate cancer,
particularly in young men, as well as the risk of aggressive disease in
all men.

"The exact relationship between obesity and prostate cancer is still
very much a point of controversy and debate in urology," says Dr.
Martha K. Terris, urologist at the Veterans Affairs Medical Center in
Augusta and the Medical College of Georgia.

"One consensus that seems to be evolving is that obese men have an
increased risk of more aggressive, and therefore potentially more
deadly, disease," she says. "The take-home message for men and for
all of us really is that we should try to maintain a healthy weight for
a variety of health reasons."

Obesity may literally be a deterrent to finding prostate cancer because
it makes digital rectal exams, a major screening tool, more difficult,
says Dr. Terris. Also, in men and women alike, fat makes estrogen-like
compounds, which lowers circulating levels of prostate specific
antigen, or PSA, a marker for prostate cancer. If PSA levels are lower
due to hormone changes from obesity, the prostate cancer is less likely
to be detected at an early stage.

Hormone changes observed with obesity also cause decreased levels of
the male hormone testosterone. Since testosterone feeds prostate
cancer, obesity could, in theory at least, reduce the risk of prostate
cancer. This reasoning remains controversial, however since the current
study and others suggest that obese men actually may be at increased
risk for prostate cancer. However, researchers are more convinced of
the link between obesity and aggressive prostate cancers that do not
rely on testosterone to grow.

"Hormone balance has potent effects on the prostate and prostate
cancer," Dr. Terris says. "Most prostate cancer researchers have
accepted the suggestion that higher estrogen and lower testosterone
suppress prostate cancer growth with the exception of those cancers
that are not sensitive to testosterone. However, when we adjusted for
age in this study, we didn't necessarily find less cancer. We did find
that men with a higher body mass index did indeed have higher-grade,
more aggressive-appearing cancer."

A study published in February 2004 in Journal of Clinical Oncology also
found higher rates of aggressive cancer in obese men as well as higher
recurrence rates after surgery. That study, for which Dr. Terris was
the senior author, looked at 1,106 men who had cancerous prostate
glands removed at Veterans Affairs Medical Centers in Augusta, West Los
Angeles, San Francisco and Palo Alto, Calif., as well as the San Diego
Naval Medical Center from 1988 to 2002. The hospitals comprise the
Shared Equal Access Research Cancer Hospital, or SEARCH, Database, so
named because access is based on military service requirements rather
than paying status.

The 1,106 men included 330 of normal weight, 528 considered overweight
and 214 mildly, moderately or severely obese. "Obesity was associated
with higher-grade tumors, increased risk of positive surgical margins,
and higher biochemical failure rates among men with clinically
localized prostate cancer treated with (radical prostatectomy)," the
study authors concluded. "Severely and moderately obese patients were
at higher risk of failure than mildly obese patients," with risks two
to three times that of slimmer patients.

The new study exploring the relationship between the size of the
prostate gland and severity of disease also looked at patients in the
SEARCH Database.

"Men with smaller prostates tend to have smaller cancers than men
with larger prostates. But this is not as good as it sounds," says
Dr. Terris, a Georgia Cancer Coalition Distinguished Scholar. "If you
have a large prostate, cancer can grow to a fairly large size before it
outgrows the surrounding prostate and spreads out into other areas of
the body. However, if the prostate containing the cancer is small, the
cancer does not have to grow very much before it is big enough to
spread outside the gland." But this story gets more complicated. Men
with larger prostates naturally have higher PSA levels, which means
they may be more closely followed so their cancers are caught earlier.
Also, the size of the prostate is linked to genetic and testosterone
levels.

"Similar to the findings in obese men with prostate cancer, the
explanation may be differences in hormone levels," says Dr. Terris.
"If you have estrogen or less testosterone in your system, your
prostate will not be as large as a man with a high testosterone because
these hormone affect both benign prostate growth and cancer. As a
result, the same hormone balance that result in a small prostate gives
hormone insensitive tumors more chance to grow."

Dr. Terris conducted the studies with colleagues at Johns Hopkins
University, University of California Los Angeles, University of
California San Francisco, and Stanford University.

Contact: Toni Baker
tbaker@mcg.edu
706-721-4421
Medical College of Georgia
http://www.mcg.edu

Ed Friedman · medicine forum beginner Joined: 02 May 2005 Posts: 27

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