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Study
Links Obesity to Cervical Cancer
A study by researchers at the National Cancer Institute
(NCI) suggests being overweight could double a woman's risk
of developing one type of cervical
cancer, known as cervical adenocarcinoma. Although infection
with certain strains of the human
papillomavirus (HPV) is the primary risk factor for
cervical cancer, the latest research could help shed light
on why some women with HPV develop cervical cancer while
others don't.
The findings also give women another reason to try to avoid
being overweight or obese. "This might add a small
bit of evidence that trying to maintain a healthy body weight
would be desirable," said lead researcher James Lacey,
PhD.
An American Cancer Society expert agreed. "We're starting
to refine our knowledge about obesity and various cancers,"
said Eugenia Calle, PhD, director of analytic epidemiology
at ACS. Calle published research earlier this year that
attributed 90,000 cancer deaths in the US each year to excess
weight.
Lacey's study was published in the journal Cancer (Vol.
98, No. 4: 814-821).
Seeking Co-factors to HPV
Obesity is already a well-known risk factor for the most
common gynecological cancer, endometrial
cancer (cancer of the uterus). It was this relationship,
in part, that led the NCI researchers to investigate how
obesity might affect cervical adenocarcinoma, which accounts
for 10% to 20% of cervical cancers (squamous cell cancers
account for most of the rest).
Studies in the 1980s suggested that these two types of cancer
had similar risk factors, "and that made sense because
of where these tumors occur in the cervix," said researcher
Lacey, of the NCI's Division of Cancer Epidemiology and
Genetics. Cervical adenocarcinomas typically develop high
in the cervical canal, close to the endometrial tissue of
the uterus.
The research was also prompted by a better understanding
of the role HPV plays in cervical cancer development. Although
most HPV infections clear up on their own, certain strains
of the virus can cause changes in the cervix that can lead
to cancer if the body is not able to eliminate the virus.
Now that HPV's role in cervical cancer is clearer, Lacey
said, researchers can look for other factors -- like obesity,
sexual history, smoking, or hormone use, for example --
that might influence whether the virus leads to cancer.
Screening May Also Have an Effect
Lacey and colleagues compared 124 women with cervical adenocarcinoma
to 139 similar women with squamous cell cervical cancer,
and 307 similar women without cervical cancer. The researchers
calculated their body
mass index, or BMI, a ratio of height to weight. A BMI
between 18.5 and 24.9 is considered normal weight; a BMI
of 25 to 29.9 is considered overweight, and a BMI of 30
or above is considered obese.
Women with a BMI of 25 or higher had about twice the risk
of getting cervical adenocarcinoma as women of normal weight.
Weight did not seem to influence whether women developed
squamous cell carcinoma.
The researchers weren't certain why only adenocarcinoma
seemed to be influenced by obesity. It could be that hormonal
factors play a greater role in this type of cervical cancer,
as they are thought to do in endometrial cancer. However,
more research would be needed to make that determination.
Another theory is that screening differences play a role,
Lacey said.
Regular Pap
tests can detect changes in cervical tissue that could
lead to cancer, allowing them to be treated before that
happens. But because adenocarcinomas develop higher in the
cervix, it may be more difficult to get a good tissue sample
for the test, so precancerous changes can be overlooked.
This problem may be compounded in overweight and obese women,
because excess abdominal fat may make it even more difficult
to get a good tissue sample.
Keep Exercising, Eating Right
Until more is known about just how excess weight relates
to cervical cancer, experts say it is wise for women to
watch their weight by getting lots of regular exercise and
eating a healthful diet.
ACS recommends eating at least five servings of fruits and
vegetables every day, as well as plenty of whole grains.
Red meat should be eaten in moderation; poultry, fish and
beans are better choices. Adults should also get at least
30 minutes of moderate exercise five days a week or more.
Longer, more vigorous exercise is even better.
In addition, ACS recommends regular
Pap tests to detect any changes in the cervix before
they become cancerous.
Article Source: Yahoo Health
Article Author: N/A
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