Health: Obesity - cancer

Obesity worsens ovarian-cancer survival odds, study finds

By Nicholas Bakalar
August 31, 2006

Obesity makes ovarian cancer more deadly, a new study reports. Obese
women with advanced ovarian cancer have a shorter time to recurrence
and a shorter overall survival time than women of ideal weight - and
not because obese people often have other medical problems. Obesity
itself, the researchers suggest, is the problem.
Ovarian cancer is fairly common. "About one in 60 American women
will develop ovarian cancer," said Dr. Andrew J. Li, the senior
author of the study, a physician at the Cedars-Sinai Medical Center
in Los Angeles. "It's the fifth most common cancer in women, and the
fifth most lethal."
It is well known that obesity is associated with various
malignancies, including kidney, throat, breast and colon cancers.
Findings about obesity and ovarian cancer have been somewhat less
clear.
The scientists reviewed the medical records of 216 patients at
Cedars-Sinai who had surgery for ovarian cancer. Half the patients
had ideal weight, with a body mass index from 18.5 to 24.9, and 8
percent had a BMI less than 18.5, which is considered underweight.
Twenty-six percent were overweight, with indexes exceeding 25, and
16 percent were obese, with indexes more than 30.
The overweight and obese differed little from normal and underweight
people in age or in health status, except that they had more
hypertension and diabetes.
Among patients with the most advanced stages of cancer, those with
BMI's higher than 25 survived disease free for an average of 17
months, compared with 25 months for people with indexes lower than
25.
For each increase of one unit in the index, the researchers found a
4 percent increase in the risk of recurrence and a 5 percent
increase in the risk of death.
The researchers acknowledge that their study, published in the
journal Cancer, has certain weaknesses.
They found a slightly lower dose of chemotherapy relative to body
surface was given to obese patients, and it is possible that this
underdosing may have a role.
Also, fluid in the body cavity, a symptom of the disease, may have
artificially increased the BMI of some patients. And it is possible
that other diseases, especially hypertension and diabetes, more
prevalent among the obese, could have decreased survival among those
patients.
The study was also limited by its retrospective method and small
sample population.
The researchers said they believed that it was unlikely that those
factors could have accounted for the decreased overall survival time
of obese women. The most likely reason, they concluded, is that the
presence of fat tissue encourages tumor growth or increases
resistance to treatment.
"There may be some factor secreted by adipose tissue that makes
tumors less sensitive to chemotherapy," Li said, referring to fat
tissue. "We have some ideas, and we're working on looking at those
factors now."



.... Science asks how. Philosophy asks why. Cats couldn't care less.
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