Trim Down to Fight Prostate Cancer

Obesity may fuel the disease's aggressive growth and recurrence

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By
HealthDay Reporter

MONDAY, June 14, 2004 (HealthDayNews) -- If you're a man who is suffering from prostate cancer, check to see if there's a spare tire hanging around your middle.

Two recent studies suggest obesity is a risk factor for aggressive prostate cancer. The findings, published in the Journal of Clinical Oncology, may help explain why black men, who are more likely to be obese than white men, have worse prostate cancer outcomes.

Dr. Stephen J. Freeland, a clinical instructor at Johns Hopkins School of Medicine and lead author of one of the two studies, concedes there's no consensus about obesity being a risk for developing prostate cancer. "But once diagnosed, the obese men's disease is usually a more aggressive disease," he said.

The findings give men a potentially important clue about the disease's progression. That's an insight that bears repeating during National Men's Health Week, June 14-20.

"I think the study findings do reinforce the message that men should maintain a healthy weight," said Ralph Coates, associate director for science in the U.S. Centers for Disease Control and Prevention's Division of Cancer Prevention and Control.

And as Dr. Alfred Neugut, a professor of medicine and epidemiology at Columbia University in New York City, wrote in an editorial in the same issue of the journal, the two studies present "a provocative thesis relating obesity to prostate cancer aggressiveness and outcome."

The prostate is a walnut-sized gland that surrounds the urethra, the passageway that expels urine from the bladder. The prostate makes the milky liquid contained in semen.

The American Cancer Society estimates that about 230,900 new cases of prostate cancer will be diagnosed in the United States this year and about 29,900 men will die of the disease.

While prostate cancer usually grows at a slow pace, sometimes it can spread quickly. Yet even with the latest diagnostic methods, it is difficult to tell which cancers will progress sluggishly and which will proceed rapidly, the society notes.

Freeland's study examined data on 1,106 men who had prostate cancer surgery. A man with a body mass index (BMI) of 35 or higher -- the equivalent of carrying 245 pounds on a 5-foot, 10-inch frame -- had almost a 60 percent risk of cancer recurrence within three years, or more than twice the rate of normal weight men.

A similar study led by Dr. Christopher L. Amling, an assistant professor of urology at Navy Medical Center in San Diego, included 3,162 prostate cancer patients and defined obesity as a BMI of 30 or higher -- say a man who is 5 foot 10 inches and weighs 215 pounds. Men in that category were 20 percent more likely to have a recurrence of prostate cancer.

Scientists don't know why obesity worsens the progression of prostate cancer. But the authors suspect hormonal changes may play a role, since obesity has been linked to lower levels of sex hormones.

Experts also can't agree on what causes prostate cancer to begin with. Could excess weight be a trigger? While there's some evidence that a diet high in fat and low in fruits and vegetables may influence a man's risk of developing the disease, there's no evidence to confirm that obesity is a risk factor.

"I think that we can't really say for sure what the prostate cancer risk factors are," Coates said.

Scientists also are investigating other possible culprits, including smoking, physical inactivity and unsafe sex.

For now, the best advice for a healthy prostate is the same advice men have been hearing for years about maintaining a healthy heart: Lose weight if you need to, eat a diet that includes plenty of fruits and vegetables and whole grains, exercise regularly and quit smoking.

Those lifestyle changes couldn't hurt, since men are 10 times more likely to die from heart disease than prostate cancer, Coates said.

There is also a lack of consensus on whether men should be routinely screened for prostate cancer.

"The CDC's position on screening is it's not clear whether the benefits outweigh the harms, and therefore we encourage informed decision making," Coates said.

But as a urologist, Freeland considers screening a must for men over 50 with a life expectancy of 10 years or more.

"I think the literature that supports screening in terms of reducing the risk of dying from prostate cancer is only now starting to mature," he said. "We will see more data that screening is beneficial."

More information

Check with the American Cancer Society to learn more about detecting, treating and preventing prostate cancer.

SOURCES: Stephen J. Freeland, M.D., urology instructor, Johns Hopkins School of Medicine; Ralph Coates, Ph.D., associate director, science, Division of Cancer Prevention and Control, U.S. Centers for Disease Control and Prevention, Atlanta; Feb. 1, 2004, Journal of Clinical Oncology

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