Reducing a weighty prognosis for prostate cancer

Alan Kristal and PHS colleagues find that obesity at the time of prostate-cancer diagnosis dramatically increases the risk of dying from the disease

Center News File Photo Dr. Alan Kristal's study reports that the link between obesity, prostate-cancer metastasis and death may involve the massively inflammatory nature of fat. He said obesity also increases levels of serum estrogens and growth factors that can promote cancer growth.

Obese men who are diagnosed with prostate cancer have more than two-and-a-half times the risk of dying from the disease as compared to men of normal weight at the time of diagnosis, according to a study by researchers in the Public Health Sciences Division. The findings by senior author Dr. Alan Kristal and colleagues appear online and in the March 15 print edition of the journal Cancer.

"I was very surprised by the findings," said Kristal, associate head of the Cancer Prevention Program. "We found the prostate-cancer-specific mortality risk associated with obesity was similar regardless of treatment, disease grade or disease stage at the time of diagnosis."

"If a man is obese at the time of diagnosis, he faces a 2.6-times greater risk of dying as compared to a normal-weight man with the same diagnostic profile, regardless of whether he has a radical prostatectomy or radiation therapy, whether or not he gets androgen-deprivation therapy, whether he has low- or high-grade disease and whether he has localized, regional or distant disease," Kristal said, referring to the degree of cancer spread.

The researchers also found that obese men whose disease is confined to the prostate or has spread to into surrounding tissue face a 3.6-times increased risk of cancer spreading into distant organs, compared to prostate-cancer patients of normal weight. Kristal's study, which followed 752 middle-aged Seattle area patients for about 10 years, is the first long-term, population-based study of prostate-cancer patients who have undergone a variety of treatments.

"I think this study represents the first good piece of evidence that losing weight may in fact reduce the risk of dying of prostate cancer," Kristal said.

Co-author Dr. Janet Stanford, of PHS, provided data for the study. Funding came from the National Institutes of Health, the National Cancer Institute and the Hutchinson Center. To read the full Cancer article, please log onto www3.interscience.wiley.com/cgi-bin/fulltext/114124829/HTMLSTART.

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