DURHAM, N.C. -- Doctors may be missing cancers in obese men because the telltale blood marker used to detect the disease can be falsely interpreted as low in this population, according to a new study led by Duke Prostate Center researchers.
Obese men have more blood circulating throughout their bodies than normal weight men, and as a result, the concentration of prostate-specific antigen, or PSA, in the blood -- the gold standard for detecting prostate cancer -- can become diluted, said Stephen Freedland, M.D., a Duke urologist and senior researcher on a study appearing in the November 21, 2007 issue of the Journal of the American Medical Association.
Weve known for a while that obese men tend to have lower PSA scores than normal weight men, but our study really proposes a reason why this happens, and points to the need for an adjustment in the way we interpret PSA scores that will take body weight into account. If not, we may be missing a large number of cancers each year.
The study was funded by the Department of Veterans Affairs, the Duke Department of Surgery and Division of Urology, the Department of Defense Prostate Cancer Research Program, the American Urological Association Foundation, the Georgia Cancer Coalition, and the National Institutes of Health.
Researchers compared the medical records of almost 14,000 patients who had undergone radical prostatectomy surgery for the treatment of prostate cancer between 1988 and 2006 at Johns Hopkins, Duke, or at one of five Veterans Affairs hospitals making up the Shared Equal Access Regional Cancer Hospital (SEARCH) cohort. They analyzed the relationship between body mass index -- which is a measure of obesity -- and PSA concentration levels, while also examining the blood volume in the patients bodies and the total amount of PSA protein found in the blood, known as PSA mass, Freedland said.
We found that a higher body mass index directly correlated with higher blo
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Duke University Medical Center