Fat may hide start of cancer

Source: Agencies  |   2008-6-29  |     NEWSPAPER EDITION

THE test commonly used to screen men for prostate cancer may be more likely to miss tumors in obese men, a new study suggests.

In a study of 535 men in a free prostate cancer screening program, researchers found obese men were more likely to have relatively low levels of prostate specific antigen, even when their prostate findings were abnormal.

PSA levels in the blood typically rise when a man has prostate cancer, so PSA testing is often used to screen for the disease.

Men with a high PSA level can then have further testing to get a definitive diagnosis.

The new findings, published in the journal Urology, suggest that because obese men's PSA levels tend to be relatively low in general, some cancers may be missed or not detected promptly.

The generally lower PSA values in heavy men may be the result of a "dilution" effect, according to Dr Stephen J. Freedland, of Duke University School of Medicine in Durham, North Carolina, in the United States.

"Obese men probably have lower PSA values because of excess blood volume," Freedland, the senior investigator on the study, told Reuters Health.

"Thus, when interpreting a PSA value in an obese man," Freedland said, "we should adjust the value we call 'abnormal' down."