Obesity May Affect Prostate Cancer Test

Obese men may have prostate cancer despite relatively low values on the prostate cancer screening test, a new study suggests. The PSA test detects PSA – prostate-specific antigen – in the blood. Only prostate cells give off PSA, and levels of the hormone can rise as prostate tumors grow.

Earlier studies showed that obese men have slightly lower PSA concentrations than lean men do. It’s not clear why this is so. New findings from Duke University researcher Stephen J. Freedland, MD, and colleagues now suggest an answer.

“Being a big guy, you have enormous blood volume, so PSA is diluted,” Freedland said. “Obese men having these lower PSA values due to the dilution factor means we are going to miss some of them early on.”

Other recent studies have shown that obese men have a higher risk of dying from prostate cancer than other men, and a delay in cancer detection may be part of the reason.
Results of the study were published in the November 21 issue of the Journal of the American Medical Association.