In this study, PSA mass across all groups was comparable despite differences in body weight, leading the researchers to believe that the larger blood volume is responsible for lowering the concentration of PSA, which is what doctors typically measure when looking for prostate cancer, Freedland said.
Its as if you dissolve a tablet in a cup of water versus a tub of water, he said. The concentration of the drug in the cup will be much higher than that in the tub, even though the amount is the same.
These findings are very important because of the sheer number of people they affect, Freedland said.
One in three Americans is obese, and its not just the very large people that you think of who fall into this category, he said. A man who is 511 and weighs 215 pounds is considered obese.
"Our study shows yet another potentially serious consequence of this country's growing epidemic of obesity," said Carmen Rodriguez, MD, an American Cancer Society epidemiologist and co-author of the study. "Previous studies have linked obesity to more aggressive prostate cancers. Our finding that prostate cancer may also be more difficult to detect in this population generates a dangerous 'one-two punch' for men who are overweight or obese."
If their prostate cancers are being detected later because of the dilution of PSA, this may help, in part, to explain why obese men tend to have more aggressive cancers, Freedland said.
|Contact: Lauren Shaftel Williams|
Duke University Medical Center