Obese men have lower levels of a protein used to screen for prostate cancer risk, U.S. researchers said on Monday in a study that shows doctors should take weight into account when determining a man's risk, Reuters reported. The finding may help explain why overweight men are likely to be diagnosed when their disease is more advanced, the researchers wrote the journal Cancer. The test is for prostate specific antigen, or PSA. This protein is produced only by prostate cells and circulates in the blood. Levels rise when a prostate is growing -- which could indicate cancer, or a usually harmless but annoying condition called benign prostatic hypertrophy. But a PSA test can tell a doctor whether to make further tests to look for cancer. Evaluating PSA is not an exact science, and there is no clearly safe level. It may be that obese men should be concerned about a lower PSA level than if they were slender, said Jay Fowke of the Vanderbilt University Medical Center in Nashville, Tennessee. They tested blood from 150 black men and 149 white men. They found the more overweight the men were, the lower their PSA levels. Race appeared to have no effect. "Whether equal PSA levels in an obese versus thin man convey the same biologic relevance is unclear but our findings suggest that clinical suspicion might be heightened with a marginally elevated PSA level in an obese person," the researchers wrote. Prostate cancer is the most common cancer among men after lung cancer, affecting 234,460 men in the United States alone this year and killing more than 27,000, according to the American Cancer Society.
