Obesity Affects Prostate Cancer Screens

(HealthDay News) -- Doctors need to be aware that obesity can affect prostate cancer screening test results, says a U.S. study.

It found that obese white and black American men had lower levels of prostate surface antigen (PSA) and free PSA (fPSA) than men with normal body mass index (BMI). This suggests that an obese man with a slightly elevated PSA may be at higher risk for prostate cancer than a man with normal BMI, the study said.

Previous research has found that obese men and black men in the United States are often diagnosed with more advanced prostate cancer than other men. The evidence suggests that body fat decreases the amount of circulating PSA. It's also believed that height affects percent-free PSA (%fPSA).

In this study, Jay H. Fowke of Vanderbilt University Medical Center in Nashville, Tenn., and colleagues interviewed and tested blood samples from 150 black American males and 149 white males.

They found that decreased PSA and fPSA levels were associated with higher BMIs. This relationship was strongest in men younger than age 60. They also found that %fPSA increased with height. Race did not have an effect.

"Whether equal PSA levels in an obese vs. 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 study authors wrote.

The findings will be published in the Nov. 15 issue of Cancer.

More information
The U.S. National Cancer Institute has more about prostate cancer screening.