PSA Accuracy Drops and Prostate Cancer Mortality Rises with BMI >30

PSA Accuracy Drops and Prostate Cancer Mortality Rises with BMI >30

obesity, defined as a body mass index (BMI) >30 kg/m2, appears to contribute

to inaccurately low prostate- specific antigen (PSA) readings, leading

to misleading test results and the possibility of delayed diagnosis and increased

mortality, according to a study published in Cancer (2005;103:1092-1095).

“Previous studies show that obesity is associated with more aggressive prostate cancer

disease,” lead investigator Jacques Baillargeon, PhD, of the Center for Epidemiology &

Biostatistics, University of Texas Health Science Center, San Antonio, told IMWR.

“PSA levels decrease as BMI increases, even after adjusting for race and age. It is likely thatPSA is being suppressed in overweight and obese men, possibly as a result of lower testosterone

levels. This may result in delayed prostate cancer diagnosis. Such delay may

result in more aggressive disease and poorer overall survival in this group.” An American Cancer Society study published in April 2003 added prostate cancer to its list of obesity-associated diseases. Some have hypothesized that there is a tumorigenic link to elevated estrogen or human growth factor, while others, including Dr Baillargeon and colleagues, have hypothesized

that obesity could make PSA screening less sensitive, leading to later-stage disease at

diagnosis and higher mortality. In this study, BMI and PSA level correlations

were studied in 2779 men. Results showed that median PSA scores declined as median BMI rose, with statistical consistency across age and race. Men in the highest BMI group showed a 34% increase in prostate cancer mortality risk. “Some physicians feel that in obese

men it may be appropriate to assess lower PSA levels with more scrutiny,” said Dr

Baillargeon. ”Ultimately, it would be optimal to develop a more precise multifactorial

assessment of prostate cancer risk, which allowed us to adjust PSA risk

levels according to BMI and other factors in a more precise, mathematical way.”

Future goals for Dr Baillargeon’s team include developing a more specific means

of assessing the hormonal mechanisms that could underlie the BMI/PSA association.

“We plan to measure testosterone and other hormones, [and] examine the

extent to which they drive the BMI/PSA association we have observed in the present

study,” she said. Prostate cancer remains the most common cancer among US men and is expected to affect 232,090 men in 2005 and kill an estimated 30,350. One third of all

adults in the United States currently have a BMI >30 kg/m2.