How Weight Gain And Obesity In Men Reduce PSA Velocity And May Interfere With Prostate Cancer Detection

Main Category: Prostate / Prostate Cancer
Also Included In: Obesity / Weight Loss / Fitness;  Cancer / Oncology
Article Date: 23 Jul 2009 - 1:00 PDT

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EHE International recently announced the findings of a study indicating that elevated PSA levels, often associated with prostate cancer, are potentially harder to detect in men who are obese or experiencing weight gain. Prostate specific antigens (PSAs) are proteins produced by the cells of the prostate gland and because elevated levels may be indicative of prostate cancer, PSAs are regularly measured in annual physicals. PSA velocity is a measure of how fast PSA levels are changing in a man through time, and a high PSA velocity is an important indicator of prostate cancer risk. The study describes how obesity and increases in Body Mass Index (BMI) make PSA velocity scores appear lower than they really are, thereby potentially obscuring clinically relevant changes in circulating PSA.

Current data indicates that approximately 40 percent of American men aged 40-59 and 32 percent of men aged 60 and over are obese. While other studies have shown that obesity is not linked to overall prostate cancer incidence, it appears to be associated with a subset of cancers that are more aggressive. Therefore, much research is being devoted to how obesity might affect the screening for, diagnosis and treatment of prostate cancer, the most common cancer in men in the U.S.

EHE International provided funding to Columbia University researchers Dr. Andrew G. Rundle and Dr. Alfred I. Neugut, to use hemodilution theory to model how obesity and weight gain affect clinically observed PSA velocity. Hemodilution theory states that higher blood volume in obese men effectively dilutes circulating PSA levels, resulting in lower PSA test results. The results of the models very closely predict the effects of weight change on PSA observed clinically in the NIH-funded Prostate Cancer Prevention Trial (PCPT). Hemodilution formulas and models have been incorporated into a simple online calculator that adjusts PSA test scores and PSA velocity scores for obesity and weight gain between PSA tests. The calculator is available at http://www.eheintl.com/pas.jsp

"The analyses show that PSA velocity is influenced both by changes in PSA through time and by the body size of the man at the first PSA test and by changes in weight between tests, noted Dr. Andrew Rundle, the study's lead author and a member of EHE International's Medical Advisory Board. "From a clinical point of view, it means that PSA velocity scores cannot be interpreted uniformly across men without considering the man's weight and recent changes in weight."

Recently, scientists have suggested that PSA test results in obese men be adjusted for hemodilution. The online calculator developed by Dr. Rundle and programmers at EHE International provides clinicians with a tool to assess how obesity and weight gain might be affecting PSA test results in their obese patients.

The complete results of the study were published in the June 26, 2009 online edition of the scientific journal, The Prostate.

Source
EHE International