PSA mass outperforms serum PSA as prostate volume marker
MedWire News: Prostate-specific antigen (PSA) mass may be an effective new tool for estimating total prostate volume (TPV), show study findings.
The biomarker significantly outperformed serum PSA at predicting clinically significant prostate enlargement in a cohort of 1425 men with benign prostate hyperplasia (BPH), particularly in those aged 60 years or older.
Several studies have shown an inverse relationship between serum PSA and obesity and it has been proposed that men with a higher body mass index (BMI) might have larger plasma volume, which could decrease apparent serum PSA levels - an effect called hemodilution.
However, PSA mass - the total amount of PSA protein in circulation at the time of PSA concentration measurement - is not dependent on plasma volume or body size.
In the current study, Pearson's correlation testing showed that BMI, body surface area, and plasma volume had inverse linear relationships with serum PSA, after adjustment for TPV.
TPV per serum PSA value was larger in men with increased BMI or plasma volume, especially in the higher serum PSA ranges, report Hitoshi Masuda (Graduate School of Tokyo Medical and Dental University, Japan) and team.
The researchers also found that the correlation between PSA mass and TPV was stronger than that between serum PSA and TPV in all patients.
Furthermore, area under the receiver operating characteristic curve analysis showed that PSA mass performed significantly better than serum PSA at predicting a relatively wide range of prostate enlargement (namely TPV <30 mL or <40 mL), especially in men aged 60 years or older.
"This is the first study to introduce PSA mass as a tool with which to estimate prostate volume in BPH patients," write Masuda and team in the International Journal of Urology.
The researchers point out that, theoretically, serum PSA in White men might be more affected by hemodilution than that in Asian men, because obesity is more common in White than in Japanese men.
"Although the present study was not designed to compare TPV and serum PSA or the PSA mass relationship between Westerners and Japanese men, PSA mass could be used to estimate TPV instead of serum PSA for reducing the impact of racial anthropometric differences," they suggest.
By Sally Robertson