Role of the transition zone for elevating serum prostate-specific antigen in benign prostatic hyperplasia

Patients with benign prostatic hyperplasia (BPH) have a wide range of concentrations of PSA. However, it is not known what factors influence the concentration of serum PSA other than the prostate volume. BPH is composed of an enlarged transition zone (TZ) and other zones (nonTZ). The TZ is thought to play a more important role than the nonTZ in determining the concentration of serum PSA in BPH patients.

We investigated the individual glandular zone volume, the amount of PSA produced by each zone and the PSA density in each zone in 23 patients with histologically-confirmed BPH. The PSA density in the TZ was calculated by dividing the difference between the serum PSA before and after surgical resection by the specimen weight. We examined the influence of these parameters on the concentration of serum PSA in BPH patients.

The serum PSA concentration correlated with the amount of PSA produced by the TZ (r=0.90, P< 0.0 1), but not the nonTZ (r=0.25, P=0.29). The concentration of serum PSA also showed a significant correlation with the TZ volume (r=0.67, P< 0.01) and the PSA density in the TZ (r=0.51, P< 0.05), but not with the PSA density in the nonTZ (r=-0.06, P=0.81). Also, age was inversely correlated with the PSA density in the TZ (r=-0.69, P< 0.01).

The hypertrophic prostate cell volume (TZ volume) and activity (PSA density in the TZ) significantly correlated with the concentration of serum PSA in BPH patients, and the TZ cell activity decreased inversely with age in these BPH patients.