Background and aims: Although prostatitis can contribute to the lack of prostate specific antigen (tPSA) specificity, there is disagreement concerning the effect of histological inflammation on free PSA (fPSA). We investigated the correlation between aggressiveness of histological inflammation and tPSA, fPSA and f/tPSA in patients without detectable prostate cancer (PC).
Methods: The study included 106 patients with tPSA <10 ng/mL, without clinical prostatitis and with biopsy negative for PC. The inflammation in prostate biopsies was scored for aggressiveness using the four-point scale reported by Irani. The patients were divided into two groups of less aggressive and more aggressive inflammation and compared by use of regression analysis.
Results: The median tPSA, fPSA and f/tPSA levels were 6.39 ng/mL, 1.1 ng/mL and 16% in the less aggressive inflammation group and 7.3 ng/mL, 0.79 ng/mL and 10.7% in the more aggressive inflammation group, respectively. There was no significant between-group difference in tPSA levels (P=0.16), however, statistically significant between-group differences were recorded in fPSA and f/tPSA levels (P<0.001 both). Spearman's analysis yielded a significant negative correlation of inflammation aggressiveness with fPSA (r=-0.34; P<0.001) and f/tPSA (r=-0.45; P<0.001). Free PSA and f/tPSA were lower in the group with more aggressive inflammation.
Conclusions: Histological inflammation has a high prevalence in cancer-free prostate biopsy specimens and exerts similar effects on fPSA and f/tPSA levels as PC. Our study suggests histological prostatitis to be an important cause of decreased fPSA and f/tPSA values; therefore, when it is identified, antibiotic or anti-inflammatory therapy should be introduced to reduce the percentage of men with a continuing indication for prostate biopsy.