Percent of free serum prostate-specific antigen and histological findings in patients undergoing open prostatectomy for benign prostatic hyperplasia

Abstract

Purpose: To determine which pathologic features of the surgical specimen in men undergoing open prostatectomy for benign prostatic hyperplasia (BPH) correlate with preoperative and postoperative total, free prostate-specific antigen (PSA) levels and the free-to-total PSA ratio.

Methods: Forty-four patients, undergoing open prostatectomy for BPH without evidence of prostate cancer in systematic biopsies and clinical prostatitis, were included in this prospective study. Each prostatectomy specimen was weighed and each slide was evaluated for inflammation (acute prostatitis, chronic-active prostatitis and chronic-inactive prostatitis), prostatic intraepithelial neoplasia, transitional/squamous metaplasia, cystic ductal dilation, leiomyoma-resembling stromal cell proliferation, leakage of prostatic secretion, infarction and prostatic calculi.

Results: The mean preoperative (and postoperative) total PSA and free PSA levels were 6.1 +/- 4.3 (1.14 +/- 0.87) and 1.7 +/- 1.6 (0.24 +/- 0.19) ng/ml, respectively. The mean prostatic and transition zone volume was 83.9 +/- 28.4 and 55.4 +/- 27.6 cm(3), respectively. Both total PSA and free PSA levels were correlated with total gland volume (p = 0.0001; p = 0.002) and the volume of the surgical specimen (p = 0.003; p < 0.05) and, upon stepwise logistic analysis, patients with a total gland volume of <50 cm(3) had an odds ratio of 11 (CI 1.6-71.3) for having a free-to-total ratio of <18%. No minimal change pathology or prostatic inflammation were associated with preoperative total or free PSA levels. The free-to-total PSA ratio was higher in the group of patients with histologically acute and moderate to severe chronic-active prostatitis (mean ratio 27 +/- 12%) than in patients with chronic-inactive prostatitis and minimal chronic-active prostatitis (mean ratio 0.19 +/- 13%; p = 0.05), showing an odds ratio of 5 (CI 1.1-22.1) for having a free-to-total PSA ratio of <18%.

Conclusions: Prostate volume and, in particular, transition zone volume seem to influence both free and total PSA levels in men with BPH. The free-to-total PSA ratio seems to be influenced by the presence of histological prostatitis in the surgical specimen. In particular, patients with a prostate volume of <50 cm(3) and an inactive form of prostatitis seem to have a relatively higher risk of having a free-to-total PSA ratio of <18%.