Abstract
Objective The current study was undertaken to investigate the utility of total prostate-specific
antigen (tPSA), its isoform [-2] proPSA (p2PSA), and prostate health index (PHI) in
the diagnosis of metastatic prostate cancer (PCa).
Materials and Methods This study was conducted from March 2016 to May 2019. Eighty-five subjects who were
diagnosed with PCa for the first time, following transrectal ultrasound-guided prostate
biopsy, were included in the study. The prebiopsy blood samples were analyzed in Beckman
Coulter Access-2 Immunoanalyzer for tPSA, p2PSA, and free PSA (fPSA), and the calculated
parameters included %p2PSA, %fPSA, and PHI. Mann–Whitney's U test was used as test of significance, and p-value less than 0.05 was considered statistically significant.
Results Of the 85 participants, 81.2% (n = 69) had evidence of metastasis, both clinically and pathologically. The median
tPSA (ng/mL), p2PSA (pg/mL), %p2PSA, and PHI were significantly higher in the group
with evidence of metastasis (46.5 vs. 13.76; 198.0 vs. 35.72; 3.25 vs. 1.51; 237.58
vs. 59.74, respectively). The sensitivity (%), specificity (%), negative predictive
value (%), and positive predictive value (%) to diagnose metastatic PCa of tPSA at
a cutoff of 20 ng/mL, PHI at a cutoff of 55, and %p2PSA at a cutoff of 1.66 were 92.7,
98.5, and 94.2; 37.5, 43.7, and 62.5; 54.5, 87.5, and 71.4; and 86.4, 88.3, and 91.5,
respectively.
Conclusion Using tests such as %p2PSA and PHI in the standard armamentarium for the diagnosis
of metastatic PCa in addition to PSA will help in selecting the appropriate treatment
strategy, including active surveillance.
Keywords
prostate cancer - prostate health index - prostate-specific antigen - PSA isoforms
