AB013. The study on the diagnostic value of f/tPSA to the prostate cancer with tPSA greater than 10 ng/mL

Background: To investigate the differential value of the percentage of free to total prostate specific antigen (f/tPSA) in the diagnosis of prostate cancer (PCa) and benign prostatic hyperplasia (BPH) when the tPSA greater than or equal to 10 ng/mL.

Methods: A retrospective study was performed among 361 cases of PCa or BPH whose tPSA greater than or equal to 10 ng/mL and whose diagnosis were confirmed by pathology through prostate biopsy or prostate surgery in our hospital from December 1, 2011 to December 1, 2014. Logistic regression and receiver operating characteristic curve (ROC) were employed to analyze the value of f/tPSA in the differential diagnosis of PCa and BPH.

Results: In the 361 cases, 155 cases were PCa (42.9%), 206 cases were BPH (57.1%). When tPSA were in the range of 10–100 ng/mL, the median of f/tPSA in PCa and BPH groups were 0.09 and 0.15 (P<0.001), respectively; When tPSA were 10–40 ng/mL, the median of f/tPSA in PCa and BPH groups were 0.10 and 0.16 (P<0.001), respectively; When tPSA were in the range of 10–100 ng/mL, the diagnostic accuracy to PCa by using the combination of f/tPSA and tPSA or f/tPSA and fPSA, were significantly increased by 3.4% (P<0.019) or 24.6 (P<0.001), when compared with using tPSA or fPSA alone; When tPSA were 10–40 ng/mL, the diagnostic accuracy of PCa by using the combination of f/tPSA and tPSA or f/tPSA and fPSA were significantly increased by 5.0% (P<0.019) or 17.1% (P<0.001). In the cases of tPSA in 10–40 ng/mL, when the diagnostic sensitivity to PCa were reached to 80.2%, the specificity of the diagnosis to PCa by using f/tPSA (cut off 0.145) was significantly increased by 7.2% and 29.0%, compared with tPSA or fPSA, respectively.

Conclusion: f/tPSA still have significant value for the differentiation of PCa and BPH when tPSA in the range of 10–100 ng/mL, especially in 10–40 ng/mL. It may greatly improve the diagnostic accuracy of PCa and reduce unnecessary biopsies.

Keywords: Prostate cancer (PCa); benign prostatic hyperplasia (BPH); prostate specific antigen (PSA); prostate biopsy