Application of PSA and related indicators in early screening of prostate cancer

ObjectiveSerum total prostatic specific antigen (tPSA), free prostatic specific antigen (fPSA), fPSA/tPSA ratio, and prostate cancer-specific antigen density (PSAD) were determined to explore the best identification point, thus improving the specificity of early screening of prostate cancer.

MethodsThe tPSA, fPSA, fPSA/tPSA, and PSAD of patients with benign prostatic hyperplasia group (n=250) and prostate cancer group (n=92) were tested, and the receiver operating characteristic (ROC) curve was drawn to determine the best cutoff value for the evaluation.

ResultsWhen the cutoff values of tPSA, fPSA/tPSA, and PSAD were at 11.3 mg/L, 0.16, and 0.18 mg/(L·cm³), respectively, the specificity and sensitivity were the best:82.4% and 84.2% for tPSA, 76.9% and 81.7% for fPSA/tPSA, and 83.1% and 80.4% for PSAD.When the best cutoff values of tPSA, fPSA/tPSA, and PSAD were combined in analysis, the specificity and sensitivity of fPSA/tPSA and PSAD combination showed the best result (92.4% and 81.4%, respectively).When the tPSA value was in the range of 4-10 mg/L, the optimal cutoff values of PSAD and fPSA/tPSA were 0.21 mg/(L·cm³) and 0.15, and the specificity and sensitivity reach the best, which were 84.1% and 80.1%, 81.0 % and 80.3%, respectively.

ConclusionCombination of tPSA, fPSA/tPSA and PSAD analysis is better than any single of them in early screening of prostate cancer.The specificity and sensitivity of combined use of fPSA/tPSA and PSAD could serve as an optimal screening reference value.