A multicenter clinical trial on the use of (-5, -7) pro prostate specific antigen

The determination of pro prostate specific antigen (proPSA) forms has been suggested to be promising in prostate cancer diagnosis. In this multicenter trial we evaluated the diagnostic usefulness of (-5, -7) proPSA.

A total of 2,055 white men, including 1,046 with and 1,009 without prostate cancer, with total PSA (tPSA) between 0.28 and 81 ng/ml were retrospectively analyzed. Of these men 2,026 and 1,727 had tPSA less than 20 and less than 10 ng/ml, respectively. All subjects were untreated for prostatic disease and underwent multisector needle biopsy of the prostate. An Elecsys 2010 analyzer was used to determine tPSA, free PSA (fPSA) and (-5, -7) proPSA in the 2,055 serum samples. ROC analyses were performed to discriminate men with biopsy positive and negative results in the entire and in select tPSA ranges.

In the select tPSA range 2 to 4 ng/ml the area under the ROC curve for proPSA (0.53) and proPSA/fPSA (0.59) was not significantly larger than that for tPSA (0.60) or the fPSA/tPSA (f/tPSA) ratio (0.64). In the tPSA range 4 to 10 ng/ml the area under the curve for the ratio proPSA/fPSA (0.67) was larger than for tPSA (0.53) but not larger than for f/tPSA (0.69). The f/tPSA ratio demonstrated the best discriminatory power in this tPSA range of 4 to 10 ng/ml.

In this multicenter study no improvement in diagnostic accuracy was shown when comparing (-5, -7) proPSA and the corresponding ratios with tPSA or f/tPSA. Further studies using other proPSA forms or tumor associated proteins should be done.