Evaluation of the diagnostic and predictive power of PCA3 in the prostate cancer. A different best cut-off in each different scenario. Preliminary results

Introduction: Aim of this study is to evaluate the diagnostic performance of PCA3 in patients with indication to perform a new biopsy, according to the histological doubt such as High Grade Prostatic Intraepithelial Neoplasia (HGPIN) or Atypical Small Gland Proliferation (ASAP) or the clinical suspicion. Materials and Methods: One hundred men were enrolled. We used the PCA3 - PROGENSA™ procedure. After the PCA3 test a repeated prostate biopsy was proposed. The histological findings were correlated to the PCA3 scores. We calculated the positive predictive value (PPV), the sensibility, the specificity, the Youden's index, the ROC curves, the area under the curve (AUC) for each cut-off value of PCA3 score. Results: These results are preliminary, because at present only 50 of the 100 enlisted men were subjected to rebiopsy. We calculated the best cut-off PCA3 score 20 at the first diagnosis; for patients with HGPIN or ASAP at first biopsy the best sensitivity cut-off is 45; the best cutoff is 45 when you already have a diagnosis of HGPIN, and 35 for ASAP. If we normalize the PCA3 score to the prostate volume, the best cut-off would be 20, with 100% sensitivity with a prostate volume of 65 ml. All results are statistically significant. The real problem, also present in literature, is the constant presence of not diagnosed prostate cancers, for any cut-off value. Conclusions: Our preliminary results suggest that, to get the best diagnostic performance, it would be wrong to maintain a single cut-off, but it should be chosen according to the scenario of the patients subgroup. It is to explore the possibility to search for the PCA3 in the serum to bridge the gap of the aggressive PCa missed by the urinary test.