The value of prostate-specific antigen density in the prediction of extraprostatic extension in patients with clinically organ-confined prostate cancer

Objective To evaluate the role of PSA density with prostate volume determined by MR images in the prediction of extraprostatic extension in patients with clinically organ-confined prostate cancer. Method A total of 71 patients with clinically organ-confined prostate cancer who underwent radical prostatectomy from January 2009 to December 2013 were included in the study.MRI PSAD, preoperative total serum PSA (tPSA), free PSA/total PSA(fPSA/tPSA), biopsy Gleason score, prostate volume, age, body mass index in patients with extraprostatic extension were compared with those in patients with organ-confined disease.The receiver operating characteristic (ROC)curve was used to analyze the performance of each of the above parameters to predict the extraprostatic extension.Multivariate logistic regression analysis was used to select the independent influencing factors for extraprostatic extension. Results Pathologic examination revealed 32 patients were positive for extraprostatic extension and 39 patients had organ-confined disease.MRI PSAD(P<0.001), tPSA(P<0.001) and biopsy Gleason score levels(P=0.006) were higher in patients with extraprostatic extension than that in patients with organ-confined disease, and prostate volume was lower(P=0.009). MRI PSAD showed the largest area under ROC curve(AUC) among those parameter(AUC=0.852, P<0.001), and tPSA was the second(AUC=0.764). Multivariate logistic regression analyses showed that MRI PSAD was an independent predictor of extraprostatic extension. Conclusions MRI PSAD was better than tPSA in predicting pathological stage of extraprostatic extension.The value of PSAD should not be ignored in the prediction of pathological stage. Key words: Prostatic neoplasms; Prostate specific antigen; Prostate specific antigen density; Pathological stage; Extraprostatic extension.