Multiparametric magnetic resonance imaging of the prostate can improve the predictive value of the urinary prostate cancer antigen 3 test in patients with elevated prostate-specific antigen levels and a previous negative biopsy

摘要

Study Type - Clinical (prospective trial) Level of Evidence 2b What's known on the subject? and What does the study add? In clinical practice, we know that it is necessary to identify new biomarkers that can better detect prostate cancer (PC), at the same time as reducing the number of unnecessary biopsies. Recently, studies have suggested that the most relevant clinical scenario in which the prostate cancer antigen 3 (PCA3) score could be used comprises patients with a previous negative prostate biopsy and persistently elevated PSA levels. At the same time, although multiparametric MRI is not currently used as a first approach for diagnosing PC, it can be useful for directing targeted biopsies, especially in those patients with elevated PSA levels and a previous negative TRUS-guided biopsy. Considering all of these aspects, the present study aimed to evaluate the role of multiparametric MRI as an additional diagnostic tool for improving the accuracy of the urinary PCA3 test in patients with increased PSA levels and a previous negative prostate biopsy. Our hypothesis is that the potential value of the PCA3 test as a biomarker for PC diagnosis could be improved by the use of multiparametric MRI in directing prostate biopsy. In the present study, we show that, in cases with a previous negative biopsy and persistently elevated PSA levels submitted to multiparametric MRI to direct biopsies, the sensitivity of the PCA3 test significantly improved (79% vs 68%). However, further larger randomized studies on this combination using a new biomarker and a new imaging modality for PC diagnosis are expected. OBJECTIVE To evaluate the role of multiparametric magnetic resonance imaging (MRI) as an additional diagnostic tool for improving the accuracy of the urinary prostate cancer antigen 3 (PCA3) test in patients with an increase in prostate-specific antigen (PSA) levels and a previous negative prostate biopsy. PATIENTS AND METHODS The present study comprised a prospective randomized study on patients with a previous negative transrectal ultrasonography (TRUS)-guided prostate biopsy and elevated PSA levels. In total, 180 cases were analyzed, and all were submitted to PCA3 assay. Patients in group A were submitted to a second random TRUS-guided prostate biopsy, whereas patients in group B were submitted to a multiparametric MRI examination and then to a second TRUS-guided prostate biopsy. RESULTS At the second biopsy, a histological diagnosis of prostate cancer was found in 26 of 84 cases (30.9%) in group A and in 29 of 84 cases (34.5%) in group B. In group A, the sensitivity and specificity of the PCA3 score were 68.0% and 74.5% respectively (positive predictive value of 53.1%, negative predictive value of 84.6% and accuracy of 72.6%). In group B, the sensitivity and specificity of the PCA3 score were 79.3% and 72.7%, respectively (positive predictive value of 60.5%, negative predictive value of 86.9% and accuracy of 75.0%). For the PCA3 score, the area under the receiver-operator characteristic curve was 0.825 (95% confidence interval, 0.726-0.899) in group A and 0.857 (95% confidence interval, 0.763-0.924) in group B (P < 0.001). CONCLUSION In patients with a previous negative biopsy and persistently elevated PSA levels, the use of multiparametric MRI for indicating sites suitable for rebiopsy can significantly improve the sensitivity of the PCA3 test in the diagnosis of prostate cancer.