PD41-02: Diagnosis of Prostate cancer in men treated with 5-alpha-reducates inhibitors with Multiparametric MRI: results of a multicenter international collaboration

Ugo Falagario*, Foggia, Italy, Anna Lantz, Stockholm, Sweden, Ivan Jambor, Turku, Finland, Luca Carmignani, Emanuele Montanari, Milan, Italy, Pierluigi Bove, Rome, Italy, Paolo Gontero, Turin, Italy, Alessandro Sciarra, Rome, Italy, Pasquale Di Tonno, bari, Italy, Carlo Trombetta, trieste, Italy, Pierfrancesco Bassi, Giuseppe Simone, Rome, Italy, vincenzo Mirone, Naples, Italy, Alessandro Antonelli, Verona, Italy, Luigi Schips, Chieti, Italy, Gian Maria Busetto, Foggia, Italy, Matteo Ferro, Milan, Italy, Peter Bostrom, Turku, Finland, Tobias Nordström, Stockholm, Sweden, Ottavio de Cobelli, Milan, Italy, Luigi Cormio, Giuseppe Carrieri, Foggia, Italy

Introduction: 5-alpha reductase inhibitors (5-ARIs) are used for treatment of bladder outlet obstruction symptoms. 5-ARIs cause a decrease in serum PSA, leading to delayed diagnosis of PCa and worse cancer-specific outcomes. Aim of this study was to evaluate accuracy of MRI for diagnosis of clinically significant Prostate Cancer (csPCa) in men treated with 5-ARIs.

Methods: Retrospective analysis of an international database (PROMOD) including data of patients undergoing biopsy with a pre-biopsy MRI in 20 European centers. Patients treated with 5-ARIs for=3months at the time of MRI were included in the study group while 5-ARIs naïve patients were used as controls. Patients with previous positive biopsy, patients who had undergone short course of 5-ARIs or other surgical treatments for BPH were excluded. Outcome of the study was csPCa defined as Biopsy Gleason Group (GG)=2. Sensitivity specificity, negative (NPV) and positive (PPV) predictive values were used to assess accuracy of MRI in predicting the outcome of interest.

Results: 5135 patients were eligible for the present study. 502 patients were treated with 5-ARIs. They were older (66vs69), had lower PSA values (6.6vs6.3, p 0.007) and higher prostate volumes (48vs54, p<0.0001). Prostate MRI showed PIRADS 3, 4 and 5 lesions in 26, 42 and 21% of the patients in the control group and 26, 38 and 22% of the patients in the 5-ARI’s group (p0.06). Central zone and transition zone lesions were more frequent in the 5-ARI’s group. There was no difference in csPCa detection rates (41.5%vs37.3%, p0.07), however detection of GG 1 PCa was higher in the control group (18%vs11%) and the detection of high Grade PCa (GG=3) was significantly higher in patients treated with 5-ARI’s (20%vs24%, p<0.0001). The accuracy of mpMRI was similar in the two groups with no difference Sensitivity, specificity, PPV, NPV and detection rates by PIRADS score (all P>0.1).

Conclusions: Patients treated with 5-ARIs undergoing prostate biopsy with prebiopsy MRI are less likely to have a positive biopsy but have a higher risk of being diagnosed with a high-grade PCa. In contrast to serum PSA values, MRI is not affected by treatment with 5-ARIs and should be considered the first tool for the decision whether or not to submit these patients to prostate biopsy.

Source of Funding: None