The Role of Multiparametric Magnetic Resonance Imaging in the Detection of Prostate Cancer

Case of the Month The Role of Multiparametric Magnetic Resonance Imaging in the Detection of Prostate Cancer NYU Case of the Month, October 2016 Department of Urology NYU Langone Medical Center, New York, NY [Rev Urol. 2016;18(4):231-233 doi: 10.3909/riu0734a] ® © 2016 MedReviews , LLC A 62-year-old man presents with a progressively rising serum prostate-specific antigen (PSA) level and two prior negative transrectal ultrasound (TRUS)–guided systematic biopsies (SBs). His brother underwent radical prostatectomy for an intermediate-risk clinically localized prostate cancer. Relevant prior history and evaluation are found in Table 1. Physical Examination Physical examination revealed a benign 50-g prostate. Evaluation A multiparametric magnetic resonance imaging (MRI) scan was obtained. The pertinent image shows a large prostate imaging reporting and data system (PI-RADS) 5 lesion in the left transition zone (Figure 1). T2-weighted imaging and the diffusion-weighted imaging shows a low signal intensity lesion in the left anterior transition zone. Dynamic contrast enhancement demonstrates early uptake and rapid wash out of the transition zone lesion. There was capsular bulging likely associated with extracapsular extension. Prostate Biopsy Magnetic resonance fusion-target biopsy (MRFTB) was performed. Four biopsies were directed into the MRI target following coregistration and fusion of the three-dimensional MRI and ultrasound images; 12 SBs were performed using an automatically generated template. Gleason 7 (413) prostate cancer was detected in three of four targeted biopsies. The Vol. 18 No. 4 • 2016 • Reviews in Urology • 231 13_4004170006_RIU0734a.indd 231 12/12/16 3:52 pm Multiparametric MRI in the Detection of Prostate Cancer continued TABLE 1 Relevant Prior History and Evaluation PSA History 2013 2014 2015 2016 2.6 3.2 (negative TRUS SB) 5.2 (negative TRUS SB) 9.7 PCA3 Score 2015 52 2016 75 4KScore® 2016 36% PSA, prostate-specific antigen; SB, systematic biopsy; TRUS, transrectal ultrasound. 4KScore is a registered trademark of OPKO Health, Miami, FL. largest core length was 10 mm. All SB results were negative. Management A nerve-sparing radical retropubic prostatectomy was performed. Because of the anterior location of the tumor and negative SB result, a nerve-sparing procedure was performed despite the high-risk disease. Comment Widespread PSA screening coupled with TRUS-guided random SB and aggressive curative treatment has decreased mortality of prostate cancer by over 40%. This impressive decline in mortality has been accomplished at the expense of over-biopsy and overtreatment. The challenge to the urology community is to screen and detect smarter in order to, ultimately, treat smarter. In essence, the goal should be to detect and treat only significant cancers. The definition of significant disease is controversial and depends on the patient’s life expectancy. Most agree that significant disease includes Gleason score . 6 and high-volume Gleason 6 disease. There is increasing evidence that MRFTB increases detection of significant prostate cancer compared with TRUS-guided SB. For those who have adopted MRFTB, should the SB be performed along with the MRFTB? Our preliminary results suggest the random SB ipsilateral to the MRI target detects a greater proportion of significant disease, whereas the random SB contralateral to the MRI target detects almost exclusively insignificant disease. This is consistent with a high negative predictive value of multiparametric MRI for significant disease. Should the multiparametric MRI be performed prior to the first biopsy or only if the PSA value persistently rises after a negative SB result? At NYU Langone Medical Center (New York, NY), we believe the MRI should be performed prior to initial biopsy. Do it right the first time! If the patient has low risk for detecting significant prostate cancer based on risk calculators, one may forego prostate biopsy if multiparametric MRI shows no suspicious areas. This will significantly decrease risk of detecting incidental cancer. The prostate health index or 4KScore® (OPKO Health, Miami, FL) assays have been shown to predict risk of detecting significant Figure 1. Multiparametric magnetic resonance imaging scan showing a large prostate imaging reporting and data system (PI-RADS) 5 lesion in the left transition zone. ADC, apparent diffusion coefficient; DCE, dynamic contrast-enhanced (image); T2WI, T2-weighted image. T2Wl ADC DCE 232 • Vol. 18 No. 4 • 2016 • Reviews in Urology 13_4004170006_RIU0734a.indd 232 12/12/16 3:52 pm Multiparametric MRI in the Detection of Prostate Cancer cancer for men with an elevated PSA level. The tests may be useful in avoiding both an MRI and prostate biopsy for men presenting with low risk of significant prostate cancer based on a risk calculator. In the present case, the progressively rising PSA value is indicative of aggressive prostate cancer likely in the target zone, so it is most appropriate to proceed directly to an MRI. In this case, an MRI would have likely identified the cancer on the first biopsy precluding the ­additional biopsies and delay in diagnosis. in detection, localization and risk assessment. J Urol. 2014;192:648-658. Loeb S, Lilja H, Vickers A. Beyond prostate-specific antigen: utilizing novel strategies to screen men for prostate cancer. Curr Opin Urol. 2016;26:459-465. Meng X, Rosenkrantz AB, Mendhiratta N, et al. ­Relationship between prebiopsy multiparametric magnetic resonance imaging (MRI), biopsy indication and MRI-ultrasound fusion-targeted prostate biopsy ­outcomes. Eur Urol. 2016;69:512-517. References Bjurlin MA, Meng X, Le Nobin J, et al. Optimization of prostate biopsy: the role of MRI targeted biopsy Vol. 18 No. 4 • 2016 • Reviews in Urology • 233 13_4004170006_RIU0734a.indd 233 12/12/16 3:52 pm