development and validation of a nomogram for predicting pirads 4-5 ...

THE JOURNAL OF UROLOGYâ

Vol. 197, No. 4S, Supplement, Friday, May 12, 2017

MP08-14 DEVELOPMENT AND VALIDATION OF A NOMOGRAM FOR PREDICTING PIRADS 4-5 LESIONS ON MULTIPARAMETRIC PROSTATE MRI Matthew Truong*, Thomas Frye, Dang Lam, Ji Hae Park, Bokai Wang, Changyong Feng, Gary Hollenberg, Eric Weinberg, Edward Messing, Rochester, NY INTRODUCTION AND OBJECTIVES: Multiparametric MRI (mpMRI) of the prostate is gaining popularity for use in prostate cancer (PCa) detection in patients with a prior negative sextant biopsy as well as in low risk PCa patients on active surveillance. The presence of PIRADS 4 and PIRADS 5 lesions on mpMRI have the highest diagnostic yield for clinically significant PCa on subsequent MRI-ultrasound fusion biopsy. Counseling patients regarding the benefit of mpMRI is becoming an increasingly important aspect of urologic practice. Nomograms may be clinically useful to individualize decisions to perform mpMRI based on patient risk profiles. METHODS: We identified 1023 patients who underwent mpMRI of the prostate from July 2014-October 2016 at our institution. Inclusion criteria were patients who underwent mpMRI to aid PCa detection or while on active surveillance. Using clinical variables, nomogram development was performed using 883 consecutive patients who met the inclusion criteria for the study. Clinical variables assessed included age, PSA, prostate volume, and PSA density (PSAD). Multivariable logistic regression generated a nomogram incorporating age, PSA, and prostate volume for finding PIRAD 4 or 5 lesions on mp MRI. A separate nomogram using PSAD alone was generated. Internal validation of each nomogram was performed by generating an ROC, calibration, and decision analysis curves. RESULTS: Age, PSA, prostate volume, and PSAD were all significant predictors of PIRADS 4-5 lesions on univariable analysis (all p < 0.001). Upon internal validation, a nomogram incorporating age, PSA, and prostate volume had an AUC of 0.746 (p < 0.001). A separate nomogram using PSAD alone had an AUC of 0.729 (p < 0.001). Both nomograms had excellent calibration and high net benefit on decision curve analysis across a wide range of predicted probabilities. The two nomograms performed similarly regardless of indication for mpMRI. CONCLUSIONS: We developed two clinical nomograms that accurately predict the probability of finding PIRADS 4-5 lesions on mpMRI, which may be useful in counseling patients undergoing prostate cancer screening or who are on active surveillance. These nomograms pose no additional cost given that age and PSA are readily available and prostate volume obtained at previous transrectal ultrasound-guided biopsy can be used as input. Externally validation should be performed to confirm the utility of this nomogram in other cohorts. Source of Funding: none

MP08-15 MULTI INSTITUTIONAL STUDY ON MULTI-PARAMETRIC MAGNETIC RESONANCE IMAGING/ULTRASOUND FUSION BIOPSY, ARE WE GETTING BETTER? Wei Phin Tan*, Thomas Hwang, Mukund Gande, Daniel Dalton, Paul Yonover, Kalyan Latchamsetty, Christopher Coogan, Chicago, IL INTRODUCTION AND OBJECTIVES: The usage of multiparametric Magnetic Resonance Imaging/Ultrasound fusion biopsy (Fbx) to aid in the diagnosis of clinically significant (CS) prostate cancer (CaP) has taken place in recent years. Our objective was to determine if the detection rate of our multi institutional experience with Fbx and standard 12 core sextant biopsy (SBx) in detecting clinically significant prostate cancer is improving over time. METHODS: A retrospective review of 803 patients who underwent FBx biopsy and SBx in the same setting between September 2014 and September 2016 was performed. Group 1 consisted of patients who underwent FBx and SBx in the first year of starting FBx and group 2 consisted of patients who underwent FBx and SBx in the second year of starting FBx. All patients underwent a 3-Tesla multi-

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parametric MRI (mpMRI) performed at 3 different institutions. mpMRI was performed using T1/T2 phases, dynamic contrast enhancement and diffusion weighted imaging. Using a 3-dimensional model fusion software [InVivo (Phillips), Gainesville (USA)], 2-5 fusion biopsies were performed on each prostate lesion. FBx was only performed on patients with at least 1 PIRADS ¼3 lesion on mpMRI. Gleason score ¼ 7 was considered as clinically significant prostate cancer. RESULTS: 341 patients underwent an FBx and SBx between September 2014-2015 and 462 patients underwent FBx and SBx between September 2015-2016. Age, PSA, race, BMI and location where mpMRI was not significantly different between both groups, p>0.05. 109/341 patients (32%) were diagnosed with CaP in 2015 and 162/462 patients (35%) were diagnosed with CaP in group 2. 56/341 patients (16%) were diagnosed with CS CaP in group 1 and 96/462 (21%) patients were diagnosed with CS CaP based off fusion biopsy in group 2 (Table 1). Compared to SBx, FBx is likely to detect clinically CS CaP as can be seen in both years on table 1. CONCLUSIONS: Our experience show that FBx may have a learning curve with lower detection rate initially which improves over time. Although FBx is better at detecting CS CaP compared to SBx, more studies are required to determine the ideal number of FBx needed to overcome this initial learning curve and where detection rate would start to plateau.

Source of Funding: none

MP08-16 USE OF DUPLICATE AXIAL IMAGING IN NEWLY DIAGNOSED PROSTATE CANCER e TRENDS ACROSS THE PENNSYLVANIA UROLOGIC REGIONAL COLLABORATIVE (PURC) Serge Ginzburg*, Adam Reese, Edouard Trabulsi, Tianyu Li, Claudette Fonshell, Bret Marlowe, Thomas Guzzo, Thomas Lanchoney, Marc Smaldone, Robert Uzzo, Philadelphia, PA INTRODUCTION AND OBJECTIVES: NCCN prostate cancer (CaP) guidelines currently designate either CT or MRI as recommended staging modality in select patients. The versatility of MRI may provide an additional aide in surgical planning or risk-stratification for active surveillance. Potential exists for overuse, resulting in duplicate axial imaging (CT + MRI) in same patient. We sought to analyze axial imaging utilization and to quantify the incidence of duplicate axial imaging in patients with newly diagnosed CaP across a regional collaborative. METHODS: PURC is a prospective regional collaborative comprised of six large academic and private urology practices in Southeastern Pennsylvania launched in 2014. Demographic and clinicopathologic data for patients with newly-diagnosed CaP were abstracted. Rates of duplicate axial imaging (CT+MRI) were examined using chi-square and Spearman0 s correlation statistical analyses. RESULTS: Data from 1892 patients with newly diagnosed CaP (May 2015 to Nov 2016) were abstracted. Median age was 63 [IQR 58-68], 66.1% were Caucasian and 26.2% African American. Median PSA was 6.1 [IQR 4.6-9.4] and NCCN risk category was very low, low, intermediate and high/very high in 7.4%, 22.5%, 45.0% and 25.1%, respectively. Overall, 923 patients (48.8%) underwent axial imaging. MRI alone was utilized in 659 (34.8%) and CT in 332 (17.5%). Duplicate