failure and early recurrence of LUTS with the need of medication or surgery. Endpoints were change in objective (uroflowmetry, postvoid residual [PVR]), and subjective (International Prostate Symptoms Score [IPSS], Life Quality Index [LQI]; Danish prostate symptom score sex questionnaire (DAN-PSSsex). Evaluation was performed at 1-3, 3-6, 6- 12, 12-24, 24-36, >36 months. RESULTS: Overall, 65 patients with mean age of 62.15 years were included. Antegrade ejaculation was preserved in 59 of 65 (90.7%) patients at 1-3 months (Table 1). This rate remained constant until 24- 36 months. Significant improvements in maximum flow rate, micturition volume, and PVR were observed at 3 months. Micturition symptoms, as measured by IPSS and LQI, were also significantly reduced. Improve- ments were maintained up to 36 months (Table 2). No serious adverse events were reported. Seven (10.8%) patients received a second ejaculation-preserving Greenlight photovaporization due to recurrence in symptoms. CONCLUSIONS: Antegrade ejaculation was preserved with the use of ejaculation-preserving Greenlight photovaporization with excel- lent outcome. Observed symptomatic and functional outcomes were comparable with conventional TURP. The results from this study un- derline the necessity of reviewing the old concept of ejaculation physiology. Source of Funding: none MP62-04 COMPARISON OF CONVECTIVE RADIOFREQUENCY THERMAL THERAPY OF PROSTATE (REZUMâ) TO MTOPS STUDY COHORT SEXUAL FUNCTION RESPONSE AT 3 YEARS Sevann Helo*, Nicholas Tadros, Springfield, IL; Nikhil Gupta, New Brunswick, NJ; Bradley Holland, Danuta Dynda, Kevin McVary, Springfield, IL INTRODUCTION AND OBJECTIVES: Medical therapy is commonly used to treat lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH), but can negatively impact sexual function. Data over three years shows that convective radiofrequency thermal therapy, Rezum (REZ), treats LUTS/BPH while preserving sexual function. We report the 3-year data on the effect of REZ on LUTS and sexual function compared to the cohort from the Medical Therapy of Prostatic Symptoms (MTOPS) study. METHODS: Results from the treatment arm of a double-blin- ded, randomized, controlled trial of REZ were compared to results of the MTOPS therapy arms, doxazosin (DOX), finasteride (FIN), or combi- nation of both (COM) in subjects who were sexually active at baseline. Sexual function was assessed using the international index of erectile function (IIEF) questionnaire in REZ subjects and brief male sexual function inventory (BSFI) questionnaire in the MTOPS cohort. Erectile function, orgasmic function, sexual desire, and satisfaction percentiles were compared at 1, 2, and 3 years by matching BSFI questions to IIEF subdomain scores. Propensity score weighting was performed to adjust for baseline differences in demographics, LUTS, and uroflowmetry be- tween groups at baseline; outcomes were assessed over 3 years. RESULTS: Treatment arms included 86 (REZ), 301 (DOX), 319 (FIN), and 310 (COM) sexually active subjects. Baseline age, BMI, PSA, Qmax, and PVR were similar. At baseline, REZ subjects had substantially higher erectile function, but lower PSA, larger prostate volume, and worse QOL compared to the MTOPS cohort. All treatment arms experienced a slight decline in erectile and orgasmic function at 3 years. There was no change in sexual desire percentile for REZ and COM subjects, while DOX subject experienced a 17% decline at 3 years (p¼0.003). REZ subjects also experienced a 17% improvement in satisfaction percentile, while subjects receiving COM therapy demon- strated a 28% decline at 3 years. CONCLUSIONS: REZ achieves similar outcomes compared to combined medical therapy for treatment of LUTS/BPH when adjusted for propensity score. Although baseline erectile function was higher in REZ subjects, it is unclear to what degree these differences are attributable to instrument versus cohort differences. REZ offers a favorable sexual side effect profile, which may be a superior option for patients unwilling to sacrifice sexual function. Primary treatment deci- sion depends on a discussion of adverse events and medication burden. Source of Funding: Southern Illinois University, Division of Urology Grant MP62-05 OUTCOMES ASSESSMENT OF AQUABLATION IN PROSTATES 50 TO 80ML IN VOLUME - A SUBGROUP ANALYSIS FROM THE PHASE III BLINDED RANDOMIZED WATER STUDY COMPARING AQUABLATION VS. TRANSURETHRAL RESECTION OF THE PROSTATE FOR MODERATE-TO-SEVERE LUTS IN MEN WITH BPH Claus Roehrborn*, Dallas, TX; Peter Gilling, Tauranga, New Zealand INTRODUCTION AND OBJECTIVES: Prostate resection for patients with LUTS remains the gold standard for surgical treatment of BPH. The length of resection time and the risk of complications during a transurethral resection of the prostate (TURP) are a direct correlation with the size of the prostate. We aimed to compare the safety and ef- ficacy of prostate ablation using Aquablation (A) vs TURP (T) in pros- tates between 50 and 80mL in volume and analyze as a subgroup from the WATER Study METHODS: In this randomized, blinded, multicenter phase III trial, men with moderate-to-severe LUTS related to BPH were assigned to transurethral resection of the prostate (TURP) or robotically-assisted waterjet ablation (Aquablation). A pre-identified subgroup analysis based on prostate volume (<50 vs. 50 mL) used the trial s co-primary safety and efficacy endpoint. The primary safety endpoint was the occurrence of Clavien-Dindo Grade 1 (persistent ejaculatory dysfunc- tion, erectile dysfunction, or urinary incontinence) or Grade 2 or higher operative complications at 3 months. The primary efficacy endpoint was the reduction IPSS score at 6 months. RESULTS: The mean baseline IPSS score (T: 22.2 vs. A: 22.9, p¼0.43), demographic profile, and mean prostate volume (T: 52 mL vs. A: 54 mL, p¼0.31) were similar in both arms. Mean operative time was equivalent between the two groups (T: 35.5 vs. A:32.8 minutes, p¼0.28), but mean resection time was significantly lower in the Aqua- blation group (28 vs. 4 minutes, p<.0001). The primary safety endpoint (Clavien-Dindo grade 1 persistent or grade 2 or higher event in the first 3 months) occurred in 19% of Aquablation subjects and 43% of TURP subjects, p-value < 0.01; therefore, demonstrating superiority of Aquablation versus TURP in men with 50-80mL prostates. For men with large prostates (>50mL) IPSS change scores were larger after Aqua- blation compared to TURP (by approximately 4 points, p¼.0056). For men with both larger (>50 mL) baseline prostate volume and lower (<9 mL/sec) flow rates, the improvement in IPSS scores was 7 points larger in Aquablation compared to TURP (p<.0001). For men with prostate size <50 mL and maximum flow rate >9 mL/sec, the change with TURP was 4.3 points larger after TURP (p¼.0963). Vol. 199, No. 4S, Supplement, Sunday, May 20, 2018 THE JOURNAL OF UROLOGY â e833