MP64-19 FACTORS PREDICTING BLOOD LOSS AND POSITIVE MARGINS AT TIME OF PARTIAL NEPHRECTOMY: ANALYSIS OF A CONTEMPORARY COHORT Harras Zaid*, Stephen Boorjian, William Parker, Christine Lohse, John Cheville, Bradley Leibovich, R. Houston Thompson, Rochester, MN INTRODUCTION AND OBJECTIVES: Partial nephrectomy (PN) has become the treatment of choice for small renal masses. While obtaining negative margins with minimal blood loss are goals of PN, predictors of positive surgical margin (PSM) and transfusion require- ment in contemporary patients are lacking. METHODS: We performed a single-institution retrospective study evaluating all adult patients undergoing PN between 2001-2012 for non-hereditary renal masses at the Mayo Clinic. Univariable and multivariable logistic regression models were evaluated to assess clinicopathologic predictors of PSM and perioperative blood loss requiring transfusion. RESULTS: We identified 1763 patients who underwent 1773 PNs between 2001-2012. Clinicopathologic variables are provided in the Table below by year (2001-2006 vs. 2007-2012). We identified 51 (3%) of PNs with a PSM. In a multivariable model, the following factors predicted PSM during PN: the presence of a solitary kidney (OR 3.81, p < 0.001), ECOG  1 (OR 2.33, p ¼ 0.036), and robotic approach (OR 2.84, p ¼ 0.006). A total of 258 (15%) patients were transfused during their hospitalization including 150 (8%) patients who required at least one unit of blood during surgery. In a multivariable analysis, several factors predicted need for transfusion: increasing age (OR 1.22, p ¼ 0.006), solitary kidney (OR 2.02, p ¼ 0.003), eGFR < 30 (OR 4.17, p < 0.001), higher Charlson score (OR 1.23, p < 0.001), and increasing tumor size (OR 1.25, p < 0.001); and the following features were associated with decreased need for transfusion: male gender (OR 0.61, p ¼ 0.001), laparoscopic PN (OR 0.31, p ¼ 0.001), and robotic PN (OR 0.25, p ¼ 0.003). Year of surgery was not significantly associated with transfusion. CONCLUSIONS: In this contemporary series, while robotic PN offered the advantage of fewer transfusions, it was associated with higher PSM. Furthermore, patients with solitary kidneys or significant co-morbidity undergoing PN were noted to be at higher risk for trans- fusion and PSM. Further evaluation, including longer term oncologic outcomes, are needed, though these data may be of value in coun- seling patients prior to surgery. Source of Funding: None. MP64-20 RETROPERITONEOSCOPIC RADICAL NEPHRECTOMY WITH THE PATIENT IN A COMPLETELY SUPINE POSITION Han-Yu Weng*, Chien-Hui Ou, Wen-Horng Yang, Tainan, Taiwan INTRODUCTION AND OBJECTIVES: We evaluated the feasibility of retroperitoneoscopic radical nephrectomy for renal cell carcinoma with the patient completely supine. METHODS: From October 2006 to Oct 2015 hand assisted retroperitoneoscopic radical nephrectomy was performed in 62 patients with renal cell carcinoma. The patient was placed supine with the legs extended and abducted at 45 to 60 degrees, and the arms stretched out to the sides in the spread-eagle position. The patient was secured to the operation table with 3-inch tapes to permit lateral table tilt. The operation was completed via a 7 or 8 cm Gibson incision plus 2 laparoscopic ports. RESULTS: All procedures were successful. The mean time needed for hand assisted retroperitoneoscopic radical nephrectomy was 127 minutes. Mean estimated blood loss was 167ml. Time to oral intake was 2.1 days and time to ambulation was 2.5 days. No specific complication was related to the position. All patients recovered to normal daily activity uneventfully. CONCLUSIONS: Hand assisted retroperitoneoscopic radical nephrectomy with the patient completely supine is feasible and safe. The completely supine position has several advantages, including ease of patient positioning and the ability to avoid potential risks associated with the lateral decubitus position. Bowel interference with the visual field and mechanical bowel injury are not a concern using this approach. Source of Funding: None Sexual Function/Dysfunction: Penis/Testis/Urethra: Benign Disease & Malignant Disease I Podium Monday, May 9, 2016 8:00 AM-10:00 AM PD34-01 SURVIVAL OUTCOMES OF ADOLESCENT PATIENTS WITH NON- SEMINOMA TESTICULAR GERM-CELL TUMORS: A POPULATION- BASED STUDY Arya Amini, Timothy Waxweiler, Paul Maroni, Elizabeth Kessler, Carrye Cost, Brian Greffe, Timothy Garrington, Arthur Liu, Aurora, CO; Nicholas Cost*, Denver, CO INTRODUCTION AND OBJECTIVES: Testicular germ cell tu- mors (TGCT) are the most common solid malignancy in adolescent and young adult men. In adolescents, approximately 90% of TGCTs are non-seminomas (NS). Few studies have evaluated the impact of age, specifically adolescence, on outcomes of NS TGCTs. METHODS: The SEER database was queried for individuals 13yr diagnosed with NS TGCTs from 1995-2012. Patients were categorized into adolescent (13-19yr) and adult ( 20yr) cohorts. A Cox proportional hazards model was used for multivariate analysis (MVA). RESULTS: 13,964 patients (1,496 adolescents, 12,467 adults) were included. Median follow up was 71mo (range, 1-215mo). 5yr OS for adolescent and adult patients was 94% and 92% respectively (log- rank p¼0.007); 5yr CSS was 95% and 94% respectively (log-rank p¼0.139), Fig 1. Under MVA, adolescent patients had both improved OS (HR, 0.61; 95% CI, 0.50-0.75; p<0.001) and CSS (HR, 0.65; 95% CI, 0.51-0.82; p<0.001), when compared to adults. Additional predictors for improved OS included: Pure embryonal histology (HR 0.55; p<0.001), being married (HR 0.80; p¼0.001), and e838 THE JOURNAL OF UROLOGY â Vol. 195, No. 4S, Supplement, Monday, May 9, 2016