Source of Funding: none MP75-16 OUTCOMES OF ROBOT-ASSISTED PARTIAL NEPHRECTOMY IN PATIENTS WITH COMPLEX RENAL TUMORS AND PRE-EXISTING CHRONIC KIDNEY DISEASE: A MULTI-INSTITUTIONAL ANALYSIS Deepansh Dalela*, Ravi Barod, Detroit, MI; Giorgio Gandaglia, Melle, Belgium; Ronney Abaza, Dublin, OH; Rajesh Ahlawat, Gurgaon, India; Nicolomaria Buffi, Rozzano, Italy; Ben Challacombe, Prokar Dasgupta, London, United Kingdom; Daniel Moon, Melbourne, Australia; Dipen Parekh, Miami, FL; Francesco Porpiglia, Orbassano, Italy; Sudhir Rawal, New Delhi, India; Giacomo Novara, Melle, Belgium; Mahendra Bhandari, Detroit, MI; Alexandre Mottrie, Melle, Belgium; Craig Rogers, Detroit, MI INTRODUCTION AND OBJECTIVES: Partial nephrectomy can help preserve renal function, but may be more challenging in patients with complex tumors. We compare outcomes of robot-assisted partial nephrectomy (RAPN) for complex tumors in patients with and without pre-existing chronic kidney disease (CKD). METHODS: Using the Vattikuti Collective Quality Initiative (VCQI) database (representing patients and surgeons from 11 centers across 4 continents), we identified 250 patients undergoing RAPN for complex tumors (identified by RENAL or PADUA score of >10) be- tween 2008-2013. Peri-operative (estimated blood loss [EBL], warm ischemia time [WIT], complications and positive surgical margins [PSM]) and functional outcomes (estimated glomerular filtration rate [eGFR] at 12-month follow-up) were assessed and stratified by preop- erative CKD (CKD stage 3 or greater; n¼33, 13.2%) vs. no significant CKD (eGFR >60 ml/min/1.73 m2; n¼217, 86.8%). RESULTS: Overall, patients had a median (interquartile range) body mass index of 25.7 (23.3-28.9) kg/m 2 and pre-operative eGFR of 83 (70-98) ml/min/1.73 m 2 respectively. 48.4% tumors were >4 cm radius and 29.6% entirely endophytic. 95 (38%) tumors were posterior, 118 (47.2%) mid-polar and 67.2% had renal sinus involvement on preoperative imaging. Patients with CKD were older (median age 62 vs. 54; p¼0.001), had higher median age-adjusted Charlson comorbidity score (5.5 vs. 2; p<0.001) and significantly larger tumors (median 4.7 vs. 4 cm; p¼0.036) than patients without CKD. There were no signifi- cant differences in other tumor characteristics. Perioperatively, there were no significant differences in median WIT (24.5 vs. 22.5 min; p¼0.5), operative (OR) time (175 vs. 180 min; p¼0.2) and EBL (200 vs. 200 ml; p¼0.9) between patients with vs. without CKD. A total of 26 patients overall experienced postoperative complications, of which 9 (3 in CKD group and 6 in non-CKD; p¼0.09) were Clavien Grade 3 or higher. PSM were comparable: 9.1% in CKD vs. 6.0% in non-CKD group (p¼0.2). Patients with preoperative CKD had a greater percent decrease in eGFR at median 12-month follow up (4.06% vs. 0.3%; p¼0.05), but it did not translate into significantly higher incidence of new-onset CKD >¼Stage 3. CONCLUSIONS: Despite the surgical challenges, RAPN for patients with complex renal tumors is safe and feasible, even for patients with CKD. Perioperative and functional outcomes 1 year after surgery appear acceptable, despite heterogeneity in surgical tech- niques, experience and patient population across multiple centers. Source of Funding: Vattikuti Foundation MP75-17 THE RISK OF CHRONIC KIDNEY DISEASE IN THE ELDERLY AFTER RADICAL OR PARTIAL NEPHRECTOMY FOR MASSES LARGER THAN PT1A Lisly Chery*, Mehrad Adibi, Leonardo Borregales, Jessica Brandt, Devin Gu, Akshat Kumar, Surena Matin, Jose Karam, Christopher Wood, Houston, TX INTRODUCTION AND OBJECTIVES: The incidence of kidney cancer continues to rise, including patients 75 and older. This patient pop- ulation presents a challenge as the benefits of preserved kidney function with a partial nephrectomy may be limited. The renal function outcomes after surgery in this patient population have not been well described. METHODS: Using a retrospective analysis of a prospectively maintained database, we examined patients  75 who underwent radical or partial nephrectomy for masses other than pT1a from 2001 to 2014. Patients had a solitary renal mass and normal contralateral kid- ney. The Modification of Diet in Renal Disease equation was used to estimate glomerular filtration rates before and after surgery. The Nation Kidney Foundation stages of chronic kidney disease [CKD] were used to categorize patients. RESULTS: Preoperative glomerular filtration rate [GFR] was similar between the radical nephrectomy [RN] group [n¼112, GFR ¼ 67.6 mL/min per 1.73 m2] and the partial nephrectomy [PN] group [n¼43, GFR ¼ 62.7]. Postoperative GFR was lower in the RN group [47.8 vs 54.7, p < 0.05]. Postoperatively, when compared to the PN group, the RN group had a higher rate of new onset CKD Stage 3 [45.5% vs 25.6%, p < 0.05]. The rate of new onset CKD Stage 4 [11.6% vs 9.3%, p ¼ 0.68] and CKD Stage 5 [2.7% vs 2.3%] were equal in the 2 groups. Clavien 3-5 complication rate in the RN group [6.3%] was not significantly different from the PN group [11.6%, p ¼ 0.26]. A sub analysis was performed on patients with preoperative GFR < 60 who had a RN [n¼38] or PN [n¼19]. Postoperative GFR was similar between the RN and PN groups [35.7 vs 42.5, respectively, p ¼ 0.08]. There was no difference in the onset of new CKD Stage 4 [28.9% vs 21.1%, respectively, p ¼ 0.53] or CKD Stage 5 [7.9% vs 5.3%, p ¼ 0.72]. CONCLUSIONS: For patients 75 years and older with renal masses bigger than pT1a, the use of radical nephrectomy was asso- ciated with a higher incidence of CKD Stage 3, and lower post-operative GFR when compared to partial nephrectomy. This effect was attenu- ated in patients with pre-existing CKD. The benefit of partial nephrec- tomy in this population may not outweigh the costs. Source of Funding: none MP75-18 PARTIAL NEPHRECTOMY VERSUS RADICAL NEPHRECTOMY FOR CLINICAL T1B AND T2 RENAL MASS: A META-ANALYSIS OF OVER 9000 CASES Maria Carmen Mir*, Cleveland, OH; Ithaar Derweesh, , Please choose an option below; Francesco Porpiglia, Torino, Italy; Alessandro Volpe, Novara, Italy; Giacomo Novara, Padua, Italy; Vincenzo Ficarra, Udine, Italy; Nicola Pavan, Trieste, Italy; Humberto Laydner, Jihad Kaouk, Cleveland, OH; Homi Zargar, Melbourne, Australia; Riccardo Autorino, Cleveland, OH INTRODUCTION AND OBJECTIVES: Partial nephrectomy (PN) is the reference standard of management for cT1a (<4 cm) renal mass. However, its role in the management of larger tumors is still debated. We performed a meta-analysis of studies comparing radical nephrectomy (RN) to PN for cT1b and T2 renal mass. Vol. 195, No. 4S, Supplement, Monday, May 9, 2016 THE JOURNAL OF UROLOGY â e985