MP55-03 DOES HISTOLOGY SUBTYPE NEED TO BE CONSIDERED AFTER PARTIAL NEPHRECTOMY IN PATIENTS WITH PATHOLOGIC T1A RENAL CELL CARCINOMA?: PAPILLARY VS. CLEAR CELL RENAL CELL CARCINOMA Sangjun Yoo, Jeman Ryu*, Han-Kyu Chae, Jae Hyeon Han, Se Young Choi, In Gab Jeong, Cheryn Song, Bumsik Hong, Jun Hyuk Hong, Hanjong Ahn, Choung-Soo Kim, Seoul, Korea, Republic of INTRODUCTION AND OBJECTIVES: We assessed the impact of papillary renal cell carcinoma (RCC) on oncological outcomes after partial nephrectomy compared to clear cell RCC in patients with path- ologic T1a RCC. METHODS: After excluding patients with synchronous multiple renal tumors, familial renal cell carcinoma, pathologic T1b or greater disease, and metastatic disease, 759 patients with clear cell and 84 patients with papillary RCC were included for the analysis. We compared the impacts of papillary RCC with clear cell RCC on onco- logic outcomes. Median follow-up duration was 67 months. RESULTS: There was no differences in patient and tumor characteristics between the 2 groups except for Fuhrman grade (p¼0.006). In Kaplan-Meier analysis, 5-year recurrence free survival was 98.7% in patients with clear cell RCC and 95.6% in patients with papillary RCC. However, 10-year recurrence free survival in patients with clear cell and papillary RCC was 96.1% and 73.0%, respectively (p<0.001). Median time to recurrence was 31 months in patients with clear cell RCC and 77 months in patients with papillary RCC although statistical significance was not achieved (p¼0.190). In multivariate analysis, papillary RCC (HR; 5.309, p¼0.001) was determined as a significant risk factor for recurrence after partial nephrectomy in path- ologic T1a RCC patients in addition to tumor size (HR; 1.861, p¼0.038) and Fuhrman grade (¼3) (HR; 5.176, p¼0.003). CONCLUSIONS: Recurrence after partial nephrectomy was more commonly occurred in pathologic T1a papillary RCC compared to clear cell RCC. Because median time to recurrence in papillary RCC was greater than 5-year after surgery, longer follow-up is needed for patients with papillary RCC even though pathologic stage is T1a. Source of Funding: None MP55-04 PERINEPHRIC VERSUS SINUS FAT INVASION IN PT3A TUMORS MANAGED BY PARTIAL NEPHRECTOMY Pascal Mouracade*, Onder Kara, Matthew Maurice, Julien Dagenais, Ercan Malkoc, Ryan Nelson, Jeremy Reese, Jihad Kaouk, Cleveland, OH INTRODUCTION AND OBJECTIVES: With adoption of partial nephrectomy (PN), the last few years have been marked by a growth in the use of PN for complex renal masses. This has led to an overall increase in the number of tumors found to have adverse pathological features. There are two types of pathological findings in the current T3a fat invasion renal cell carcinoma (RCC): renal sinus fat invasion (SFI) and perinephric fat invasion (PFI). From an anatomical perspective, after PN, RCC with SFI could be considered more likely to develop recurrence and may be associated with worse prognosis. The aim of our study was to evaluate the influence of SFI and PFI on progression-free survival and overall survival after PN for stage pT3a RCC. METHODS: We retrospectively reviewed our institutional re- view board-approved PN database. Data consisted of consecutive re- cords of patients who underwent PN for cT1-3a renal cell carcinoma (RCC) between 2007 and 2016. Overall 1306 patients were included in this study. Of this cohort, 143 patients were staged pT3a with SFI (85 patients) or PFI (58 patients) on final pathology. Demographic, periop- erative and pathological variables were reviewed. We compared the clinico-pathological characteristics, perioperative morbidity and onco- logical outcomes between SFI and PFI groups. Progression-free sur- vival (PFS) and overall survival (OS) analyses were performed. Survival curves were compared using Log-rank test. RESULTS: There were no differences between the 2 groups in terms of age, gender, race, Body mass index, Charlson comorbidity index, cTstage and surgical approach. SFI group had a higher clear cell subtype (p<0.01), Higher R.E.N.A.L score (median 9 vs. 7, p<0.01), Higher hilar (h) location (p<0.01). Positive surgical margin rate was higher in SFI group (21.1% vs. 10.3%) but the dif- ference was not statistically significant(p¼0.09). SFI group had higher warm ischemia time (median 28 vs. 21, p<0.01), while estimated blood loss (p¼0.6), transfusion rate (p¼0.2), Clavien complications (p¼0.6) were not different between the 2 groups. After a median 28 months, there were 19 recurrences (13.3%) and 7 deaths (4.9%). When comparing the survival curves between the 2 groups, there were no differences in PFS (Log rank, p¼0.5) and OS (Log rank, p¼0.8). Tumors size (HR:1.5, 95% CI [1.1-1.9], p <0.01, and tumor grade (HR:3.6, 95% CI [1.1-4.6], p¼0.04) were independent pre- dictors of recurrence. CONCLUSIONS: In our cohort of patients with pT3a renal cell carcinoma following partial nephrectomy, sinus fat invasion compared to perinephric fat invasion was not associated with an increased risk of progression or death. The independent predictors of recurrence in this population were tumor size and tumor grade. Source of Funding: None MP55-05 PARTIAL NEPHRECTOMY IN THE TREATMENT OF RENAL TUMORS WITH CONCOMITANT VENOUS TUMOR THROMBOSIS (VTT) OF RENAL VEIN BRANCHES: RETROSPECTIVE, MULTI-CENTER ANALYSIS OF PERIOPERATIVE, FUNCTIONAL, AND ONCOLOGIC OUTCOMES Fabio Zattoni*, Padua and Udine, Italy; Robert H. Thompson, Rochester, MN; Umberto Capitanio, Milan, Italy; Alessandro Crestani, Vincenzo Ficarra, Udine, Italy; Alexander Kutikov, Philadelphia, PA; Alessandro Larcher, Milan, Italy; Brian R. Lane, Grand Rapids, MI; Bradley C. Leibovich, Rochester, MN; Andrew McIntosh, Philadelphia, PA; Francesco Montorsi, Milan, Italy; Daniel Moon, Melbourne, Australia; Tim Muilwijk, Leuven, Belgium; Katie Murray, Columbia, MT; Sabrina Noyes, Grand Rapids, MI; Paul Russo, New York, NY; Robert G Uzzo, Philadelphia, PA; Hein Van Poppel, Leuven, Belgium; David Yang, Rochester, MN; Filiberto Zattoni, Padua, Italy; Alexander Mottrie, Aalst, Belgium; Giacomo Novara, Padua, Italy INTRODUCTION AND OBJECTIVES: To evaluate the periop- erative, functional, and oncologic outcomes of partial nephrectomy (PN) in renal tumors with concomitant venous tumor thrombosis (VTT) of renal vein branches. METHODS: Data of open, laparoscopic or robotic PN with concomitant VTT removal was collected retrospectively in a Vol. 197, No. 4S, Supplement, Sunday, May 14, 2017 THE JOURNAL OF UROLOGY â e731