groups respectively. Mean patient age, creatinine, and overall opera-tive time were not significantly different. Major/minor complication ratesfor all three groups were 12%/10% (OPN), 4%/6% (LPN), and 2%/2%(RPN). Mean tumor size for the OPN, LPN, and RPN groups was 2.5cm, 2.0 cm, and 2.8 cm respectively. Pathology demonstrated renal cellcarcinoma in 92%, 70%, and 82% while microscopic positive marginson final pathology were seen in 2%, 12%, and 4% of the OPN, LPN,and RPN specimens respectively. Median follow up for OPN, LPN, andRPN were 21 months, 40 months, and 12 months respectively. Therewere no cancer recurrences in the LPN and RPN groups, but 2 patientswith local recurrence in the OPN arm were detected with one patientundergoing cryotherapy after recurrence was diagnosed.

CONCLUSIONS: LPN and RPN have several similar operativecharacteristics and outcomes compared to OPN. However, in thehands of experienced laparoscopic and robotic surgeons, LPN andRPN appear to be associated with decreased length of stay andestimated blood loss. Although the robotic approach to NSS may betechnically challenging, equivalent, if not improved, perioperative com-plication rates and oncologic outcomes are demonstrated when com-pared to OPN and LPN. Larger comparative studies with longer followup and standardized reporting of tumor difficulty are needed to furtherevaluate the optimal role for each approach to NSS.

Source of Funding: Work supported by the Fox Chase CancerCenter Keystone Program in Personalized Kidney CancerTherapy.

989PREDICTORS OF WORSENING GFR FOLLOWING PARTIALNEPHRECTOMY: IS BEING OFF-CLAMP THE FINAL STRATEGY?

Arun Srinivasan*, Amin Herati, Arvin George, Soroush Rais-Bahrami,Louis Kavoussi, New Hyde Park, NY

INTRODUCTION AND OBJECTIVES: Recent focus in laparo-scopic nephron sparing surgery has been to identify techniques todecrease warm ischemia time and thus scale down renal insult. Weendeavored to identify the preoperative and intraoperative factors thatbest predict renal injury. Identifying these factors would lend them-selves for innovation and eventually decrease renal injury.

METHODS: We retrospectively evaluated patients who under-went laparoscopic partial nephrectomy. We utilized univariate analysisby general linear model to identify preoperative and intraoperativevariables that best correlate with renal insult evidenced by post oper-ative deterioration in glomerular filtration rate. A regression analysiswas then performed to identify the best predictor of this injury control-ling for their inter-relationship.All preoperative and intra-operative fac-tors were included in the prediction model including history of diabetesor hypertension, preoperative creatinine, ASA class, estimated bloodloss, on-clamp surgery or off-clamp surgery, clamp time, location oftumors, size of tumors, hilar position or not, age at surgery and BMI.

RESULTS: We retrospectively studied 273 patients who under-went laparoscopic partial nephrectomy between June 2006 and July2009 by a single surgeon. 32% of these patients had off-clamp partialnephrectomy. By univariate analysis, significant predictors of renalinsult were age at surgery, hilar location of tumors, clamp time, off-clamp partial nephrectomy and duration of surgery. Off-clamp surgeryand clamp time as variables are mutually exclusive. Hence we con-structed our regression models with either clamp time or off clampsurgery. By multivariate regression analysis, clamp time(p�0.015) andoff-clamp surgery(p�0.02) emerged as the only significant predictors ofrenal injury.

CONCLUSIONS: The best predictor of renal injury after lapa-roscopic partial nephrectomy is shorter clamp time during on-clamppartial nephrectomy or performing laparoscopic partial nephrectomyoff-clamp. We find that performing off-clamp laparoscopic partial ne-phrectomy might be the ultimate strategy to protect renal function.

Source of Funding: None

990PARTIAL NEPHRECTOMY VERSUS RADIAL NEPHRECTOMYFOR T1B RENAL CELL CARCINOMA: ONCOLOGICAL ANDFUNCTIONAL OUTCOMES

Sangjun Yoo*, Taejin Kang, Cheryn Song, Jun Hyuk Hong,Choung-Soo Kim, Hanjong Ahn, SEOUL, Korea, Republic of

INTRODUCTION AND OBJECTIVES: To compare the onco-logical and functional outcomes of radical nephrectomy (RN) andpartial nephrectomy (PN) for T1b renal cell carcinoma.

METHODS: We identified 27 patients who underwent PN forT1b renal cell carcinoma at Asan Medical Center between Jan 1991and Dec 2007. Each case was matched with 2 patients with identicaldemographic, clinical and pathological characteristics who underwentRN during the same period. Recurrence-free and cancer specific sur-vival, glomerular filtration rate (GFR) calculated by modification of dietin renal disease equation and chronic kidney disease (CKD) statuswere compared between the PN and RN group. All cases were doneelectively and there were no patients with single kidney in both groups.

RESULTS: Mean tumor size was 5 cm in both groups butextra-renal tumor diameter/total tumor diameter ratio was higher in thePN group (PN, 56.7%; RN, 38.1%, p�0.001). PN group had longerrenal sinus-tumor length than RN group (PN, 0.54cm; RN, 0.22cm,p�0.017). In RN group, one local recurrence was observed and nocancer-specific death occurred during a mean follow up of 45 months.In PN group, there was no local recurrence or cancer-specific deathduring a mean follow up of 48 months demonstrating equivalent onco-logical outcome to RN group. Number of patients with hypertension ordiabetes preoperatively was 7 and 11 in PN and RN groups, respec-tively. Incidence of CKD was 1 in both groups (3.7% and 1.9%).Pre-operative GFR of PN group was 88.4ml/min/1.73min2 and of RNgroup was 93.0ml/min/1.73min2 (p�0.298). At postoperative 1 year, 2years, and 3 years GFR changed to 82.8ml/min/1.73min2, 80.6ml/min/1.73min2, and 80.9ml/min/1.73min2 in PN group and 62.3ml/min/1.73min2, 64.2ml/min/1.73min2, 66.6ml/min/1.73min2 in RN group (PNvs. RN; preop. vs. postop., all p�0.05). Postoperative CKD developedin 1 patient in PN group (3.8%, 1/26) whereas 18(34.0%, 18/53)patients demonstrated CKD in the RN group.

CONCLUSIONS: In T1b renal cell carcinoma, PN exhibitedcomparable oncological outcome and superior renal function preserva-tion compared to RN. In technically amenable cases, PN can be safelyconsidered as a primary option.

Source of Funding: None

991ASSESSMENT OF RENAL DAMAGE FOLLOWING WARMISCHEMIA TIME DURING LPN: RESULTS OF A PROSPECTIVESTUDY

Francesco Porpiglia*, Cristian Fiori, Ivano Morra, Riccardo Bertolo,Patrizia Angusti, Valerio Podio, Roberto Mario Scarpa, Orbassano(Torino), Italy

INTRODUCTION AND OBJECTIVES: The aim of this prospec-tive study is to evaluate the renal damage and the impairment of renalfunction due to warm ischemia time after laparoscopic partial nephrec-tomy (LPN).

METHODS: fter Institutional approval, 57 patients were in-volved in the study which lasted from October 2006 to December 2008.Patients underwent LPN for renal tumour with transperitoneal or retro-peritoneal approach, in all cases tumour resection and parenchymalreconstruction were performed after the clamp of renal artery. Patientswere divided into three Groups according to WIT: Group A � 20 min;group B � 20 and � 30 min; Group C � 30 min. Daily proteinuria,serum creatinine (CrS), and creatinine clearance (CrCl) were assessedpreoperatively, at 5th postoperative day and at 3rd month. Renalscintigraphy was performed before the procedure, at 5th day, at 3rdmonth and at one year postoperatively to evaluate the percentage ofcontribution to renal function (%RF) by the injured kidney and to

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estimate normalized renal plasma flow (ERPF). The data of threegroups were compared with a statistical analysis, a p-value � 0.05 wasconsidered statistically significant. For the purpose of this study, weconsidered only data until post operative 3rd month.

RESULTS: The groups A, B, and C consisted of 22, 23 and 12patients respectively. The three groups were comparable about demo-graphic data and baseline CrS, CrCl, daily proteinuria and %RF. MeanWIT was 14.3 in group A; 25.22’ in group B and 36.16’in Group C(p�0.001). At the 5th postoperative day Renal function markers weresimilar through all the Groups whilst daily proteinuria was significantlylower in Group A with respect to Groups B and C (p�0.0009). Therewas a statistical difference between the % RF in Groups A vs Group Cand B vs group C too (p�0.01). At 3rd month CrS was similar in all theGroups (p�0.05); daily proteinuria was significantly higher in Groups Band C respect to that in Group A (p�0.04); CrCl in Groups A and B(p�0.05) was significantly higher than that in Group C (p�0.01). Thecontribute to renal function of operated kidney was lower in the groupC vs group A and B (p�0.04), whilst no significant difference wasrecorded between Groups A and B. Statistical analysis through eachGroup revealed a recover towards pre-operative conditions of %RF inGroup A and B whilst in Group C the %RF did not return to baselineconditions, remaining significantly lower (p�0.0001).

CONCLUSIONS: Our results demonstrate that kidney damagesurely occurs during LPN when WIT is over 30 minutes. The Cut off of20 minutes which is usually proposed by some Authors is not confirmedby our results.

Source of Funding: None

992POST OPERATIVE MORBIDITY OF ROBOTIC VERSUS OPENPARTIAL NEPHRECTOMY: THE IMPACT OF PREOPERATIVETUMOR CHARACTERISTICS

Tariq A. Khemees*, Benjamin J. Yuh, Andrew Stacey, David S.Sharp, Ronney Abaza, Geoffrey N. Box, Robert R. Bahnson, AhmadShabsigh, Columbus, OH

INTRODUCTION AND OBJECTIVES: Published literature indi-cates that laparoscopic partial nephrectomy (LPN) may have higherpost operative complications compared to open partial nephrectomy(OPN). Robotic assisted partial nephrectomy (RPN) may offer a lessmorbid alternative. The impact of tumor characteristics on surgicaldecision making and post operative outcome is not known. The aim ofthis study is to compare robotic vs open partial nephrectomy andthe impact of tumor characteristics on early post operative surgicalcomplications.

METHODS: An independent review board approved the reviewof 133 consecutive partial nephrectomies. The data from these caseswere entered into a retrospective complication database. Tumors char-acteristics were defined according to the R.E.N.A.L. NephrometryScore (RNS). All complications within 30 days of surgery were definedand graded using the Clavien system. Univariate and multivariablelogistic regression were used to evaluate variables associated withcomplications

RESULTS: 59 OPN and 74 RPN were compared. There was nodifference in mean patient’s age, median ASA score, BMI, preoperativeGFR or past abdominal surgery. The median RNS was 7.04 for OPNand 5.73 for RPN (p�0.001). The median post operative length of staywas 3.2 days for OPN and 2.1 days for RPN (p�0.007), the estimateblood loss (EBL) was 351ml and 199ml respectively (p�0.005). OPNhad longer ischemic time (28.9 minutes) compared to RPN (19.1min-utes) (p�0.001). There was no difference in positive surgical margins,incidence of post operative complications (22.8% vs 24.7%) or grade ofcomplications. There were no post operative deaths. The RNS did notcorrelate with age, ASA score, BMI, surgical technique, preoperativeGFR, operative time or incidence of post operative complications,however, it did correlate with EBL (p�0.001) and ischemic time(p�0.001)

CONCLUSIONS: Robotic partial nephrectomy had shorterlength of stay and lower blood loss compared to open partial nephrec-tomy with similar rates of positive surgical margins and early postop-erative complications. Patients with higher RNS were more likely toundergo OPN. Higher RNS did not predict the incidence of postoperative complications; however, it did correlate with increased bloodloss and ischemic time.

Source of Funding: None

993FEASIBILITY AND OUTCOMES OF PARTIAL NEPHRECTOMYFOLLOWING THERAPY WITH A HEAT SHOCK PROTEIN 90INHIBITOR

Heinric Williams*, Rockville, MD; Aaron Krill, Sally Fowler, LeonardNeckers, Peter A Pinto, Percy Ivy, Ramaprasand Srinivasan, WMarston Linehan, Gennady Bratslavsky, Bethesda, MD

INTRODUCTION AND OBJECTIVES: Tyrosine kinase inhibi-tors targeting the von Hippel-Lindau (VHL) pathway are routinely usedin the management of renal cell carcinoma. Another class of novelagents includes the inhibitors of heat shock protein 90 (hsp90) whichdownregulate hypoxia inducible factor (HIF) in an VHL ubiquitinylationindependent manner. Experience with agents such as bevacizumabhave highlighted the potential for surgical morbidity and perioperativecomplications when used in the neoadjuvant setting. To our knowledge,there are no reports on the perioperative outcomes associated withneoadjuvant use of HSP90 inhibitors in the management of renal cellcarcinoma. We describe the outcomes of partial nephrectomy followingneoadjuvant use of the HSP90 inhibitor, 17-Allylamino-17-demethoxy-geldanamycin (17-AAG).

METHODS: The study cohort included 8 patients with VHL thatwere treated at NCI on an IRB-approved phase II trial of intravenous 17AAG for multifocal localized RCC. These patients underwent partialnephrectomy due to the lack of clinical response to systemic treatment.The surgeries were performed at least 30 days following completion oftherapy. The charts of these patients were reviewed for perioperativeoutcomes as well as renal functional data.

RESULTS: Partial nephrectomy was completed in all cases andno renal units were lost. All procedures except one were completed inan open fashion. The mean number of tumors removed was 4.8 (1-15).The median size of the largest mass was 3.7 cm (3 - 4.2). Median EBLwas 1750 mL (200-2500). There were two major complications: aureteral transection (repaired primarily) in a patient who had partialnephrectomy on the same unit performed for the third time and apleural injury during initial partial nephrectomy in another patient thatrequired tube thoracostomy. There was no statistically significant dif-ference between mean preoperative and postoperative creatinineclearance, 79.6 mL/min and 86.3 mL/min, respectively (p�0.997).

CONCLUSIONS: Partial nephrectomy is a feasible procedurefollowing systemic treatment with HSP 90 inhibitors. These findingsmay be helpful for treatment and counseling patients that may requiresystemic therapy with heat shock protein inhibitors alone or in combi-nation with other molecular therapies.

Source of Funding: None

994CHANGE IN GFR AFTER RADICAL NEPHRECTOMY: WHEN DOPATIENTS REACH A NEW BASELINE?

Michael Garcia-Roig*, Michael Gorin, Vincent Bird, Janice Santos,Miami, FL

INTRODUCTION AND OBJECTIVES: Patients undergoingradical nephrectomy generally experience a modest but significantpostoperative decrease in GFR. Several factors can impact renalfunction overall such as age, sex, and comorbidities. We evaluatedpostoperative estimated GFR (eGFR) in patients with multiple comor-

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