MP68-02 COMPARATIVE ANALYSIS OF FUNCTIONAL OUTCOMES OF OPEN AND MINIMALLY INVASIVE PARTIAL NEPHRECTOMY STRATIFIED BY TUMOR COMPLEXITY

Abstract

INTRODUCTION AND OBJECTIVE: Partial nephrectomy (PN) for localized renal masses has become standard of care, though impact of surgical approach [open vs. minimally invasive (MIS)] as it relates to tumor complexity remains controversial. We sought to evaluate the impact of RENAL score and surgical approach on functional outcomes. METHODS: Multi-institutional retrospective analysis of PN performed between 2000-2016. The cohort was divided into open vs. MIS approach, and descriptive analyses were conducted. Primary outcome was devlelped of new onset CKD (defined as eGFR<60 mL/min/1.73m2). Linear regression was conducted to evaluate factors associated with increasing DeGFR. Kaplan-Meier analysis (KMA) was conducted for freedom of de novo CKD comparing Open vs. MIS approaches based on RENAL score category. RESULTS: A total of 3,529 patients were included in the analysis, 1,464 (41.56%) underwent open surgery while 2060 (58.37%) underwent MIS. Open PN greater proportion of patients with Diabetes Mellitus (p=0.035), larger clinical tumor size (3.4 vs. 3.1 cm, p<0.001), intermediate RENAL (44.5 vs. 38.4%, p<0.001) and complex (7.0 vs. 4.6%, p=0.003) RENAL scores. Intraoperatively, Open PN had longer warm ischemia time (WIT 23.9 vs. 22.3 mins, p<0.001). Patients with Open PN also higher preoperative eGFR (90.3 vs 88.7 mL/min/1.73m2, p=0.013), and DeGFR (11.93 vs 9.64, p<0.001). Linear Regression demonstrated increasing age (B 0.125, p<0.001), Increasing preoperative eGFR (B 0.393, p=0.001), female sex (B 0.34, p=0.023), Diabetes (B 5.23, p<0.001), increasing RENAL score (B 0.764, p<0.001), and open surgery (B -1.333, p=0.022) as being associated with increasing DeGFR on linear regression. KMA demonstrated no significant difference in 5 year freedom from CKD in simple RENAL (open 90% vs. MIS 93%, p=0.642), though open PN had higher freedom from de novo CKD in intermediate (83% vs 78%, p=0001) and complex RENAL (78% vs. 57%, p=0.041) groups (Figure). CONCLUSIONS: Open PN was associated with progressively higher rates of freedom from novo eGFR<60 in intermediate and complex tumors. Open approach may be considered as a viable option in patients with increasingly complex masses in whom preservation of renal function is imperative and where functional reserve may be limited.Source of Funding: Stephen Weissman Kidney Cancer Research Fund