Presentation Authors: Asha Mannancheril*, Arpeet Shah, Sarah Capodice, Cara Joyce, Marcus Quek, Gopal Gupta, Maywood, IL
Introduction: Tumor enucleation (TE) has the potential to optimize parenchymal preservation and potentially yields better functional outcomes than standard partial nephrectomy (SPN). The objective of our study is to compare the surgical precision of SPN and TE for optimizing nephron-mass preservation specifically in the operated kidney and comparing that to functional outcomes.
Methods: Robotic partial nephrectomy patients who had suitable pre- and post-operative imaging studies for analysis of parenchymal mass preservation were included. Of 337 robotic partial nephrectomies performed between 2011 and 2017, 174 met our inclusion criteria. Computed tomography or magnetic resonance imaging were required to be less than 3 months prior and 3-12 months after surgery. Parenchymal mass preservation and surgical precision were estimated for both TE and SPN; precision was defined as actual postoperative parenchymal volume versus predicted postoperative parenchymal volume, presuming a loss of a 5-mm rim of parenchyma in SPN tumor excision and reconstruction. Patient demographics and clinical characteristics were presented as counts and percentages, means and standard deviations, or medians and interquartile ranges overall and by procedure type. Nominal variables were compared by procedure type with chi-square tests or Fishers exact tests. Differences in means and medians were assessed by t-tests and Wilcoxon rank sum tests, respectively. Analyses were performed in SAS 9.4 (Cary, NC).
Results: Analysis included 93 TEs and 81 SPNs. Median age, body mass index, and tumor size were comparable. Precision of excision or reconstruction was 96% (IQR=88-101) for TE vs 90% (IQR=81-97) for SPN (P=0.010). We then compared global renal function in both cohorts 3-12 months following the procedure and found that eGFR in SPN patients decreased whereas in TE patients, eGFR did not decrease and these results are statistically significant (P=0.024).
Conclusions: Our analysis demonstrates that TE maximally spares normal ipsilateral parenchyma compared to SPN. We also demonstrate that renal function is spared in TE; this suggests that efforts to maximally spare renal parenchyma may lead to better post-operative renal functional outcomes.