Thirteen patients (1.5%) were converted from PN to RN mostly due to high tumor complexity, extensive infiltrative features, or other intraoperative findings demonstrating that PN was unfeasible. All other patients, mostly with small renal masses, were managed with either thermal ablation (10%) or active surveillance (2%).1
Functional recovery is a key element of cancer survivorship in patients with localized kidney cancer, and RMSK is the ideal clinical model to study because the absence of a contralateral kidney reveals the full impact of ischemia and other factors on both short-term and long-term functional outcomes.2,3 In the current study our objective was to provide a more comprehensive analysis of functional outcomes after PN in RMSK, including the importance of parenchymal volume loss relative to ischemia characteristics and patient-related factors.4 We hypothesized that improved methodology, specifically more objective and accurate measurement of parenchymal volumes before and after surgery via semi-automated software, would facilitate a more informative and discerning analysis of secondary factors that might negatively impact functional recovery after PN.4
We found that clamped PN for RMSK typically saved about 80% of the preoperative function, and at 5 years post-surgery renal function remained stable in most patients with over 95% remaining dialysis-free. Functional recovery correlated strongly with parenchymal volume preserved (r=0.84, p<0.01), and parenchymal volume loss represented the lion’s share (69%) of the functional loss related to PN.4
On average, the median decline of GFR related to ischemia and other factors was only 3-4 ml/min/1.73m2, altogether accounting for only about 30% of the functional decline associated with PN. The current study represents the first time we have been able to provide an estimate of the relative impact of these factors on functional recovery after PN. Acute kidney injury (AKI) was common in RMSK (52% incidence) and correlated strongly with ischemia time, whether warm or cold. The main independent predictors of reduced functional recovery after PN for RMSK, beyond parenchymal volume loss, were increased age, warm ischemia, and AKI.4
Figure: Violin plots of GFR values for the overall group of patients (n=841) preoperatively, 1-12 months after PN (new baseline GFR), and 3, 5, and 10 years after PN. Medians are shown with the width reflecting the number of patients with that GFR.
Our study confirms that parenchymal volume preservation is the main determinant of functional recovery after PN in RMSK. Secondary factors, including type and duration of ischemia and AKI also correlated, although their contributions were less impactful. Our findings suggest multiple opportunities for optimizing functional outcomes after PN. Long-term function generally remains stable after PN for RMSK with dialysis only required in about 5% of patients (See Figure).4
Given the substantially improved tools available and the robust number of patients with RMSK that could be evaluated, we believe this study represents the most comprehensive and informative analysis of functional recovery after PN to date.2,4
Written by: Carlos Munoz-Lopez, Kieran Lewis, and Steven C. Campbell, MD, PhD; Department of Urology, Glickman Urological and Kidney Institute, Cleveland Clinic
Co-Authors: Eran Maina, Worapat Attawettayanon, Akira Kazama; Department of Urology, Glickman Urological and Kidney Institute, Cleveland Clinic
References:
- Yasuda Y, Zhang JH, Attawettayanon W, et al. Comprehensive Management of Renal Masses in Solitary Kidneys. Eur Urol Oncol. Published online December 12, 2022:S2588-9311(22)00201-2.
- Campbell SC, Campbell JA, Munoz-Lopez C, Rathi N, Yasuda Y, Attawettayanon W. Every decade counts: a narrative review of functional recovery after partial nephrectomy. BJU Int. Published online July 14, 2022.
- Munoz-Lopez C, Lewis K, Attawettayanon W, et al. Functional recovery after partial nephrectomy: next generation analysis. BJU Int. Published online April 5, 2023.
- Attawettayanon W, Yasuda Y, Zhang JH, et al. Functional recovery after partial nephrectomy in a solitary kidney. Urol Oncol. Published online December 22, 2023:S1078-1439(23)00467-2.