Impact of tumour morphology on renal function decline after partial nephrectomy

Abstract

Objective• To examine the association of renal morphology with renal function after partial nephrectomy (PN). Patients and Methods• We conducted a multi-institutional retrospective analysis of 322 PNs performed between 2003 and 2011.• The RENAL nephrometry score for each lesion was determined and the estimated glomerular filtration rate (eGFR) was calculated preoperatively and at last follow-up.• We divided patients into two RENAL nephrometry score groups, low (<8) and high (Ն8), and analysed and compared the outcomes of each group. • The primary outcome was median change in eGFR between preoperative and last follow-up (DeGFR). The secondary outcome was eGFR <60 mL/min/1.73m 2 at last follow-up.• Multivariable analysis was conducted to evaluate the risk factors for eGFR <60 mL/min/1.73 m 2 at last follow-up. Results• The median (interquartile range) follow-up was 25.2 (13.5-39.3) months. Low (n = 165) and high (n = 157) RENAL score groups were well-matched for baseline eGFR. The median tumour size (4.2 vs 2.4 cm, P < 0.001) was greater for the high group.• In all, 64% of the low and 88.2% of the high RENAL score group (P < 0.001) had decreased eGFR at last follow-up.• Median eGFR was -7 for the low vs -13.8 mL/min/ 1.73 m 2 for the high group (P = 0.001); eGFR <60 mL/ min/1.73 m 2 at last follow-up was 27.3% for the low vs 37.6% for the high group (P = 0.057).• Linear regression analysis showed that for each 1-point increase in RENAL score, there was 2.5% decrease in eGFR (P = 0.002); for each 1-cm increase in tumour size, there was 1.8% decrease in eGFR (P = 0.013). Area under curve analyses showed no significant difference between RENAL score and tumour size for prediction of de novo eGFR <60 mL/min/1.73 m 2 (P = 0.920) and DeGFR Ն50% (P = 0.85).• Multivariable analysis showed that increasing RENAL score (odds ratio [OR] 1.24, P = 0.046) and decreasing preoperative eGFR (OR 1.10, P < 0.001) were risk factors for eGFR <60 mL/min/1.73 m 2 at last follow-up. Conclusions• Increasing RENAL nephrometry score is an independent risk factor for eGFR <60 mL/min/1.73 m 2 after PN.• RENAL nephrometry score may serve as an additional measure for risk stratification before PN, but further investigation is required.

An Arterial Based Complexity (ABC) Scoring System to Assess the Morbidity Profile of Partial Nephrectomy

“…However, reports have shown each of those systems to be inconsistent in predicting PN outcomes, rendering their universal applicability and reproducibility difficult [4,12,16–18]. The inherent characteristics of existing nephrometry systems may partially be responsible for their limitations.…”

Interobserver variability of R.E.N.A.L., PADUA, and centrality index nephrometry score systems

“…Conflicting studies suggest unresolved aspects of renal nephrometry [9-13], including: 1) determining the level of a reader's clinical expertise and training required for adequate score assignment; 2) choosing the most reliable and clinically relevant system among those available; and 3) identifying truly relevant biometric data to be reported. In an attempt to address these problems, we applied the R.E.N.A.L., the Preoperative Aspects and Dimensions Used for an Anatomical Classification System (PADUA), and the centrality index (C-Index) systems to patients undergoing either open, laparoscopic, or robot-assisted laparoscopic PN at Memorial Sloan Kettering Cancer Center (MSKCC); and evaluated the interobserver variability (IOV) among observers with varying degrees of clinical experience; each system's ability to predict surgical complexity and clinical outcomes; and the clinical relevance of nephrometry subscales.…”

Tumor Anatomy Scoring and Renal Function for Nephron-Sparing Treatment Selection in Patients With Small Renal Masses: A Microsimulation-Based Decision Analysis

“…For patients undergoing partial nephrectomy, renal function decline was determined using published multivariable regression equations, where the estimated GFR decrease was determined as a function of nephrometry score while accounting for potential confounding comorbidities (e.g., hypertension or diabetes) and differences in surgical technique; the predicted functional decline was applied in the model over the time period specified in the source studies, which was approximately 25 months [17,26]. After this time period, the rate of estimated GFR decrease after surgery was equal to that of the general population in this age group [28].…”

“…Furthermore, complex tumor anatomy has been shown to predict renal function loss after partial nephrectomy [17,26]. At the risk of slightly inferior cancer control, thermal ablation theoretically offers superior kidney function benefits by sparing patients potential nephrotoxicity from applied ischemia and loss of normal renal parenchyma.…”

“…The R.E.N.A.L. nephrometry score, introduced by Kutikov and Uzzo [15], was developed by urologists to provide a standardized numeric scale describing the anatomic complexity of a renal mass and has been shown to correlate with perioperative renal function loss, as well as major surgical complications [16,17]. Scoring is based on five anatomic parameters at standard abdominal CT or MRI and, thus, could be easily incorporated into a potential decision-making algorithm along with other oncologic and nononcologic risk factors.…”