Impact of tumour morphology on renal function decline after partial nephrectomy

Associations between R.E.N.A.L. nephrometry score and survival outcomes in renal tumours

OBJECTIVE

The radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry score could be used to predict surgical outcomes and renal tumour aggressiveness. We aimed to analyse its associations with survival outcomes.

METHODS

We included 1368 patients with sporadic, unilateral and non-metastatic renal tumours who received curative nephrectomy in Zhongshan Hospital from January 2009 to September 2019. Radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry scores were assigned by three urologists based on preoperative CT/MRI scans. Correlations between parameters or sum of radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry scores, overall survival and recurrence-free survival were analysed by Kaplan-Meier analyses and the multivariate Cox regression model. We further compared survival outcomes between patients who received partial nephrectomy and patients who received radical nephrectomy.

RESULTS

We observed statistically significant associations between all components of radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry scores and oncologic outcomes, including R (radius) (overall survival, P < 0.001; recurrence-free survival , P < 0.001), E (exophytic/endophytic) (overall survival, P = 0.003; recurrence-free survival, P < 0.001), N (nearness) (overall survival, P = 0.063; recurrence-free survival, P < 0.001), A (anterior/posterior) (overall survival, P < 0.001; recurrence-free survival, P = 0.005), L (location) (overall survival, P = 0.008; recurrence-free survival, P < 0.001) and suffix 'h' (overall survival, P = 0.237; recurrence-free survival, P = 0.034). Kaplan-Meier curves of overall survival and recurrence-free survival rates were significantly different when stratified by radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry score complexity group (overall survival, P < 0.001; recurrence-free survival, P < 0.001). After adjusting for tumour stage and grade, radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry score as continuous variables was an adverse independent risk factor for survival outcomes [P = 0.027, hazard ratio (95% confidence interval) = 1.151 (1.016-1.303)] and recurrence-free survival [P < 0.001, hazard ratio (95% confidence interval) = 1.299 (1.125-1.501)]. For tumours with radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry scores of 4 and 5, partial nephrectomy showed a survival benefit than radical nephrectomy.

CONCLUSION

Both components and complexity groups of the radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry score are associated with survival outcomes in renal tumour patients.

Partial versus radical nephrectomy for complex renal mass: multicenter comparative analysis of functional outcomes (Rosula collaborative group)

BACKGROUND

Utility of partial nephrectomy (PN) for complex renal mass (CRM) is controversial. We determined the impact of surgical modality on postoperative renal functional outcomes for CRM.

METHODS

We retrospectively analyzed a multicenter registry (ROSULA). CRM was defined as RENAL Score 10-12. The cohort was divided into PN and radical nephrectomy (RN) for analyses. Primary outcome was development of de-novo estimated glomerular filtration rate (eGFR)<45 mL/min/1.73 m². Secondary outcomes were de-novo eGFR<60 and ΔeGFR between diagnosis and last follow-up. Cox proportional hazards was used to elucidate predictors for de-novo eGFR<60 and <45. Linear regression was utilized to analyze ΔeGFR. Kaplan-Meier Analysis (KMA) was performed to analyze 5-year freedom from de-novo eGFR<60 and <45.

RESULTS

We analyzed 969 patients (RN=429/PN=540; median follow-up 24.0 months). RN patients had lower BMI (P<0.001) and larger tumor size (P<0.001). Overall postoperative complication rate was higher for PN (P<0.001), but there was no difference in major complications (Clavien III-IV; P=0.702). MVA demonstrated age (HR=1.05, P<0.001), tumor-size (HR=1.05, P=0.046), RN (HR=2.57, P<0.001), and BMI (HR=1.04, P=0.001) to be associated with risk for de-novo eGFR<60 mL/min/1.73 m². Age (HR=1.03, P<0.001), BMI (HR=1.06, P<0.001), baseline eGFR (HR=0.99, P=0.002), tumor size (HR=1.07, P=0.007) and RN (HR=2.39, P<0.001) were risk factors for de-novo eGFR<45 mL/min/1.73 m². RN (B=-10.89, P<0.001) was associated with greater ΔeGFR. KMA revealed worse 5-year freedom from de-novo eGFR<60 (71% vs. 33%, P<0.001) and de-novo eGFR<45 (79% vs. 65%, P<0.001) for RN.

CONCLUSIONS

PN provides functional benefit in selected patients with CRM without significant increase in major complications compared to RN, and should be considered when technically feasible.

Prediction of surgical decision and postoperative renal function using RENAL nephrometry score for localized renal masses: A prospective study

Purpose

The purpose of the study is to assess the value of RENAL nephrometry score (RNS) in predicting surgical decisions, complications, and decreases in kidney function in patients with localized renal tumors.

Methods

Cases with solitary, solid, and enhancing renal masses were included, scheduled for nephron-sparing surgery (NSS), and assessed using routine laboratory and radiological data necessary for calculating the RENAL score. The primary endpoint was conversion to radical nephrectomy (RN), while the secondary endpoint was the prediction of a drop in renal function assessed by postoperative estimated glomerular filtration rate (eGFR) at the last follow-up visit compared with the preoperative values. The association between the scoring system and perioperative outcomes was evaluated.

Results

In all, 84 cases were included, NSS was accomplished in 67 cases while conversion to RN was mandatory in 17 patients, median (interquartile range) RENAL score was 6.2 (4-10) for NSS and 9.7 (6-12) for RN (P < 0.001). Higher grades of complications were observed in the high-complexity subgroup. eGFR was 79.8 that dropped to 75.6 ml/min/1.73 m2 in the late value in patients who underwent NSS, while it was 82.9 that dropped to 58.3 ml/min/1.73 m2 in the late value in patients who converted into RN (P < 0.001). The percentage of drop in eGFR was significantly higher in the moderate and high-risk groups, which was positively correlated with the warm ischemia time. Regression analysis revealed that the continuous RENAL score was a more significant predictor of conversion to RN than tumor size alone. In the 67 NNS cases, the percentage decrease in eGFR was predicted using the continuous RENAL score.

Conclusion

The RNS is a significant predictor of conversion to RN and can predict the percentage decrease in eGFR after NSS. Further investigations and follow-ups are necessary.

Predicting short- and long-term renal function following partial and radical nephrectomy

OBJECTIVES

To externally validate the previously published Mayo clinic model for the prediction of early (<30 days) postoperative renal failure, which relies solely on preoperative estimated glomerular filtration rate (eGFR) and develop a novel model for the prediction of long-term (>30 days) renal function after partial nephrectomy (PN) and radical nephrectomy (RN), including patient factors and nephrometry scores.

PATIENTS AND METHODS

Retrospective, single-center cohort study on patients who underwent PN or RN for a unilateral renal tumor between 2003 and 2019 with a preoperative eGFR of at least 15 ml/min/1.73m². Early postoperative renal failure was defined as eGFR <15 ml/min/1.73 m² or receipt of dialysis within 30 days. We determined the area under the receiver operating characteristics curve (AUC) to assess the Mayo clinic model's discriminative power. We used hierarchical linear mixed models with backward selection of candidate variables to develop a prediction model for long-term eGFR following PN and RN, separately. Their predictive ability was quantified using the marginal and conditional R²_GLMM and an internal validation.

RESULTS

We included 421 patients (7,548 eGFR observations) who underwent PN and 271 patients (6,530 eGFR observations) who underwent RN. The Mayo clinic model for prediction of early postoperative renal failure following PN and RN showed an AUC of 0.816 (95% CI 0.718-0.920) and 0.825 (95% CI 0.688-0.962), respectively. In multivariable models, long-term eGFR following PN was associated with age, diabetes, the presence of a solitary kidney, tumor diameter and preoperative eGFR, while long-term eGFR following RN was associated with age, body mass index, RENAL nephrometry score and preoperative eGFR. Marginal and conditional R²_GLMM were 0.591 and 0.855 for the PN model, and 0.363 and 0.849 for the RN model, respectively.

CONCLUSIONS

The Mayo clinic model for short-term renal failure prediction showed good accuracy on external validation. Our long-term eGFR prediction models depend mostly on host factors as opposed to tumor complexity and can aid in decision-making when considering PN vs. RN.

Comparison of two techniques for the management of 2-3 cm lower pole renal calculi in obese patients

OBJECTIVE

To compare the outcomes of mini percutaneous nephrolithotomy (mPNL) and retrograde intrarenal surgery (RIRS) for the management of 2-3 cm lower pole renal calculi (LPC) in obese patients.

PATIENTS AND METHODS

120 obese patients with 2-3 cm LPC were randomly divided into mPNL group and RIRS group. Demography, clinical characteristics, perioperative complications, and stone free rate (SFR) were recorded. Stone-free status means no stone on computed tomography 3 months after surgery, or residual fragments were less than 3 mm.

RESULTS

Baseline characteristics were similar between the two groups. The mean stone burden was 585.39 ± 131.06 mm² in the mPNL group and 548.64 ± 123.55 mm² in the RIRS group (P = 0.125). The SFR of mPNL group was significantly better than that of RIRS group (86.2% vs 61.4%, P = 0.002). Besides, the overall complication rate was 22.4% in the mPNL group and 7% in the RIRS group (P = 0.02). Patients performed with mPNL required longer length of hospital stay than those with RIRS (P = 0.001). There were no significant differences in operative time and stone composition between the two groups.

CONCLUSION

In our study, both mPNL and RIRS are safe and effective techniques for the treatment of 2-3 cm LPC in obese patients. Compared to RIRS, mPNL has better SFR at the expense of the higher incidence of complications and prolonged length of hospital stay.

Gap between UAS and ureteroscope predicts renal stone-free rate after flexible ureteroscopy with the fragmentation technique

PURPOSE

To assess the effect of our new classification on surgical outcomes after flexible ureteroscopy (fURS) for kidney stones.

METHODS

We retrospectively examined 128 patients after single renal fURS procedures performed using ureteral access sheaths (UASs) with the fragmentation technique. Based on the gap (calculated by subtracting the ureteroscope diameter from the UAS diameter), enrolled patients were divided into three groups: small (< 0.6 mm), medium (0.6 to < 1.2 mm), and large space groups (≥ 1.2 mm). Stone-free (SF) status was defined as either complete absence of stones (SF) or the presence of stones < 4 mm in diameter on non-contrast computed tomography (NCCT).

RESULTS

The SF rate was significantly lower in the small space group (50% in small, 97.9% in medium, 89.2% in large; p = 0.001). Perioperative complications over Clavien-Dindo Grade I were observed in 16.7%, 4.2%, and 8.1% of patients, respectively (p = 0.452). The ratio of stone volume and operative time (efficiency of stone removal) was significantly higher in the large space group compared to the small and medium space groups (0.009 ± 0.003 ml/min, 0.013 ± 0.005 ml/min, 0.027 ± 0.012 ml/min, respectively; p < 0.001).

CONCLUSION

Our findings that gaps > 0.6 mm (1.8 Fr), including the combination of a 9.5-Fr UAS and a small caliber ureteroscope, improve SF rates, and larger gaps facilitate stone removal efficiency providing the basis for future development of clinical protocols aimed at improving outcomes.

MB-FSGAN: Joint segmentation and quantification of kidney tumor on CT by the multi-branch feature sharing generative adversarial network

The segmentation of the kidney tumor and the quantification of its tumor indices (i.e., the center point coordinates, diameter, circumference, and cross-sectional area of the tumor) are important steps in tumor therapy. These quantifies the tumor morphometrical details to monitor disease progression and accurately compare decisions regarding the kidney tumor treatment. However, manual segmentation and quantification is a challenging and time-consuming process in practice and exhibit a high degree of variability within and between operators. In this paper, MB-FSGAN (multi-branch feature sharing generative adversarial network) is proposed for simultaneous segmentation and quantification of kidney tumor on CT. MB-FSGAN consists of multi-scale feature extractor (MSFE), locator of the area of interest (LROI), and feature sharing generative adversarial network (FSGAN). MSFE makes strong semantic information on different scale feature maps, which is particularly effective in detecting small tumor targets. The LROI extracts the region of interest of the tumor, greatly reducing the time complexity of the network. FSGAN correctly segments and quantifies kidney tumors through joint learning and adversarial learning, which effectively exploited the commonalities and differences between the two related tasks. Experiments are performed on CT of 113 kidney tumor patients. For segmentation, MB-FSGAN achieves a pixel accuracy of 95.7%. For the quantification of five tumor indices, the R² coefficient of tumor circumference is 0.9465. The results show that the network has reliable performance and shows its effectiveness and potential as a clinical tool.

Predictive Value of Nephrometry Scores in Nephron-sparing Surgery: A Systematic Review and Meta-analysis

CONTEXT

Over the last decade, several nephrometry scores (NSs) have been introduced with the aim of facilitating preoperative decision making, planning, and counseling in the field of nephron-sparing surgery. However, their predictive role remains controversial.

OBJECTIVE

To describe currently available nephrometry scores and to determine their predictive role for different outcomes by performing a systematic review and meta-analysis of the literature.

EVIDENCE ACQUISITION

PubMed, Embase®, and Web of Science were screened to identify eligible studies. Identification and selection of the reports were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). A pooled analysis of NS predictive role of intraoperative, postoperative, oncological, and functional outcomes was performed. Odds ratio was considered the effect size. All the analyses were performed using Stata 15.0, and statistical significance was set at p≤ 0.05.

EVIDENCE SYNTHESIS

Overall, 51 studies meeting our inclusion criteria were identified and considered for the analysis. Except for one prospective randomized trial, all the studies were retrospective. All the studies were found to be of intermediate quality, except for one of high quality. Most studies assessed the predictive role of the Radius-Exophytic/Endophytic-Nearness-Anterior/Posterior-Location (RENAL) and Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) scores, mostly regarding complications after nephron-sparing surgery. RENAL was an independent predictor of an on-clamp procedure (p< 0.001). Mayo Adhesive Probability score was related to adhesive perinephric fat (p= 0.005). Continuous and high-complexity RENAL scores were predictors of warm ischemia time (WIT; p= 0.006 and p< 0.001, respectively). Continuous (p< 0.001) and high-complexity (p< 0.001) PADUA scores were related to WIT. Continuous and high-complexity RENAL scores were predictors of overall complications (p= 0.002 and p< 0.001, respectively). PADUA score was related to complications both as continuous (p< 0.001) and as a categorical value (p< 0.002). The RENAL scores R=3 (p= 0.008), E=2 (p= 0.039), and hilar location (p= 0.006) were predictors of histological malignancy. Continuous and categorical RENAL scores were independent predictors of an estimated glomerular filtration rate (eGFR) increase (p= 0.006 and p< 0.001, respectively). The Diameter-Axial-Polar score (p= 0.018) and Peritumoral Artery Scoring System (PASS; p= 0.02) were also independent predictors.

CONCLUSIONS

The literature regarding nephrometry scoring systems is sparse, and mostly focused on RENAL and PADUA, which are easy to calculate and have a good correlation with most outcomes. Renal Pelvic Score is the best predictor of pelvicalyceal entry/repair and urine leak, whereas Surgical Approach Renal Ranking and PASS strongly predict surgical approach and renal function variation, respectively. Other nephrometry scores based on mathematical models are limited by their complexity, and they lack evidence supporting their predictive value.

PATIENT SUMMARY

We reviewed the medical literature regarding the use and value of so-called "nephrometry scores," which are scoring systems based on radiological imaging and made to grade the complexity of a renal tumor. We analyzed whether these scoring systems can predict some of the outcomes of patients undergoing surgical removal of renal tumors.

Percutaneous Ablation Versus Robotic Partial Nephrectomy in the Treatment of cT1b Renal Tumors: Oncologic and Functional Outcomes of a Propensity Score-weighted Analysis

INTRODUCTION

The purpose of this study was to assess oncologic and functional outcomes of both percutaneous ablation (cryoablation and radiofrequency ablation) and robot-assisted partial nephrectomy (RAPN) in the treatment of renal tumors larger than 4 cm.

MATERIALS AND METHODS

We retrospectively analyzed prospectively collected data from 102 consecutive patients, who underwent minimally invasive treatment for cT1b renal tumors at our institution. Primary renal function outcome was assessed by estimated glomerular filtration rate preservation at baseline and 1 year postoperatively. Perioperative data and functional and oncologic outcome were collected. Multivariate regression models were used to compare functional outcomes between groups. Cancer-specific survival and recurrence-free survival were estimated at 2 years using the Kaplan-Meier method and compared with Cox proportional hazards regression model to calculate hazard ratios (HRs). To control for selection bias between the different treatments, we adjusted our models with an inverse probability of treatment weighting propensity score.

RESULTS

There was no significant difference in renal preservation between the groups (P = .664). Multivariate analysis did not show a statistically significant difference in terms of renal function outcomes between the RAPN and percutaneous thermal ablation groups. The adjusted HR regarding the local recurrence-free survival was significantly shorter for the cryoablation group (HR, 4.3; 95% confidence interval, 1.78-10.37; P = .001).

CONCLUSIONS

Our study demonstrated the equivalence between RAPN and percutaneous ablative techniques for the preservation of renal function in the treatment of T1b tumors. RAPN offers a better local control than percutaneous ablation, in terms of primary success rate.

Value of Partial Nephrectomy for Renal Cortical Tumors of cT2 or Greater Stage: A Risk-benefit Analysis of Renal Function Preservation Versus Increased Postoperative Morbidity

BACKGROUND

Indications for partial nephrectomy (PN) have expanded to include larger tumors. Compared with radical nephrectomy (RN), PN reduces the risk of chronic kidney disease but is associated with higher morbidity.

OBJECTIVE

To explore whether the benefit of PN (preservation of estimated glomerular filtration rate [eGFR] ≥60ml/min/1.73m² 1yr postoperatively) over RN is offset by higher morbidity for cT2-cT3a tumors.

DESIGN, SETTING, AND PARTICIPANTS

A total of 1921 patients with renal cortical tumors who underwent nephrectomy between 2000 and 2012 were analyzed, with 297 having clinical stage T2 or higher disease.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Multivariable logistic regression models adjusted for age, tumor size, and comorbidities were used to calculate the risk of complications within 90d and the risk of low eGFR across a range of tumor sizes. Models were created separately for RN and PN, and the difference between risk estimates was calculated.

RESULTS AND LIMITATIONS

For tumors with diameters between 7 and 12cm, the risk of eGFR downgrade associated with RN was higher than the risk of complications associated with PN. The magnitude of the risk of eGFR downgrade was similar to the magnitude of complications risk across all tumor sizes. Our analysis was performed at a single institution, and used only tumor size to compare the risk and benefits of surgery.

CONCLUSIONS

Our study suggests that PN is associated with higher eGFR preservation than RN for cT2 or greater renal tumors. The magnitude of this advantage offsets the higher morbidity observed with PN.

PATIENT SUMMARY

When treating a large kidney tumor, it is difficult to decide whether it is better to remove the whole kidney or remove just the tumor. The second option improves postoperative renal function but is more complex. We tried to find whether there is a tumor size at which one technique should be used over the other.

Personalized Treatment for Small Renal Tumors: Decision Analysis of Competing Causes of Mortality

Purpose To compare the effectiveness of personalized treatment for small (≤4 cm) renal tumors versus routine partial nephrectomy (PN), accounting for various competing causes of mortality. Materials and Methods A state-transition microsimulation model was constructed to compare life expectancy of management strategies for small renal tumors by using 1 000 000 simulations in the following ways: routine PN or personalized treatment involving percutaneous ablation for risk factors for worsening chronic kidney disease (CKD), and otherwise PN; biopsy, with triage of renal cell carcinoma (RCC) to PN or ablation depending on risk factors for worsening CKD; active surveillance for growth; and active surveillance when MRI findings are indicative of papillary RCC. Transition probabilities were incorporated from the literature. Effects of parameter variability were assessed in sensitivity analysis. Results In patients of all ages with normal renal function, routine PN yielded the longest life expectancy (eg, 0.67 years in 65-year-old men with nephrometry score [NS] of 4). Otherwise, personalized strategies extended life expectancy versus routine PN: in CKD stages 2 or 3a, moderate or high NS, and no comorbidities, MRI guidance for active surveillance extended life expectancy (eg, 2.60 years for MRI vs PN in CKD 3a, NS 10); and with Charlson comorbidity index of 1 or more, biopsy or active surveillance for growth extended life expectancy (eg, 2.70 years for surveillance for growth in CKD 3a, NS 10). CKD 3b was most effectively managed by using MRI to help predict papillary RCC for surveillance. Conclusion For patients with chronic kidney disease and small renal tumors, personalized treatment selection likely extends life expectancy. © RSNA, 2019 Online supplemental material is available for this article.

DDD score for renal tumor: An intuitive and comprehensive anatomical scoring system to access the outcomes of retroperitoneal laparoscopic partial nephrectomy

OBJECTIVE

To present a DDD scoring system in assessing the complexity and outcomes of retroperitoneoscopic nephron-sparing surgery for kidney tumor.

METHODS

We retrospectively evaluated 232 patients who underwent retroperitoneoscopic nephron-sparing surgery between January 2013 and September 2017 for a renal tumor. Both the DDD score and RENAL score were used to classify the tumors. The DDD score consisted of the maximal tumor diameter inside the kidney, the maximal tumor depth into the medulla or collecting system and the minimal distance from the tumor to the main renal vessels.

RESULTS

The DDD scoring systems were significantly associated with warm ischemia time (P = 0.007) and estimated blood loss (P = 0.017). There was an insignificant positive correlation between the DDD score and the operative time (P = 0.051). Meanwhile, the RENAL score had a significant correlation with the decreasing value of the estimated glomerular filtration rate. Patients with high or moderate DDD scores had a 13.6-fold or 8.4-fold risk of overall complications than those with low DDD scores, respectively (all P < 0.05). As for RENAL score, patients with moderate scores had a 2.9-fold risk of overall complications compared with patients in the low scores group (P = 0.004). In the receiver operating characteristic curve analysis, the DDD score had the greatest area under the curve for overall complications (area under the curve 0.625, P = 0.009), which was more than the RENAL score (area under the curve 0.620, P = 0.013).

CONCLUSIONS

The DDD score is an intuitive renal tumor scoring system that is more effective than the RENAL score in complexity assessment, and marginally better in prediction of the risk of overall complications of retroperitoneal laparoscopic nephron-sparing surgery.

Yonsei nomogram: A predictive model of new-onset chronic kidney disease after on-clamp partial nephrectomy in patients with T1 renal tumors

OBJECTIVES

To develop a predictive nomogram for chronic kidney disease-free survival probability in the long term after partial nephrectomy.

METHODS

A retrospective analysis was carried out of 698 patients with T1 renal tumors undergoing partial nephrectomy at a tertiary academic institution. A multivariable Cox regression analysis was carried out based on parameters proven to have an impact on postoperative renal function. Patients with incomplete data, <12 months follow up and preoperative chronic kidney disease stage III or greater were excluded. The study end-points were to identify independent risk factors for new-onset chronic kidney disease development, as well as to construct a predictive model for chronic kidney disease-free survival probability after partial nephrectomy.

RESULTS

The median age was 52 years, median tumor size was 2.5 cm and mean warm ischemia time was 28 min. A total of 91 patients (13.1%) developed new-onset chronic kidney disease at a median follow up of 60 months. The chronic kidney disease-free survival rates at 1, 3, 5 and 10 year were 97.1%, 94.4%, 85.3% and 70.6%, respectively. On multivariable Cox regression analysis, age (1.041, P = 0.001), male sex (hazard ratio 1.653, P < 0.001), diabetes mellitus (hazard ratio 1.921, P = 0.046), tumor size (hazard ratio 1.331, P < 0.001) and preoperative estimated glomerular filtration rate (hazard ratio 0.937, P < 0.001) were independent predictors for new-onset chronic kidney disease. The C-index for chronic kidney disease-free survival was 0.853 (95% confidence interval 0.815-0.895).

CONCLUSION

We developed a novel nomogram for predicting the 5-year chronic kidney disease-free survival probability after on-clamp partial nephrectomy. This model might have an important role in partial nephrectomy decision-making and follow-up plan after surgery. External validation of our nomogram in a larger cohort of patients should be considered.

Estimated glomerular filtration rate's time to nadir after robot-assisted partial nephrectomy: Predictors and clinical significance on renal functional recovery

OBJECTIVES

To investigate the impact of postoperative time to nadir of estimated glomerular filtration rate on renal functional changes after robot-assisted partial nephrectomy.

METHODS

From 2006 to 2015, 287 patients with renal mass who underwent robot-assisted partial nephrectomy in a referral center were analyzed. The cohort was evaluated based on their time to develop nadir: group 1 (no nadir), group 2 (<48 h) and group 3 (≥48 h). The outcome measures were to evaluate the renal function recovery between groups, risk factors for development of nadir ≥48 h, as well as predictors of chronic kidney disease upstaging.

RESULTS

The mean estimated glomerular filtration rate percentage change was the worst in group 3 compared with groups 1 and 2, with 13.8%, -0.67% and 8%, respectively (P < 0.001). Chronic kidney disease upstaging was more common in group 3 compared with the other groups (P < 0.001). Age, tumor size, PADUA score and warm ischemia time were predictors of developing ≥48 h estimated glomerular filtration rate nadir (odds ratio 1.04, P = 0.002; odds ratio 1.43, P < 0.001; odds ratio 1.24, P = 0.018; odds ratio 1.05, P < 0.001), respectively. The 5-year probability of freedom from chronic kidney disease upstaging was lower in group 3 (75.6%) compared with the other groups - 88.1% and 100% (P = 0.003). Time to nadir ≥48 h was a predictor of chronic kidney disease upstaging (odds ratio 3.02, P = 0.022).

CONCLUSIONS

A continuous decline in estimated glomerular filtration rate (≥48 h) after partial nephrectomy is associated with increased risk of poor functional recovery overtime. Age, tumor size, PADUA score and warm ischemia time are independent predictors of developing ≥48 h time to nadir of estimated glomerular filtration rate. This higher risk subgroup should be targeted for stricter follow up to allow early detection of future risk of renal functional decline.

Kidney, Ureteral, and Bladder Cancer: A Primer for the Internist

Malignancies of the urinary tract (kidney, ureter, and bladder) are distinct clinical entities. Hematuria is a unifying common presenting symptom for these malignancies. Surgical management of localized disease continues to be the mainstay of treatment, and early detection is important in the prognosis of disease. Patients often require life-long follow-up and assessment for recurrence.

Renal Mass and Localized Renal Cancer: AUA Guideline

PURPOSE

This AUA Guideline focuses on evaluation/counseling and management of adult patients with clinically localized renal masses suspicious for cancer, including solid-enhancing tumors and Bosniak 3/4 complex-cystic lesions.

MATERIALS AND METHODS

Systematic review utilized research from the Agency for Healthcare Research and Quality and additional supplementation by the authors and consultant methodologists. Evidence-based statements were based on body of evidence strength Grade A/B/C (Strong/Moderate/Conditional Recommendations, respectively) with additional statements presented as Clinical Principles or Expert Opinions.

RESULTS

Great progress has been made since the previous guidelines on management of localized renal masses were released (2009). The current guidelines provide updated, evidence-based recommendations regarding evaluation/counseling of patients with clinically localized renal masses, including the evolving role of renal mass biopsy. Given great variability of clinical, oncologic and functional characteristics, index patients are not utilized and the panel advocates individualized counseling/management. Management options (partial nephrectomy/radical nephrectomy/thermal ablation/active surveillance) are reviewed including recent data about comparative effectiveness and potential morbidities. Oncologic issues are prioritized while recognizing that functional outcomes are of great importance for survivorship for most patients with localized kidney cancer. A more restricted role for radical nephrectomy is recommended following well-defined selection criteria. Priority for partial nephrectomy is recommended for clinical T1a lesions, along with selective use of thermal ablation, particularly for tumors ≤3.0 cm. Important considerations for shared decision-making about active surveillance are explicitly defined.

CONCLUSIONS

Several factors should be considered during counseling/management of patients with clinically localized renal masses, including general health/comorbidities, oncologic potential of the mass, pertinent functional issues and relative efficacy/potential morbidities of various management strategies.

Body mass index and comorbidity are associated with postoperative renal function after nephrectomy

PURPOSE

To explore the association of body mass index (BMI) and comorbidity with renal function after nephrectomy.

MATERIALS AND METHODS

We retrospectively analyzed 263 patients submitted to partial or radical nephrectomy from 2000-2013. Variables assessed included BMI, Charlson Comorbidity Index (CCI), race, tobacco use, tumor histology, surgical approach, Fuhrman nuclear grade, and tumor (T) classification. Glomerular filtration rate (GFR) was estimated using the Cockroft-Gault equation, adjusted for gender. Logistic regression was performed and included all interaction terms.

RESULTS

Median follow-up was 19.6 months (IQR 5.2, 53.7). Median preoperative GFR was 86.2 mL/min/1.73 m2 and median postoperative GFR was 68.4 mL/min/1.73 m2. BMI (OR 1.07, 95%CI 1.02-1.11), CCI (OR 1.19, 95%CI 1.04-1.37), and radical nephrectomy (OR 3.09, 95%CI 1.51-6.33) were significantly associated with a decline in renal function of ≥ 25%.

CONCLUSION

BMI and CCI are associated with postoperative decline in renal function after nephrectomy. Additionally, radical nephrectomy is significantly associated with decreasing renal function compared to partial nephrectomy. These findings highlight the importance of assessing patient comorbidity in the decision making process for patients presenting with a renal mass.

Percutaneous Renal Biopsies for Small Renal Masses: Complex Tumors on Nephrometry Should Be the First Targets

OBJECTIVE

To assess the diagnostic yield, accuracy, and complications rate for computed tomography (CT)-guided renal biopsies for solid renal masses (SRM); to analyze predictive factors for diagnostic biopsies.

PATIENTS AND METHODS

We performed a single-center, retrospective study based on a pathologic database query for CT-guided, percutaneous renal biopsies. Inclusion criteria included presence of SRM; exclusion criteria included the presence of metastases, non-cT1a or higher cancer (> 4 cm), and non-CT-guided techniques. Of 119 patients who underwent renal biopsies, 40 (34%) were excluded from the study; 79 (66%) biopsy outcomes were analyzed. Clinical, radiologic (RENAL score), and pathologic features were reported. Differences between contributive and noncontributive biopsies were tested with Mann-Whitney U or chi-square tests, as appropriate. Multiple-variable analyses searching for predicting factors of biopsy contribution were performed with binary logistic regressions.

RESULTS

CT-guided renal biopsies for SRM present a high yield (88.6%) and high accuracy for differentiating malignant from benign tumors (96%). They are less accurate for histologic subtype (93%) and unreliable for Fuhrman grading (64%). CT-guided renal biopsy is safe (minor complication rate, 2.5%) and helped prevent unnecessary surgery in 30.4% of the cohort. Tumor complexity with high RENAL score was a predictive factor (P = .02) of contributive biopsy.

CONCLUSION

SRM biopsy is a safe, reliable procedure that can help determine the best treatment strategy for patients. It seems more beneficial for nephrometry complex tumors when surgical extirpation is more likely to be complicated. SRM biopsy might be encouraged in clinical practice for complex tumors.

Recovery of renal function after radical nephrectomy and risk factors for postoperative severe renal impairment: A Japanese multicenter longitudinal study

OBJECTIVES

To investigate longitudinal changes in renal function after radical nephrectomy, and to explore risk factors of postoperative severe renal impairment in a Japanese multicenter cohort.

METHODS

The present retrospective study included 701 patients who had no metastasis, end-stage kidney disease or bilateral kidney cancer, who underwent radical nephrectomy and who were followed up for at least 1 year. The longitudinal change in postoperative renal function during a 10-year follow-up period was evaluated according to the presence or absence of potential risk factors including greater age, chronic kidney disease, hypertension, diabetes mellitus and cardiovascular disease. A slope of annual change in estimated glomerular filtration rate was analyzed using a linear mixed model. Associations between the potential risk factors and a >50% estimated glomerular filtration rate decrease were evaluated using a multivariate Cox regression model.

RESULTS

Overall, the postoperative estimated glomerular filtration rate recovered over time with a significant positive slope of 0.34 mL/min/1.73 m(2)/year. Renal function did not tend to recover in patients with chronic kidney disease, hypertension, diabetes mellitus or cardiovascular disease. The multivariate analysis showed that greater age and diabetes mellitus were independent risk factors for severe renal impairment.

CONCLUSIONS

Overall, patients who had deteriorated renal function immediately after radical nephrectomy recovered over time. However, patients with chronic kidney disease, hypertension, diabetes mellitus and cardiovascular disease did not tend to recover renal function postoperatively. Greater age and diabetes mellitus were independent risk factors for a >50% decrease in estimated glomerular filtration rate.

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

BACKGROUND

Tumor characteristics affect surgical complexity and outcomes of partial nephrectomy (PN).

OBJECTIVE

To develop an Arterial Based Complexity (ABC) scoring system to predict morbidity of PN.

DESIGN, SETTING, AND PARTICIPANTS

Four readers independently scored contrast-enhanced computed tomography images of 179 patients who underwent PN.

INTERVENTION

Renal cortical masses were categorized by the order of vessels needed to be transected/dissected during PN. Scores of 1, 2, 3S, or 3H were assigned to tumors requiring transection of interlobular and arcuate arteries, interlobar arteries, segmental arteries, or in close proximity of the renal hilum, respectively during PN.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Interobserver variability was assessed with kappa values and percentage of exact matches between each pairwise combination of readers. Linear regression was used to evaluate the association between reference scores and ischemia time, estimated blood loss, and estimated glomerular filtration rates at 6 wk and 6 mo after surgery adjusted for baseline estimated glomerular filtration rate. Fisher's exact test was used to test for differences in risk of urinary fistula formation by reference category assignment.

RESULTS AND LIMITATIONS

Pairwise comparisons of readers' score assignments were significantly correlated (all p<0.0001); average kappa = 0.545 across all reader pairs. The average proportion of exact matches was 69%. Linear regression between the complexity score system and surgical outcomes showed significant associations between reference category assignments and ischemia time (p<0.0001) and estimated blood loss (p=0.049). Fisher's exact test showed a significant difference in risk of urinary fistula formation with higher reference category assignments (p=0.028). Limitations include use of a single institutional cohort to evaluate our system.

CONCLUSIONS

The ABC scoring system for PN is intuitive, easy to use, and demonstrated good correlation with perioperative morbidity.

PATIENT SUMMARY

The ABC scoring system is a novel anatomy-reproducible tool developed to help patients and doctors understand the complexity of renal masses and predict the outcomes of kidney surgery.

Outcomes of partial nephrectomy for clinical T1b and T2 renal tumors

PURPOSE OF REVIEW

To review current status of partial nephrectomy for treatment of T1b and T2 renal mass, focusing oncological and renal functional outcomes reported in the last 18 months, and to understand the emerging role of minimally invasive surgery (MIS) techniques in nephron-sparing management of T1b/T2 tumors.

RECENT FINDINGS

With recent long-term oncological equivalence to radical nephrectomy and renal functional benefit, partial nephrectomy is becoming an alternate standard to radical nephrectomy in the management of T1b tumors. The role of partial nephrectomy in nonelective treatment of T2 tumors is more controversial; however, recent publication of two large North American series have added to other contemporary work that suggests oncologic equivalence and renal functional benefit compared to radical nephrectomy in select patients. Emerging data demonstrate feasibility of MIS for increasing the proportion of T1b/T2 tumors; however, recent trends analyses demonstrate that the majority of T1b/T2 partial nephrectomy are still carried out by open surgery, and concerns continue about prolonged ischemic times and risk of bleeding in various MIS settings.

SUMMARY

Management of T1b and T2 renal masses is transforming with adoption of partial nephrectomy as a safe and feasible surgical option with comparable oncological and improved renal function outcomes compared to radical nephrectomy. MIS techniques play an expanding, though still limited, role, and more robust prospective data is requisite before drawing overarching conclusions.

Prediction of complications after partial nephrectomy by RENAL nephrometry score

INTRODUCTION

Discussing and planning the appropriate management for suspicious renal masses can be challenging. With the development of nephrometry scoring methods, we aimed to evaluate the ability of the RENAL nephrometry score to predict both the incidence of postoperative complications and the change in renal function after a partial nephrectomy.

METHODS

This was a retrospective study including 128 consecutive patients who underwent a partial nephrectomy (open and laparoscopic) for renal lesions in a tertiary UK referral centre. Univariate and multivariate ordinal regression models were used to identify associations between Clavien-Dindo classification and explanatory variables. The Kendall rank correlation coefficient was used to examine an association between RENAL nephrometry score and a drop in estimated glomerular filtration rate (eGFR) following surgery.

RESULTS

An increase in the RENAL nephrometry score of one point resulted in greater odds of being in a higher Clavien-Dindo classification after controlling for RENAL suffix and type of surgical procedure (odds ratio [OR]: 1.29, 95% confidence interval [CI]: 1.04-1.64, p=0.043). Furthermore, a patient with the RENAL suffix 'p' (ie posterior location of tumour) had increased odds of developing more serious complications (OR: 2.60, 95% CI: 1.07-6.30, p=0.042). A correlation was shown between RENAL nephrometry score and postoperative drop in eGFR (Kendall's tau coefficient -0.24, p=0.004).

CONCLUSIONS

To our knowledge, this is the first study that has shown the predictive ability of the RENAL nephrometry scoring system in a UK cohort both in terms of postoperative complications and change in renal function.

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

PURPOSE

To assess interobserver variability of R.E.N.A.L., preoperative aspects and dimensions used for an anatomical classification system (PADUA), and centrality index (C-Index) systems among observers with varying degrees of clinical experience and each system's subscale correlation with surgical outcome metrics.

METHODS

Computed tomography images of 90 patients who underwent open, laparoscopic, or robot-assisted laparoscopic partial nephrectomy were scored by one radiology fellow, two urology fellows, one radiology resident, and one secondary school student. Agreement among readers was determined calculating intraclass correlation coefficients. Associations between radiology fellow scores (reference standard as reader with greatest clinical experience), ischemia time, and percent change in postoperative estimated glomerular filtration rate (eGFR) were evaluated using Spearman's correlation.

RESULTS

Agreement using C-Index method (ICC = 0.773) was higher than with PADUA (ICC = 0.677) or R.E.N.A.L (ICC = 0.660). Agreement between reference and secondary school student was lower than with other physicians, although the differences were not statistically significant. The reference's scores were significantly (p < 0.05) associated with ischemia time on all three scoring systems and with percent change in eGFR at 6 weeks using C-Index (p = 0.016). Tumor size, nearness to sinus, and location relative to polar lines (R.E.N.A.L.) and tumor size, renal sinus involvement, and collecting system involvement (PADUA) correlated with ischemia time (all p ≤ 0.001). No R.E.N.A.L. or PADUA subscales significantly correlated with percent change in postoperative eGFR.

CONCLUSIONS

Clinical experience reduces interobserver variability of existing nephrometry systems though not significantly and less so when using directly measureable anatomic variables. Consistently, only measures of tumor size and distance to intrarenal structures were useful in predicting clinically relevant outcomes.