A Nomogram for the Prediction of Intermediate Significant Renal Function Loss After Robot-assisted Partial Nephrectomy for Localized Renal Tumors: A Prospective Multicenter Observational Study (RECORd2 Project)

Minimally invasive transperitoneal partial versus radical nephrectomy in obese patients: perioperative and long-term functional outcomes from a large perspective contemporary series (RECORd2 project)

BACKGROUND

The aim of this study is to evaluate the perioperative and long-term functional outcomes of laparoscopic (LPN) and robot-assisted partial nephrectomy (RAPN) in comparison to laparoscopic radical nephrectomy (LRN) in obese patients diagnosed with renal cell carcinoma.

METHODS

Clinical data of 4325 consecutive patients from The Italian REgistry of COnservative and Radical Surgery for cortical renal tumor Disease (RECORD 2 Project) were gathered. Only patients treated with transperitoneal LPN, RAPN, or LRN with Body Mass Index (BMI) ≥30 kg/m2, clinical T1 renal tumor and preoperative estimated glomerular filtration rate (eGFR) ≥60 mL/min, were included. Perioperative, and long-term functional outcomes were examined.

RESULTS

Overall, 388 patients were included, of these 123 (31.7%), 120 (30.9%) and 145 (37.4%) patients were treated with LRN, LPN, and RAPN, respectively. No significant difference was observed in preoperative characteristics. Overall, intra and postoperative complication rates were comparable among the groups. The LRN group had a significantly increased occurrence of acute kidney injury (AKI) compared to LPN and RAPN (40.6% vs. 15.3% vs. 7.6%, P=0.001). Laparoscopic RN showed a statistically significant higher renal function decline at 60-month follow-up assessment compared to LPN and RAPN. A significant renal function loss was recorded in 30.1% of patients treated with LRN compared to 16.7% and 10.3% of patients treated with LPN and RAPN (P=0.01).

CONCLUSIONS

In obese patients, both LPN and RAPN showcased comparable complication rates and higher renal function preservation than LRN. These findings highlighted the potential benefits of minimally invasive PN over radical surgery in the context of obese individuals.

Impact of chronic kidney disease stages on surgical and functional outcomes in robot-assisted partial nephrectomy for localized renal tumors

The influence of chronic kidney disease stage on robot-assisted partial nephrectomy outcomes remains underexplored. This study aimed to assess the impact of chronic kidney disease stage on functional and surgical outcomes of robot-assisted partial nephrectomy and identify preoperative predictors of significant postoperative 1-year renal-function loss (RFL). Clinical data of 408 patients who underwent robot-assisted partial nephrectomy at Yokohama City University Hospital between 2016 and 2023 were retrospectively reviewed. The da Vinci Surgical System was applied in all patients, and outcomes assessed included surgical parameters, postoperative estimated glomerular filtration rate, trifecta and pentafecta achievements, and complications. Significant RFL was defined as estimated glomerular filtration rate reduction ≥ 25% from baseline. Higher chronic kidney disease stages correlated with older age, hypertension, diabetes, and solitary kidneys. Postoperative estimated glomerular filtration rate decline was most pronounced in patients with chronic kidney disease stages 4-5. Although the chronic kidney disease stage did not significantly affect most surgical parameters, pentafecta achievement was higher in patients with chronic kidney disease stage 3 than in those with stages 4-5. Two patients required hemodialysis after robot-assisted partial nephrectomy. Multivariable logistic regression analysis showed that preoperative hemoglobin level and maximum tumor diameter were significant predictive factors for significant RFL. In conclusion, preoperative CKD stage did not influence on surgical outcome except for pentafecta achievement. RAPN may be feasible for patients with CKD stages 4-5 because of no rapid progression to hemodialysis induction and no procedure-related mortality. Preoperative hemoglobin levels and tumor diameter emerged as predictors of significant RFL.

Development and internal validation of a nomogram predicting 3-year chronic kidney disease upstaging following robot-assisted partial nephrectomy

PURPOSE

Aim of the present study was to develop and validate a nomogram to accurately predict the risk of chronic kidney disease (CKD) upstaging at 3 years in patients undergoing robot-assisted partial nephrectomy (RAPN).

METHODS

A multi-institutional database was queried to identify patients treated with RAPN for localized renal tumor (cT1-cT2, cN0, cM0). Significant CKD upstaging (sCKD-upstaging) was defined as development of newly onset CKD stage 3a, 3b, and 4/5. Model accuracy was calculated according to Harrell C-index. Subsequently, internal validation using bootstrapping and calibration was performed. Then nomogram was depicted to graphically calculate the 3-year sCKD-upstaging risk. Finally, regression tree analysis identified potential cut-offs in nomogram-derived probability. Based on this cut-off, four risk classes were derived with Kaplan-Meier analysis tested this classification.

RESULTS

Overall, 965 patients were identified. At Kaplan-Meier analysis, 3-year sCKD-upstaging rate was 21.4%. The model included baseline (estimated glomerular filtration rate) eGFR, solitary kidney status, multiple lesions, R.E.N.A.L. nephrometry score, clamping technique, and postoperative acute kidney injury (AKI). The model accurately predicted 3-year sCKD-upstaging (C-index 84%). Based on identified nomogram cut-offs (7 vs 16 vs 26%), a statistically significant increase in sCKD-upstaging rates between low vs intermediate favorable vs intermediate unfavorable vs high-risk patients (1.3 vs 9.2 vs 22 vs 54.2%, respectively, p < 0.001) was observed.

CONCLUSION

Herein we introduce a novel nomogram that can accurately predict the risk of sCKD-upstaging at 3 years. Based on this nomogram, it is possible to identify four risk categories. If externally validated, this nomogram may represent a useful tool to improve patient counseling and management.

Practical Prediction of New Baseline Renal Function After Partial Nephrectomy

BACKGROUND

Partial nephrectomy (PN) is generally preferred for localized renal masses due to strong functional outcomes. Accurate prediction of new baseline glomerular filtration rate (NBGFR) after PN may facilitate preoperative counseling because NBGFR may affect long-term survival, particularly for patients with preoperative chronic kidney disease. Methods for predicting parenchymal volume preservation, and by extension NBGFR, have been proposed, including those based on contact surface area (CSA) or direct measurement of tissue likely to be excised/devascularized during PN. We previously reported that presuming 89% of global GFR preservation (the median value saved from previous, independent analyses) is as accurate as the more subjective/labor-intensive CSA and direct measurement approaches. More recently, several promising complex/multivariable predictive algorithms have been published, which typically include tumor, patient, and surgical factors. In this study, we compare our conceptually simple approach (NBGFRPost-PN = 0.90 × GFRPre-PN) with these sophisticated algorithms, presuming that an even 90% of the global GFR is saved with each PN.

PATIENTS AND METHODS

A total of 631 patients with bilateral kidneys who underwent PN at Cleveland Clinic (2012-2014) for localized renal masses with available preoperative/postoperative GFR were analyzed. NBGFR was defined as the final GFR 3-12 months post-PN. Predictive accuracies were assessed from correlation coefficients (r) and mean squared errors (MSE).

RESULTS

Our conceptually simple approach based on uniform 90% functional preservation had equivalent r values when compared with complex, multivariable models, and had the lowest degree of error when predicting NBGFR post-PN.

CONCLUSIONS

Our simple formula performs equally well as complex algorithms when predicting NBGFR after PN. Strong anchoring by preoperative GFR and minimal functional loss (≈ 10%) with the typical PN likely account for these observations. This formula is practical and can facilitate counseling about expected postoperative functional outcomes after PN.

A new machine-learning model to predict long-term renal function impairment after minimally invasive partial nephrectomy: the Fundació Puigvert predictive model

PURPOSE

To provide a new model to predict long-term renal function impairment after partial nephrectomy (PN).

METHODS

Data of consecutive patients who underwent minimally invasive PN from 2005 to 2022 were analyzed. A minimum of 12 months of follow-up was required. We relied on a machine-learning algorithm, namely classification and regression tree (CART), to identify the predictors and associated clusters of chronic kidney disease (CKD) stage migration during follow-up.

RESULTS

568 patients underwent minimally invasive PN at our center. A total of 381 patients met our inclusion criteria. The median follow-up was 69 (IQR 38-99) months. A total of 103 (27%) patients experienced CKD stage migration at last follow-up. Progression of CKD stage after surgery, ACCI and baseline CKD stage were selected as the most informative risk factors to predict CKD progression, leading to the creation of four clusters. The progression of CKD stage rates for cluster #1 (no progression of CKD stage after surgery, baseline CKD stage 1-2, ACCI 1-4), #2 (no progression of CKD stage after surgery, baseline CKD stage 1-2, ACCI ≥ 5), #3 (no progression of CKD stage after surgery and baseline CKD stage 3-4-5) and #4 (progression of CKD stage after surgery) were 6.9%, 28.2%, 37.1%, and 69.6%, respectively. The c-index of the model was 0.75.

CONCLUSION

We developed a new model to predict long-term renal function impairment after PN where the perioperative loss of renal function plays a pivotal role to predict lack of functional recovery. This model could help identify patients in whom functional follow-up should be intensified to minimize possible worsening factors of renal function.

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.

Estimating Postoperative Renal Function After Surgery for Nonmetastatic Renal Masses: A Systematic Review of Available Prediction Models

CONTEXT

A variety of models predicting postoperative renal function following surgery for nonmetastatic renal tumors have been reported, but their validity and clinical usefulness have not been formally assessed.

OBJECTIVE

To summarize prediction models available for estimation of mid- to long-term (>3 mo) postoperative renal function after partial nephrectomy (PN) or radical nephrectomy (RN) for nonmetastatic renal masses that include only preoperative or modifiable intraoperative variables.

EVIDENCE ACQUISITION

A systematic review of the English-language literature was conducted using the MEDLINE, Embase, and Web of Science databases from January 2000 to March 2022 according to the PRISMA guidelines (PROSPERO ID: CRD42022303492). Risk of bias was assessed according to the Prediction Model Study Risk of Bias Assessment Tool.

EVIDENCE SYNTHESIS

Overall, 21 prediction models from 18 studies were included (nine for PN only; eight for RN only; four for PN or RN). Most studies relied on retrospective patient cohorts and had a high risk of bias and high concern regarding the overall applicability of the proposed model. Patient-, kidney-, surgery-, tumor-, and provider-related factors were included among the predictors in 95%, 86%, 100%, 61%, and 0% of the models, respectively. All but one model included both patient age and preoperative renal function, while only a few took into account patient gender, race, comorbidities, tumor size/complexity, and surgical approach. There was significant heterogeneity in both the model building strategy and the performance metrics reported. Five studies reported external validation of six models, while three assessed their clinical usefulness using decision curve analysis.

CONCLUSIONS

Several models are available for predicting postoperative renal function after kidney cancer surgery. Most of these are not ready for routine clinical practice, while a few have been externally validated and might be of value for patients and clinicians.

PATIENT SUMMARY

We reviewed the tools available for predicting kidney function after partial or total surgical removal of a kidney for nonmetastatic cancer. Most of the models include patient and kidney characteristics such as age, comorbidities, and preoperative kidney function, and a few also include tumor characteristics and intraoperative variables. Some models have been validated by additional research groups and appear promising for improving counseling for patients with nonmetastatic cancer who are candidates for surgery.

Validation of new baseline renal function predictive model in robotic-assisted partial nephrectomy cohort

OBJECTIVE

To validate a new baseline estimated glomerular filtration rate (NB-GFR) formula in a cohort of robotic-assisted partial nephrectomies (RAPN).

METHODS

NB-GFR = 35 + preoperative GFR (× 0.65) - 18 (if radical nephrectomy) - age (× 0.25) + 3 (if tumor size >7 cm) - 2 (if diabetes). NB-GFR was calculated in 464 consecutive RAPN from a single surgeon cohort. 143 patients were excluded secondary to insufficient eGFR follow up. We analyzed NB-GFR accuracy utilizing the last observed eGFR 3-12 months post RAPN. Categorical variables were summarized with the frequency and percentage of patients. Numerical variables were summarized with the median, 25^th percentile, and 75^th percentile.

RESULTS

The mean difference between observed and predicted NB-GFR was 4.6 ml/min/1.73m² (95% CI -6.9 to 16.1 ml/min/1.73m² ). There was a pattern of higher observed NB-GFRs being underestimated by the NB-GFR equation while lower observed NB-GFRs were overestimated by the NB-GFR equation. The NB-GFR formula had a high level of accuracy with 98.8% of predicted NB-GFRs falling within 30% of the observed NB-GFR (95% CI 86.8% to 99.5%). The median and interquartile range of the difference between observed and predicted NB-GFR was 3.9 ml/min/1.73m² (IQR 0.7 to 8.2 ml/min/1.73m² ). The sensitivity, specificity, positive predictive value, and negative predictive value for the ability of predicted NB-GFR to identify those with an observed NB-GFR <60 ml/min/1.73m² after RAPN was 98%, 92%, 88%, and 99%, respectively.

CONCLUSION

The NB-GFR equation developed with partial and radical nephrectomy cohorts is accurate in predicting post-operative eGFR 3-12 months following RAPN.

Development and Validation of a Nomogram Predicting Intraoperative Adverse Events During Robot-assisted Partial Nephrectomy

BACKGROUND

Ability to predict the risk of intraoperative adverse events (IOAEs) for patients undergoing partial nephrectomy (PN) can be of great clinical significance.

OBJECTIVE

To develop and internally validate a preoperative nomogram predicting IOAEs for robot-assisted PN (RAPN).

DESIGN, SETTING, AND PARTICIPANTS

In this observational study, data for demographic, preoperative, and postoperative variables for patients who underwent RAPN were extracted from the Vattikuti Collective Quality Initiative (VCQI) database.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

IOAEs were defined as the occurrence of intraoperative surgical complications, blood transfusion, or conversion to open surgery/radical nephrectomy. Backward stepwise logistic regression analysis was used to identify predictors of IOAEs. The nomogram was validated using bootstrapping, the area under the receiver operating characteristic curve (AUC), and the goodness of fit. Decision curve analysis (DCA) was used to determine the clinical utility of the model.

RESULTS AND LIMITATIONS

Among the 2114 patients in the study cohort, IOAEs were noted in 158 (7.5%). Multivariable analysis identified five variables as independent predictors of IOAEs: RENAL nephrometry score (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.02-1.25); clinical tumor size (OR 1.01, 95% CI 1.001-1.024); PN indication as absolute versus elective (OR 3.9, 95% CI 2.6-5.7) and relative versus elective (OR 4.2, 95% CI 2.2-8); Charlson comorbidity index (OR 1.17, 95% CI 1.05-1.30); and multifocal tumors (OR 8.8, 95% CI 5.4-14.1). A nomogram was developed using these five variables. The model was internally valid on bootstrapping and goodness of fit. The AUC estimated was 0.76 (95% CI 0.72-0.80). DCA revealed that the model was clinically useful at threshold probabilities >5%. Limitations include the lack of external validation and selection bias.

CONCLUSIONS

We developed and internally validated a nomogram predicting IOAEs during RAPN.

PATIENT SUMMARY

We developed a preoperative model than can predict complications that might occur during robotic surgery for partial removal of a kidney. Tests showed that our model is fairly accurate and it could be useful in identifying patients with kidney cancer for whom this type of surgery is suitable.

Estimated Glomerular Filtration Rate Decline at 1 Year After Minimally Invasive Partial Nephrectomy: A Multimodel Comparison of Predictors

Background

Long-term renal function after partial nephrectomy (PN) is difficult to predict as it is influenced by several modifiable and nonmodifiable variables, often intertwined in complex relations.

Objective

To identify variables influencing long-term renal function after PN and to assess their relative weight.

Design, setting, and participants

A total of 457 patients who underwent either robotic (n = 412) or laparoscopic PN (n = 45) were identified from a multicenter international database.

Outcome measurements and statistical analysis

The 1-yr estimated glomerular filtration rate (eGFR) percentage loss (1YPL), defined as the eGFR percentage change from baseline at 1 yr after surgery, was the outcome endpoint. Predictors evaluated included demographic data, tumor features, and operative and postoperative variables. Bayesian multimodel analysis of covariance was used to build all possible models and compare the fit of each model to the data via model Bayes factors. Bayesian model averaging was used to quantify the support for each predictor via the inclusion Bayes factor (BF_incl). High-dimensional undirected graph estimation was used for network analysis of conditional independence between predictors.

Results and limitations

Several models were found to be plausible for estimation of 1YPL. The best model, comprising postoperative eGFR percentage loss (PPL), sex, ischemia technique, and preoperative eGFR, was 207 times more likely than all the other models regarding relative predictive performance. Its components were part of the top 44 models and were the predictors with the highest BF_incl. The role of cold ischemia, solitary kidney status, surgeon experience, and type of renorraphy was not assessed.

Conclusions

Preoperative eGFR, sex, ischemia technique, and PPL are the best predictors of eGFR percentage loss at 1 yr after minimally invasive PN. Other predictors seem to be irrelevant, as their influence is insignificant or already nested in the effect of these four parameters.

Patient summary

Kidney function at 1 year after partial removal of a kidney depends on sex, the technique used to halt blood flow to the kidney during surgery, and kidney function at baseline and in the early postoperative period.

Prediction of significant renal function decline after open, laparoscopic, and robotic partial nephrectomy: External validation of the Martini's nomogram on the RECORD2 project cohort

OBJECTIVES

Martini et al. developed a nomogram to predict significant (>25%) renal function loss after robot-assisted partial nephrectomy and identified four risk categories. We aimed to externally validate Martini's nomogram on a large, national, multi-institutional data set including open, laparoscopic, and robot-assisted partial nephrectomy.

METHODS

Data of 2584 patients treated with partial nephrectomy for renal masses at 26 urological Italian centers (RECORD2 project) were collected. Renal function was assessed at baseline, on third postoperative day, and then at 6, 12, 24, and 48 months postoperatively. Multivariable models accounting for variables included in the Martini's nomogram were applied to each approach predicting renal function loss at all the specific timeframes.

RESULTS

Multivariable models showed high area under the curve for robot-assisted partial nephrectomy at 6- and 12-month (87.3% and 83.6%) and for laparoscopic partial nephrectomy (83.2% and 75.4%), whereas area under the curves were lower in open partial nephrectomy (78.4% and 75.2%). The predictive ability of the model decreased in all the surgical approaches at 48 months from surgery. Each Martini risk group showed an increasing percentage of patients developing a significant renal function reduction in the open, laparoscopic and robot-assisted partial nephrectomy group, as well as an increased probability to develop a significant estimated glomerular filtration rate reduction in the considered time cutoffs, although the predictive ability of the classes was <70% at 48 months of follow-up.

CONCLUSIONS

Martini's nomogram is a valid tool for predicting the decline in renal function at 6 and 12 months after robot-assisted partial nephrectomy and laparoscopic partial nephrectomy, whereas it showed a lower performance at longer follow-up and in patients treated with open approach at all these time cutoffs.

Partial and Radical Nephrectomy Provides Equivalent Oncologic Outcomes in pT3a Renal Cell Carcinoma: A Population-Based Study

Purpose

To compare the cause-specific survival (CSS) and overall survival (OS) of patients with localized T3a renal cell carcinoma (RCC) after partial nephrectomy (PN) or radical nephrectomy (RN).

Methods

We obtained the demographic and clinicopathological data of 7,127 patients with localized T3a RCC and who underwent PN or RN from the Surveillance, Epidemiology, and End Results (SEER) database. These patients were divided into fat invasion cohort and venous invasion cohort for subsequent analysis. Kaplan–Meier analysis (KMA) and univariate and multivariate Cox proportional hazards regression analyses were used to evaluate the effects of PN or RN on OS and CSS. Meanwhile, 65 cases with clinical T1 (cT1) RCC upstaged to pathological T3a (pT3a) who were treated in Tongji Hospital (TJH) from 2011 to 2020 and underwent PN or RN were identified.

Results

In the study cohort, 2,085 (29.3%) patients died during the 1–172 months’ follow-up, of whom 1,155 (16.2%) died of RCC. In the two cohorts of fat invasion and venous invasion, KMA indicated that the PN group had favorable survival (p < 0.001). However, after propensity score matching (PSM), univariate and multivariate Cox regression analyses showed that the PN and RN groups had comparable CSS in the fat invasion cohort (p = 0.075) and the venous invasion cohort (p = 0.190). During 1–104 months of follow-up, 9 cases in the Tongji cohort had disease recurrence. There was no significant difference in recurrence-free survival between the RN group and the PN group (p = 0.170).

Conclusions

Our analysis showed that after balancing these factors, patients with localized pT3a RCC receiving PN or RN can achieve comparable oncologic outcomes. PN is safe for selected T3a patients.