Longitudinal Change in Renal Function After Radical Nephrectomy in Japanese Patients With Renal Cortical Tumors

Machine learning models for predicting the onset of chronic kidney disease after surgery in patients with renal cell carcinoma

BACKGROUND

Patients with renal cell carcinoma (RCC) have an elevated risk of chronic kidney disease (CKD) following nephrectomy. Therefore, continuous monitoring and subsequent interventions are necessary. It is recommended to evaluate renal function postoperatively. Therefore, a tool to predict CKD onset is essential for postoperative follow-up and management.

METHODS

We constructed a cohort using data from eight tertiary hospitals from the Korean Renal Cell Carcinoma (KORCC) database. A dataset of 4389 patients with RCC was constructed for analysis from the collected data. Nine machine learning (ML) models were used to classify the occurrence and nonoccurrence of CKD after surgery. The final model was selected based on the area under the receiver operating characteristic (AUROC), and the importance of the variables constituting the model was confirmed using the shapley additive explanation (SHAP) value and Kaplan-Meier survival analyses.

RESULTS

The gradient boost algorithm was the most effective among the various ML models tested. The gradient boost model demonstrated superior performance with an AUROC of 0.826. The SHAP value confirmed that preoperative eGFR, albumin level, and tumor size had a significant impact on the occurrence of CKD after surgery.

CONCLUSIONS

We developed a model to predict CKD onset after surgery in patients with RCC. This predictive model is a quantitative approach to evaluate post-surgical CKD risk in patients with RCC, facilitating improved prognosis through personalized postoperative care.

Incidence, risk factors, and significance of 20% decrease from new baseline estimated glomerular filtration rate after radical and partial nephrectomy within 2 years

OBJECTIVES

To evaluate the incidence and risk factors of a 20% decrease from new baseline (NB)-estimated glomerular filtration rate (eGFR) within 2 years after radical nephrectomy (RN) and partial nephrectomy (PN) and to examine the difference in the incidence of end-stage renal disease (ESRD) with or without the 20% decrease.

METHODS

This retrospective study included 238 patients undergoing RN and 369 undergoing PN for cT1a-cT3a renal cancer. The incidence of a 20% decrease from NB-eGFR within 2 years after RN/PN was examined and its potential risk factors including surgery type were assessed by multivariate logistic regression analysis. The development of ESRD was analyzed as an endpoint and its incidence was compared according to the presence or absence of the 20% decrease from NB-eGFR within 2 years.

RESULTS

Overall, the 20% decrease from NB-eGFR within 2 years was observed in 37 patients (6.1%), including 10 (4.2%) and 27 (7.3%) after RN and PN, respectively (p = 0.117). Diabetes mellitus, proteinuria, and perioperative complications were shown to be independent risk factors for the 20% decrease from NB-eGFR, while surgery type was not. During the median follow-up of 65 months, the ESRD-free survival rate at 6 years was 75.5% and 99.6% in patients with and without the 20% decrease from NB-eGFR, respectively (p < 0.001), while no significant difference was observed between patients undergoing RN and PN (98.1% and 98.7%, p = 0.561).

CONCLUSIONS

Because the incidence of ESRD after the 20% decrease from NB-eGFR within 2 years was as high as 24.5% at 6 years, these patients should be followed with utmost care.

The incidence and risk factors of chronic kidney disease after radical nephrectomy in patients with renal cell carcinoma

Background

Radical nephrectomy (RN) is the standard treatment for localized renal cell carcinoma. The decrease in nephrons from RN could lead to postoperative chronic kidney disease (CKD). In this study, we aim to investigate the incidence and risk factors for CKD in patients who have received RN.

Methods

A Total of 1233 patients underwent radical nephrectomy in Zhejiang Provincial People’s Hospital from January 2010 to December 2018. Those who had an abnormal renal function before surgery or were lost to follow-up were excluded. Five hundred patients were enrolled in the end. eGFR was calculated using the abbreviated MDRD equation. CKD was defined as eGFR less than 60 ml/min/1.73m². The incidence of postoperative CKD was estimated using the Kaplan-Meier method. The independent risk factors for CKD occurrence were determined through logistic multivariate regression analysis.

Results

Patients were followed up for a median of 40 month (3–96 months), with CKD occurring in 189 cases. The 5-year cumulative incidence of CKD was 43.4%. There was a significant difference between these189 patients and the remaining patients without post nephrectomy CKD in terms of age, sex, weight, and preoperative eGFR(P<0.05). Multivariate regression analysis showed that age (OR = 1.038, 95%CI = 1.002–1.076), preoperative eGFR of the contralateral kidney (OR = 0.934, 95%CI = 0.884–0.988) and Immediate postoperative eGFR (OR = 0.892, 95%CI = 0.854–0.931) were independent risk factors for postoperative CKD.

Conclusions

The incidence of CKD after radical nephrectomy was not uncommon. Age, preoperative eGFR of the contralateral kidney and Immediate postoperative eGFR are independent risk factors for postoperative CKD.

Comparison of Risk Factors for the Development of Proteinuria After Radical Nephrectomy for Renal Cell Carcinoma

Purpose

We investigated compensatory structural hypertrophy and functional hyperfiltration in patients with renal cell carcinoma (RCC) after radical nephrectomy (RN) according to the presence of proteinuria.

Patients and Methods

We retrospectively enrolled 471 patients who underwent RN for RCC between October 2005 and December 2013. These patients were divided into two groups according to the presence of postoperative proteinuria (trace or greater (≥1+) urine dipstick). We obtained computed tomography images before and 1 year after surgery to calculate the functional renal volume (FRV). The preoperative and postoperative Chronic Kidney Disease Epidemiology Collaboration equation-calculated glomerular filtration rates (CKD-EPI GFRs) per unit FRV (GFR/FRV) were used to calculate the degree of hyperfiltration.

Results

The mean patient age was 54.7±11.1 years, and the mean preoperative CKD-EPI GFR, FRV, and GFR/FRV were 89.3±13.3 mL/min/1.73 m², 357.2±71.8 cm³, and 0.26±0.05 mL/min/1.73 m²/cm³, respectively. The percentage reduction rate of the GFR was not significantly different according to the presence of proteinuria (normal: −28.5±11.6% vs proteinuria: −28.7±15%; p=0.902); however, the postoperative hypertrophic FRV in the remnant kidney was significantly different (normal: 17.5±9.1% vs proteinuria: 13.8±14.1%; p=0.001). Meanwhile, the change in the percentage rate of the GFR/FRV was not significantly different (normal: 21.1±23% vs proteinuria: 23.8±28.3%; p=0.324). Multivariate logistic regression analysis revealed that age (p=0.010) and the GFR/FRV (p<0.001) were significant predictors of postoperative proteinuria.

Conclusion

Compensatory structural hypertrophy and functional hyperfiltration are positive adaptations that reduce the occurrence of proteinuria.

Acute kidney injury after nephrectomy: a new nomogram to predict postoperative renal function

Background

We aimed to develop a nomogram based on preprocedural features for early prediction of acute kidney injury (AKI) and to assess the prognosis in patients after radical and partial nephrectomy.

Methods

The study included a development cohort of 1111 patients who were treated between June 2012 and June 2017 and an additional validation cohort of 356 patients who were treated between July 2017 and June 2018. Stepwise regression and logistic regression analyses were used to evaluate the association between predictors and AKI. Incorporating all independent predictors, a nomogram for postoperative AKI was developed and externally validated. Patients were followed up for 5 years to assess renal function, acute kidney disease (AKD), chronic kidney disease (CKD), hospital readmission and mortality were key prognosis we focused on.

Results

After multivariate logistic regression, radical nephrectomy (odds ratio (OR) = 3.57, p < 0.001), aspirin (OR = 1.79, p = 0.008), systolic blood pressure (OR = 1.41, p = 0.004), triglyceride (OR = 1.26, p = 0.024), and alkaline phosphatase (OR = 1.75, p = 0.034) were independent risk factors for postoperative AKI, while albumin (OR = 0.72, p = 0.031) was a protective factor for postoperative AKI. Patients with a higher estimated glomerular filtration rate (eGFR) (60–90 ml/min/1.73 m², OR = 0.41, p = 0.004; ≥ 90 ml/min/1.73 m², OR = 0.37, p < 0.001) were less prone to AKI than those with a lower eGFR (< 15 ml/min/1.73 m²). These predictors were all included in the final nomogram. The area under the receiver operating characteristics curve for the model were 0.77 (p < 0.001) in the development cohort and 0.72 (p < 0.001) in the validation cohort. The incidence of AKD and CKD were 27.12 and 18.64% in AKI group, which were much higher than those in no AKI group (p < 0.001).

Conclusions

The nomogram had excellent predictive ability and might have significant clinical implications for the early detection of AKI in patients undergoing nephrectomy.

Robust Association between Acute Kidney Injury after Radical Nephrectomy and Long-term Renal Function

The association between acute kidney injury (AKI) and long-term renal function after radical nephrectomy has not been evaluated fully. We reviewed 558 cases of radical nephrectomy. Postoperative AKI was defined by the Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria. Values of estimated glomerular filtration rate (eGFR) were collected up to 36 months (median 35 months) after surgery. The primary outcome was new-onset chronic kidney disease (CKD) stage 3a or higher or all-cause mortality within three years after nephrectomy. The functional change ratio (FCR) of eGFR was defined as the ratio of the most recent GFR (24-36 months after surgery) to the new baseline during 3-12 months. A multivariable Cox proportional hazard regression analysis for new-onset CKD and a multivariable linear regression analysis for FCR were performed to evaluate the association between AKI and long-term renal outcomes. A correlation analysis was performed with the serum creatinine ratio and used to determine AKI and FCR. AKI occurred in 43.2% (n = 241/558) and our primary outcome developed in 40.5% (n = 226/558) of patients. The incidence of new-onset CKD was significantly higher in patients with AKI than those without at all follow-up time points after surgery. The Cox regression analysis showed a graded association between AKI and our primary outcome (AKI stage 1: Hazard ratio 1.71, 95% confidence interval 1.25-2.32; AKI stage 2 or 3: Hazard ratio 2.72, 95% confidence interval 1.78-4.10). The linear regression analysis for FCR showed that AKI was significantly associated with FCR (β = -0.168 ± 0.322, p = 0.011). There was a significant negative correlation between the serum creatinine ratio and FCR. In conclusion, our analysis demonstrated a robust and graded association between AKI after radical nephrectomy and long-term renal functional deterioration.

The effect of renal function change on renal cell carcinoma patients with tumor thrombus after nephrectomy and thrombectomy: a large Chinese center experience

Background

To explore the influencing factors of perioperative renal function change and their relationship with prognosis on renal cell carcinoma (RCC) patients with tumor thrombus after nephrectomy and thrombectomy.

Methods

The clinical and pathological data of 135 patients with RCC and tumor thrombus, who underwent nephrectomy and thrombectomy at Peking University Third Hospital from May 2015 to July 2018, was retrospectively analyzed. Absolute change in estimated glomerular filtration rate (eGFR) (ACE) and percent change in eGFR (PCE) were calculated by preoperative and postoperative renal function. Linear regression analysis was used to explore the influencing factors of ACE and PCE, and logistic regression analysis was used to explore the influencing factors of worse postoperative renal function [eGFR≤60 mL/(min × 1.73 m^2)]. Cancer-specific survival (CSS) was estimated by Kaplan-Meier method and multivariate Cox regression, which were used to explore the effect of ACE and PCE on prognosis.

Results

Of all the 135 patients, 101 patients (74.8%) were male and 34 patients (25.2%) were female. The mean preoperative eGFR was 73.9 ± 21.8 mL/(min × 1.73 m^2) and postoperative eGFR was 69.5 ± 25.2 mL/(min × 1.73 m^2). In multivariate linear regression analysis, preoperative eGFR (P < 0.001) and pathological type (P = 0.038) were significant predictive factors of ACE. In aspect of PCE, preoperative eGFR (P < 0.001) and pathological type (P = 0.002) were significant predictors. In multivariate logistic regression analysis, preoperative eGFR (P = 0.016) was the only risk factor of predicting worse postoperative renal function. During follow-up, 22 patients (16.3%) were dead due to RCC. According to ROC analysis, the cut off value of ACE and PCE was 13.9 and 0.16, respectively. ACE> 13.9 and PCE > 0.16 indicated worse CSS (P = 0.006 and P = 0.047, respectively). However, in multivariate Cox regression analysis of several related factors, perinephric tissues invasion (P = 0.001), sarcomatoid differentiation (P = 0.001) and ACE> 13.9 (P = 0.002) were significant prognostic factors for CSS. PCE > 0.16 seemed to be not (P = 0.055).

Conclusion

We explored several clinicopathological risk factors of predicting renal function change and their relationship with prognosis of RCC patients with tumor thrombus after nephrectomy and thrombectomy. The renal function change, which was associated with preoperative eGFR and pathological type, was prognostic risk factor for CSS and ACE> 13.9 indicated the worse prognosis.

Efficacy and safety of sorafenib for advanced renal cell carcinoma: real-world data of patients with renal impairment

Background

We retrospectively analysed the efficacy and safety of sorafenib in patients with advanced renal cell carcinoma with renal impairment.

Methods

Patients were divided into two groups by an estimated glomerular filtration rate (eGFR) cut-off of 45 mL/min/1.73 m². Background factors considered to affect prognosis were well balanced by propensity score matching between the groups. Demographics, dose modification, adverse events, tumour response, progression-free survival, and renal function (eGFR) were evaluated.

Results

Among 935 and 2008 patients with an eGFR of <45 and ≥45, respectively, 613 pairs were matched. The mean starting dose was significantly lower in patients with an eGFR of <45; however, the mean daily dose, median treatment duration, progression-free survival, and tumour response were similar between the groups. In terms of safety, no significant differences were found in serious adverse events, although cytopaenia (16.6% vs 10.6%) and renal dysfunction (4.4% vs 0.7%) were higher in patients with an eGFR of <45 than ≥45 in all adverse events. There were also no differences in dose modification, including dose reduction, dose interruption, and treatment discontinuation.

Conclusion

Throughout the 12-month observation period, sorafenib in patients with an eGFR of <45 and ≥45 showed similar safety and efficacy, and treatment was continued without affecting renal function.

Partial nephrectomy for T3aN0M0 renal cell carcinoma: shall we step forward?

Objectives:

To evaluate the prognosis of non-metastatic T3a renal cell carcinoma (RCC) with partial nephrectomy (PN).

Patients and Methods:

We retrospectively evaluated 125 patients with non-metastatic T3a RCC. Patients undergoing PN and radical nephrectomy (RN) were strictly matched by clinic-pathologic characteristics. Log-rank test and Cox regression model were used for univariate and multivariate analysis.

Results:

18 pair patients were matched and the median follow-up was 35.5 (10-86) months. PN patients had a higher postoperative eGFR than RN patients (P=0.034). Cancer-specific survival (CSS) and recurrence-free survival (RFS) did not differ between two groups (P=0.305 and P=0.524). On multivariate analysis, CSS decreased with positive surgical margin and anemia (both P <0.01) and RFS decreased with Furhman grade, positive surgical margin, and anemia (all P<0.01).

Conclusions:

For patients with non-metastatic pT3a RCC, PN may be a possible option for similar oncology outcomes and better renal function.

Clinical predictors of the estimated glomerular filtration rate 1 year after radical nephrectomy in Japanese patients

Purpose

To evaluate renal function 1 year after radical nephrectomy (RN) for renal cell carcinoma, the preoperative predictors of postnephrectomy renal function were investigated by sex, and equations to predict the estimated glomerular filtration rate (eGFR) 1 year after RN were developed.

Materials and Methods

A total of 525 patients who underwent RN between May 2007 and August 2011 at Tohoku University Hospital and its affiliated hospitals were prospectively evaluated. Overall, 422 patients were analyzed in this study.

Results

Independent preoperative factors associated with postnephrectomy renal function were different in males and females. Preoperative eGFR, age, tumor size, and body mass index (BMI) were independent factors in males, while tumor size and BMI were not independent factors in females. The equations developed to predict eGFR 1 year after RN were: Predicted eGFR in males (mL/min/1.73 m²)=27.99−(0.196×age)+(0.497×eGFR)+(0.744×tumor size)−(0.339×BMI); and predicted eGFR in females=44.57−(0.275×age)+(0.298×eGFR). The equations were validated in the validation dataset (R²=0.63, p<0.0001 and R²=0.31, p<0.0001, respectively).

Conclusions

The developed equations by sex enable better prediction of eGFR 1 year after RN. The equations will be useful for preoperative patient counseling and selection of the type of surgical procedure in elective partial or RN cases.

Histologic Abnormalities in Non-neoplastic Renal Parenchyma and the Risk of Chronic Kidney Disease Following Radical Nephrectomy

OBJECTIVE

To assess the association of histopathological parameters in non-neoplastic renal parenchyma with the development of new-onset chronic kidney disease (CKD) after radical nephrectomy.

PATIENTS AND METHODS

Data were extracted from 222 patients who underwent radical nephrectomy. The Modification of Diet in Renal Disease formula was used. The study end point was development of CKD, defined as an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73 m². A renal pathologist assessed three histologic features in the non-neoplastic parenchyma, namely global glomerulosclerosis (GS), arteriosclerosis (AS), and interstitial fibrosis (IF). For GS assessment, the percent of affected glomeruli was determined. AS was graded and divided into three groups, namely 1-0%-25%, 2-26%-50%, and 3-greater than 50%. IF was evaluated as absent or present.

RESULTS

After a mean follow-up of 49.06 months, the mean eGFR rate decrease was 26.5% after radical nephrectomy. Almost half of the patients (53.8%) developed CKD. For each 2.5% increase in GS, each point increase in Charlson comorbidity index (CCI), and each 10-year increase in patient's age, the eGFR decreased 28%, 33%, and 39%, respectively (P < .05). In a univariate analysis, age, CCI, GS, AS, IF, hypertension, and diabetes mellitus were associated with new-onset CKD after radical nephrectomy (P < .05). After multivariate logistic regression, CCI, GS, and baseline eGFR were associated with new-onset CKD after radical nephrectomy.

CONCLUSION

Histopathological evaluation of non-neoplastic renal parenchyma in patients who undergo radical nephrectomy can be used to predict the development of new-onset CKD.

Nephrectomy Type Was Not Associated with a Subsequent Risk of Coronary Heart Disease: A Population-Based Study

Previous studies investigated the impacts of a partial nephrectomy (PN) or radical nephrectomy (RN) on cardiovascular events and death. However, the association between the type of nephrectomy (PN vs. RN) and cardiovascular disease is still equivocal. This retrospective cohort study aimed to compare the risk of coronary heart disease (CHD) between patients who underwent a PN and those who underwent an RN. We used data from the Taiwan Longitudinal Health Insurance Database 2005. In total, 60 patients who underwent a PN and 545 patients who underwent an RN were included. Each patient was tracked for 1-, 2-, 3-, and 5-year periods to identify those who were subsequently diagnosed with CHD. Cox proportional hazard regression analyses were used to calculate hazard ratios (HRs) for CHD during 1-, 2-, 3-, and 5-year follow-up periods between these two cohorts. For the 1-year follow-up period, the adjusted HR was 0.39 (95% CI: 0.05~2.90, p = 0.355) for patients who underwent a PN compared to those who underwent an RN. Additionally, the adjusted HRs of CHD in patients who underwent a PN for 2-, 3- and 5-year follow-up periods were 1.40 (95% CI: 0.62~3.16, p = 0.417), 1.09 (95% CI: 0.52~2.31, p = 0.814), and 1.02 (95% CI: 0.48~2.18, p = 0.961), respectively, compared to those who underwent an RN. We concluded that there was no significant difference in the risk of CHD between patients who underwent a PN and those who underwent an RN.

Renal cell carcinoma: risks and benefits of nephron-sparing surgery for T1 tumors

Renal cell carcinoma is the most common cancer of the kidneys that is primarily treated with surgery, including removal of part or all the involved kidney depending on size and tumor, complexity, and patient characteristics. Partial nephrectomy historically was restricted to cases of solitary kidney or bilateral tumors. It was then started for masses smaller than 4 cm and currently is even studied and justified in tumors smaller than 7 cm if surgically feasible. Although partial nephrectomy preserves kidney tissue and, therefore, delays or prevents the new onset of CKD and ESRD, radical nephrectomy is still overused even for the small tumors. Studies have shown that although this practice is driven by an easier complete removal of the kidney especially in the era of minimally invasive surgery, partial nephrectomy is successful in curing cancer and achieving excellent cancer-specific survival in addition to its benefits on cardiovascular health. Nowadays interest in preserving healthy kidney tissue is increasing to the level of studying the impact of larger volume removed around the kidney and the histopathology of that non-neoplastic tissue to predict kidney function behavior postoperatively.

Compensatory Structural and Functional Adaptation after Radical Nephrectomy for Renal Cell Carcinoma According to Preoperative Stage of Chronic Kidney Disease

PURPOSE

We investigated structural hypertrophy and functional hyperfiltration as compensatory adaptations after radical nephrectomy in patients with renal cell carcinoma according to the preoperative chronic kidney disease stage.

MATERIALS AND METHODS

We retrospectively identified 543 patients who underwent radical nephrectomy for renal cell carcinoma between 1997 and 2012. Patients were classified according to preoperative glomerular filtration rate as no chronic kidney disease--glomerular filtration rate 90 ml/minute/1.73 m(2) or greater (230, 42.4%), chronic kidney disease stage II--glomerular filtration rate 60 to less than 90 ml/minute/1.73 m(2) (227, 41.8%) and chronic kidney disease stage III--glomerular filtration rate 30 to less than 60 ml/minute/1.73 m(2) (86, 15.8%). Computerized tomography performed within 2 months before surgery and 1 year after surgery was used to assess functional renal volume for measuring the degree of hypertrophy of the remnant kidney, and the preoperative and postoperative glomerular filtration rate per unit volume of functional renal volume was used to calculate the degree of hyperfiltration.

RESULTS

Among all patients (mean age 56.0 years) mean preoperative glomerular filtration rate, functional renal volume and glomerular filtration rate/functional renal volume were 83.2 ml/minute/1.73 m(2), 340.6 cm(3) and 0.25 ml/minute/1.73 m(2)/cm(3), respectively. The percent reduction in glomerular filtration rate was statistically significant according to chronic kidney disease stage (no chronic kidney disease 31.2% vs stage II 26.5% vs stage III 12.8%, p <0.001). However, the degree of hypertrophic functional renal volume in the remnant kidney was not statistically significant (no chronic kidney disease 18.5% vs stage II 17.3% vs stage III 16.5%, p=0.250). The change in glomerular filtration rate/functional renal volume was statistically significant (no chronic kidney disease 18.5% vs stage II 20.1% vs stage III 45.9%, p <0.001). Factors that increased glomerular filtration rate/functional renal volume above the mean value were body mass index (p=0.012), diabetes mellitus (p=0.023), hypertension (p=0.015) and chronic kidney disease stage (p <0.001).

CONCLUSIONS

Patients with a lower preoperative glomerular filtration rate had a smaller reduction in postoperative renal function than those with a higher preoperative glomerular filtration rate due to greater degrees of functional hyperfiltration.

Risk of chronic kidney disease after cancer nephrectomy

The incidence of early stage renal cell carcinoma (RCC) is increasing and observational studies have shown equivalent oncological outcomes of partial versus radical nephrectomy for stage I tumours. Population studies suggest that compared with radical nephrectomy, partial nephrectomy is associated with decreased mortality and a lower rate of postoperative decline in kidney function. However, rates of chronic kidney disease (CKD) in patients who have undergone nephrectomy might be higher than in the general population. The risks of new-onset or accelerated CKD and worsened survival after nephrectomy might be linked, as kidney insufficiency is a risk factor for cardiovascular disease and mortality. Nephron-sparing approaches have, therefore, been proposed as the standard of care for patients with type 1a tumours and as a viable option for those with type 1b tumours. However, prospective data on the incidence of de novo and accelerated CKD after cancer nephrectomy is lacking, and the only randomized trial to date was closed prematurely. Intrinsic abnormalities in non-neoplastic kidney parenchyma and comorbid conditions (including diabetes mellitus and hypertension) might increase the risks of CKD and RCC. More research is needed to better understand the risk of CKD post-nephrectomy, to develop and validate predictive scores for risk-stratification, and to optimize patient management.