A Simple Clinical Tool for Stratifying Risk of Clinically Significant CKD after Nephrectomy: Development and Multinational Validation

Perioperative systemic treatments in renal cell carcinoma

In this review, we aim to provide a comprehensive assessment of the evolving landscape of the perioperative management in renal cell carcinoma (RCC), emphasizing its dynamic and intricate nature. We explore academic and clinical insights into the perioperative treatment paradigm of RCC. Up-to-date treatment options are discussed and the evolving role of neoadjuvant and adjuvant therapy in RCC is highlighted.

Beyond the knife: strategic patient selection for cytoreductive nephrectomy

PURPOSE OF REVIEW

To evaluate the current role of cytoreductive nephrectomy (CN) in metastatic renal cell carcinoma (mRCC) within the context of evolving treatment paradigms, focusing on implications for patient selection.

RECENT FINDINGS

Two randomized trials failed to show significant benefits from CN for intermediate and poor-risk patients undergoing targeted therapy. Despite this, subgroup analysis and retrospective data suggest potential benefits for a subset of good and intermediate-risk patients. Although currently used risk stratification tools guide CN eligibility, they have limitations, including, subjectivity, perioperative variability, and missing validation. Deferred CN may benefit patients responding to systemic treatment, whereas other patients may benefit from upfront CN. Emerging data supports the value of CN with immune checkpoint inhibitors (ICI) in selected patients, emphasizing the need for ongoing trials in the ICI era.

SUMMARY

The role and timing of CN in mRCC have evolved across therapeutic eras. Although awaiting prospective evidence in the current era of ICI, CN still has a role in the therapeutic approach for a subset of patients. The decision to recommend CN must be personalized and involve multidisciplinary discussions considering both patient- and tumor-related factors.

A Predictive Model for Kidney Failure After Nephrectomy for Localized Kidney Cancer: The Kidney Cancer Risk Equation

RATIONALE & OBJECTIVE

Nephrectomy is the mainstay of treatment for individuals with localized kidney cancer. However, surgery can potentially result in the loss of kidney function or in kidney failure requiring dialysis/kidney transplantation. There are currently no clinical tools available to preoperatively identify which patients are at risk of kidney failure over the long term. Our study developed and validated a prediction equation for kidney failure after nephrectomy for localized kidney cancer.

STUDY DESIGN

Population-level cohort study.

SETTING & PARTICIPANTS

Adults (n=1,026) from Manitoba, Canada, with non-metastatic kidney cancer diagnosed between January 1, 2004, and December 31, 2016, who were treated with either a partial or radical nephrectomy and had at least 1 estimated glomerular filtration rate (eGFR) measurement before and after nephrectomy. A validation cohort included individuals in Ontario (n=12,043) with a diagnosis of localized kidney cancer between October 1, 2008, and September 30, 2018, who received a partial or radical nephrectomy and had at least 1 eGFR measurement before and after surgery.

NEW PREDICTORS & ESTABLISHED PREDICTORS

Age, sex, eGFR, urinary albumin-creatinine ratio, history of diabetes mellitus, and nephrectomy type (partial/radical).

OUTCOME

The primary outcome was a composite of dialysis, transplantation, or an eGFR<15mL/min/1.73m2 during the follow-up period.

ANALYTICAL APPROACH

Cox proportional hazards regression models evaluated for accuracy using area under the receiver operating characteristic curve (AUC), Brier scores, calibration plots, and continuous net reclassification improvement. We also implemented decision curve analysis. Models developed in the Manitoba cohort were validated in the Ontario cohort.

RESULTS

In the development cohort, 10.3% reached kidney failure after nephrectomy. The final model resulted in a 5-year area under the curve of 0.85 (95% CI, 0.78-0.92) in the development cohort and 0.86 (95% CI, 0.84-0.88) in the validation cohort.

LIMITATIONS

Further external validation needed in diverse cohorts.

CONCLUSIONS

Our externally validated model can be easily applied in clinical practice to inform preoperative discussions about kidney failure risk in patients facing surgical options for localized kidney cancer.

PLAIN-LANGUAGE SUMMARY

Patients with localized kidney cancer often experience a lot of worry about whether their kidney function will remain stable or will decline if they choose to undergo surgery for treatment. To help patients make an informed treatment decision, we developed a simple equation that incorporates 6 easily accessible pieces of patient information to predict the risk of reaching kidney failure 5 years after kidney cancer surgery. We expect that this tool has the potential to inform patient-centered discussions tailored around individualized risk, helping ensure that patients receive the most appropriate risk-based care.

Risk factors and predictive model for acute kidney Injury Transition to acute kidney disease in patients following partial nephrectomy

PURPOSE

Acute kidney disease (AKD) is believed to be involved in the transition from acute kidney injury (AKI) to chronic kidney disease in general populations, but little is understood about this possibility among kidney surgical populations. This study aimed to elucidate the incidence of AKD after partial nephrectomy and risk factors that promote the AKI to AKD transition.

METHODS

From January 2010 to January 2020, this study retrospectively collected a dataset of consecutive patients with renal masses undergoing partial nephrectomy in 4 urological centers. Cox proportional regression analyses were adopted to identify risk factors that promoted the AKI to AKD transition. To avoid overfitting, the results were then verified by logistic least absolute shrinkage and selection operator (LASSO) regression. A nomogram was then constructed and validated for AKI to AKD transition prediction.

RESULTS

AKI and AKD occurred in 228 (21.4%) and 42 (3.9%) patients among a total of 1062 patients, respectively. In patients with AKI, multivariable Cox regression analysis and LASSO regression identified that age (HR 1.078, 1.029-1.112, p < 0.001), baseline eGFR (HR 1.015, 1.001-1.030, p < 0.001), RENAL score (HR1.612, 1.067-2.437, p = 0.023), ischemia time > 30 min (HR 7.284, 2.210-23.999, p = 0.001), and intraoperative blood loss > 300ml (HR 8.641, 2.751-27.171, p < 0.001) were risk factors for AKD transition. These five risk factors were then integrated into a nomogram. The nomogram showed excellent discrimination, calibration, and clinical net benefit ability.

CONCLUSION

Around 3.9% patients following partial nephrectomy would transit from AKI to AKD. Intraoperative blood loss and ischemia time need to be diminished to avoid on-going functional decline. Our nomogram can accurately predict the transition from AKI to AKD.

Relationship between cortical and medullary thickness and glomerular filtration rate among living kidney donors

The relationship between the kidney cortex and medulla is not well understood in healthy populations. This study characterised the relationship between cortical/medullary thickness and measured glomerular filtration rate (GFR) in 390 living kidney donors. A positive relationship was observed between medullary, but not cortical, thickness and GFR. We propose that this reflects a correlation between juxtamedullary nephron number and GFR.

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.

Bloodless surgery in urologic oncology: A review of hematologic, anesthetic, and surgical considerations

The urologic oncology patient who refuses blood transfusion can present unique challenges in perioperative blood management. Since blood loss and associated transfusion can be expected in many complex urologic oncology surgeries, a multidisciplinary approach may be required for optimal outcomes. Through collaboration with the hematologist, anesthesiologist, and urologist, various techniques can be employed in the perioperative phases to minimize blood loss and the need for transfusion. We review the risks and benefits of these techniques and offer recommendations specific to the urologic oncology patient.

The multispeciality approach to the management of localised kidney cancer

Historically, kidney cancer was approached in a siloed single-speciality way, with urological surgeons managing the localised stages of the disease and medical oncologists caring for patients if metastases developed. However, improvements in the management of localised kidney cancer have occurred rapidly over the past two decades with greater understanding of the disease biology, diagnostic options, and innovations in curative treatments. These developments are favourable for patients but provide a substantially more complex landscape for patients and clinicians to navigate, with associated challenging decisions about who to treat, how, and when. As such, the skill sets needed to manage the various aspects of the disease and guide patients appropriately outstrips the capabilities of one particular specialist, and the evolution of a multispeciality approach to the management of kidney cancer is now essential. In this Review, we summarise the current best multispeciality practice for the management of localised kidney cancer and the areas in need of further research and development.

Overview of clinical management for older patients with renal cell carcinoma

The rapidly increasing pool of older patients being diagnosed with and surviving their cancer is creating many challenges. Regarding localized renal cell carcinoma, surgery is considered as gold standard treatment options even in older men, whereas active surveillance and ablation therapy are alternative options for a proportion of these patients. With regard to advanced disease, anti-vascular endothelial growth factor tyrosine kinase inhibitors (VEGFR-TKI) and immune check point inhibitor are standard treatment modalities, although treatment choice from multiple regimens and prevention of adverse events need to be considered. Better assessment techniques, such as comprehensive geriatric assessment to meet the unique needs of older patients, are a central focus in the delivery of high-quality geriatric oncology care. Through this process, shared decision-making should be adopted in clinical care to achieve optimal goals of care that reflect patient and caregiver hopes, needs and preferences. It is necessary to continue investigating oncological outcomes and complications associated with treatment in this population to ensure appropriate cancer care. In this narrative review, we completed a literature review of the various treatments for renal cell carcinoma in older patients that aimed to identify the current evidence related to the full range of the treatments including active surveillance, surgery, ablation therapy and systemic therapy. Prospectively designed studies and studies regarding geriatric assessment were preferentially added as references. Our goals were to summarize the real-world evidence and provide a decision framework that guides better cancer practices for older patients with renal cell carcinoma.

Kidney failure, CKD progression and mortality after nephrectomy

Purpose

This study tested the hypothesis that progression of chronic kidney disease (CKD) is less aggressive in patients whose primary cause of CKD was nephrectomy, compared with non-surgical causes.

Methods

A sample of 5983 patients from five specialist nephrology practices was ascertained from the Queensland CKD Registry. Rates of kidney failure/death were compared on primary aetiology of CKD using multivariable Cox proportional hazards models. CKD progression was compared using multivariable linear and logistic regression analyses.

Results

Of 235 patients with an acquired single kidney as their primary cause of CKD, 24 (10%) and 38 (17%) developed kidney failure or died at median [IQR] follow-up times of 12.9 [2.5–31.0] and 33.6 [18.0–57.9] months after recruitment. Among patients with an eGFR < 45 mL/min per 1.73m² at recruitment, patients with diabetic nephropathy and PCKD had the highest rates (per 1000 person-years) of kidney failure (107.8, 95% CI 71.0–163.8; 75.5, 95% CI 65.6–87.1); whereas, patients with glomerulonephritis and an acquired single kidney had lower rates (52.9, 95% CI 38.8–72.1; 34.6, 95% CI 20.5–58.4, respectively). Among patients with an eGFR ≥ 45 mL/min per 1.73m², those with diabetic nephropathy had the highest rates of kidney failure (16.6, 95% CI 92.5–117.3); whereas, those with glomerulonephritis, PCKD and acquired single kidney had a lower risk (11.3, 95% CI 7.1–17.9; 11.7, 95% CI 3.8–36.2; 10.7, 95% CI 4.0–28.4, respectively).

Conclusion

Patients who developed CKD after nephrectomy had similar rates of adverse events to most other causes of CKD, except for diabetic nephropathy which was consistently associated with worse outcomes. While CKD after nephrectomy is not the most aggressive cause of kidney disease, it is by no means benign, and is associated with a tangible risk of kidney failure and death, which is comparable to other major causes of CKD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11255-022-03114-7.

CT-measured Cortical Volume Ratio Is an Accurate Alternative to Nuclear Medicine Split Scan Ratio Among Living Kidney Donors

BACKGROUND

The 125I-iothalamate clearance and 99mTc diethylenetriamine-pentaacetic acid (99mTc-DTPA) split scan nuclear medicine studies are used among living kidney donor candidates to determine measured glomerular filtration rate (mGFR) and split scan ratio (SSR). The computerized tomography-derived cortical volume ratio (CVR) is a novel measurement of split kidney function and can be combined with predonation estimated GFR (eGFR) or mGFR to predict postdonation kidney function. Whether predonation SSR predicts postdonation kidney function better than predonation CVR and whether predonation mGFR provides additional information beyond predonation eGFR are unknown.

METHODS

We performed a single-center retrospective analysis of 204 patients who underwent kidney donation between June 2015 and March 2019. The primary outcome was 1-y postdonation eGFR. Model bases were created from a measure of predonation kidney function (mGFR or eGFR) multiplied by the proportion that each nondonated kidney contributed to predonation kidney function (SSR or CVR). Multivariable elastic net regression with 1000 repetitions was used to determine the mean and 95% confidence interval of R2, root mean square error (RMSE), and proportion overprediction ≥15 mL/min/1.73 m2 between models.

RESULTS

In validation cohorts, eGFR-CVR models performed best (R2, 0.547; RMSE, 9.2 mL/min/1.73 m2, proportion overprediction 3.1%), whereas mGFR-SSR models performed worst (R2, 0.360; RMSE, 10.9 mL/min/1.73 m2, proportion overprediction 7.2%) (P < 0.001 for all comparisons).

CONCLUSIONS

These findings suggest that predonation CVR may serve as an acceptable alternative to SSR during donor evaluation and furthermore, that a model based on CVR and predonation eGFR may be superior to other methods.

More than ancillary records: clinical implications of renal pathology examination in tumor nephrectomy specimens

Background

Nephrectomy is the management of choice for the treatment of renal tumors. Surgical pathologists primarily focus on tumor diagnosis and investigations relating to prognosis or therapy. Pathological changes in non-neoplastic tissue may, however, be relevant for further management and should be thoroughly assessed.

Methods

Here, we examined the non-neoplastic renal parenchyma in 206 tumor nephrectomy specimens for the presence of glomerular, tubulo-interstitial, or vascular lesions, and correlated them with clinical parameters and outcome of renal function.

Results

We analyzed 188 malignant and 18 benign or pseudo-tumorous lesions. The most common tumor type was clear cell renal cell carcinoma (CCRCC, n = 106) followed by papillary or urothelial carcinomas (n = 25). Renal pathology examination revealed the presence of kidney disease in 39 cases (18.9%). Glomerulonephritis was found in 15 cases (7.3%), and the most frequent was IgA nephropathy (n = 6; 2.9%). Vasculitis was found in two cases (0.9%). In 15 cases we found tubulo-interstitial nephritis, and in 9 severe diabetic or hypertensive nephropathy. Partial nephrectomy was not linked to better eGFR at follow-up. Age, vascular nephropathy, glomerular scarring and interstitial fibrosis were the leading independent negative factors influencing eGFR at time of surgery, whereas proteinuria was associated with reduced eGFR at 1 year.

Conclusion

Our large study population indicates a high incidence of renal diseases potentially relevant for the postoperative management of patients with renal neoplasia. Consistent and systematic reporting of non-neoplastic renal pathology in tumor nephrectomy specimens should therefore be mandatory.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40620-021-01030-0.

Effects of metabolic syndrome on renal function after radical nephrectomy in patients with renal cell carcinoma

PURPOSE

Nephrectomy, partial or radical, remains the standard treatment for renal cell carcinoma (RCC). However, increased risk of chronic kidney disease (CKD) must still be considered. This study aimed to evaluate the effects of concomitant metabolic syndrome (MetS) on renal function in patients with RCC after radical nephrectomy.

METHODS

Medical records of 310 patients who underwent radical nephrectomy for clear-cell RCC at 900th Hospital of the Joint Logistics Support Force, PLA from December 2012 to January 2017 were reviewed retrospectively. Estimated glomerular filtration rate (eGFR) and CKD stages were calculated at one week preoperative as baseline and then at postoperative 1 week, 3 months, 12 months and 24 months. MetS patients were identified and enrolled in the MetS group (n = 31), and a non-MetS group was selected by propensity score matching (n = 31). Non-neoplastic renal parenchyma specimens taken at least 2 cm from edge of tumor were evaluated.

RESULTS

Baseline characteristics between the two groups were comparable. At 24 months postoperative, mean eGFR levels of the MetS group were significantly lower than those in the non-MetS group (62.7 vs. 73.3 ml/min/1.73 m²; p = 0.004). CKD stages were still more severe in the MetS group than those in the non-MetS group (p = 0.006). The proportions of global sclerosis, tubular atrophy and interstitial fibrosis were all significantly more prevalent in MetS patients, compared to non-MetS patients (all p < 0.05).

CONCLUSION

In RCC patients with MetS, the possibility of declining eGFR and CKD progression must be considered after radical nephrectomy. Routine monitoring of renal function must be emphasized.

Kidney Microstructural Features at the Time of Donation Predict Long-term Risk of Chronic Kidney Disease in Living Kidney Donors

OBJECTIVE

To determine whether microstructural features on a kidney biopsy specimen obtained during kidney transplant surgery predict long-term risk of chronic kidney disease in the donor.

PATIENTS AND METHODS

We studied kidney donors from May 1, 1999, through December 31, 2018, with a follow-up survey for the results of recent blood pressure and kidney function tests (estimated glomerular filtration rate [eGFR] and proteinuria). If not recently available, blood pressure and eGFRs were requested from a local clinic. Microstructural features on kidney biopsy at the time of donation were assessed as predictors of hypertension and kidney function after adjusting for years of follow-up, baseline age, sex, and clinical predictors.

RESULTS

There were 807 donors surveyed a mean 10.5 years after donation. An eGFR less than 45 mL/min/1.73 m2 in 6.4% (43/673) of donors was predicted by larger glomerular volume per standard deviation (odds ratio [OR], 1.48; 95% CI, 1.08 to 2.04) and nephron number below the age-specific 5th percentile (OR, 3.38; 95% CI, 1.31 to 8.72). An eGFR less than 60 mL/min/1.73 m2 in 42.5% (286/673) of donors was not predicted by any microstructural feature. Residual eGFR (postdonation/predonation eGFR) was predicted by nephron number below the age-specific 5th percentile (difference, -6.07%; 95% CI, -10.24% to -1.89%). Self-reported proteinuria in 5.1% (40/786) of donors was predicted by larger glomerular volume (OR, 1.42; 95% CI, 1.08 to 1.86). Incident hypertension in 18.8% (119/633) of donors was not predicted by any microstructural features.

CONCLUSION

Low nephron number for age and larger glomeruli are important microstructural predictors for long-term risk of chronic kidney disease after living kidney donation.