Kidney function following nephrectomy: Similitude and discrepancies between kidney cancer and living donation

Use of Circular RNAs in Diagnosis, Prognosis and Therapeutics of Renal Cell Carcinoma

Renal cell carcinoma is the most common type of kidney cancer, representing 90% of kidney cancer diagnoses, and the deadliest urological cancer. While the incidence and mortality rates by renal cell carcinoma are higher in men compared to women, in both sexes the clinical characteristics are the same, and usually unspecific, thereby hindering and delaying the diagnostic process and increasing the metastatic potential. Regarding treatment, surgical resection remains the main therapeutic strategy. However, even after radical nephrectomy, metastasis may still occur in some patients, with most metastatic renal cell carcinomas being resistant to chemotherapy and radiotherapy. Therefore, the identification of new biomarkers to help clinicians in the early detection, and treatment of renal cell carcinoma is essential. In this review, we describe circRNAs related to renal cell carcinoma processes reported to date and propose the use of some in therapeutic strategies for renal cell carcinoma treatment.

Glomerular hyperfiltration

Circulating blood is filtered across the glomerular barrier to form an ultrafiltrate of plasma in the Bowman's space. The volume of glomerular filtration adjusted by time is defined as the glomerular filtration rate (GFR), and the total GFR is the sum of all single-nephron GFRs. Thus, when the single-nephron GFR is increased in the context of a normal number of functioning nephrons, single glomerular hyperfiltration results in 'absolute' hyperfiltration in the kidney. 'Absolute' hyperfiltration can occur in healthy people after high protein intake, during pregnancy and in patients with diabetes, obesity or autosomal-dominant polycystic kidney disease. When the number of functioning nephrons is reduced, single-nephron glomerular hyperfiltration can result in a GFR that is within or below the normal range. This 'relative' hyperfiltration can occur in patients with a congenitally reduced nephron number or with an acquired reduction in nephron mass consequent to surgery or kidney disease. Improved understanding of the mechanisms that underlie 'absolute' and 'relative' glomerular hyperfiltration in different clinical settings, and of whether and how the single-nephron haemodynamic and related biomechanical forces that underlie glomerular hyperfiltration promote glomerular injury, will pave the way toward the development of novel therapeutic interventions that attenuate glomerular hyperfiltration and potentially prevent or limit consequent progressive kidney injury and loss of function.

Unexpected Outcomes of Renal Function after Radical Nephrectomy: Histology Relevance along with Clinical Aspects

Acute kidney injury (AKI) and chronic kidney disease (CKD) are common events after radical nephrectomy (RN). In this study we aimed to predict AKI and CKD after RN relying on specific histological aspects. We collected data from a cohort of 144 patients who underwent radical nephrectomy. A histopathological review of the healthy part of the removed kidney was performed using an established chronicity score (CS). Logistic regression analyses were performed to predict AKI after RN, while linear regression analysis was adopted for estimated glomerular filtration rate (eGFR) variation at 1 year. The outcomes of the study were to determine variables correlated with AKI onset, and with eGFR decay at 1 year. The proportion of AKI was 64%. Logistic analyses showed that baseline eGFR independently predicted AKI (odds ratio 1.04, 95%CI 1.02:1.06). Moreover, AKI (Beta −16, 95%CI −21:−11), baseline eGFR (Beta −0.42, 95%CI −0.52:−0.33), and the presence of arterial narrowing (Beta 10, 95%CI 4:15) were independently associated with eGFR decline. Our findings showed that AKI onset and eGFR decline were more likely to occur with higher baseline eGFR and lower CS, highlighting that RN in normal renal function patients represents a more traumatic event than its CKD counterpart.

Evaluation of functional outcome of bilateral kidney tumors after sequential surgery

Background

There are limited data concerning patients treated with sequential bilateral kidney surgery. Current guidelines still lack an optimal surgical sequencing approach. We evaluated renal functional outcomes after sequential partial nephrectomy (PN) and radical nephrectomy (RN) in patients with bilateral renal cell carcinoma (RCC).

Methods

A propensity score matched cohort of 267 patients (synchronous bilateral RCCs, N = 44 [88 lesions]; metachronous bilateral, N = 45 [90 lesions]; unilateral, N = 178) from two tertiary institutions were retrospectively analyzed. Synchronous bilateral RCCs were defined as diagnosis concomitantly or within 3 months of former tumor. Renal functional outcomes were defined as estimated glomerular filtration rate (eGFR) changes and de novo chronic kidney disease (CKD, stage ≥3) after surgery. Renal functional outcomes and clinical factors predicting de novo CKD were assessed using descriptive statistics and Cox regression analysis.

Results

In subgroup of bilateral RCCs, patients underwent sequential PN (N = 48), PN followed by RN (N = 8), or RN followed by PN (N = 25). Final postoperative estimated glomerular filtration rates (eGFRs) were 79.4, 41.4, and 61.2 ml/minute/1.73 m2, respectively (p = 0.003). There were significant differences in eGFR decline from baseline and de novo chronic kidney disease (CKD stage ≥ III) among groups, with PN followed by RN group showing the worst functional outcomes (all p <  0.05). Moreover, sequential PN subgroup in bilateral RCC showed significantly higher rate of de novo CKD than unilateral RCC group (13.8% vs. 6.9%, p = 0.016). On multivariate analysis, hypertension (p = 0.010) and surgery sequence (PN followed by RN, p <  0.001) were significant predictors of de novo CKD.

Conclusions

The surgery sequence should be prudently determined in bilateral renal tumors. PN followed by RN showed a negative impact on renal functional preservation. Nephron-sparing surgery should be considered for all amenable bilateral RCCs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08324-3.

Significance of preoperative hematologic scoring in predicting death among patients with non-metastatic renal cell carcinoma undergoing nephrectomy

PURPOSE

Neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) are hematologic scoring and indicators of the systemic inflammatory response. The increasing use of NLR and PLR have been associated with poor outcome in various types of malignancy. We evaluated the effect of NLR and PLR on survival outcomes of nonmetastatic renal cell carcinoma (RCC).

MATERIALS AND METHODS

We retrospectively review 150 patients who had undergone nephrectomy for nonmetastatic RCC between 2006 and 2016. Cancer specific survival (CSS) was assessed using Kaplan-Meier method and compared using log-rank test. We applied univariate and multivariate Cox regression model to analyze the association of NLP and PLR with clinical outcome.

RESULTS

At median follow up of 33 months, 45 patients had died. High PLR (>100) was an independent prognostic hematologic marker for CSS (hazard ratio [HR] 2.61, 95% confidence interval [CI],1.08-6.31; P = 0.034). Univariate analysis identified elevated NLR (p = 0.005), and anemia (p = 0.023) were significantly associated with CSS.

CONCLUSION

Elevated PLR is a strong hematologic prognosis factor in term of survival for patients with nonmetastatic RCC undergoing nephrectomy with curative intent. The PLR is an easily obtained biomarker which is useful for preoperative risk stratification.

Association of Early Postdonation Renal Function With Subsequent Risk of End-Stage Renal Disease in Living Kidney Donors

Importance

Living kidney donation is associated with increased long-term risk of end-stage renal disease (ESRD). An early postdonation marker of ESRD risk could improve postdonation risk assessment and counseling for kidney donors and allow early intervention for donors at increased risk.

Objective

To determine the association between renal function in the first 6 months postdonation and subsequent risk of ESRD in kidney donors.

Design, Setting, and Participants

This secondary analysis of a prospective national cohort uses a population-based registry of all living kidney donors in the United States between October 26, 1999, and January 1, 2018, with follow-up through December 31, 2018. All kidney donors who had donated in the date range and had serum creatinine measured at 6 months (±3 months) postdonation were included.

Exposures

Renal function as measured by estimated glomerular filtration rate 6 months after donation (eGFR6).

Main Outcomes and Measures

End-stage renal disease, ascertained via linkage to Centers for Medicare & Medicaid Services data.

Results

A total of 71 468 living kidney donors were included (of 109 065 total donors over this period). Their median (interquartile range) eGFR6 was 63 (54-74) mL/min/1.73 m2. Cumulative incidence of ESRD at 15 years postdonation ranged from 11.7 donors per 10 000 donors with eGFR6 values greater than 70 mL/min/1.73 m2 to 33.1 donors per 10 000 donors with eGFR6 values of 50 mL/min/1.73 m2 or less. Adjusting for age, race, sex, body mass index, and biological relationship, every 10 mL/min/1.73 m2 reduction in eGFR6 was associated with a 28% increased risk of ESRD (adjusted hazard ratio, 1.28 [95% CI, 1.06-1.54]; P = .009). The association between predonation eGFR and ESRD was not significant and was fully mediated by eGFR6 (adjusted hazard ratio, 1.00 [95% CI, 0.86-1.17]; P = .97). The postdonation eGFR value was a better marker of ESRD than eGFR decline after donation or the ratio of eGFR6 to predonation eGFR, as determined by the Akaike information criterion (in which a lower value indicates a better model fit; eGFR6, 1495.61; predonation eGFR - eGFR6, 1503.58; eGFR6 / predonation eGFR, 1502.30).

Conclusions and Relevance

In this study, there was an independent association of eGFR6 with subsequent ESRD risk in living kidney donors, even after adjusting for predonation characteristics. The findings support measurement of early postdonation serum creatinine monitoring in living kidney donors, and the use of these data to help identify donors who might need more careful surveillance and early intervention.

Hyperfiltration-mediated Injury in the Remaining Kidney of a Transplant Donor

Kidney donors face a small but definite risk of end-stage renal disease 15 to 30 years postdonation. The development of proteinuria, hypertension with gradual decrease in kidney function in the donor after surgical resection of 1 kidney, has been attributed to hyperfiltration. Genetic variations, physiological adaptations, and comorbidities exacerbate the hyperfiltration-induced loss of kidney function in the years after donation. A focus on glomerular hemodynamics and capillary pressure has led to the development of drugs that target the renin-angiotensin-aldosterone system (RAAS), but these agents yield mixed results in transplant recipients and donors. Recent work on glomerular biomechanical forces highlights the differential effects of tensile stress and fluid flow shear stress (FFSS) from hyperfiltration. Capillary wall stretch due to glomerular capillary pressure increases tensile stress on podocyte foot processes that cover the capillary. In parallel, increased flow of the ultrafiltrate due to single-nephron glomerular filtration rate elevates FFSS on the podocyte cell body. Although tensile stress invokes the RAAS, FFSS predominantly activates the cyclooxygenase 2-prostaglandin E2-EP2 receptor axis. Distinguishing these 2 mechanisms is critical, as current therapeutic approaches focus on the RAAS system. A better understanding of the biomechanical forces can lead to novel therapeutic agents to target FFSS through the cyclooxygenase 2-prostaglandin E2-EP2 receptor axis in hyperfiltration-mediated injury. We present an overview of several aspects of the risk to transplant donors and discuss the relevance of FFSS in podocyte injury, loss of glomerular barrier function leading to albuminuria and gradual loss of renal function, and potential therapeutic strategies to mitigate hyperfiltration-mediated injury to the remaining kidney.

Incident Chronic Kidney Disease After Radical Nephrectomy for Renal Cell Carcinoma

BACKGROUND

Chronic kidney disease (CKD) after surgery for kidney cancer is common, and is associated with increased morbidity and mortality. This study aimed to identify factors associated with incident CKD in patients managed with radical nephrectomy.

PATIENTS AND METHODS

All patients diagnosed with renal cell carcinoma between January 2012 and December 2013 were ascertained from state-based cancer registries in Queensland and Victoria. Information on patient, tumor, and health service characteristics was obtained via chart review. Multivariable logistic regression was used to evaluate exposures associated with incident CKD (estimated glomerular filtration rate [eGFR] <60 mL per minute per 1.73 m²) at 12 months after nephrectomy.

RESULTS

Older age (adjusted odds ratio [aOR] per 5-year increase, 1.5; 95% confidence interval [CI], 1.4-1.6), male sex (aOR, 1.4; 95% CI, 1.0-2.0), obese compared with not obese (aOR, 1.8; 95% CI, 1.2-2.7), rural compared with urban place of residence (aOR, 1.8; 95% CI, 1.1-3.0) were associated with a higher risk of incident CKD. Lower preoperative eGFR was also associated with a higher risk of incident CKD. Management in private compared with public hospitals was also associated with a higher risk of CKD (aOR, 1.6; 95% CI, 1.2-2.2). Factors related to tumor size and cancer severity were also associated with worse postoperative kidney function, although it is likely this was a consequence of selection bias.

CONCLUSION

Patient characteristics have the strongest associations with incident CKD after radical nephrectomy. Potential risk factors were reasonably similar to recognized CKD risk factors for the general population. Patients who undergo nephrectomy who have CKD risk factors might benefit from ongoing postoperative screening for deterioration of kidney function.

Quality and Quantity in Kidney Cancer Surgery: The Role of Nonneoplastic Kidney and Kidney Volumetrics in Predicting Postoperative Renal Function

Objectives

To model renal function 2 years following radical nephrectomy with quantitative analyses using clinical, histopathologic, and renal composite cortical volumes (CCV).

Methods

This retrospective study involved an assessment of the nonneoplastic kidney tissue by three blinded nephropathologists using modified Banff 1997 criteria for renal allograft pathology. Volumetric image acquisition was obtained by three independent radiologists using preoperative imaging. A 2-year estimated glomerular filtration (eGFR) calculator was created.

Results

Among the 126 patients, median age was 60 years; median CCV, 398.1 cm3; preoperative eGFR, 77 mL/min/1.73 m2; and 2-year postoperative eGFR, 54 mL/min/1.73 m2. Of the subjects, 64% had hypertension, 26% diabetes, and 37% were smokers. Increasing age, glomerulopathy/sclerosis, tubulointerstitial scarring, and arteriosclerosis were statistically significantly and adversely associated with eGFR. Conversely, increasing CCV was associated with a higher eGFR.

Conclusions

Quantitative analysis of the nephrectomized kidney in conjunction with patient age can accurately predict renal function at 2 years.

The Correlates of Kidney Dysfunction – Tumour Nephrectomy Database (CKD-TUNED) Study: Protocol for a Prospective Observational Study

Background:

Tumour nephrectomy conveys a significant risk of adverse renal functional outcomes postoperatively, however there are limited strategies for predicting patients at increased risk of these outcomes. The Correlates of Kidney Dysfunction – Tumour Nephrectomy Database (CKD-TUNED) study is a prospective observational study evaluating the risk of chronic kidney disease and end-stage kidney disease in tumour nephrectomy patients.

Methods:

The CKD-TUNED study involves analysis of clinical data and collection of tissue, urine and blood samples for the purposes of forming a tissue repository resource for future investigation. Recruitment began in 2013 and is expected to continue until 2023, with a projected sample size between 700-1000 subjects.

Results:

All relevant ethics and site-specific approvals have been granted and all relevant infrastructure is in place. Study methods are undergoing validation and refinement. As of June 2017 there are 267 participants enrolled in the study.

Conclusion:

It is anticipated that this study will have the potential to identify risk factors for adverse renal functional outcomes following tumour nephrectomy, which can be used in the development of predictive models with clinical utility, and in turn improve patient outcomes.

Predictive model of 1-year postoperative renal function after living donor nephrectomy

OBJECTIVE

Kidney transplantation from a living donor nephrectomy (LDN) is the best treatment for end-stage renal disease, but decrease in donor renal function is often revealed. The aim of this study was to evaluate the association between preoperative factors and postoperative estimated glomerular filtration rate (eGFR) and test a predictive model to estimate postoperative eGFR, 1 year after LDN.

PATIENTS AND METHODS

We reviewed 226 records of consecutive patients who underwent laparoscopic live donor nephrectomy between 2006 and 2014 in a single tertiary center. Of these, complete data on 202 patients were analyzed. A training (2/3 of the whole population) and a validation set (1/3) were randomized. A multivariate regression model was used to identify predictors and a formula to estimate of 1-year postoperative eGFR in the training set, using the CKD-EPI formula. Then, the formula was subjected to internal validation using the validation set using receiver operating characteristic (ROC) curves.

RESULTS

Two hundred and two LLDN were evaluated with a mean preoperative eGFR of 94.1 ± 15.5 ml/min/1.73 m² and postoperative eGFR of 64.6 ± 14.5 ml/min/1.73 m² (p < 0.0001). In multivariable analysis, age and preoperative eGFR were independent predictors of postoperative eGFR in the training set. A formula to estimate postoperative eGFR was generated with Pearson r = 0.70 in the training cohort and 0.65 in the validation cohort (both p < 0.0001). Area under the ROC curve of the formula was 0.89 in the training cohort and 0.83 in the validation cohort (both p < 0.0001).

CONCLUSIONS

Preoperative eGFR and age are predictors of postoperative eGFR after LDN. The internally validated predictive model of postoperative eGFR developed could be an accurate tool to improve the selection of LDN candidates.

Collaborative Review of Risk Benefit Trade-offs Between Partial and Radical Nephrectomy in the Management of Anatomically Complex Renal Masses

BACKGROUND

While partial nephrectomy (PN) is the recommended treatment for many small renal masses, anatomically complex tumors necessitate a clear understanding of the potential risks and benefits of PN and radical nephrectomy (RN).

OBJECTIVE

To critically review the comparative effectiveness evidence of PN versus RN; to describe key trade-offs involved in this treatment decision; and to highlight gaps in the current literature.

EVIDENCE ACQUISITION

A collaborative critical review of the medical literature was conducted.

EVIDENCE SYNTHESIS

Patients who undergo PN for an anatomically complex or large mass may be exposed to perioperative and potential oncologic risks that could be avoided if RN were performed, while patients who undergo RN may forgo long-term benefits of renal preservation. Decision-making regarding the optimal treatment with PN or RN among patients with anatomically complex or large renal mass is highly nuanced and must balance the risks and benefits of each approach. Currently, high-quality evidence on comparative effectiveness is sparse. Retrospective comparisons are plagued by selection biases, while the one existing prospective randomized trial, albeit imperfect, suggests that nephron-sparing surgery may not benefit all patients.

CONCLUSIONS

For anatomically complex tumors, PN preserves renal parenchyma but may expose patients to higher perioperative risks than RN. The risks and benefits of each surgical approach must be better objectified for identification of patients most suitable for complex PN. A prospective randomized trial is warranted and would help in directing patient counseling.

PATIENT SUMMARY

Treatment decisions for complex renal masses require shared decision-making regarding the risk trade-offs between partial and radical nephrectomy.

Comparison of postoperative estimated glomerular filtration rate between kidney donors and radical nephrectomy patients, and risk factors for postoperative chronic kidney disease

OBJECTIVES

To compare post-nephrectomy renal function between kidney donors and renal cell carcinoma patients, to evaluate trends in recovery, and to identify factors relevant to renal failure.

METHODS

Patients who had radical or donor nephrectomy from four different institutions between 2003 and 2012 were reviewed. Propensity score matching was carried out and 79 patients were selected for each group. The estimated glomerular filtration rate was calculated using the Modification of Diet in Renal Disease formula preoperatively and postoperatively at 1, 3, 6, 12, 24 and 36 months. Mean estimated glomerular filtration rate was compared, and the difference between preoperative values and each preceding date was calculated. A multivariate logistic regression was used to determine independent factors for a decrease in estimated glomerular filtration rate to <60 mL/min/1.73 m(2) .

RESULTS

The donor nephrectomy group showed a trend of improved estimated glomerular filtration rate recovery at 24 months and 36 months compared with the radical nephrectomy group, which was statistically significant (P = 0.028, P = 0.012). Multivariate logistic regression showed that renal cell carcinoma (odds ratio 4.605, 95% confidence interval 1.626-13.040, P = 0.004), a baseline estimated glomerular filtration rate lower than 110 (odds ratio 4.477, 95% confidence interval 1.360-14.742, P = 0.014) and age older than 40 years (odds ratio 21.616, 95% confidence interval 2.761-169.222, P = 0.003) were predictive factors for a decrease in renal function.

CONCLUSIONS

Renal cell carcinoma is an independent risk factor for chronic kidney disease after nephrectomy. In addition, age older than 40 years and a baseline estimated glomerular filtration rate of 110 mL/min/1.73 m(2) or less seem to represent risk factors associated with chronic kidney disease after nephrectomy.

Comparison of renal function after donor and radical nephrectomy

Glomerular filtration rate (GFR) is directly proportionate to nephron reserves. In this respect, it is known that the patients who underwent radical nephrectomy due to renal tumor are under high risk of chronic kidney disease (CKD) in the long term. In this study, it was aimed to compare post-operative renal functions of patients who underwent radical nephrectomy due to renal malignancy and who underwent donor nephrectomy as renal donors, to observe whether renal failure process develops or not, and to determine the factors that affect post-operative renal functions. 70 patients who underwent donor nephrectomy as renal donors and 130 patients who underwent radical nephrectomy due to renal tumor were studied. When we divided the groups as those with a GFR of below 60 mL/min/1.73 m(2) and those with a GFR of above 60 mL/min/1.73 m(2), we observed that GFR values of patients who underwent radical nephrectomy had a significantly stronger tendency to stay below 60 mL/min/1.73 m(2) compared to patients who underwent donor nephrectomy (p < 0.001). When we divided the groups as those with a GFR of below 30 mL/min/1.73 m(2) and those with a GFR of above 30 mL/min/1.73 m(2), we observed that there were no patients in donor nephrectomy group whose GFR values dropped below 30 mL/min/1.73 m(2) and there was not a statistically significant difference between the groups (p = 0.099). If possible, nephron sparing methods should be preferred for patients to undergo nephrectomy because of the tumor without ignoring oncologic results and it should be remembered that patient's age and pre-operative renal functions may affect post-operative results in donor selection.

Kidney function following partial or radical nephrectomy for renal cell carcinoma: a population-based study

OBJECTIVE

The aim of this retrospective study was to compare kidney function in a population-based cohort of renal cell carcinoma (RCC) patients after partial (PN) or radical nephrectomy (RN).

MATERIAL AND METHODS

Forty-four consecutive RCC patients who had undergone PN in Iceland between 2000 and 2010 were compared with 44 controls matched for tumour, node, metastasis (TNM) stage who had undergone RN during the same period. Estimated glomerular filtration rate (eGFR) and survival were calculated, and predictors of chronic kidney disease (CKD) were evaluated with multivariate analysis.

RESULTS

In 16 cases (36%), PN was performed for imperative reasons (single kidney, decreased kidney function or bilateral kidney tumours) but 28 patients had a normal contralateral kidney. The groups were similar regarding preoperative eGFR, median follow-up and TNM stage, but age and American Society of Anesthesiologists (ASA) score were significantly higher in the RN group. Six months after surgery, eGFR was significantly higher in the PN group. By multivariate analysis, RN contributed negatively to eGFR 6 months after surgery (-12.6 ml/1.73 m², p < 0.001) and increased the risk of new-onset CKD (odds ratio = 3.07, 95% confidence interval 1.03-9.79, p = 0.04), compared to PN. At median follow-up of 44 months, no patients in either group had a recurrence of RCC. The 5-year overall survival (Kaplan-Meier) was 100% and 65% in the PN and RN groups, respectively (log-rank test, p < 0.001).

CONCLUSION

eGFR was significantly lower after RN, and these patients were three times more likely to develop new-onset CKD. These findings suggest that PN successfully preserves kidney function compared to RN, with good oncological outcome and survival.