Renal Functional Outcomes after Surgery, Ablation, and Active Surveillance of Localized Renal Tumors: A Systematic Review and Meta-Analysis

Ablation of Kidney Tumors in Patients with Substantial Kidney Impairment: Current Status

PURPOSE OF REVIEW

To review the current status of kidney tumor ablation in patients with substantial kidney impairment.

RECENT FINDINGS

Few reports of kidney tumor ablation in such patients have recently been published. The reported prevalence of patients with stage 4 or 5 chronic kidney disease (CKD) among patients undergoing ablation is 2.0%-10%. In patients with stage 4 or 5 CKD, local tumor control rates were 88%-100%. The effect of ablation on CKD stage is unclear, and the observed deteriorations in kidney function are consistent with both the effect of cryoablation and the natural course of advanced CKD. According to guidelines, active surveillance may be selected. The goals of treatment are complete tumor removal and maintenance of kidney function, both of which can be met by ablation. Given the limited treatment options, ablation may play a pivotal role in the management of patients with advanced CKD.

Percutaneous Image-Guided Cryoablation of Endophytic Renal Cell Carcinoma

PURPOSE

Endophytic renal cancer treatment is a challenge. Due to difficulties in endophytic tumor visualization during surgical extirpation, image-guided percutaneous cryoablation (PCA) is an attractive alternative. The minimally invasive nature of PCA makes it favorable for comorbid patients as well as patients in which surgery is contraindicated. Oncological outcomes and complications after PCA of endophytic biopsy-proven renal cell carcinoma (RCC) were reviewed in this study.

MATERIALS AND METHODS

Patients were included after a multidisciplinary team conference from January 2015 to November 2021. Inclusion criteria were endophytic biopsy-proven T1 RCC treated with PCA with one year of follow-up. Complications were reported according to the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) classification system and the Clavien-Dindo classification (CDC) system. Major complications were defined as a grade ≥ 3 according to the CDC.

RESULTS

Fifty-six patients were included with a total of 56 endophytic tumors treated during 61 PCA sessions. The median RENAL nephrometry score was 9 (IQR 2), and the mean tumor size was 25.7 mm (SD ± 8.9 mm). Mean hospitalization time was 0.39 (SD ± 1.1) days. At a mean follow-up of 996 days (SD ± 559), 86% of tumors were recurrence free after one PCA. No patients progressed to metastatic disease. According to the CIRSE classification, 10.7% (n = 6) had grade 3 complications, and 5.4% (n = 3) had CDC major complications.

CONCLUSION

This study demonstrates that PCA of endophytic biopsy-proven T1 RCC is safe with few major complications and excellent local tumor control rates at almost three-year mean follow-up. LEVEL OF EVIDENCE 3: Retrospective cohort study.

Stereotactic ablative body radiotherapy for primary kidney cancer (TROG 15.03 FASTRACK II): a non-randomised phase 2 trial

BACKGROUND

Stereotactic ablative body radiotherapy (SABR) is a novel non-invasive alternative for patients with primary renal cell cancer who do not undergo surgical resection. The FASTRACK II clinical trial investigated the efficacy of SABR for primary renal cell cancer in a phase 2 trial.

METHODS

This international, non-randomised, phase 2 study was conducted in seven centres in Australia and one centre in the Netherlands. Eligible patients aged 18 years or older had biopsy-confirmed diagnosis of primary renal cell cancer, with only a single lesion; were medically inoperable, were at high risk of complications from surgery, or declined surgery; and had an Eastern Cooperative Oncology Group performance status of 0-2. A multidisciplinary decision that active treatment was warranted was required. Key exclusion criteria were a pre-treatment estimated glomerular filtration rate of less than 30 mL/min per 1·73 m2, previous systemic therapies for renal cell cancer, previous high-dose radiotherapy to an overlapping region, tumours larger than 10 cm, and direct contact of the renal cell cancer with the bowel. Patients received either a single fraction SABR of 26 Gy for tumours 4 cm or less in maximum diameter, or 42 Gy in three fractions for tumours more than 4 cm to 10 cm in maximum diameter. The primary endpoint was local control, defined as no progression of the primary renal cell cancer, as evaluated by the investigator per Response Evaluation Criteria in Solid Tumours (version 1.1). Assuming a 1-year local control of 90%, the null hypothesis of 80% or less was considered not to be worthy of proceeding to a future randomised controlled trial. All patients who commenced trial treatment were included in the primary outcome analysis. This trial is registered with ClinicalTrials.gov, NCT02613819, and has completed accrual.

FINDINGS

Between July 28, 2016, and Feb 27, 2020, 70 patients were enrolled and initiated treatment. Median age was 77 years (IQR 70-82). Before enrolment, 49 (70%) of 70 patients had documented serial growth on initial surveillance imaging. 49 (70%) of 70 patients were male and 21 (30%) were female. Median tumour size was 4·6 cm (IQR 3·7-5·5). All patients enrolled had T1-T2a and N0-N1 disease. 23 patients received single-fraction SABR of 26 Gy and 47 received 42 Gy in three fractions. Median follow-up was 43 months (IQR 38-60). Local control at 12 months from treatment commencement was 100% (p<0·0001). Seven (10%) patients had grade 3 treatment-related adverse events, with no grade 4 adverse events observed. Grade 3 treatment-related adverse events were nausea and vomiting (three [4%] patients), abdominal, flank, or tumour pain (four [6%]), colonic obstruction (two [3%]), and diarrhoea (one [1%]). No treatment-related or cancer-related deaths occurred.

INTERPRETATION

To our knowledge, this is the first multicentre prospective clinical trial of non-surgical definitive therapy in patients with primary renal cell cancer. In a cohort with predominantly T1b or larger disease, SABR was an effective treatment strategy with no observed local failures or cancer-related deaths. We observed an acceptable side-effect profile and renal function after SABR. These outcomes support the design of a future randomised trial of SABR versus surgery for primary renal cell cancer.

FUNDING

Cancer Australia Priority-driven Collaborative Cancer Research Scheme.

The evolving management of small renal masses

Small renal masses (SRMs) are a heterogeneous group of tumours with varying metastatic potential. The increasing use and improving quality of abdominal imaging have led to increasingly early diagnosis of incidental SRMs that are asymptomatic and organ confined. Despite improvements in imaging and the growing use of renal mass biopsy, diagnosis of malignancy before treatment remains challenging. Management of SRMs has shifted away from radical nephrectomy, with active surveillance and nephron-sparing surgery taking over as the primary modalities of treatment. The optimal treatment strategy for SRMs continues to evolve as factors affecting short-term and long-term outcomes in this patient cohort are elucidated through studies from prospective data registries. Evidence from rapidly evolving research in biomarkers, imaging modalities, and machine learning shows promise in improving understanding of the biology and management of this patient cohort.

Papillary Renal Cell Carcinoma: Demographics, Survival Analysis, Racial Disparities, and Genomic Landscape

Papillary renal cell carcinoma (PRCC) is the second most common histological subtype of renal cell cancer. This research aims to present a large database study highlighting the demographic, clinical, and pathological factors, racial disparities, prognosis, and survival of PRCC. The clinical and demographic data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database, and molecular data was cured from the Catalogue Of Somatic Mutations in Cancer (COSMIC) database. PRCC had a median age of diagnosis at 64 years, with a higher incidence in men (77%), and Whites (68%). 70.3% of cases were Grades I-IV (13, 53, 31, and 3%, respectively). In patients with known data, 85% were localized to the kidney, and 84% of cases were 7 cm in size. No metastasis occurred in 97% of the known data. The most common treatment offered was surgical resection (9%). The 5-year overall survival was 79%, with patients undergoing surgery having a 90.6% 5-year survival. Multivariable analysis revealed age > 60 years, Black race, poor histologic differentiation, distant metastases, and tumor size > 10 cm as independent risk factors for mortality. The most common mutations identified from the COSMIC database were MET, KMT2D, KMT2C, ARID1A, and SPEN. PRCC affects male individuals in the sixth decade of life. Increased age, Black race, distant metastases, and tumors > 10 cm are associated with a worse prognosis. Surgical resection offers a favorable survival outcome. Next-generation sequencing (NGS) could identify potentially targetable alterations and future personalized therapeutic approaches.

Renal functional outcomes after robot-assisted partial nephrectomy and percutaneous cryoablation of clinical T1 renal cell carcinoma - A prospective study

Objectives

The objective of this study was to investigate renal function after robot-assisted partial nephrectomy (RAPN) and percutaneous cryoablation (PCA) in clinical stage T1 (cT1) renal cell carcinoma (RCC) and evaluate the relationship between baseline renal function and renal functional outcome.

Material and Methods

Patients with cT1 RCC treated with RAPN or PCA were prospectively enrolled between June 2019 and January 2021. Renal function was evaluated using estimated glomerular filtration rate, Tc-99m diethylenetriamine-pentaacetate plasma clearance, Tc-99m mercaptoacetyltriglycine renography, and renal volume at baseline and 6 months after treatment.

Results

Fifty-six patients were included (18 RAPN, 38 PCA). PCA patients had a significantly higher age (68.5 years; P = 0.019) and Charlson comorbidity index (3.0; P = 0.007). Tumor characteristics did not differ significantly between RAPN and PCA. Total renal volume decreased significantly after PCA (-18.2 cm3; P = 0.001). Baseline chronic disease stage IIIb-IV leads to a greater reduction in renal volume (-31.8 cm3; P = 0.003) but not other renal function measures. Renal function declined significantly after either treatment without significant differences between RAPN and PCA.

Conclusion

This study found a small, similar decrease in renal function 6 months after RAPN or PCA, despite significant differences in baseline patient characteristics. Reduced renal function at baseline did not lead to a worse renal functional outcome.

Percutaneous ablation of renal tumors: Long-term outcomes

OBJECTIVE

To evaluate the long-term outcomes of renal tumor ablation, analyzing efficacy, long-term survival, and factors associated with complications and therapeutic success.

MATERIAL AND METHODS

We retrospectively reviewed 305 ablations (generally done with expandable electrodes) of 273 renal tumors between May 2005 and April 2019. We analyzed survival, primary and secondary efficacy, and complications according to various patient factors and tumor characteristics.

RESULTS

Mean blood creatinine was 1.14 mg/dL before treatment and 1.30 mg/dL after treatment (p < 0.0001). Complications were observed in 13.25% of the ablations, including major complications in in 4.97%. Complications were associated with age (p = 0.013) and tumor diameter (p < 0.0001). Primary efficacy was 96.28%. Incomplete ablation was more common in lesions measuring > 4 cm in diameter (p = 0.002). Secondary efficacy was 95.28%. The only factor associated with the risk of recurrence was the size of the tumor (p = 0.02). Overall survival was 95.26% at 1 year, 77.01% at 5 years, and 51.78% at 10 years, with no differences between patients with malignant and benign lesions. Mortality was higher in patients with creatinine >1 (p = 0.05) or ASA > 2 (p = 0.0001).

CONCLUSIONS

Percutaneous ablation is extremely efficacious for renal tumors; it improves the prognosis of renal carcinoma to the point where it does not differ from that of benign lesions. Complications are rare. Like survival, complications are associated with age and overall health status.

Percutaneous Renal Tumor Cryoablation Effect on Renal Function

Background: Percutaneous cryoablation (PCA) of renal tumors is a well-established alternative to partial nephrectomy, but the effects on renal function after the procedure are not well-documented. The purpose of this study was to evaluate renal function after computed tomography-guided PCA. Materials and Methods: A retrospective cohort study including 259 patients treated with PCA at Odense University Hospital, Denmark from January 1, 2015 to December 31, 2019. Both patients with malignant (96%) and benign tumors (4%) were included. Mean age of patients was 66.5 years (standard deviation [SD] = 10.9, range: 27-91) and 174 (67%) patients were men. Baseline estimated glomerular filtration rate (eGFR) was recorded at baseline and 12 months after cryoablation. Results: Mean tumor size was 27.5 mm (SD = 10.0) distributed in seven different histopathological types, mainly clear cell renal-cell carcinoma (RCC) (64%) and papillary RCC (22%). Mean eGFR at baseline was 73.7 mL/min/1.73 m2 (SD = 23.2) with a follow-up mean eGFR of 69.7 (SD = 23.7) (p < 0.0001). At baseline before intervention 190 patients (73%) had eGFR matching chronic kidney disease (CKD) groups 1 and 2 (normal to mild CKD), 64 patients (24%) matching CKD group 3 (average CKD), and 1% in groups 4 and 5. At 12-month follow-up, 171 patients (66%) had eGFR matching CKD groups 1 and 2, 77 patients (30%) matching CKD group 3 and 11 patients (4%) matching CKD groups 4 and 5. In patients with skewed renography who had PCA in the kidney with better excretion, eGFR at baseline was 64.7 and 61.2 at follow-up (p = 0.703). Conclusions: This study showed minimal decline in renal function 12 months after PCA, even for patients with reduced renal function. PCA is therefore considered a safe and relevant intervention.

Effects of remote ischemic preconditioning on renal protection in patients undergoing robot-assisted laparoscopic partial nephrectomy

We aimed to evaluate the renoprotective effects of remote ischemic preconditioning (RIPC) in patients undergoing robot-assisted laparoscopic partial nephrectomy (RAPN). Data from 59 patients with solitary renal tumors who underwent RAPN with RIPC comprising three cycles of 5-min inflation to 200 mmHg of a blood pressure cuff applied to one lower limb followed by 5-min reperfusion by cuff deflation, from 2018 to 2020 were analyzed. Patients who underwent RAPN for solitary renal tumors without RIPC between 2018 and 2020 were selected as controls. The postoperative estimated glomerular filtration rate (eGFR) at the nadir during hospitalization and the percentage change from baseline were compared using propensity score matching analysis. We performed a sensitivity analysis with imputations for missing postoperative renal function data weighted by the inverse probability of the data being observed. Of the 59 patients with RIPC and 482 patients without RIPC, 53 each were matched based on propensity scores. No significant differences in the postoperative eGFR in mL/min/1.73 m2 at nadir (mean difference 3.8; 95% confidence interval [CI] - 2.8 to 10.4) and its percentage change from baseline (mean difference 4.7; 95% CI - 1.6 to 11.1) were observed between the two groups. Sensitivity analysis also indicated no significant differences. No complications were associated with the RIPC. In conclusion, we found no significant evidence of the protective effect of RIPC against renal dysfunction after RAPN. Further research is required to determine whether specific patient subgroups benefit from RIPC.Trial registration number: UMIN000030305 (December 8, 2017).

Renal cryoablation combined with prior transcatheter arterial embolization in non-dialysis patients with stage 4 or 5 chronic kidney disease: a retrospective study

PURPOSE

To retrospectively evaluate cryoablation combined with prior transcatheter arterial embolization (TAE) for renal cell carcinoma (RCC) in non-dialysis patients with stage 4 or 5 chronic kidney disease (CKD).

MATERIALS AND METHODS

Patients with stage 4 or 5 CKD undergoing TAE and cryoablation for RCC between May 2012 and October 2021 were included. TAE was selectively performed using iodized oil with absolute ethanol or gelatin sponge 1-14 days before cryoablation. Local efficacy, safety, and changes in renal function were evaluated.

RESULTS

Nine patients (seven men and two women; median age, 64 years; range 52-88 years) with nine RCCs (mean diameter, 3.0 ± 1.0 cm; range 1.7-4.7 cm) were included. The mean pre-treatment estimated glomerular filtration rate (eGFR) was 24.2 ± 5.6 ml/min/1.73 m2 (range 10.4-29.2 ml/min/1.73 m2). The mean amount of contrast medium used in TAE was 58 ± 29 ml (range 40-128 ml). Except in one patient (grade 3 pyelonephritis), no grade ≥ 3 complications occurred. During the follow-up period (median, 18 months; range 7-54 months), no local tumor progression occurred. In two patients with pre-treatment eGFR of < 20 ml/min/1.73 m2, hemodialysis was initiated at 3 and 19 months after cryoablation. At their last follow-up, the remaining seven patients showed a decrease of 6.2 ± 5.3 ml/min/1.73 m2 (range 0.7-17.2 ml/min/1.73 m2) in their eGFR.

CONCLUSION

Cryoablation combined with TAE for RCC in non-dialysis patients with stage 4 or 5 CKD was effective and safe, with an acceptable impact on renal function.

[Nephron sparing in the management of localized solid renal mass]

Managing a malignant renal tumor requires, first of all, a reflection on the necessity of its treatment. It must consider the renal function, altered at the time of diagnosis in 50% of cases. The treatment method chosen depends on many factors, in particular, the predicted residual renal function, the risk of chronic kidney disease, the need for temporary or long-term dialysis, and overall long-term survival. Other factors include the size, position, and number of tumors and a hereditary tumor background. When a renal-sparing management alternative is available, total nephrectomy should no longer be performed in patients with small malignant renal masses (cT1a). This may consist of surgery (partial nephrectomy or lumpectomy), percutaneous thermo-ablation (by radiofrequency, microwave, or cryotherapy). In patients with limited life expectancy, imaging-based surveillance may be proposed to suggest treatment in case of local progression. Good coordination between urologist, radiologist, nephrologist, and sometimes radiotherapist should allow optimal management of patients with a malignant renal tumor with or without underlying renal failure.

The Changing Role of Renal Mass Biopsy

The incidence and prevalence of small renal masses (SRMs) continues to rise and with increased detection comes increases in surgical management, although the probability of an SRM being benign is upward of 30%. An extirpative treatment first diagnose-later strategy persists and clinical tools for risk stratification such as renal mass biopsy remain severely underutilized. The overtreatment of SRMs has multiple detrimental effects including surgical complications, psychosocial stress, financial loss, and reduced renal function leading to downstream effects such as the need for dialysis and cardiovascular disease.

Novel Biomarkers for Early Detection of Acute Kidney Injury and Prediction of Long-Term Kidney Function Decline after Partial Nephrectomy

Background: Identifying acute kidney injury (AKI) within few hours of onset is certainly helpful. However, early prediction of a long-term eGFR decline may be an even more important goal. Our aim was to identify and compare serum [creatinine, kineticGFR, cystatin C, neutrophil gelatinase–associated lipocalin (NGAL)] and urinary (NephroCheck, NGAL, proteinuria, albuminuria, acantocytes at urinary sediment) predictors of AKI that might efficiently predict long-term GFR decline after robotic Nephron-Spearing Surgery (rNSS). Methods: Monocentric prospective observational study. Patients scheduled for rNSS for suspected localized Renal Cell Carcinoma from May 2017 to October 2017 were enrolled. Samples were collected preoperatively and postoperatively (timepoints: 4 h, 10 h, 24 h, 48 h), while kidney function was re-assessed up to 24 months. Results: 38 patients were included; 16 (42%) developed clinical AKI. The eGFR decline at 24 months was more pronounced after postoperative AKI (−20.75 vs. −7.20, p < 0.0001). KineticGFR at 4 h (p = 0.008) and NephroCheck at 10 h (p = 0.001) were, at multivariable linear regression analysis, efficient predictors of post-operative AKI and long-term eGFR decline if compared to creatinine (R2 0.33 vs. 0.04). Conclusions: NephroCheck and kineticGFR have emerged as promising noninvasive, accurate, and early biomarkers of postoperative AKI and long-term GFR decline after rNSS. Combining NephroCheck and kineticGFR in clinical practice would allow to identify high risk of postoperative AKI and long-term GFR decline as early as 10 h after surgery.

Operative and oncological outcomes of salvage robotic radical and partial nephrectomy: a multicenter experience

We aim to describe the perioperative and oncological outcomes for salvage robotic partial nephrectomy (sRPN) and salvage robotic radical nephrectomy (sRRN). Using a prospectively maintained multi-institutional database, we compared baseline clinical characteristics and perioperative and postoperative outcomes, including pathological stage, tumor histology, operative time, ischemia time, estimated blood loss (EBL), length of stay (LOS), postoperative complication rate, recurrence rate, and mortality. We identified a total of 58 patients who had undergone robotic salvage surgery for a recurrent renal mass, of which 22 (38%) had sRRN and 36 (62%) had sRPN. Ischemia time for sRPN was 14 min. The median EBL was 100 mL in both groups (p = 0.581). One intraoperative complication occurred during sRRN, while three occurred during sRPN cases (p = 1.000). The median LOS was 2 days for sRRN and 1 day for sRPN (p = 0.039). Postoperatively, one major complication occurred after sRRN and two after sRPN (p = 1.000). The recurrence reported after sRRN was 5% and 3% after sRPN. Among the patients who underwent sRRN, the two most prevalent stages were pT1a (27%) and pT3a (27%). Similarly, the two most prevalent stages in sRPN patients were pT1a (69%) and pT3a (6%). sRRN and sRPN have similar operative and perioperative outcomes. sRPN is a safe and feasible procedure when performed by experienced surgeons. Future studies on large cohorts are essential to better characterize the importance and benefit of salvage partial nephrectomies.

Acute kidney injury as an independent predicting factor for stage 3 or higher chronic kidney disease after nephrectomy

BACKGROUND

The association between postoperative acute kidney injury (AKI) and long-term renal function after nephrectomy has not been fully explored, with accurate prognostic models in which AKI is an independent predicting variable still being absent.

METHODS

We conducted a retrospective study of 528 patients who underwent unilateral radical nephrectomy or partial nephrectomy owing to renal cell carcinoma between January 2013 and December 2016. Postoperative AKI was defined as an absolute increase in serum creatinine level by 0.3 mg/dl or ≥5 0% increase from the preoperative value within 48 hours after surgery. The endpoint was the time to the incident stage 3 or higher chronic kidney disease (defined as eGFR<60 ml/min/1.73m²), or any claim for initiation of dialysis. Cox proportional hazards regression analysis was conducted to construct the final model. Internal validation was performed using 10-fold cross-validation. The model was evaluated in discrimination by Harrell's C-index and area under curve (AUC) values, and calibration by calibration plots.

RESULTS

Five hundred twenty-eight patients were finally enrolled in the study cohort, and the median follow-up period was 38 months. Among 528 admitted patients, 232 (43.9%) developed AKI, and stage 3 or higher CKD occurred in 47 (8.9%) patients during the follow-up time, with 33 in 47 patients (70.2%) having postoperative AKI. AKI was significantly correlated with poor prognosis of renal function (HR = 3.079, P < 0.001). After the adjustment of conventional predictors, AKI was still independently related to kidney function deterioration, and the correlation was influenced by the severity of AKI. Five variables were selected to establish the prognostic model, including age, surgery type, preoperative estimated glomerular filtration rate, preoperative blood urea nitrogen, and postoperative AKI. The model had good discrimination, with the Harrell's C-index of 0.92 (95% CI 0.89-0.95), and AUC values varying from 87.7 to 95.7 at different time points.

CONCLUSIONS

AKI during the perioperative period is an independent predicting factor of stage 3 or higher CKD after nephrectomy.

Percutaneous Ablation vs Robot-Assisted Partial Nephrectomy for Completely Endophytic Renal Masses: A Multicenter Trifecta Analysis with a Minimum 3-Year Follow-Up

Purpose: To compare outcomes of robot-assisted partial nephrectomy (RAPN) and percutaneous tumor ablation (PTA) for completely endophytic renal masses. Methods: Data of patients who underwent RAPN or PTA for treatment of completely endophytic (three points for "E" domain of R.E.N.A.L. score) were collected from seven high-volume U.S. and European centers. PTA included cryoablation, radiofrequency, or microwave ablation. Baseline characteristics, clinical, surgical, and postoperative outcomes were compared. Recurrence-free survival (RFS) was calculated with Kaplan-Meier analysis. Trifecta was used as arbitrary combined outcome parameter as proxy for treatment "quality." Multivariable logistic regression model assessed predictors of trifecta failure. Results: One hundred fifty-two patients (RAPN, n = 60; PTA, n = 92) were included in the analysis. RAPN group was younger (p < 0.001), had lower American Society of Anesthesiologists score (p = 0.002), and higher baseline estimated glomerular filtration rate (p < 0.001). There was no difference in clinical tumor size, clinical T stage, and tumor complexity scores. PTA had significantly lower rate of overall (p < 0.001) and minor (p < 0.001) complications. ΔeGFR at 1 year was statistically higher for RAPN (-15.5 mL/min vs -3.1 mL/min; p = 0.005), no difference in ΔeGFR at last follow-up (p = 0.22) was observed. No difference in recurrences (RAPN, n = 2; PTA, n = 6) and RFS was found (p = 0.154). Trifecta achievement was higher for RAPN but not statistically different (65.3% vs 58.8%; p = 0.477). R.E.N.A.L. Nephrometry Score resulted predictive of trifecta failure (odds ratio = 1.47; confidence interval = 1.13-1.90; p = 0.004). Conclusions: PTA confirms to be an effective treatment for completely endophytic renal masses, offering low complications and good mid-term functional and oncologic outcomes. These outcomes compare favorably with those of RAPN, which seem to be the preferred option for younger and less comorbid patients.

No difference in renal function outcomes for patients with oncocytoma managed with active surveillance vs. partial nephrectomy

OBJECTIVES

To investigate the difference in renal function outcomes for patients with oncocytomas undergoing active surveillance (AS) vs. partial nephrectomy (PN).

METHODS

We reviewed our institutional database for patients with biopsy/surgically confirmed oncocytoma from 2000-2020. The primary outcome was to assess for differences in renal function outcomes in patients undergoing AS vs. PN. We fit two generalized estimating equation (GEE) with an interaction term between follow up time and management strategy to predict 1) mean eGFR for patients managed with AS and PN and 2) the probability of progression to CKD stage III or greater.

RESULTS

We identified 114 eligible patients, of which 32 were managed with AS. Median follow-up was 21 months vs. 44 months for PN vs. AS patients. AS patients tended to be older (median: 72 years vs. 65 years, P<0.001) and have lower baseline renal function (median: eGFR: 71 mL/min/1.73m2 vs. 82 mL/min/1.73m2, P<0.001) compared with PN patients. Renal mass size from baseline imaging was similar between patients undergoing PN vs. AS (2.8 cm vs. 2.9 cm, P=0.634). For patients undergoing PN vs. AS, there was not a significant difference in predicted longitudinal eGFR (-0.079, 95% CI -0.18-0.023, P=0.129) or predicted probability of progression to CKD stage III or greater (OR: 0.61, 95% CI: 0.16-2.33, P=0.47).

CONCLUSIONS

In our institutional dataset, patients undergoing AS or PN with an oncocytoma had similar long-term renal function outcomes. Given similar renal function outcomes in patients undergoing AS and PN, surgery should remain reserved for select patients with oncocytomas.

Stereotactic body radiation therapy to the kidney for metastatic renal cell carcinoma: A narrative review of an emerging concept

This narrative review provides a historical overview of cytoreductive nephrectomy for metastatic renal cell carcinoma (mRCC) and examines the safety and therapeutic potential of cytoreductive stereotactic body radiation therapy (SBRT) for mRCC in the modern immunotherapy era. In the last five years, the introduction of immune checkpoint inhibitors for the treatment of mRCC has improved outcomes for patients. This has brought forth new exploration of the role of CN in combination with immunotherapy. Early retrospective evidence suggests that there may be a benefit of deferred CN after immunotherapy (IOT) for de novo mRCC patients. However, there has also been concern regarding the feasibility of surgery after IOT due to inflammation. SBRT may be an appropriate alternative in these circumstances. Since 1999, cytoreductive SBRT has been used for inoperable primary RCC. Several prospective and retrospective studies treating the kidney tumor for localized RCC have shown that this technique is safe and produces favorable and durable local control. SBRT has also exhibited similar effectiveness to CN, while providing additional benefits including noninvasiveness and the ability to treat tumors that can't be treated with nephrectomy or ablation due to size or location. Furthermore, SBRT confers immunostimulatory effects, which are hypothesized to work synergistically with immunotherapy. Clinicians should consider SBRT a safe and reliable alternative to CN for RCC patients. Ongoing studies are exploring the utility of SBRT for treatment of the primary tumor in mRCC patients receiving standard of care immunotherapy.

Stereotactic Body Radiotherapy for Renal Cell Carcinoma: Oncological and Renal Function Outcomes

AIMS

To evaluate oncological and renal function outcomes of stereotactic body radiotherapy (SBRT) for medically inoperable patients with localised renal cell carcinoma.

MATERIALS AND METHODS

Consecutive patients treated with curative intent SBRT (30-45 Gy in five fractions or 42 Gy in three fractions) were included. Data on local control (Response Evaluation Criteria in Solid Tumors [RECIST] v1.1), distant metastasis, impact on estimated glomerular filtration rate (eGFR) and proportional ipsilateral and contralateral renal functions (measured through renal scans) were collected. Univariate and multivariable analyses were conducted to determine association of variables with oncological and renal function outcomes.

RESULTS

Seventy-four patients were analysed. The median follow-up was 27.8 months (interquartile range 17.6-41.7). Fifty-seven per cent had tumours ≥ T1b. One-, 2- and 4-year cumulative incidence of local failure was 5.85, 7.77 and 7.77%, respectively. The cumulative incidence of distant metastasis at 2 years was 4.24%. On multivariable analysis, a lower planning target volume (PTV) mean dose (P = 0.019) and a larger PTV (P = 0.005) were significantly associated with the risk of developing local failure. A lower PTV maximum dose (P = 0.039) was significantly associated with the risk of developing distant metastasis. The median change in global eGFR (ml/min) from pre-SBRT levels was -7.0 (interquartile range -14.5 to -1.0) at 1 year and -11.5 (interquartile range -19.5 to -4.0) at 2 years. The proportion of ipsilateral (differential) renal function decreased over time from 47% of overall renal function pre-SBRT to 36% at 2 years, whereas the proportion of contralateral renal function correspondingly improved. On multivariable analysis, a higher volume of uninvolved renal cortex (P < 0.0001) was significantly associated with a smaller decrease in eGFR over time.

CONCLUSION

In this large institutional cohort, oncological outcomes of renal cell carcinoma treated with SBRT were favourable and a longitudinal decline in renal function in the ipsilateral kidney and compensatory increase in the contralateral kidney were observed. Clinical and dosimetric factors were significantly associated with oncological and renal function outcomes.

Safety and Efficacy of Stereotactic Ablative Radiation Therapy for Renal Cell Cancer: 24-Month Results of the RSR1 Phase 1 Dose Escalation Study

PURPOSE

Stereotactic body radiation therapy (SBRT) has become a new therapeutic option for primary renal cell carcinoma. However, treatment doses lack consistency in the literature. The primary objective of this study was to determine the maximum tolerated dose for renal cancer SBRT.

METHODS AND MATERIALS

This phase 1 multicentric dose-escalation study assessed 4 dose levels: 8 Gy × 4, 8 Gy × 5, 10 Gy × 4, and 12 Gy × 4. The primary objective of this study was to determine the maximal tolerated dose, defined by the occurrence of dose-limiting toxicity was defined as any acute side effect of grade ≥4 based on the Common Terminology Criteria for Averse Events, version 4.0.

RESULTS

From October 2010 to September 2017, 13 patients were enrolled. The median follow-up was 23 months. There was no dose-limiting toxicity in our study, and the highest dose was reached successfully. No acute or late toxic effects above grade 2 were seen. There was no significant alteration of renal function after treatment. At 24 months, 2 patients had partial response and the others had stable disease.

CONCLUSIONS

After 24 months of follow-up, no dose-limiting toxicity was seen at any of the prescribed dose levels in our study. The findings suggest that our last dose level of 48 Gy in 4 12-Gy fractions can be considered safe and can be used in further studies.

5-year outcomes after stereotactic ablative body radiotherapy for primary renal cell carcinoma: an individual patient data meta-analysis from IROCK (the International Radiosurgery Consortium of the Kidney)

BACKGROUND

Stereotactic ablative body radiotherapy (SABR) is a non-invasive treatment option for primary renal cell carcinoma, for which long-term data are awaited. The primary aim of this study was to report on long-term efficacy and safety of SABR for localised renal cell carcinoma.

METHODS

This study was an individual patient data meta-analysis, for which patients undergoing SABR for primary renal cell carcinoma across 12 institutions in five countries (Australia, Canada, Germany, Japan, and the USA) were eligible. Eligible patients had at least 2 years of follow-up, were aged 18 years or older, had any performance status, and had no previous local therapy. Patients with metastatic renal cell carcinoma or upper-tract urothelial carcinoma were excluded. SABR was delivered as a single or multiple fractions of greater than 5 Gy. The primary endpoint was investigator-assessed local failure per the Response Evaluation Criteria in Solid Tumours version 1.1, and was evaluated using cumulative incidence functions.

FINDINGS

190 patients received SABR between March 23, 2007, and Sept 20, 2018. Single-fraction SABR was delivered in 81 (43%) patients and multifraction SABR was delivered in 109 (57%) patients. Median follow-up was 5·0 years (IQR 3·4-6·8). 139 (73%) patients were men, and 51 (27%) were women. Median age was 73·6 years (IQR 66·2-82·0). Median tumour diameter was 4·0 cm (IQR 2·8-4·9). 96 (75%) of 128 patients with available operability details were deemed inoperable by the referring urologist. 56 (29%) of 190 patients had a solitary kidney. Median baseline estimated glomerular filtration rate (eGFR) was 60·0 mL/min per 1·73 m2 (IQR 42·0-76·0) and decreased by 14·2 mL/min per 1·73 m2 (IQR 5·4-22·5) by 5 years post-SABR. Seven (4%) patients required dialysis post-SABR. The cumulative incidence of local failure at 5 years was 5·5% (95% CI 2·8-9·5) overall, with single-fraction SABR yielding fewer local failures than multifraction (Gray's p=0·020). There were no grade 3 toxic effects or treatment-related deaths. One (1%) patient developed an acute grade 4 duodenal ulcer and late grade 4 gastritis.

INTERPRETATION

SABR is effective and safe in the long term for patients with primary renal cell carcinoma. Single-fraction SABR might yield less local failure than multifraction, but further evidence from randomised trials is needed to elucidate optimal treatment schedules. These mature data lend further support for renal SABR as a treatment option for patients unwilling or unfit to undergo surgery.

FUNDING

None.

Transplant or dialysis: What’s the better choice for RCC-induced ESRD patients? A 20-year analysis of OPTN/UNOS data

Purpose

The incidence of end-stage renal disease (ESRD) caused by renal cell carcinoma (RCC) is increasing with the high prevalence of RCC as well as those with treatment-related renal function impairment. Worries about tumor recurrence after transplant-related immunosuppression hinder the recommendation of kidney transplantation for RCC-induced ESRD patients. However, no direct analysis has been performed to identify whether kidney transplantation can offer better survival than maintaining dialysis.

Materials and methods

This retrospective population-based cohort study was based on Organ Procurement and Transplantation Network data released in March 2021. Characteristics and outcomes were compared, including the patient and graft survival of candidates and recipients with RCC-induced ESRD etiology as well as other primary diseases.

Results

Patients with RCC-induced ESRD were older; more likely to be male, White, and obese; and more likely to have a history of diabetes and dialysis. They also had higher creatinine levels, more delayed graft function, more primary non-function, and higher Kidney Donor Profile Index score donors, compared with the glomerulonephritis (GN) group. While waiting, RCC candidates suffered the worst outcomes of all groups, a 44% (adjusted hazard ratio [aHR], 1.44 [1.27–1.62]) higher risk of removal than GN patients. After transplantation, RCC recipients demonstrated comparable patient survival and better graft survival (p=0.21 and p=0.13, respectively). Compared with still-waiting RCC patients, the RCC recipients who received kidney transplants had significantly better outcomes (13.6 [9.3–17.8] vs. 61 [52–68.4] %), decreasing the death or deteriorating risk by 84% (aHR, 0.16 [0.13–0.20]).

Conclusions

Patients with RCC-induced ESRD can dramatically benefit from kidney transplantation. Hence, these patients should not be limited to transplantation by strict strategies or a delayed waiting time out of their malignancy history.

A “3S+f” Nephrometry Score System to Predict the Clinical Outcomes of Laparoscopic Nephron-Sparing Surgery

Background

When we treat renal cell carcinoma by laparoscopic nephron-sparing surgery (NSS), it is essential to use an evaluation system to predict clinical outcomes. Hitherto, there are more than a dozen nephrometry score systems. In this study, through assessing the correlations between nephrometry score systems and clinical outcomes, we aim to provide a novel nephrometry score system—the “3S+f” score system—to simplify the evaluation of technical complexity of partial nephrectomy.

Methods

We retrospectively collected the data of 131 patients who underwent NSS, which was performed by a single surgeon (SZ) from January 2013 to July 2018 at Peking University Third Hospital. The “3S+f” score system contains four parameters: “size, side, site, and fat”, all of which can be obtained from preoperative imaging data. We evaluated the correlations between the “3S+f” score and clinical outcomes, and compared R.E.N.A.L. score and PADUA score.

Results

All the three nephrometry score systems were related to some clinical outcomes in univariate analyses. In multivariate regression models, the “3S+f” score, the R.E.N.A.L. score, and the PADUA score were significantly associated with operative time (p = 0.016, p = 0.035, and p = 0.001, respectively) and warm ischemia time (all p = 0.008, p < 0.001, and p < 0.001, respectively). “3S+f” was also significantly related to extubation time > 5 days (p = 0.018). In predicting operative time > 120 min and extubation time >5 days from ROC curves, the AUCs of the “3S+f” score (0.717 and 0.652, respectively) were larger than both the R.E.N.A.L (0.598 and 0.554, respectively) and PADUA (0.600 and 0.542, respectively) score systems.

Conclusion

A novel nephrometry score system—the “3S+f” score system—shows equivalent correlation and the ability in predicting clinical outcomes when compared to the R.E.N.A.L. score system and the PADUA score system, which can describe renal tumors.

Robotic-assisted tumor enucleation versus standard margin partial nephrectomy: Perioperative, renal functional, and oncologic outcomes for low and intermediate complexity renal masses

PURPOSE

Standard margin partial nephrectomy (SPN) with sharp incision across normal renal parenchyma carries perioperative morbidity and renal functional implications. Tumor enucleation (TE) is an alternative approach using a natural plane of dissection around the tumor pseudocapsule to maximize parenchymal preservation. We compared perioperative, functional, and oncologic outcomes for robotic-assisted TE to SPN.

MATERIALS AND METHODS

Patients ≥18 years of age undergoing robotic-assisted TE or SPN were included (2008-2020). Baseline demographics and tumor characteristics were compared. Perioperative, renal functional, and oncologic outcomes were assessed for comparative effectiveness.

RESULTS

A total of 467 patients were included with 176 (37.7%) TE and 291 (62.3%) SPN. Baseline characteristics and final histology were comparable; 18% of patients had baseline stage 3 chronic kidney disease. TE had lower median blood loss, operative time, length of stay, and fewer complications compared to SPN. Positive margin rates were higher for TE vs. SPN (8.5% vs. 3.4%, P = 0.04) with similar recurrence rates (2.3% vs. 3.4%, P = 0.48) and no difference in cancer-specific or overall survival with median 4.0 years follow-up. Baseline estimated glomerular filtration rate was comparable (76.1 vs. 78.2, P = 0.63) while renal function in the first year was better preserved with TE (74.6 vs. 68.1, P < 0.001) showing an 8-point estimated glomerular filtration rate (P = 0.001) advantage after adjustment. The rate of stage ≥3 chronic kidney disease by 12 months was lower for TE compared to SPN (21.5% vs. 34.1%, P = 0.006).

CONCLUSIONS

TE is an alternative approach to SPN associated with favorable perioperative and renal functional outcomes. While positive margin rates are higher, longer-term recurrence rates are no different suggesting pseudocapsule disruption during TE has limited impact on oncologic outcomes.

Long Non-Coding RNAs as Novel Biomarkers in the Clinical Management of Papillary Renal Cell Carcinoma Patients: A Promise or a Pledge?

Papillary renal cell carcinoma (pRCC) represents the second most common subtype of renal cell carcinoma, following clear cell carcinoma and accounting for 10–15% of cases. For around 20 years, pRCCs have been classified according to their mere histopathologic appearance, unsupported by genetic and molecular evidence, with an unmet need for clinically relevant classification. Moreover, patients with non-clear cell renal cell carcinomas have been seldom included in large clinical trials; therefore, the therapeutic landscape is less defined than in the clear cell subtype. However, in the last decades, the evolving comprehension of pRCC molecular features has led to a growing use of target therapy and to better oncological outcomes. Nonetheless, a reliable molecular biomarker able to detect the aggressiveness of pRCC is not yet available in clinical practice. As a result, the pRCC correct prognosis remains cumbersome, and new biomarkers able to stratify patients upon risk of recurrence are strongly needed. Non-coding RNAs (ncRNAs) are functional elements which play critical roles in gene expression, at the epigenetic, transcriptional, and post-transcriptional levels. In the last decade, ncRNAs have gained importance as possible biomarkers for several types of diseases, especially in the cancer universe. In this review, we analyzed the role of long non-coding RNAs (lncRNAs) in the prognosis of pRCC, with a particular focus on their networking. In fact, in the competing endogenous RNA hypothesis, lncRNAs can bind miRNAs, resulting in the modulation of the mRNA levels targeted by the sponged miRNA, leading to additional regulation of the target gene expression and increasing complexity in the biological processes.

Risk Factors for Renal Function Impairment Following Radiofrequency Ablation of Renal Tumors

Purpose

Materials and Methods

Results

Conclusion

Active Surveillance of Renal Masses: The Role of Radiology

Active surveillance of renal masses, which includes serial imaging with the possibility of delayed treatment, has emerged as a viable alternative to immediate therapeutic intervention in selected patients. Active surveillance is supported by evidence that many benign masses are resected unnecessarily, and treatment of small cancers has not substantially reduced cancer-specific mortality. These data are a call to radiologists to improve the diagnosis of benign renal masses and differentiate cancers that are biologically aggressive (prompting treatment) from those that are indolent (allowing treatment deferral). Current evidence suggests that active surveillance results in comparable cancer-specific survival with a low risk of developing metastasis. Radiology is central in this. Imaging is used at the outset to estimate the probability of malignancy and degree of aggressiveness in malignant masses and to follow up masses for growth and morphologic change. Percutaneous biopsy is used to provide a more definitive histologic diagnosis and to guide treatment decisions, including whether active surveillance is appropriate. Emerging applications that may improve imaging assessment of renal masses include standardized assessment of cystic and solid masses and radiomic analysis. This article reviews the current and future role of radiology in the care of patients with renal masses undergoing active surveillance.

Imaging considerations for thermal and radiotherapy ablation of primary and metastatic renal cell carcinoma

Ablative (percutaneous and stereotactic) thermal and radiotherapy procedures for management of both primary and metastatic renal cell carcinoma are increasing in popularity in clinical practice. Data suggest comparable efficacy with lower cost and morbidity compared to nephrectomy. Ablative therapies may be used alone or in conjunction with surgery or chemotherapy for treatment of primary tumor and metastatic disease. Imaging plays a crucial role in pre-treatment selection and planning of ablation, intra-procedural guidance, evaluation for complications, short- and long-term post-procedural surveillance of disease, and treatment response. Treatment response and disease recurrence may differ considerably after ablation, particularly for stereotactic radiotherapy, when compared to conventional surgical and chemotherapies. This article reviews the current and emerging role of imaging for ablative therapy of renal cell carcinoma.

Long-term renal function outcomes after renal cryoablation complicated by major hemorrhage requiring selective transarterial embolization

PURPOSE

To determine long-term renal function outcomes after renal cryoablation complicated by major hemorrhage requiring transarterial embolization compared to patients who underwent uncomplicated renal cryoablation without major hemorrhage.

METHODS

Utilizing a matched cohort study design, retrospective review identified 23 patients who underwent percutaneous image-guided renal cryoablation complicated by major hemorrhage requiring ipsilateral transarterial embolization (TAE group) and a control group of 23 patients who underwent uncomplicated renal cryoablation matched 1:1 by age, gender and RENAL Nephrometry score at a single institution from 1/1/2005 to 12/31/2019. Primary outcome parameters included change in creatinine (mg/dl) and estimated glomerular filtration rate (ml/min/1.73 m²; eGFR) from baseline and were compared between TAE and control group using a paired t-test.

RESULTS

There was a significantly higher proportion of patients on pre-ablation anticoagulation in the TAE v. control group (30% v. 4%; p = 0.047), but all patients were off anticoagulation and with normal coagulation parameters at the time of cryoablation. Otherwise there were no significant differences in clinical, renal tumor, Charlson co-morbidity index, baseline renal function or cryoablation parameters between the TAE and control group. In the post-ablation period, there was trend toward greater increase in creatinine from baseline to worst post-ablation creatinine in the TAE v. the control group (+ 0.5 ± 0.7 mg/dl v. 0.2 ± 0.1 mg/dl; p = 0.056). However, at a mean follow-up of 42.7 ± 35.7 months, there was no significant difference between the TAE and control group in creatinine (p = 0.68), eGFR (p = 0.60) or change from baseline in creatinine (p = 0.28), eGFR (p = 0.80) or CKD stage (p = 0.74). No patient required initiation of hemodialysis.

CONCLUSION

Selective transarterial embolization for post-renal cryoablation hemorrhage does not significantly affect long-term renal function compared to cryoablation alone. Pre-ablation anticoagulation despite normal coagulation at time of ablation may be a risk factor for post-ablation hemorrhage, and warrants further evaluation when considering pre-ablation embolization.

Comparison of Sutureless Versus Suture Partial Nephrectomy for Clinical T1 Renal Cell Carcinoma: A Meta-Analysis of Retrospective Studies

Background

Partial nephrectomy (PN) is the recommended treatment for T1 renal cell carcinoma (RCC). Compared with suture PN, sutureless PN reduces the difficulty and time of operation, but the safety and feasibility have been controversial. This meta-analysis was conducted to compare the function and perioperative outcomes of suture and sutureless PN for T1 RCC.

Methods

Systematic literature review was performed up to April 2021 using multiple databases to identify eligible comparative studies. According to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) criteria, identification and selection of the studies were conducted. Meta-analysis was performed for studies comparing suture to sutureless PN for both T1a and T1b RCC. In addition, subgroup analysis was performed on operation time, warm ischemia time, estimated blood loss, and postoperative complications. Sensitivity analysis was used in analysis with high heterogeneity (operation time and estimated blood loss).

Results

Eight retrospective studies were included with a total of 1,156 patients; of the 1,156 patients, 499 received sutureless PN and 707 received suture PN. The results showed that sutureless PN had shorter operative time (I² = 0%, P < 0.001), warm ischemia time (I² = 97.5%, P < 0.001), and lower clamping rate (I² = 85.8%, P = 0.003), but estimated blood loss (I² = 76.6%, P = 0.064) had no difference. In the comparison of perioperative outcomes, there was no significant difference in postoperative complications (I² = 0%, P = 0.999), positive surgical margins (I² = 0%, P = 0.356), postoperative estimated glomerular filtration rat (eGFR) (I² = 0%, P = 0.656), and tumor recurrence (I² = 0%, P = 0.531).

Conclusions

In T1a RCC with low RENAL score, sutureless PN is a feasible choice, whereas it should not be overestimated in T1b RCC.

Chronic Kidney Disease in Cancer Survivors

As breakthroughs in cancer care are leading to improved long-term outcomes in a subset of advanced cancers, there is a growing population of long-term cancer survivors that are at risk of long-term complications. In this review, we summarize what is known about chronic kidney disease in cancer survivors, focusing on the following high-risk groups: survivors of childhood cancers, stem cell transplant recipients, patients with renal cell carcinoma, patients exposed to cisplatin and other nephrotoxic chemotherapies, and patients receiving immunotherapy for cancer. As new anticancer therapies are developed, more research is needed to understand the long-term risks of kidney function decline and to devise methods to prevent chronic kidney disease.

Split renal function after treatment of small renal masses: comparison between radiofrequency ablation and laparoscopic partial nephrectomy

BACKGROUND

Radiofrequency ablation (RFA) and laparoscopic partial nephrectomy (LPN) are used to treat small renal masses (SRM; ≤4 cm), although there are conflicting results in the changes in creatinine and estimated glomerular filtration rate (eGFR) after treatment. On contrast-enhanced computed tomography (CE-CT) images, the quantity and quality of renal function can be evaluated by calculating the split renal function (SRF).

PURPOSE

To compare renal function after RFA or LPN treatment of SRMs through evaluation of the SRF in the affected kidney.

MATERIAL AND METHODS

Single T1a renal tumors successfully treated with RFA (n = 60) or LPN (n = 31) were retrospectively compared. The SRF was calculated on pre-treatment CE-CT images and the first follow-up exam after completed treatment. Serum creatinine and eGFR values were collected simultaneously. To compare renal function outcomes, Student's t-test and multivariable linear regression models (adjusted to RFA/LPN treatment, pre-treatment SRF/eGFR, BMI, age, tumor characteristics, and Charlson Comorbidity Index) were used.

RESULTS

SRF was reduced in both groups, although reduction was greater in the LPN group (LPN -5.7%) than in the RFA group (RFA -3.5%; P = 0.013). After adjusted analysis, the LPN group still had greater SRF reduction (difference 3.2%, 95% confidence interval 1.3-1.5; P = 0.001). There was no difference between groups in the change of creatinine/eGFR after treatment.

CONCLUSION

Both RFA and LPN are nephron-sparing when treating SRMs. However, in this series, reduction of SRF in the affected kidney was smaller after RFA, having a more favorable preservation of renal function than LPN.

Acute kidney injury promotes development of papillary renal cell adenoma and carcinoma from renal progenitor cells

Acute tissue injury causes DNA damage and repair processes involving increased cell mitosis and polyploidization, leading to cell function alterations that may potentially drive cancer development. Here, we show that acute kidney injury (AKI) increased the risk for papillary renal cell carcinoma (pRCC) development and tumor relapse in humans as confirmed by data collected from several single-center and multicentric studies. Lineage tracing of tubular epithelial cells (TECs) after AKI induction and long-term follow-up in mice showed time-dependent onset of clonal papillary tumors in an adenoma-carcinoma sequence. Among AKI-related pathways, NOTCH1 overexpression in human pRCC associated with worse outcome and was specific for type 2 pRCC. Mice overexpressing NOTCH1 in TECs developed papillary adenomas and type 2 pRCCs, and AKI accelerated this process. Lineage tracing in mice identified single renal progenitors as the cell of origin of papillary tumors. Single-cell RNA sequencing showed that human renal progenitor transcriptome showed similarities to PT1, the putative cell of origin of human pRCC. Furthermore, NOTCH1 overexpression in cultured human renal progenitor cells induced tumor-like 3D growth. Thus, AKI can drive tumorigenesis from local tissue progenitor cells. In particular, we find that AKI promotes the development of pRCC from single progenitors through a classical adenoma-carcinoma sequence.

A 25 year perspective on the evolution and advances in an understanding of the biology, evaluation and treatment of kidney cancer

The diagnosis, evaluation and management of patients with renal cell carcinoma has transformed in the 21st century. Utilizing biological discoveries and technological advances, the field has moved from blunt surgical and largely ineffective medical treatments, to nuanced and fine-tuned approaches based on biology, extent of disease and patient preferences. In this review we will summarize the last 25 years of progress in kidney cancer.

Microwave ablation of cT1a renal cell carcinoma: oncologic and functional outcomes at a single center

PURPOSE

Percutaneous ablation is an established alternative to surgical intervention for small renal masses. Radiofrequency and cryoablation have been studied extensively in the literature. To date, series assessing the efficacy and safety of microwave ablation (MWA) are limited. We present a cohort of 110 renal tumors treated with MWA.

METHODS

A review of the medical record between January 2015 and July 2019 was performed, retrospectively identifying 101 patients (110 tumors). All ablations were performed by a single board-certified urologist/interventional radiologist. Demographic information, intraoperative, postoperative, and follow-up surveillance data were recorded.

RESULTS

Median (IQR) age was 69.7 years (60.8-77.0); 27 (24%) were female. Median (IQR) BMI was 27.0 (25.1-30.2) and Charleston Comorbidity Index was 5.0 (4.0-6.0). 82 tumors were biopsy-confirmed renal cell carcinoma/oncocytic neoplasms. Median (IQR) tumor size was 2.0 cm (1.5-2.6). Median (IQR) RENAL nephrometry score was 6.0 (5.0-8.0). Technical success was achieved in all patients and all but one patient were discharged on the same day. Median (IQR) eGFR at baseline and 1 year were 71.9 mL/min/1.73 m² (56.5-82) and 63.0 mL/min/1.73 m² (54.0-78.2); the difference was -5.3 (p = 0.12). Two Clavien-Dindo type-I complications, one type-II complication, and one type-III complication were experienced in this cohort. Median radiographic follow-up was 376.5 days with 2 tumors (2.4% of RCC/oncocytic neoplasms) having recurred to date.

CONCLUSIONS

MWA is a safe and efficacious treatment option for small renal masses with minimal adverse events and low rates of recurrence in this cohort of 101 patients. Continued follow-up is needed to assess long-term outcomes.

The Nephrologist's Management of Renal Cell Carcinoma After Kidney Surgery

Renal cell carcinoma is associated with chronic kidney disease as well as with common risk factors including hypertension and diabetes mellitus. Localized renal cell carcinoma is treated surgically and in these cases has a favorable prognosis. In particular, in those individuals with small renal masses (≤4 cm), preservation of kidney function should be prioritized. Postoperative chronic kidney disease or end-stage renal disease prevention should include baseline kidney function and risk factor assessment, nontumor renal biopsy, as well as counseling on treatment options to discuss maximizing kidney function preservation. Postnephrectomy prognosis can be determined with repeat laboratory and clinical assessment. Ultimately, early involvement of the nephrologist in a multidisciplinary team including the urology team will enable the reduction of postsurgical kidney disease related morbidity and potentially mortality.

Collaborative Review: Factors Influencing Treatment Decisions for Patients with a Localized Solid Renal Mass

CONTEXT

With the addition of active surveillance and thermal ablation (TA) to the urologist's established repertoire of partial (PN) and radical nephrectomy (RN) as first-line management options for localized renal cell carcinoma (RCC), appropriate treatment decision-making has become increasingly nuanced.

OBJECTIVE

To critically review the treatment options for localized, nonrecurrent RCC; to highlight the patient, renal function, tumor, and provider factors that influence treatment decisions; and to provide a framework to conceptualize that decision-making process.

EVIDENCE ACQUISITION

A collaborative critical review of the medical literature was conducted.

EVIDENCE SYNTHESIS

We identify three key decision points when managing localized RCC: (1) decision for surveillance versus treatment, (2) decision regarding treatment modality (TA, PN, or RN), and (3) decision on surgical approach (open vs minimally invasive). In evaluating factors that influence these treatment decisions, we elaborate on patient, renal function, tumor, and provider factors that either directly or indirectly impact each decision point. As current nomograms, based on preselected patient datasets, perform poorly in prospective settings, these tools should be used with caution. Patient decision aids are an underutilized tool in decision-making.

CONCLUSIONS

Localized RCC requires highly nuanced treatment decision-making, balancing patient- and tumor-specific clinical variables against indirect structural influences to provide optimal patient care.

PATIENT SUMMARY

With expanding treatment options for localized kidney cancer, treatment decision is highly nuanced and requires shared decision-making. Patient decision aids may be helpful in the treatment discussion.

Percutaneous tumor ablation versus partial nephrectomy for small renal mass: the impact of histologic variant and tumor size

BACKGROUND

The aim, of this study was to investigate recurrence rates in patients with T1 renal cell carcinoma (RCC) undergone partial nephrectomy (PN), radiofrequency ablation (RFA) or cryoablation (Cryo).

METHODS

We retrospectively evaluated data from 665 (81.4%), 68 (8.3%) and 83 (10.3%) patients who underwent PN, RFA and Cryo, respectively. Kaplan-Meier curves depict recurrence-free survival (RFS) rates in the overall population and after stratifying according to tumor's histology (namely, clear cell RCC and non-clear RCC) and size (namely <2 cm and 2-4 cm). Multivariable Cox regression model was used to identify predictors of recurrence. Cumulative-incidence plots evaluated disease recurrence and other causes of mortality (OCM).

RESULTS

Patients referred to PN experienced higher RFS rate compared to those treated with RFA and Cryo at 60-month in the overall population (96.4% vs. 79.4% vs. 87.8%), in patients with clear cell RCC (93.3% vs. 75% vs. 80.4%) and in those with tumor of 2-4 cm (97.3% vs. 78% and 84.4%; all P≤0.01). In patients with non-clear cell RCC and with tumor <2cm, PN showed higher RFS rate at 60-month as compared to RFA (97.9% vs. 84.4% and 95.1% vs. 78.1%, respectively: all P≤0.02). At multi-variate analysis, ablative techniques (RFA [HR=4.03] and Cryo [HR=3.86]) were independent predictors of recurrence (all P<0.03). At competing risks analysis, recurrence rate and OCM were 7.3% and 1.3% vs. 25% and 7.2% vs. 19.9% and 19.9% for PN, RFA and Cryo, respectively.

CONCLUSIONS

PN and Cryo showed similar RFS rates in patients with non-clear cell RCC and with renal mass <2cm.

Preventive strategies for acute kidney injury in cancer patients

Acute kidney injury (AKI) is a common complication of cancer that occurs in up to 50% of neoplastic patients during the natural history of their disease; furthermore, it has a huge impact on key outcomes such as overall prognosis, length of hospitalization and costs. AKI in cancer patients has different causes, either patient-, tumour- or treatment-related. Patient-related risk factors for AKI are the same as in the general population, whereas tumour-related risk factors are represented by compression, obstruction, direct kidney infiltration from the tumour as well by precipitation, aggregation, crystallization or misfolding of paraprotein (as in the case of multiple myeloma). Finally, treatment-related risk factors are the most common observed in clinical practice and may present also with the feature of tumour lysis syndrome or thrombotic microangiopathies. In the absence of validated biomarkers, a multidisciplinary clinical approach that incorporates adequate assessment, use of appropriate preventive measures and early intervention is essential to reduce the incidence of this life-threatening condition in cancer patients.

Utilization of renal mass biopsy in patients with localized renal cell carcinoma: A population-based study utilizing the National Cancer Database

OBJECTIVE

To evaluate trends and factors predicting use of renal mass biopsy (RMB) for localized Renal Cell Carcinoma in the United States (US) in the context of current guidelines recommendations.

METHODS

We queried the National Cancer Database for cT1-cT3N0M0 Renal Cell Carcinoma diagnosed between 2004 and 2015. Temporal trends of RMB were characterized based on tumor size, treatment (partial nephrectomy [PN], radical nephrectomy [RN], ablation, and no treatment), age and Charlson Comorbidity Index with slopes compared using analysis of variance. Multivariable analysis was used to determine factors associated with use of RMB.

RESULTS

Of 338,252 patients analyzed, 11.9% (40,276) underwent RMB. Use of RMB increased throughout the study period from 1,586 (7.6%) in 2004 to 5,629 (16.2%) in 2015 (P < 0.001). Use of RMB increased greatest for ablation (27 to 63%, P < 0.001) and tumors 2-4 cm (9 to 20%, P < 0.001). Multivariable analysis showed year of diagnosis (OR = 1.06; P < 0.001), higher education (OR = 1.09; P < 0.001) and insured status (OR = 1.23; P < 0.001) were associated with increased RMB. Compared to tumors ≤2 cm, tumors 2.1-4 cm (OR = 1.36; P=<0.001), 4.1-7 cm (OR = 1.18; P <0.001) and >7 cm (OR = 1.05; P = 0.03) were associated with higher rates of RMB. Compared to RN, PN was not associated with increased RMB (OR = 1.00; P = 0.92), while ablation (OR = 10.90; P < 0.001) and no surgical treatment (OR = 4.83; P < 0.001) were.

CONCLUSION

RMB utilization increased overall, with largest increase associated with ablation. Nonetheless, only two-thirds of patients underwent RMB with ablation, suggesting persistent underutilization. Rates of RMB for tumors ≤2 cm and in those undergoing no treatment increased less, suggesting less utilization for surveillance. However, rates for tumors >2-4 cm increased more, suggesting selective utilization of RMB to guide decision-making and risk stratification in small renal masses.

Robotic-assisted Partial Nephrectomy for "Very Small" (<2 cm) Renal Mass: Results of a Multicenter Contemporary Cohort

BACKGROUND

Patient with "very small" (<2 cm) renal mass can be offered active surveillance, thermal ablation, or partial nephrectomy. The management strategy will consider patient preferences and prioritize potential harms associated with each of these options. To date, outcomes of robot-assisted partial nephrectomy (RAPN) in patients with "very small" renal masses have not been reported.

OBJECTIVE

To assess the outcomes of RAPN among patients with "very small" renal masses.

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective analysis of a multi-institutional database including RAPN cases performed at eight high-volume US and European centers between 2009 and 2019. Patients were stratified into two groups according to clinical tumor size: <2 cm ("very small" renal mass, study group) and 2-4 cm (control group).

INTERVENTION

RAPN for renal masses.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Baseline characteristics and intraoperative, pathological, and postoperative data were compared between the study and the control group. A "trifecta" was used as surrogate of "surgical quality."

RESULTS AND LIMITATIONS

Overall, a total of 1019 patients were included in the analysis. Of these, 352 had a renal mass of <2 cm (34.5%) and 667 (65.5%) had a renal mass of 2-4 cm. At baseline, the study group presented a lower rate of chronic kidney disease ≥stage III (p < 0.001), a lower RENAL score (p = 0.001), and lower rates of hilar (p = 0.04) and endophytic (p = 0.02) masses. Warm ischemia time was shorter for the study group (median 14 vs 18 min, p < 0.001), which also showed a lower rate of overall postoperative complications (9.6% vs 14.7%, p < 0.001) and no major complications. In terms of oncological outcomes, three and ten patients developed a local recurrence in the study and the control group, respectively (p = 0.1). In the study group, higher estimated glomerular filtration rates were found at discharge (p = 0.001) and at the last follow-up (p = 0.007), which showed a "trifecta" achievement of 90.6%. The retrospective design may limit the generalizability of the findings.

CONCLUSIONS

Whenever an active treatment is indicated or warranted, RAPN represents a minimally invasive management option for "very small" renal masses, as it carries minimal risk of complications and has minimal impact on renal function. While both active surveillance and kidney ablation remain valid management options in these cases, RAPN can be offered and discussed with patients as it provides excellent outcomes with low morbidity.

PATIENT SUMMARY

In this report, we observed that robot-assisted partial nephrectomy represents a true minimally invasive active treatment for "very small" renal masses (<2 cm), as it carries minimal risk of complications and has minimal impact on renal function.

Perspectives From an Onconephrology Interest Group: Conference Report

Introduction and objective:

Onconephrology is a new and evolving field that deals with kidney complications in patients with cancer as well as the management of cancer in patients with preexisting kidney disease. With increasing numbers of patients with cancer with kidney-related complications, the field has garnered increased attention. Thus, an annual Greater Toronto Area Onconephrology Interest Group symposium was held in May 2019. The objective of the meeting was to demonstrate the junctures between oncology and nephrology by highlighting recent data regarding (1) kidney impairment in solid organ malignancies, (2) management and treatment of kidney cancer, (3) kidney impairment in hematologic malignancies, (4) malignancy and kidney transplantation, and (5) hyponatremia in patients with cancer.

Methods and sources of information:

Through a structured presentation, the group explored key topics discussed at a Kidney Disease Improving Global Outcomes (KDIGO) Controversies Conference on Onconephrology. Expert opinions, clinical trial findings, and publication summaries were used to illustrate patient and treatment-related considerations in onconephrology.

Key findings:

Kidney complications in patients with cancer are a central theme in onconephrology. An estimated 12% to 25% of patients with solid organ malignancies have chronic kidney disease (CKD), although in certain cancers, the prevalence of CKD is higher. Kidney impairment is also a common complication of some hematologic malignancies. The incidence of renal failure in patients with multiple myeloma is estimated at 18% to 56% and light chain cast nephropathy is seen in approximately 30% of these patients. In addition, there appears to be a bidirectional relationship between kidney cancer and CKD, with some data sets suggesting the risk increases as kidney function declines. Cancer is also of concern in patients with preexisting kidney disease. Kidney transplant recipients have a greater risk of cancer and a higher risk of cancer-related mortality. Kidney complications have also been associated with novel cancer therapies, such as immune checkpoint inhibitors and chimeric antigen receptor (CAR) T-cell therapy. An estimated 2% to 4% of patients initiating an immune checkpoint inhibitor may develop nephrotoxicity, whereas up to 40% of patients on CAR T-cell therapy experience cytokine release syndrome (CRS). Tumor lysis syndrome and electrolyte abnormalities, such as hyponatremia, have also been reported with CAR T-cell therapy. While the incidence and prevalence of hyponatremia vary depending on the cancer type and serum sodium cutoff point, hyponatremia may be seen in up to 46% of patients hospitalized in cancer centers.

Conclusions:

Onconephrology is a developing field and the themes arising from this meeting indicate a need for greater collaboration between oncologists and nephrologists. Educational symposia and onconephrology fellowship programs may allow for improved cancer care for patients with kidney disease.

Renal cryoablation - a practical guide for interventional radiologists

Renal cryoablation is a treatment option for early stage renal cell carcinomas with excellent oncological outcomes and low morbidity. This review outlines the technique of renal cryoablation and provides a guide for interventional radiologists on setting up an integrated service within a renal cancer network multidisciplinary setting. Patient selection and preparation, together with the technical aspects which ensure optimal oncological outcomes and avoid collateral damage to adjacent organs are highlighted.

Repeat ablative therapy in hereditary or multifocal renal cancer: Functional and oncological outcomes

OBJECTIVES

To report managing renal tumors in patients at greater risk of repeated interventions (genetic predisposition, multifocal tumors) with thermoablative treatments (AT). A known significant challenge in these patients is the balance between nephron preservation and oncologic outcome.

MATERIAL AND METHODS

This retrospective, single-center study was based on data from patients treated with one or more AT for hereditary or multifocal renal tumors between 2007 and 2017. All medical records were systematically reviewed, and 10 patients meeting inclusion criteria were selected. Six patients had confirmed von Hippel-Lindau disease, 1 Bird-Hogg-Dubé syndrome, 1 chromosome 3 translocation, and 2 had a presumed genetic predisposition.

RESULTS

Median age at cancer diagnosis was 39.5 years (±8.9). Fifty-seven tumors, including 41 de novo tumors that appeared during follow-up, were treated with 32 AT sessions (cryotherapy or radiofrequency) with an average tumor size of 13.5 mm (±9) and a median RENAL score of 6 [5; 7]. One patient underwent concomitant partial nephrectomy for a 55 mm lesion which was close to the bowel. Treatment was unsuccessful in 2 cases, subsequently managed successfully by retreatment with AT. Median delay of appearance of de novo tumor after the first AT was 18 months [6 ; 24]. One patient had metastatic progression. Overall and cancer specific survival was 90% and 100%, respectively, with a mean follow-up of 7.5 years (±4.9). The mean decrease in Chronic Kidney Disease - Epidemiological Collaboration equation-estimated glomerular filtration rate at the end of follow-up was 5.5 ml/min/1.73 m² (±24).

CONCLUSION

This study suggests that AT allows to meet the oncological objectives whilst preserving renal function in patients with renal cancer at greater risk of repeated treatments.

Computed tomography (CT)-guided percutaneous coaxial biopsy combined with microwave ablation for the treatment of renal masses

PURPOSE

This study aimed to investigate the feasibility, safety, and efficacy of computed tomography (CT)-guided percutaneous coaxial biopsy combined with microwave ablation (MWA) for the treatment of renal masses.

MATERIAL AND METHODS

The clinical data of ten patients (14 tumors) treated with CT-guided percutaneous coaxial biopsy combined with MWA from January 2017 to November 2019 were retrospectively analyzed. The patients were followed up for 2-33 months. The outcomes were evaluated with plain and contrast spiral CT scans. Renal function was assessed using the estimated glomerular filtration rate.

RESULTS

No severe MWA-related complication was observed. All the tumors were successfully ablated. There was no imaging evidence of local residual tumor, local tumor recurrence, or disease progression during the follow-up period.

CONCLUSIONS

CT-guided percutaneous coaxial biopsy combined with MWA might be an effective option for the diagnosis and treatment of renal masses in selected patients.