Single-cell multiomics reveals ENL mutation perturbs kidney developmental trajectory by rewiring gene regulatory landscape.

How disruptions to normal cell differentiation link to tumorigenesis remains incompletely understood. Wilms tumor, an embryonal tumor associated with disrupted organogenesis, often harbors mutations in epigenetic regulators, but their role in kidney development remains unexplored. Here, we show at single-cell resolution that a Wilms tumor-associated mutation in the histone acetylation reader ENL disrupts kidney differentiation in mice by rewiring the gene regulatory landscape. Mutant ENL promotes nephron progenitor commitment while restricting their differentiation by dysregulating transcription factors such as Hox clusters. It also induces abnormal progenitors that lose kidney-associated chromatin identity. Furthermore, mutant ENL alters the transcriptome and chromatin accessibility of stromal progenitors, resulting in hyperactivation of Wnt signaling. The impacts of mutant ENL on both nephron and stroma lineages lead to profound kidney developmental defects and postnatal mortality in mice. Notably, a small molecule inhibiting mutant ENL's histone acetylation binding activity largely reverses these defects. This study provides insights into how mutations in epigenetic regulators disrupt kidney development and suggests a potential therapeutic approach.

Comparing ECIRS with MPCNL for Complex Renal Calculi: A Retrospective Single-Centre Study on Efficacy and Safety.

BACKGROUND: Kidney stones, a common urinary system ailment, often necessitate surgical intervention. Endoscopic combined intrarenal surgery (ECIRS) and multi-channel percutaneous nephron lithotripsy (MPCNL) are key modalities for treating complex renal stones, prompting the need for a comparative analysis to enhance clinical decision-making. METHODS: Patients undergoing surgical treatment for complex kidney stones from April 2018 to April 2022 were divided into the control (MPCNL) and observation (ECIRS) groups. Propensity score matching was used to balance baseline data, and t-tests and chi-square tests were employed to compare the perioperative indicators between the two groups. RESULTS: A total of 210 patients were enrolled in this study for pre-observational comparison, and they were divided into the control group (110 patients) and observation group (100 patients). Following matching, each group comprised 85 patients. Pre-observational comparison revealed significant differences between the groups in age, disease duration, and stone diameter (p < 0.05). However, after matching, baseline data comparison showed no statistically significant differences (p > 0.05). Surgery-related parameters, including operation time, intraoperative blood loss, postoperative activity duration and hospital stay, did not significantly differ between the groups (p > 0.05). The observation group exhibited a significantly higher stone retention-free rate after initial treatment compared with the control group (p < 0.05), although overall stone clearance rates did not significantly differ between the groups (p > 0.05). We found no significant differences in perioperative complications between the two groups (p > 0.05). Moreover, the observation group experienced significantly lower postoperative pain levels at 6, 24 and 48 h compared with the control group (p < 0.001). CONCLUSIONS: Conclusively, ECIRS and MPCNL are viable options for treating complex renal calculi, with similar operation times, complication rates and stone clearance rates. ECIRS may offer advantages including lower postoperative pain and higher initial stone clearance rates than MPCNL. However, large-scale studies with long follow-up times are needed for validation.

Long-term expandable mouse and human-induced nephron progenitor cells enable kidney organoid maturation and modeling of plasticity and disease.

Nephron progenitor cells (NPCs) self-renew and differentiate into nephrons, the functional units of the kidney. Here, manipulation of p38 and YAP activity allowed for long-term clonal expansion of primary mouse and human NPCs and induced NPCs (iNPCs) from human pluripotent stem cells (hPSCs). Molecular analyses demonstrated that cultured iNPCs closely resemble primary human NPCs. iNPCs generated nephron organoids with minimal off-target cell types and enhanced maturation of podocytes relative to published human kidney organoid protocols. Surprisingly, the NPC culture medium uncovered plasticity in human podocyte programs, enabling podocyte reprogramming to an NPC-like state. Scalability and ease of genome editing facilitated genome-wide CRISPR screening in NPC culture, uncovering genes associated with kidney development and disease. Further, NPC-directed modeling of autosomal-dominant polycystic kidney disease (ADPKD) identified a small-molecule inhibitor of cystogenesis. These findings highlight a broad application for the reported iNPC platform in the study of kidney development, disease, plasticity, and regeneration.

Management of renal sinus angiomyolipoma: modified robotic nephron-sparing surgery in a single center.

BACKGROUND: Renal sinus angiomyolipoma (RSAML) is a rare and typically complex renal tumor. The objective is to present our single-center experience with a modified technique of robotic nephron-sparing surgery (NSS) for treating RSAML. METHODS: We retrospectively evaluated 15 patients with RSAMLs who were treated with robotic NSS at the Department of Urology of Tongji hospital, ranging from November 2018 to September 2022. Renal vessels and ureter were dissected. The outer part of RSAML was resected. The rest of tumor was removed by bluntly grasp, curettage and suction. Absorbable gelatin sponges were filled in the renal sinus. The preoperative parameters, operative measures and postoperative outcomes were all collected. Follow-up was performed by ultrasonography and estimated glomerular filtration rate (eGFR). RESULTS: Robotic NSS was successfully performed in all the patients, without any conversion to open surgery or nephrectomy. The mean operation time was 134.13 ± 40.56 min. The mean warm ischemia time was 25.73 ± 3.28 min. The median estimated blood loss was 100 [50, 270] ml and 1 patient required blood transfusion. The mean drainage duration was 5.77 ± 1.98 days. The median postoperative hospital stay was 6.90 [5.80, 8.70] days. Two patients experienced postoperative urinary tract infection (Clavien-Dindo Grade II). During the median follow-up of 25.53 ± 15.28 months, patients received 91.18% renal function preservation. No local recurrence occurred in all the patients. CONCLUSIONS: Robotic NSS for RSAML is a complicated procedure that demands technical expertise and a well-designed strategy is critical in the operation. Treating RSAML with modified robotic NSS is safe, effective and feasible.

[Oncological results of repeat partial nephrectomy in patients with recurrence after nephron-sparing procedures].

AIM: To carried out a comparative analysis of the risk of complications and oncological results of repeat partial nephrectomy and radical nephrectomy in patients with local recurrence after previous organ-sparing procedures. MATERIALS AND METHODS: Retrospective and prospective data of 64 patients with local recurrence of kidney cancer after nephron-sparing procedures. who underwent surgical treatment in the department of oncourology of the National Medical Research Center of Oncology named after N.N. Blokhin in the period from 2000 to 2022. A total of 37 (57.8%) patients of the main group underwent repeat partial nephrectomy, while in 27 (42.2%) patients in the control group a radical nephrectomy was done. Median follow-up was 35 (3-131; Q1-Q3: 13-57) months. Both groups were comparable in terms of demographic and clinical characteristics (p>0.05). The median time to detect relapse after previous partial nephrectomy was 24 (2-172) months. RESULTS: Complications were noted in 8 (21.6%) patients after repeat partial nephrectomy, compared to 29.6% in the control group (n=8) (p=0.563). A comparative analysis revealed a significant advantage in overall survival in patients of the main group (p=0.042). There were no significant differences between groups in cancer-specific and disease-free survival (p=0.369 and p=0.537, respectively). CONCLUSION: Repeat partial nephrectomy for local recurrence of kidney cancer leads to an increase in overall survival compared to radical nephrectomy, in the absence of significant differences in cancer-specific and relapse-free survival.

Renal artery pseudoaneurysm following robot assisted nephron sparing surgery: two case reports.

BACKGROUND: Renal artery pseudoaneurysm following partial nephrectomy is a rare entity, the incidence of this entity is more common following penetrating abdominal injuries, percutaneous renal interventions such as percutaneous nephrostomy(PCN) or Percutaneous nephrolithotomy (PCNL). Although rare, renal artery pseudoaneurysm can be life threatening if not managed timely, they usually present within two weeks postoperatively with usual presenting complains being gross haematuria, flank pain and/or anaemia. CASE PRESENTATION: We report case of two female patients 34 and 57 year old respectively of South Asian ethnicity, presenting with renal artery pseudoaneurysm following left sided robot assisted nephron sparing surgery for interpolar masses presenting clinically with total, painless, gross haematuria with clots within fifteen days postoperatively and their successful treatment by digital subtraction angiography and coil embolization. CONCLUSION: Renal artery aneurysm is a rare fatal complication of minimally invasive nephron sparing surgery however considering the preoperative and intraoperative risk factors for its development and prompt suspicion at the outset can be life saving with coil embolization of the bleeding arterial aneurysm.

Preoperative three-dimensional modelling and virtual reality planning aids nephron sparing surgery in a child with bilateral Wilms tumour.

Bilateral Wilms tumour (BWT) is a surgically challenging condition. Virtual reality (VR) reconstruction aids surgeons to foresee the anatomy ahead of Nephron Sparing Surgery (NSS). Three-dimensional (3D) visualisation improves the anatomical orientation of surgeons performing NSS. We herewith report a case of BWT where VR planning and 3D printing were used to aid NSS. Conventional imaging is often found to be inadequate while assessing the tumour-organ-vascular anatomy. Advances like VR and 3D printing help surgeons plan better for complex surgeries like bilateral NSS. Next-generation extended reality tools will likely aid robotic-assisted precision NSS and improve patient outcomes.

Preoperative risk calculator for the probability of completing nephron sparing for kidney cancer.

PURPOSE: In absence of predictive models, preoperative estimation of the probability of completing partial (PN) relative to radical nephrectomy (RN) is invariably inaccurate and subjective. We aimed to develop an evidence-based model to assess objectively the probability of PN completion based on patients' characteristics, tumor's complexity, urologist expertise and surgical approach. DESIGN, SETTING AND PARTICIPANTS: 675 patients treated with PN or RN for cT1-2 cN0 cM0 renal mass by seven surgeons at one single experienced centre from 2000 to 2019. OUTCOMES MEASUREMENTS AND STATISTICAL ANALYSES: The outcome of the study was PN completion. We used a multivariable logistic regression (MVA) model to investigate predictors of PN completion. We used SPARE score to assess tumor complexity. We used a bootstrap validation to compute the model's predictive accuracy. We investigated the relationship between the outcomes and specific predictors of interest such as tumor's complexity, approach and experience. RESULTS: Of 675 patients, 360 (53%) were treated with PN vs. 315 (47%) with RN. Smaller tumors [Odds ratio (OR): 0.52, 95%CI 0.44-0.61; P < 0.001], lower SPARE score (OR: 0.67, 95%CI 0.47-0.94; P = 0.02), more experienced surgeons (OR: 1.01, 95%CI 1.00-1.02; P < 0.01), robotic (OR: 10; P < 0.001) and open (OR: 36; P < 0.001) compared to laparoscopic approach resulted associated with higher probability of PN completion. Predictive accuracy of the model was 0.94 (95% CI 0.93-0.95). CONCLUSIONS: The probability of PN completion can be preoperatively assessed, with optimal accuracy relaying on routinely available clinical information. The proposed model might be useful in preoperative decision-making, patient consensus, or during preoperative counselling. PATIENT SUMMARY: In patients with a renal mass the probability of completing a partial nephrectomy varies considerably and without a predictive model is invariably inaccurate and subjective. In this study we build-up a risk calculator based on easily available preoperative variables that can predict with optimal accuracy the probability of not removing the entire kidney.

Risk Factors of Open Surgery Conversion in Laparoscopic Partial Nephrectomy to Achieve Nephron Sparing.

OBJECTIVES: We aimed to evaluate the risk factors for the conversion from laparoscopic partial nephrectomy (LPN) to open surgery to achieve partial nephrectomy (PN). METHODS: Data from patients who underwent LPN between June 2020 and September 2023 were analyzed retrospectively. Patients in whom the PN procedure could be completed laparoscopically were recorded as the 'Fully Laparoscopic' (FL) group (n = 97), and those converted to open surgery from laparoscopy were recorded as the 'Conversion to Open' (CTO) group (n = 10). The demographic and pathologic variables were compared between groups. Regression analyses were used to define predictor factors, and receiver operating characteristic analysis was used to define the cut-off value of the surgical bleeding volume. RESULTS: Conversion to open surgery was found in 10/107 patients (9.3%). There was no statistical difference between groups in demographic and pathologic variables. Intraoperative blood loss volume, upper pole localized tumor, and posterior localized tumor were found to be statistically higher in the CTO group (p = 0.001, p = 0.001, and p = 0.043, respectively). Furthermore, these factors were only found to be statistically significant predictors of conversion to open surgery in both univariate and multivariate regression analyses. 235 cc was found to be the cut-off value of intraoperative blood loss volume for predicting conversion to open surgery (p = 0.001). CONCLUSION: Using these predictive factors in clinical practice, treatment planning will lead to the possibility of starting the treatment directly with open surgery instead of minimally invasive options, and it may also provide a chance of being prepared for the possibility of conversion to open surgery peroperatively.

Robotic transperitoneal versus retroperitoneal approach for anterior renal mass nephron-sparing surgery.

Robotic nephron-sparing surgery is traditionally performed via a transperitoneal (TP) approach. However, the retroperitoneal (RP) approach has gained popularity, particularly for posterolateral renal masses. The RP approach is associated with shorter operative time, less blood loss, and shorter length of stay, while preserving oncologic outcomes in selected masses. Here, we aim to assess the feasibility of the RP approach in excising anterior renal masses. Patients ≥ 18 years of age who underwent robotic nephron-sparing surgery for anterior renal masses were retrospectively identified (2008-2022). Baseline demographics, tumor characteristics, and perioperative data were collected and characterized based on TP vs RP approaches. Wilcoxon rank sum test and Pearson's Chi-squared test were used to compare continuous and categorical variables, respectively. Two hundred and sixteen patients were included-178 (82.4%) underwent TP approach and 38 (17.6%) underwent RP approach. Baseline demographics, preoperative tumor size, and renal nephrometry scores were similar. The RP approach was associated with shorter operative (150 vs 203 min, p < 0.001) and warm ischemia time (12 vs 21 min, p < 0.001), and less blood loss (20 vs 100 cc, p = 0.002) (Table 1). The RP approach was associated with shorter length of stay (1 vs 2 days, p < 0.001) and less total complications (5.3% vs 19.1%, p = 0.038). Major complication (Clavien-Dindo Grade > 3) rates were similar. There was no difference in positive surgical margin rates or pathologic characteristics. Robotic RP approach for nephron-sparing surgery is feasible for eligible anterior tumors and is associated with favorable perioperative outcomes with preserved negative surgical margin rates. Table 1 Patient baseline demographics Overall Transperitoneal Retroperitoneal p value Median/N IQR/% Median/N IQR/% Median/N IQR/% N 216 178 82.4% 38 17.6% Age (years) 60.5 (52.1-67.7) 60.4 (52.8-67.7) 61.6 (49.1-69.2) 0.393 Sex Male 126 58.3% 100 56.2% 26 68.4% Female 90 41.7% 78 43.8% 12 31.6% 0.165 Race White 162 75.0% 137 77.0% 25 65.8% Asian 4 1.9% 2 1.1% 2 5.3% Black 21 9.7% 18 10.1% 3 7.9% Hispanic 26 12.0% 18 10.1% 8 21.1% Other 2 0.9% 2 1.1% 0 0.0% 0.197 Body mass index (kg/m2) < 25 32 14.8% 25 14.0% 7 18.4% 25-30 68 31.5% 55 30.9% 13 34.2% 30-35 60 27.8% 50 28.1% 10 26.3% 35 + 56 25.9% 48 27.0% 8 21.1% 0.808 Prior abdominal surgery Yes 118 54.6% 104 58.4% 14 36.8% No 98 45.4% 74 41.6% 24 63.2% 0.015 Prior kidney surgery Yes 10 4.6% 9 5.1% 1 2.6% No 206 95.4% 169 94.9% 37 97.4% 0.518 Chronic kidney disease stage ≥ 3 Yes 45 20.8% 38 21.3% 7 18.4% No 171 79.2% 140 78.7% 31 81.6% 0.687 Charlson comorbidity index 0 138 63.9% 116 65.2% 22 57.9% 1 46 21.3% 38 21.4% 8 21.1% 2 19 8.8% 13 7.3% 6 15.8% ≥ 3 13 6.0% 11 6.2% 2 5.3% 0.412 Tumor size (cm) 2.7 (2-3.6) 2.8 (2-3.5) 2.55 (2-3.7) 0.796 Tumor laterality Left 100 46.3% 78 43.8% 22 57.9% Right 116 53.7% 100 56.2% 16 42.1% 0.114 Clinical T stage cT1a 186 86.1% 152 85.4% 34 89.5% cT1b 30 13.9% 26 14.6% 4 10.5% 0.509 RENAL Nephrometry score Low (4 to 6) 94 43.5% 76 42.7% 18 47.4% Intermediate (7 to 9) 112 51.9% 94 52.8% 18 47.4% High (≥ 10) 19 4.6% 8 4.5% 2 5.3% 0.829 TE tumor enucleation, SPN standard margin partial nephrectomy, IQR interquartile range.

Survival assessment of nephron-sparing surgery or radical nephrectomy in children with unilateral Wilms tumor receiving adjuvant chemotherapy: a retrospective cross-sectional study.

OBJECTIVE: Surgical treatment of unilateral Wilms tumor (WT) in children is controversial. In this study, we aimed to evaluate the survival and prognosis of radical nephrectomy (RN) and nephron-sparing surgery (NSS) in children with unilateral WT receiving adjuvant chemotherapy. PATIENTS AND METHODS: Data on pediatric patients with WT were collected from the Surveillance, Epidemiology, and End Results (SEER) database from 2000 to 2019. Multivariate logistic regression was used to analyze factors influencing the choice of surgical strategy. Cox proportional hazard models were used to assess factors associated with overall survival. RESULTS: We included 1,825 patients with unilateral WT (<14 years) who received adjuvant chemotherapy and surgery. Between 2000 and 2019, the percentage of patients treated with NSS increased from 4% in 2000 to 8% in 2019. There was no significant difference in 10-year overall survival between the two surgical strategies [NSS vs. RN, 93.26% (95% CI, 86.88%-100%) vs. 92.17% (95% CI, 90.75%-93.61%), p=0.98]. Patients with unilateral WTs ≤4 cm were more likely to be treated with NSS. There was no survival benefit for patients treated with RN compared with that for those treated with NSS (HR, 0.74; 95% CI, 0.29-1.86; p=0.5). CONCLUSIONS: The use of NSS in children with unilateral WT has increased over the last two decades. Tumor size is an important influencing factor for the surgical application of NSS. Patients who underwent NSS had an equivalent OS compared with the overall group of patients with unilateral tumors who received RN.

The safety and effectiveness of laparoscopic off-clamp tumor evacuation versus traditional nephron-sparing surgery for large (>4 cm) sporadic renal angiomyolipomas.

BACKGROUND: Off-clamp nephron-sparing surgery (NSS) have been selectively performed in renal tumors in which the majority are T1a (<4 cm) renal caners. Less is known, however, whether off-clamp is a safe and effective option for treatment of Sporadic Renal Angiomyolipomas (RAML), especially in those >4 cm. The objective of our study was to compare the perioperative and renal function outcomes of a novel off-clamp tumor evacuation technique versus conventional laparoscopic NSS for the treatment of large sporadic RAMLs (>4 cm). METHODS: From January 2021 to June 2022, 42 patients diagnosed with RAML were prospectively randomized to receive laparoscopic standard NSS (Group 1) and off-clamp tumor evacuation (Group 2). The surgical and postoperative outcomes of both groups were compared. RESULTS: Baseline characteristics demonstrated no discernible variation between Group 1 and Group 2. Compared to Group 1, Group 2 was associated shorter operative time (92.5 vs 82.3 min, p < 0.001), elimination of warm ischemic time (22.9 vs 0 min, p < 0.001), more blood loss (92.6 vs 161.9 ml, p = 0.02), and lower short-term renal function reduction of the operated kidney (17.2% vs 9%; p < 0.001). Neither major complication nor recurrence occurred. CONCLUSION: It seems that transperitoneal laparoscopic off-clamp tumor evacuation is a feasible and safe option for the treatment of RAML, with the added benefit of preserving renal function to a greater extent than the traditional methods.

Real-time estimation of nephron activity with a linear measurement system (RENAL-MS) predicts postoperative estimated glomerular filtration rate.

OBJECTIVE: To determine whether a simple point-of-care measurement system estimating renal parenchymal volume using tools ubiquitously available could be used to replace nuclear medicine renal scintigraphy (NMRS) in current clinical practice to predict estimated glomerular filtration rate (eGFR) after nephrectomy by estimating preoperative split renal function. PATIENTS AND METHODS: We performed a retrospective review of patients who underwent abdominal cross-sectional imaging (computed tomography/magnetic resonance imaging) and mercaptoacetyltriglycine (MAG3) NMRS prior to total nephrectomy at a single institution. We developed the real-time estimation of nephron activity with a linear measurement system (RENAL-MS) method of estimating postoperative renal function via the following technique: renal parenchymal volume of the removed kidney relative to the remaining kidney was estimated as the product of renal length and the average of six renal parenchymal thickness measurements. The utility of this value was compared to the utility of the split renal function measured by MAG3 for prediction of eGFR and new onset Stage 3 chronic kidney disease (CKD) at ≥90 days after nephrectomy using uni- and multivariate linear and logistic regression. RESULTS: A total of 57 patients met the study criteria. The median (interquartile range [IQR]) age was 69 (61-80) years. The median (IQR) pre- and postoperative eGFR was 74 (IQR 58-90) and 46 (35-62) mL/min/1.73 m2 , respectively. [Correction added on 29 December 2023, after first online publication: The data numbers in the preceding sentence have been corrected.] Correlations between actual and predicted postoperative eGFR were similar whether the RENAL-MS or NMRS methods were used, with correlation using RENAL-MS being slightly numerically but not statistically superior (R = 0.82 and 0.76; P = 0.138). Receiver operating characteristic curve analysis using logistic regression estimates incorporating age, sex, and preoperative creatinine to predict postoperative Stage 3 CKD were similar between RENAL-MS and NMRS (area under the curve 0.93 vs. 0.97). [Correction added on 29 December 2023, after first online publication: The data numbers in the preceding sentence have been corrected.] CONCLUSION: A point-of-care tool to estimate renal parenchymal volume (RENAL-MS) performed equally as well as NMRS to predict postoperative eGFR and de novo Stage 3 CKD after nephrectomy in our population, suggesting NMRS may not be necessary in this setting.

The rationale for nephron-sparing surgery in unilateral non-syndromic Wilms tumour.

The central question of nephron-sparing surgery in unilateral non-syndromic Wilms tumour sits at a crossroads between surgery, oncology, and nephrology. There has been a significant paradigm shift in paediatric oncology towards reducing toxicity and addressing long-term treatment-related sequalae amongst childhood cancer survivors. After paediatric nephrectomy and 30-50 years of follow-up, 40% of patients will have chronic kidney disease, including 22% with hypertension and 23% with albuminuria. It is difficult to predict which patients will progress to develop hypertension, reduced glomerular filtration rate, albuminuria, and a higher cardiovascular risk. For these reasons, nephron-sparing surgery when it is technically feasible must be considered. To decrease the incidence of positive surgical margins (viable tumour present at a resection margin), incomplete lymph node sampling, and complications, these procedures should be performed at specialist and experienced reference centres. Based on the impacts of individual treatment pathways, survivors of childhood WT need to be followed through adulthood for early detection of chronic kidney disease, hypertension, and prevention of cardiovascular events.

Ultrastructural characterization of maturing iPSC-derived nephron structures upon transplantation.

Pluripotent stem cell-derived kidney organoids hold great promise as a potential auxiliary transplant tissue for individuals with end-stage renal disease and as a platform for studying kidney diseases and drug discovery. To establish accurate models, it is crucial to thoroughly characterize the morphological features and maturation stages of the cellular components within these organoids. Nephrons, the functional units of the kidney, possess distinct morphological structures that directly correlate with their specific functions. High spatial resolution imaging emerges as a powerful technique for capturing ultrastructural details that may go unnoticed with other methods such as immunofluorescent imaging and scRNA sequencing. In our study, we have applied software capable of seamlessly stitching virtual slides generated from electron microscopy, resulting in high-definition overviews of tissue slides. With this technology, we can comprehensively characterize the development and maturation of kidney organoids when transplanted under the renal capsule of mice. These organoids exhibit advanced ultrastructural developments upon transplantation, including the formation of the filtration barrier in the renal corpuscle, the presence of microvilli in the proximal tubule, and various types of cell sub-segmentation in the connecting tubule similarly to those seen in the adult kidney. Such ultrastructural characterization provides invaluable insights into the structural development and functional morphology of nephron segments within kidney organoids and how to advance them by interventions such as a transplantation. Research Highlights High-resolution imaging is crucial to determine morphological maturation of hiPSC-derived kidney organoids. Upon transplantation, refined ultrastructural development of nephron segments was observed, such as the development of the glomerular filtration barrier.

Nephrometry Scoring Systems for Nephron Sparing Surgery in Children.

The surgical decision to attempt nephron-sparing surgery (NSS) in children with renal tumors can be difficult. In adults, nephrometric tools are used for decision-making. More than 90% of low-complexity tumors are eligible for NSS, and high-complexity tumors often require total nephrectomy. We retrospectively applied those nephrometric tools [Radius, Exophytic, Nearness to the sinus or collecting system, Anterior/posterior, Location relative to polar lines (RENAL), Preoperative Aspects and Dimensions Used for an Anatomical classification (PADUA), and Renal Tumor Invasion Index (RTII) scoring systems] to the preoperative imaging of children operated for renal tumors in our institution from 2015 to 2019 and correlated them with the type of surgery. The scores were assessed by 2 independent surgeons and 1 radiologist. Forty-four tumors were removed, including 16 NSS, 38 after neo-adjuvant chemotherapy, and 6 upfront surgeries, in 30 children. More than 50% of patients in the low and medium-risk population for RENAL, PADUA, and RTII scores, and ~15% in the high-complexity categories underwent NSS. Tumors removed through NSS were significantly less complex according to each score. Interobserver reliability was good for 3 scores. The application of the RENAL, PADUA, and RTII was able to accurately classify most of the pediatric tumors, according to their complexity. These scores could help increase the indications of NSS in renal tumor surgery.

Nephron Sparing Treatment (NEST) for Small Renal Masses: A Feasibility Cohort-embedded Randomised Controlled Trial Comparing Percutaneous Cryoablation and Robot-assisted Partial Nephrectomy.

There is a paucity of high-level evidence on small renal mass (SRM) management, as previous classical randomised controlled trials (RCTs) failed to meet accrual targets. Our objective was to assess the feasibility of recruitment to a cohort-embedded RCT comparing cryoablation (CRA) to robotic partial nephrectomy (RPN). A total of 200 participants were recruited to the cohort, of whom 50 were enrolled in the RCT. In the CRA intervention arm, 84% consented (95% confidence interval [CI] 64-95%) and 76% (95% CI 55-91%) received CRA; 100% (95% CI 86-100%) of the control arm underwent RPN. The retention rate was 90% (95% CI 79-96%) at 6 mo. In the RPN group 2/25 (8%) were converted intra-operative to radical nephrectomy. Postoperative complications (Clavien-Dindo grade 1-2) occurred in 12% of the CRA group and 29% of the RPN group. The median length of hospital stay was shorter for CRA (1 vs 2 d; p = 0.019). At 6 mo, the mean change in renal function was -5.0 ml/min/1.73 m2 after CRA and -5.8 ml/min/1.73 m2 after RPN. This study demonstrates the feasibility of a cohort-embedded RCT comparing CRA and RPN. These data can be used to inform multicentre trials on SRM management. PATIENT SUMMARY: We assessed whether patients with a small kidney tumour would consent to a trial comparing two different treatments: cryoablation (passing small needles through the skin to freeze the kidney tumour) and surgery to remove part of the kidney. We found that most patients agreed and a full trial would therefore be feasible.