Robot-assisted Partial Nephrectomy for Hilar and Nonhilar Renal Masses: Comparison of Perioperative, Oncological, and Functional Results in a Multicentre Prospective Cohort (NEPRAH Study, UroCCR 175).

BACKGROUND AND OBJECTIVE: A hilar location for a renal tumour is sometimes viewed as a limiting factor for safe partial nephrectomy. Our aim was to evaluate perioperative, oncological, and functional outcomes of robot-assisted partial nephrectomy (RAPN) for hilar tumours (RAPN-H) in comparison to RAPN for nonhilar tumours (RAPN-NH). METHODS: We conducted an observational, multicentre cohort study using prospectively collected data from the French Research Network on Kidney Cancer (UroCCR). The registry includes data for 3551 patients who underwent RAPN for localised or locally advanced renal masses between 2010 and 2023 in 29 hospitals in France. We studied the impact of a hilar location on surgery, postoperative renal function, tumour characteristics, and survival. We also compared rates of trifecta achievement (warm ischaemia time [WIT] <25 min, negative surgical margins, and no perioperative complications) between the groups. Finally, we performed a subgroup analysis of RAPN without vascular clamping. Variables were compared in univariable analysis and using multivariable linear, logistic, and Cox proportional-hazards models adjusted for relevant patient and tumour covariates. KEY FINDINGS AND LIMITATIONS: The analytical population included 3451 patients, of whom 2773 underwent RAPN-NH and 678 underwent RAPN-H. Longer WIT (ß = 2.4 min; p < 0.01), longer operative time (ß = 11.4 min; p < 0.01) and a higher risk of postoperative complications (odds ratio 1.33; p = 0.05) were observed in the hilar group. Blood loss, the perioperative transfusion rate, postoperative changes in the estimated glomerular filtration rate, and trifecta achievement rates were comparable between the groups (p > 0.05). At mean follow-up of 31.9 mo, there was no significant difference in recurrence-free survival (hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.58-1.2; p = 0.3), cancer-specific survival (HR 1.1, 95% CI 0.48-2.6; p = 0.79), or overall survival (HR 0.89, 95% CI 0.52-1.53; p = 0.69). CONCLUSIONS AND CLINICAL IMPLICATIONS: Patient and tumour characteristics rather than just hilar location should be the main determinants of the optimal surgical strategy for hilar tumours. PATIENT SUMMARY: We found that kidney tumours located close to major kidney blood vessels led to a longer operation and a higher risk of complications during robot-assisted surgery to remove the tumour. However, tumours in these locations were not related to a higher risk of kidney function loss, cancer recurrence, or death.

Orthotopic Robot-assisted Kidney Transplantation: Surgical Technique and Preliminary Results.

BACKGROUND AND OBJECTIVE: Orthotopic kidney transplantation (KT) has been proposed as an option for patients ineligible for heterotopic KT. In this scenario, orthotopic robot-assisted KT (oRAKT) represents a novel, minimally invasive alternative to the open approach. Here we describe the largest oRAKT series of patients, with a focus on the surgical technique, perioperative surgical outcomes, and functional results. METHODS: We queried prospectively maintained databases from three referral centers to identify patients who underwent oRAKT and evaluated surgical and functional outcomes. KEY FINDINGS AND LIMITATIONS: Overall, 16 oRAKT procedures were performed between January 2020 and August 2023. These involved four donors after cardiovascular death, five donors after brain death, and seven living donors. All oRAKT procedures were carried out in the left renal fossa. The indication for oRAKT was extensive calcification of the external iliac vessels (100%), frequently associated with prior KT (31%). The median operative time was 295 min (interquartile range [IQR] 268-360) and the median rewarming time 48 min (IQR 40-54). Conversion to open surgery occurred in two cases (12%), and delayed graft function was observed in two cases (12%). Postoperative complications occurred in 11 patients (69%) and three (18%) experienced Clavien-Dindo grade >II complications. At median follow-up of 9 mo (IQR 7-17), 14 patients had a functioning graft and median creatinine of 1.49 mg/dl (IQR 1.36-1.72). CONCLUSIONS AND CLINICAL IMPLICATIONS: Although oRAKT is a challenging procedure, it represents a feasible option for individuals ineligible for heterotopic KT and yields favorable perioperative and mid-term functional outcomes. PATIENT SUMMARY: We evaluated outcomes of orthotopic robot-assisted kidney transplantation (KT), in which the native kidney is removed and the donor kidney is transplanted into its place, in patients who are not eligible for heterotopic KT, in which the native kidney is left in place and the donor kidney is transplanted into a new location. We found that robot-assisted surgery is a safe and feasible alternative to traditional open surgery for orthotopic KT.

Preparing for the Worst: Management and Predictive Factors of Open Conversion During Minimally Invasive Renal Tumor Surgery (UroCCR-135 Study).

Background and objective: Data regarding open conversion (OC) during minimally invasive surgery (MIS) for renal tumors are reported from big databases, without precise description of the reason and management of OC. The objective of this study was to describe the rate, reasons, and perioperative outcomes of OC in a cohort of patients who underwent MIS for renal tumor initially. The secondary objective was to find the factors associated with OC. Methods: Between 2008 and 2022, of the 8566 patients included in the UroCCR project prospective database (NCT03293563), who underwent laparoscopic or robot-assisted minimally invasive partial (MIPN) or radical (MIRN) nephrectomy, 163 experienced OC. Each center was contacted to enlighten the context of OC: "emergency OC" implied an immediate life-threatening situation not reasonably manageable with MIS, otherwise "elective OC". To evaluate the predictive factors of OC, a 2:1 paired cohort on the UroCCR database was used. Key findings and limitations: The incidence rate of OC was 1.9% for all cases of MIS, 2.9% for MIRN, and 1.4% for MIPN. OC procedures were mostly elective (82.2%). The main reason for OC was a failure to progress due to anatomical difficulties (42.9%). Five patients (3.1%) died within 90 d after surgery. Increased body mass index (BMI; odds ratio [OR]: 1.05, 95% confidence interval [CI]: 1.01-1.09, p = 0.009) and cT stage (OR: 2.22, 95% CI: 1.24-4.25, p = 0.008) were independent predictive factors of OC. Conclusions and clinical implications: In MIS for renal tumors, OC was a rare event (1.9%), caused by various situations, leading to impaired perioperative outcomes. Emergency OC occurred once every 300 procedures. Increased BMI and cT stage were independent predictive factors of OC. Patient summary: The incidence rate of open conversion (OC) in minimally invasive surgery for renal tumors is low. Only 20% of OC procedures occur in case of emergency, and others are caused by various situations. Increased body mass index and cT stage were independent predictive factors of OC.

Open versus robotic partial nephrectomy in obese patients: a multi-institutional propensity score-matched analysis (UroCCR 43-Robese study).

INTRODUCTION: There is limited evidence on the outcomes of robotic partial nephrectomy (RPN) and open partial nephrectomy (OPN) in obese patients (BMI ≥ 30 kg/m2). In this study, we aimed to compare perioperative and oncological outcomes of RPN and OPN. METHODS: We relied on data from patients who underwent PN from 2009 to 2017 at 16 departments of urology participating in the UroCCR network, which were collected prospectively. In an effort to adjust for potential confounders, a propensity-score matching was performed. Perioperative outcomes were compared between OPN and RPN patients. Disease-free survival (DFS) and overall survival (OS) were estimated using the Kaplan-Meier method and compared using the log-rank test. RESULTS: Overall, 1277 obese patients (932 robotic and 345 open were included. After propensity score matching, 166 OPN and 166 RPN individuals were considered for the study purposes; no statistically significant difference among baseline demographic or tumor-specific characteristics was present. A higher overall complication rate and major complications rate were recorded in the OPN group (37 vs. 25%, p = 0.01 and 21 vs. 10%, p = 0.007; respectively). The length of stay was also significantly longer in the OPN group, before and after propensity-score matching (p < 0.001). There were no significant differences in Warm ischemia time (p = 0.66), absolute change in eGFR (p = 0.45) and positive surgical margins (p = 0.12). At a median postoperative follow-up period of 24 (8-40) months, DFS and OS were similar in the two groups (all p > 0.05). CONCLUSIONS: In this study, RPN was associated with better perioperative outcomes (improvement of major complications rate and LOS) than OPN. The oncological outcomes were found to be similar between the two approaches.

The Impact of Histological Variants on Oncological Outcomes After Surgical Resection of a Nonmetastatic Renal Cell Carcinoma with Tumor Thrombus: A Multi-institutional Study.

Background: There is no definitive evidence of the prognosis impact of histological variants (HVs) in patients who undergo surgical resection of a nonmetastatic renal cell carcinoma (nm-RCC) with venous tumor thrombus (TT). Objective: To investigate the impact of HVs on the prognosis of patients with nm-RCC with TT after radical surgery. Design setting and participants: Patients who underwent radical nephrectomy with the removal of the venous TT for an nm-RCC were included in a retrospective study. Outcome measurements and statistical analysis: Three groups were identified: clear cell (ccRCC), papillary (pRCC), and chromophobe (chRCC) RCC. The primary outcome measures (disease-free and overall survival [OS]) were assessed using the Kaplan-Meier method and compared using the log-rank test. Univariate and multivariate Cox proportional hazard models were used to study the impact of HVs on survival. Results and limitations: A total of 873 patients were included. The histological subtypes were distributed as follows: ccRCC in 780 cases, pRCC in 58 cases, and chRCC in 35 cases. At the time of data analysis, 612 patients were recurrence free and 228 had died. A survival analysis revealed significant differences in both OS and recurrence-free survival across histological subtypes, with the poorest outcomes observed in pRCC patients (p < 0.05). In a multivariable analysis, pRCC was independently associated with worse disease-free survival and OS (hazard ratio [HR]: 1.71; p = 0.01 and HR: 1.24; p = 0.04), while chRCC was associated with more favorable outcomes than ccRCC (HR: 0.05; p < 0.001 and HR: 0.02; p < 0.001). A limitation of the study is its retrospective nature. Conclusions: In this multicentric series, HVs appeared to impact the medium-term oncological prognosis of kidney cancer with TT. Patient summary: This study investigated the differences in oncological outcomes among histological variants (clear cell, papillary, and chromophobe) in a cohort of nonmetastatic renal cell carcinoma patients with venous tumor thrombus extension. We observed that these histological variants within this specific subgroup exhibit distinct outcomes, with papillary renal cell carcinoma being associated with the worst prognosis.

UroPredict: Machine learning model on real-world data for prediction of kidney cancer recurrence (UroCCR-120).

Renal cell carcinoma (RCC) is most often diagnosed at a localized stage, where surgery is the standard of care. Existing prognostic scores provide moderate predictive performance, leading to challenges in establishing follow-up recommendations after surgery and in selecting patients who could benefit from adjuvant therapy. In this study, we developed a model for individual postoperative disease-free survival (DFS) prediction using machine learning (ML) on real-world prospective data. Using the French kidney cancer research network database, UroCCR, we analyzed a cohort of surgically treated RCC patients. Participating sites were randomly assigned to either the training or testing cohort, and several ML models were trained on the training dataset. The predictive performance of the best ML model was then evaluated on the test dataset and compared with the usual risk scores. In total, 3372 patients were included, with a median follow-up of 30 months. The best results in predicting DFS were achieved using Cox PH models that included 24 variables, resulting in an iAUC of 0.81 [IC95% 0.77-0.85]. The ML model surpassed the predictive performance of the most commonly used risk scores while handling incomplete data in predictors. Lastly, patients were stratified into four prognostic groups with good discrimination (iAUC = 0.79 [IC95% 0.74-0.83]). Our study suggests that applying ML to real-world prospective data from patients undergoing surgery for localized or locally advanced RCC can provide accurate individual DFS prediction, outperforming traditional prognostic scores.

Nephrometry scores to predict oncological outcomes following partial nephrectomy (UroCCR Study 70).

PURPOSE: Partial nephrectomy (PN) for large or complex renal tumors can be difficult and associated with a higher risk of recurrence than radical nephrectomy. We aim to evaluate the clinical useful of nephrometry scores for predicting oncological outcomes in a large cohort of patients who underwent PN for renal cell carcinomas. METHODS: Our analysis included patients who underwent PN for renal cell carcinoma in 21 French academic centers (2010-2020). RENAL, PADUA, and SPARE scores were calculated based on preoperative imaging. Uni- and multivariate cox models were performed to identify predictors of recurrence-free survival and overall survival. The area under the curve (AUC) was used to identify models with the highest discrimination. Decision curve analyses (DCAs) determined the net benefit associated with their use. RESULTS: A total of 1927 patients were analyzed with a median follow-up of 32 months (14-45). RENAL score (p = 0.01), age (p = 0.002), histological type (p = 0.001), high nuclear grade (p = 0.001), necrotic component (p < 0.001), and positive margins (p = 0.005) were significantly related to recurrence in multivariate analyses. The discriminative performance of the 3 radiological scores was modest (65, 63, and 63%, respectively). All 3 scores showed good calibration, which, however, deteriorated with time. Decision curve analysis of the three models for the prediction of overall and recurrence-free survival was similar for all three scores and of limited clinical relevance. CONCLUSION: The association between nephrometry scores and oncological outcomes after NP is very weak. The use of these scores for predicting oncological outcomes in routine practice is therefore of limited clinical value.

Can Simplified PADUA Renal (SPARE) Nephrometry scoring system help predict renal function outcomes after robot-assisted partial nephrectomy? (UroCCR study 93).

BACKGROUND: The SPARE Nephrometry Score (NS) is described as easier to implement than the RENAL and PADUA NSs, currently more widely used. Our objective was to compare the accuracy of SPARE NS in predicting renal function outcomes following RAPN. METHODS: A multicentric retrospective study was conducted using French kidney cancer network (UroCCR, NCT03293563) database. All patients included had RAPN for cT1 renal tumors between May 2010 and March 2021. SPARE was compared to RENAL, PADUA and Tumor Size to predict postoperative acute kidney injury (AKI), chronic kidney disease (CKD) upstaging, de novo CKD at 3-6 months follow-up and Trifecta failure. The ability of the different NSs and tumor size to predict renal function outcomes was evaluated using uni- and multivariate logistic regression models. RESULTS: According to our study criteria, 1171 patients were included. Mean preoperative tumor size and estimated glomerular filtration rate (eGFR) were 3.4±1.4 cm and 85.8 mL/min/1.73 m2. In total, 266 (22.7%), 87 (7.4%), 94 (8%), and 624 (53.3%) patients had AKI, de novo CKD, CKD upstaging, and Trifecta failure, respectively. In multivariate analysis, all three NSs and tumor size were independent predictors of AKI, CKD de novo, CKD upgrade and Trifecta failure. There was no significant difference between all three NS and tumor sizes in predicting renal function outcomes. CONCLUSIONS: SPARE Score seems to be a valid alternative to predict renal function outcomes after RAPN. Nevertheless, in our study, tumor size was as accurate as NSs in predicting postoperative outcomes and, therefore, seems to be the logical choice for surgical decisions.

Retroperitoneal vs. transperitoneal robotic partial nephrectomy: a multicenter propensity-score matching analysis (PADORA Study - UroCCR n° 68).

BACKGROUND: Robot-assisted partial nephrectomy can be performed through either a transperitoneal or retroperitoneal approach. This study aimed to compare the rate of trifecta achievement between retroperitoneal (RRPN) and transperitoneal (TRPN) robot-assisted partial nephrectomy using a large multicenter prospectively-maintained database and propensity-score matching analysis. METHODS: This study was launched by the French Kidney Cancer Research Network, under the UroCCR Project (NCT03293563). Patients who underwent TRPN or RRPN by experienced surgeons in 15 participating centers were included. Data on demographic and clinical parameters, tumor characteristics, renal function, and surgical parameters were collected. The primary outcome was the rate of trifecta achievement, which was defined as a warm ischemia time of less than 25 minutes, negative surgical margins, and no major complications. Secondary outcomes included operative time, hospital length-of-stay, blood loss, postoperative complications, postoperative renal function, and each trifecta item taken alone. Subgroup analysis was done according to tumor location. RESULTS: A total of 2879 patients (2581 TRPN vs. 298 RRPN) were included in the study. Before matching, trifecta was achieved in 73.0% of the patients in the TRPN group compared to 77.5% in the RRPN group (P=0.094). After matching 157 patients who underwent TRPN to 157 patients who underwent RRPN, the trifecta rate was 82.8% in the TRPN group vs. 84.0% in the RRPN group (P=0.065). The RRPN group showed shorter operative time (123 vs. 171 min; P<0.001) and less blood loss (161 vs. 293 mL; P<0.001). RRPN showed a higher trifecta achievement for posterior tumors than TRPN (71% vs. 81%; P=0.017). CONCLUSIONS: RRPN is a viable alternative to the transperitoneal approach, particularly for posterior renal tumors, and is a safe and effective option for partial nephrectomy.

Minimally invasive nephron-sparing treatments for T1 renal cell cancer in patients over 75 years: a comparison of outcomes after robot-assisted partial nephrectomy and percutaneous ablation.

PURPOSE: To compare the oncological and perioperative outcomes of robot-assisted partial nephrectomy (RPN) and percutaneous thermal ablation (PTA) for treatment of T1 renal cell cancer (RCC) in patients older than 75 years. MATERIALS AND METHODS: Retrospective national multicenter study included all patients older than 75 years treated for a T1 RCC by RPN or PTA between January 2010 and January 2021. Patients' characteristics, tumor data, and perioperative and oncological outcomes were compared. RESULTS: A total of 205 patients for 209 procedures (143 RPN and 66 PTA) were included. In the PTA group, patients were older (80.4 ± 3.7 vs. 79 ± 3.7 years (p = 0.01)); frailer (ASA score (2.43 ± 0.6 vs. 2.17 ± 0.6 (p < 0.01)); and more frequently had a history of kidney surgery (16.7% [11/66] vs. 5.6% [8/143] (p = 0.01)) than in the RPN group. Tumors were larger in the RPN group (2.7 ± 0.7 vs. 3.2 ± 0.9 cm (p < 0.01)). Operation time, length of hospital stay, and increase of creatinine serum level were higher in RPN (respectively 92.1 ± 42.7 vs. 150.7 ± 61.3 min (p < 0.01); 1.7 ± 1.4 vs. 4.2 ± 3.4 days (p < 0.01); 1.9 ± 19.3% vs. 10.1 ± 23.7 (p = 0.03)). Disease-free survival and time to progression were similar (respectively, HR 2.2; 95% CI 0.88-5.5; p = 0.09; HR 2.1; 95% CI 0.86-5.2; p = 0.1). Overall survival was shorter for PTA that disappeared after Cox adjusting model (HR 3.3; 95% CI 0.87-12.72; p = 0.08). CONCLUSION: Similar oncological outcomes are observed after PTA and RPN for T1 RCC in elderly patients. CLINICAL RELEVANCE STATEMENT: Robot-assisted partial nephrectomy and percutaneous thermal ablation have similar oncological outcomes for T1a kidney cancer in patients over 75 years; however, operative time, decrease in renal function, and length of hospital stay were lower with ablation. KEY POINTS: • After adjusting model for age and ASA score, similar oncological outcomes are observed after percutaneous thermal ablation and robot-assisted partial nephrectomy for T1 renal cell cancer in elderly patients. • Operation time, length of hospital stay, and increase of creatinine serum level were higher in the robot-assisted partial nephrectomy group.

Nephrectomy for kidney tumour increases the risk of de novo arterial hypertension.

OBJECTIVE: To evaluate prospectively the effects of surgical excision of renal tumours on blood pressure (BP). PATIENTS AND METHODS: In a multicentre prospective study, we evaluated 200 patients who underwent nephrectomy for renal tumour between 2018 and 2020 at seven departments of the French Network for Kidney Cancer, the UroCCR. All patients had localized cancer without pre-existing hypertension (HTN). Blood pressure was measured the week before nephrectomy, and at 1 month and 6 months after nephrectomy, according to the recommendations for home BP monitoring. Plasma renin was measured 1 week before surgery and 6 months after surgery. The primary endpoint was the occurrence of de novo HTN. The secondary endpoint was clinically significant increase in BP at 6 months, defined by an increase in systolic and/or diastolic ambulatory BP ≥10 mmHg or requirement for medical antihypertensive treatment. RESULTS: Blood pressure and renin measurements were available for 182 (91%) and 136 patients (68%), respectively. We excluded from the analysis 18 patients who had undeclared HTN detected on preoperative measurements. At 6 months, 31 patients (19.2%) had de novo HTN and 43 patients (26.3%) had a significant increase in their BP. Type of surgery was not associated with an increased risk of HTN (21.7% partial nephrectomy [PN] vs 15.7% radical nephrectomy [RN]; P = 0.59). There was no difference between plasmatic renin levels before and after surgery (18.5 vs 16; P = 0.46). In multivariable analysis, age (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.02-1.12; P = 0.03) and body mass index (OR 1.14, 95% CI 1.03-1.26; P = 0.01) were the only predictors of de novo HTN. CONCLUSION: Surgical treatment of renal tumours is associated with significant changes in BP, with de novo HTN occurring in almost 20% of the patients. These changes are not impacted by the type of surgery (PN vs RN). Patients who are scheduled to undergo kidney cancer surgery should be informed of these findings and have their BP closely monitored after the operation.

Post-chemotherapy robot-assisted retroperitoneal lymph node dissection for metastatic germ cell tumors: safety and perioperative outcomes.

PURPOSE: To evaluate the feasibility, safety, and early oncologic outcomes after post-chemotherapy robot-assisted retroperitoneal lymph node dissection (PC-RARPLND) for metastatic germ cell tumors (mGCT). METHODS: We retrospectively analyzed patients from four tertiary centers who underwent PC-RARPLND for mGCT, from 2011 to 2021. Previous treatment of mGCT, intraoperative and postoperative complications, and early oncologic outcomes were assessed. RESULTS: Overall, 66 patients were included. The majority of patients had non-seminoma mTGCT (89%). Median size of retroperitoneal lymph node (RLN) before surgery was 26 mm. Templates of PC-RARPLND were left modified, right modified, and full bilateral in 56%, 27%, and 14%, respectively. Median estimated blood loss and length of stay were 50 mL [50-150] and 2 [1-3] days. Four patients (6.1%) had a vascular injury, only one with significant blood loss and conversion to open surgery (OS). Two other patients had a conversion to OS for difficulty of dissection. No patient had transfusion, most frequent complications were ileus (10.6%) and symptomatic lymphorrea (7.6%) and no complications grade IIIb or more occurred. With a median follow-up of 16 months, two patients had a relapse, all outside of the surgical template (one in the retrocrural space with reascending markers, one in lungs). CONCLUSION: PC-RARPLND is a challenging surgery. In expert centers and for selected patients, it seemed safe and feasible, with a low morbidity. Further prospective evaluation of this procedure and long-term oncologic results are needed.

Late complications and 5 years outcomes of robotic partial nephrectomy in France: prospective assessment in the French Kidney Cancer Research Network (UroCCR 10).

PURPOSE: To describe the practice of robotic-assisted partial nephrectomy (RAPN) in France and prospectively assess the late complications and long-term outcomes. METHODS: Prospective, multicenter (n = 16), observational study including all patients diagnosed with a renal tumor who underwent RAPN. Preoperative, intraoperative, postoperative, and follow-up data were collected and stored in the French research network for kidney cancer database (UroCCR). Patients were included over a period of 12 months, then followed for 5 years. RESULTS: In total, 466 patients were included, representing 472 RAPN. The mean tumor size was 3.4 ± 1.7 cm, most of moderate complexity (median PADUA and RENAL scores of 8 [7-10] and 7 [5-9]). Indication for nephron-sparing surgery was relative in 7.1% of cases and imperative in 11.8%. Intraoperative complications occurred in 6.8% of patients and 4.2% of RAPN had to be converted to open surgery. Severe postoperative complications were experienced in 2.3% of patients and late complications in 48 patients (10.3%), mostly within the first 3 months and mainly comprising vascular, infectious, or parietal complications. At 5 years, 29 patients (6.2%) had chronic kidney disease upstaging, 21 (4.5%) were diagnosed with local recurrence, eight (1.7%) with contralateral recurrence, 25 (5.4%) with metastatic progression, and 10 (2.1%) died of the disease. CONCLUSION: Our results reflect the contemporary practice of French expert centers and is, to our knowledge, the first to provide prospective data on late complications associated with RAPN. We have shown that RAPN provides good functional and oncologic outcomes while limiting short- and long-term morbidity. TRIAL REGISTRATION: NCT03292549.

Machine-learning approach for prediction of pT3a upstaging and outcomes of localized renal cell carcinoma (UroCCR-15).

OBJECTIVES: To assess the impact of pathological upstaging from clinically localized to locally advanced pT3a on survival in patients with renal cell carcinoma (RCC), as well as the oncological safety of various surgical approaches in this setting, and to develop a machine-learning-based, contemporary, clinically relevant model for individual preoperative prediction of pT3a upstaging. MATERIALS AND METHODS: Clinical data from patients treated with either partial nephrectomy (PN) or radical nephrectomy (RN) for cT1/cT2a RCC from 2000 to 2019, included in the French multi-institutional kidney cancer database UroCCR, were retrospectively analysed. Seven machine-learning algorithms were applied to the cohort after a training/testing split to develop a predictive model for upstaging to pT3a. Survival curves for disease-free survival (DFS) and overall survival (OS) rates were compared between PN and RN after G-computation for pT3a tumours. RESULTS: A total of 4395 patients were included, among whom 667 patients (15%, 337 PN and 330 RN) had a pT3a-upstaged RCC. The UroCCR-15 predictive model presented an area under the receiver-operating characteristic curve of 0.77. Survival analysis after adjustment for confounders showed no difference in DFS or OS for PN vs RN in pT3a tumours (DFS: hazard ratio [HR] 1.08, P = 0.7; OS: HR 1.03, P > 0.9). CONCLUSIONS: Our study shows that machine-learning technology can play a useful role in the evaluation and prognosis of upstaged RCC. In the context of incidental upstaging, PN does not compromise oncological outcomes, even for large tumour sizes.

Oncocytoma on renal mass biopsy: is it still the same histology when surgery is performed? Results from UroCCR-104 study.

PURPOSE: To describe clinical features of patients with oncocytoma on renal biopsy (RMB), correlation with final histology on surgically treated patients, and predictive factors of discrepancy between RMB and final histology. METHODS: This was a retrospective study conducted in the framework of the UroCCR project (NCT03293563). All tumors with oncocytoma on RMB were selected and all pathological reports were reviewed. Patients with the RMB simultaneously performed with a focal treatment, synchronous bilateral tumors and ambiguous RMB report were excluded. Discrepancy between RMB and definitive histology was evaluated using a uni- and multivariable logistic regression analyses model. RESULTS: Overall, 119 tumors with oncocytoma on RMB, from 15 centers, were included. Of those, 54 (45.4%) had upfront surgery and 65 (54.6%) had active surveillance (AS). In renal masses with initial active surveillance, with a median follow-up of 28 months, 23 (19.3%) underwent surgery, 4 (3.4%) received focal treatment and 38 (31.9%) remained on AS. On final pathology, only 51 of the 75 surgically treated tumors (68.0%) had oncocytoma, while 24 presented malignant tumors (mainly chromophobe carcinoma (19.2%), and hybrid oncocytic/chromophobe tumor (HOCT) (6.8%)) leading to a discrepancy of 32.0% between RMB and final pathology. The only predictive factor of a discrepancy between RMB and definitive histology was a biopsy done outside of the center (Odds ratio: 3.22 [95%-confidence interval: 1.08-9.61], p = 0.03). CONCLUSION: Despite the increase of RMB in more and more centers, histologic discrepancy between RMB and definitive histology remains significant. This information should be discussed with patients and taken into consideration before treatment decision.

Application of Machine Learning Models to Predict Recurrence After Surgical Resection of Nonmetastatic Renal Cell Carcinoma.

BACKGROUND: Predictive tools can be useful for adapting surveillance or including patients in adjuvant trials after surgical resection of nonmetastatic renal cell carcinoma (RCC). Current models have been built using traditional statistical modelling and prespecified variables, which limits their performance. OBJECTIVE: To investigate the performance of machine learning (ML) framework to predict recurrence after RCC surgery and compare them with current validated models. DESIGN, SETTING, AND PARTICIPANTS: In this observational study, we derived and tested several ML-based models (Random Survival Forests [RSF], Survival Support Vector Machines [S-SVM], and Extreme Gradient Boosting [XG boost]) to predict recurrence of patients who underwent radical or partial nephrectomy for a nonmetastatic RCC, between 2013 and 2020, at 21 French medical centres. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary end point was disease-free survival. Model discrimination was assessed using the concordance index (c-index), and calibration was assessed using the Brier score. ML models were compared with four conventional prognostic models, using decision curve analysis (DCA). RESULTS AND LIMITATIONS: A total of 4067 patients were included in this study (3253 in the development cohort and 814 in the validation cohort). Most tumours (69%) were clear cell RCC, 40% were of high grade (nuclear International Society of Urological Pathology grade 3 or 4), and 24% had necrosis. Of the patients, 4% had nodal involvement. After a median follow-up of 57 mo (interquartile range 29-76), 523 (13%) patients recurred. ML models obtained higher c-index values than conventional models. The RSF yielded the highest c-index values (0.794), followed by S-SVM (c-index 0.784) and XG boost (c-index 0.782). In addition, all models showed good calibration with low integrated Brier scores (all integrated brier scores <0.1). However, we found calibration drift over time for all models, albeit with a smaller magnitude for ML models. Finally, DCA showed an incremental net benefit from all ML models compared with conventional models currently used in practice. CONCLUSIONS: Applying ML approaches to predict recurrence following surgical resection of RCC resulted in better prediction than that of current validated models available in clinical practice. However, there is still room for improvement, which may come from the integration of novel biological and/or imaging biomarkers. PATIENT SUMMARY: We found that artificial intelligence algorithms could better predict the risk of recurrence after surgery for a localised kidney cancer. These algorithms may help better select patients who will benefit from medical treatment after surgery.

Evaluation of oncological outcomes of robotic partial nephrectomy according to the type of hilar control approach (On-clamp vs Off-clamp), a multicentric study of the French network of research on kidney cancer-UROCCR 58-NCT03293563.

PURPOSE: To compare off-clamp vs on-clamp robotic partial nephrectomy (RPN) for renal cell carcinoma (RCC) in terms of oncological outcomes, and to assess the impact of surgical experience (SE). METHODS: We extracted data of a contemporary cohort of 1359 patients from the prospectively maintained database of the French national network of research on kidney cancer (UROCCR). The primary objective was to assess the positive surgical margin (PSM) rate. We also evaluated the oncological outcomes regardless of the surgical experience (SE) by dividing patients into three groups of SE as a secondary endpoints. SE was defined by the caseload of RPN per surgeon per year. For the continuous variables, we used Mann-Whitney and Student tests. We assessed survival analysis according to hilar control approach by Kaplan-Meier curves with log rank tests. A logistic regression multivariate analysis was used to evaluate the independent factors of PSM. RESULTS: Outcomes of 224 off-clamp RPN for RCC were compared to 1135 on-clamp RPN. PSM rate was not statistically different, with 5.6% in the off-clamp group, and 11% in the on-clamp group (p = 0.1). When assessing survival analysis for overall survival (OS), local recurrence-free survival (LR), and metastasis-free survival (MFS) according to hilar clamping approach, there were no statistically significant differences between the two groups with p value log rank = 0.2, 0.8, 0.1, respectively. In multivariate analysis assessing SE, hilar control approach, hospital volume (HV), RENAL score, gender, Age, ECOG, EBL, BMI, and indication of NSS, age at surgery was associated with PSM (odds ratio [OR] 1.03 (95% CI 1.00-1.04), 0.02), whereas SE, HV, and type of hilar control approach were not predictive factors of PSM. CONCLUSION: Hilar control approach seems to have no impact on PSM of RPN for RCC. Our findings were consistent with randomized trials.

Predictive factors of recurrence after surgery in patients with non-metastatic renal cell carcinoma with venous tumor thrombus (UroCCR-56 Study).

PURPOSE: To assess the oncological outcomes of renal cell carcinoma (RCC) associated with tumor thrombus and identify predictive factors of recurrence. METHODS: Multi-institutional study that included patients with cT3-4N0-1M0 RCC with tumoral thrombus identified in the prospective UroCCR database (CNIL DR 2013-206; NCT03293563). pT3a without involvement of the renal vein were excluded. All patients underwent radical nephrectomy and a thrombectomy of the renal vein ± inferior vena cava ± right atrium. The primary endpoint was recurrence-free survival (RFS). Thirty-two patients who had adjuvant therapies (tyrosine kinase inhibitors or mTOR inhibitor) were compared to control group (surveillance) in a propensity score-matched 1:1 sub-analysis RESULTS: A total of 432 patients were included: 70.4% pT3a, 20.1% pT3b, 4.2% pT3c and 5.3% pT4. Tumor characteristics were: 90.7% clear cell RCC, 13.9% pN1, and 87.1% high Fuhrman grade. 173 patients (40%) had disease recurrence, and median RFS was 37.3 months (95% CI, 26.4-46.7). In a multivariate analysis (Cox model), predictive factors of recurrence were: pT4 (HR 2.66; 95% CI, 1.42-4.99; p = 0.002), pN1 (HR 2.53; 95% CI, 1.46-4.39; p < 0.001), tumor necrosis (HR 2.92; 95% CI, 1.85-4.62; p < 0.001), tumor size > 10 cm (HR 1.56; 95% CI, 1.08-2.24; p = 0.018). Adjuvant therapy was a protective factor of cancer recurrence (HR 0.33; 95% CI, 0.17-0.66; p = 0.002). Propensity score-matched sub-analysis of adjuvant vs control (surveillance) confirmed adjuvant treatment as a protective factor of cancer recurrence (Log rank p = 0.015). CONCLUSIONS: In this contemporary multi-institutional cohort of RCC + tumor thrombus, we reported higher recurrence rate shortly after surgical excision and demonstrated an oncological benefit of adjuvant treatment.