Active Surveillance for Renal Neoplasms with Oncocytic Features is Safe

Identifying the facilitators and barriers to implementation of renal tumour biopsy in the diagnostic pathway for small renal masses

OBJECTIVES

To understand the facilitators and barriers to the implementation of renal tumour biopsy (RTB) in the diagnostic pathway for renal tumours in England.

PATIENTS AND METHODS

Participants consisted of patients who had a renal tumour diagnosed and/or treated at one of five tertiary centres in England, healthcare professionals involved in the direct care of patients diagnosed with renal tumours, and clinical service managers and commissioners. The study employed a mixed-methods research methodology consisting of individual interviews and an on-line survey that explored the types of facilitators and barriers individuals perceived and experienced and the frequency in which these were reported. A public dissemination event took place following the completion of data collection; to facilitate discussion of potential solutions to implementing RTB.

RESULTS

There were 50 participant interviews (23 patients, 22 clinicians, and five health service commissioners/operations managers). The patient on-line survey received 52 responses, and the clinician survey received 22 responses. Patients most frequently reported influences in choosing whether to undergo RTB pertained to wanting to know the diagnosis of their kidney mass (40%), the advice or information provided by healthcare professionals (40%), and not wishing to delay treatment (23%). Clinicians most frequently reported barriers to recommending RTB related to their uncertainty of diagnostic accuracy (56%), availability of appointments or hospital beds (52%), concerns of risk of bleeding (44%), risk of seeding (41%), and delays in meeting national cancer pathway targets (41%). The dissemination event was attended by 18 participants (seven patients and 11 clinicians). Suggestions to improve implementation included reducing variation and promotion of standardisation of practice by a consensus statement, increasing the evidence base (clinicians) and improved communication by developing better patient aids such as videos and diagrams (patients and clinicians).

CONCLUSION

Implementation of RTB may be dependent on the quality of information provided, its format and perceived reliability of the information. Increased utilisation of RTB may be improved by development of a consensus statement on the role of biopsy, with patients expressing a preference for alternative information aids such as patient videos.

Acceptance of emerging renal oncocytic neoplasms: a survey of urologic pathologists

Oncocytic renal neoplasms are a major source of diagnostic challenge in genitourinary pathology; however, they are typically nonaggressive in general, raising the question of whether distinguishing different subtypes, including emerging entities, is necessary. Emerging entities recently described include eosinophilic solid and cystic renal cell carcinoma (ESC RCC), low-grade oncocytic tumor (LOT), eosinophilic vacuolated tumor (EVT), and papillary renal neoplasm with reverse polarity (PRNRP). A survey was shared among 65 urologic pathologists using SurveyMonkey.com (Survey Monkey, Santa Clara, CA, USA). De-identified and anonymized respondent data were analyzed. Sixty-three participants completed the survey and contributed to the study. Participants were from Asia (n = 21; 35%), North America (n = 31; 52%), Europe (n = 6; 10%), and Australia (n = 2; 3%). Half encounter oncocytic renal neoplasms that are difficult to classify monthly or more frequently. Most (70%) indicated that there is enough evidence to consider ESC RCC as a distinct entity now, whereas there was less certainty for LOT (27%), EVT (29%), and PRNRP (37%). However, when combining the responses for sufficient evidence currently and likely in the future, LOT and EVT yielded > 70% and > 60% for PRNRP. Most (60%) would not render an outright diagnosis of oncocytoma on needle core biopsy. There was a dichotomy in the routine use of immunohistochemistry (IHC) in the evaluation of oncocytoma (yes = 52%; no = 48%). The most utilized IHC markers included keratin 7 and 20, KIT, AMACR, PAX8, CA9, melan A, succinate dehydrogenase (SDH)B, and fumarate hydratase (FH). Genetic techniques used included TSC1/TSC2/MTOR (67%) or TFE3 (74%) genes and pathways; however, the majority reported using these very rarely. Only 40% have encountered low-grade oncocytic renal neoplasms that are deficient for FH. Increasing experience with the spectrum of oncocytic renal neoplasms will likely yield further insights into the most appropriate work-up, classification, and clinical management for these entities.

Avoiding "Needless" nephrectomy: What is the role of small renal mass biopsy in 2024?

Current guidelines do not mandate routine preoperative renal mass biopsy (RMB) for small renal masses (SRMs), which results in a considerable rate (18%-26%) of needless nephrectomy/partial nephrectomy for benign renal tumors. In light of this ongoing practice, a narrative review was conducted to examine the role of routine RMB for SRM. First, arguments justifying the current non-biopsy approach to SRM are critically reviewed and contested. Second, as a standalone procedure, RMB is critically assessed; RMB was found to have higher sensitivity, specificity, and an equal or lower complication rate when compared with other commonly preoperatively biopsied solid organ tumors (e.g., breast, prostate, lung, pancreas, thyroid, and liver). Based on the foregoing information, we propose a paradigm shift in SRM management, advocating for an updated policy in which partial nephrectomy or nephrectomy for SRM invariably occurs only after a preoperative biopsy confirms that a SRM is indeed malignant.

Frequency and clinicopathologic features of renal low-grade oncocytic tumour and eosinophilic vacuolated tumour: reclassification of 605 eosinophilic tumours including patients managed with active surveillance

AIMS

Low-grade oncocytic tumour (LOT) and eosinophilic vacuolated tumour (EVT) are recently described emerging entities, which demonstrate distinct features but are not yet recognised as separate neoplasms in the fifth WHO classification. Published series to date have been largely multi-institutional and based on surgically resected tumours. This study aims to determine the frequency, clinicopathologic features and outcome of LOT and EVT in a single institutional series of oncocytic/eosinophilic renal neoplasms, including patients managed with active surveillance and non-surgical intervention.

METHODS AND RESULTS

Cases were identified from a consecutive institutional series of in-house renal tumours diagnosed on biopsy and/or nephrectomy (2003-2023). Tumours with a diagnosis or differential diagnosis of oncocytoma, chromophobe renal cell carcinoma or oncocytic neoplasm not otherwise specified (including LOT, EVT and tumours with overlapping hybrid features) were retrospectively reviewed and classified/reclassified.In total, 605 oncocytic/eosinophilic renal neoplasms were reviewed, among which 33 LOT (5.5%) and 5 EVT (0.8%) were identified. LOT were CK7+, CD117- and GATA3+ (94%). EVT were CD117+, CK7 focal+ (80%) and cathepsin K+ (80%). At the median follow-up of 34 months (range 2-253) and 56 months (range 8-90) for LOT and EVT, respectively, there was no evidence of recurrence following ablation/surgical resection, metastasis or death from disease for all patients, including the 22 managed with active surveillance (20 LOT and 2 EVT).

CONCLUSIONS

LOT and EVT comprised a minority of oncocytic renal neoplasms in this series. We report a large institutional series including patients managed non-surgically, with no adverse outcome, adding to the existing literature indicating a benign outcome.

Renal mass biopsy - a practical and clinicopathologically relevant approach to diagnosis

Advancements in imaging modalities have increased the frequency of renal mass discovery. Imaging has typically been considered sufficient to guide management for a large proportion of these tumours, but renal mass biopsies (RMBs) have an increasing role in determining malignancy and can be a valuable tool for preventing unnecessary surgery in patients with benign tumours. A structured approach should be used to help to navigate the expanding repertoire of renal tumours, many of which are molecularly defined. In terms of tumour subtyping, the pathologist's strategy should focus on stratifying patients into clinically different prognostic groups according to our current knowledge of tumour behaviour, including benign, low-grade or indolent, intermediate malignant or highly aggressive. Crucial pathological features and morphological mimicry of tumours can alter the tumour's prognostic group. Thus, pathologists and urologists can use RMB to select patients with tumours at a reduced risk of progression, which can be safely managed with active surveillance within a tailored imaging schedule, versus tumours for which ablation or surgical intervention is indicated. RMB is also crucial in the oncological setting to distinguish between different high-grade tumours and guide tailored management strategies.

Stability of renal parenchymal volume and function during active surveillance of renal oncocytoma patients

INTRODUCTION AND OBJECTIVE

To evaluate whether significant loss in ipsilateral renal parenchymal volume (IRPV) and renal function occurs during active surveillance (AS) of renal oncocytoma (RO) patients.

METHODS

Renal function (estimated glomerular filtration rate, eGFR) dynamics were retrospectively analyzed in 32 consecutive biopsy-diagnosed RO patients managed with AS at a National Comprehensive Cancer Network institute. Three-dimensional kidney and tumor reconstructions were generated and IRPV was calculated using volumetry software (Myrian®) for all patients with manually estimated RO growth >+10 cm3. GFR and IRPV were compared at AS initiation vs. the last follow-up using 2-sided paired t-tests. The correlation between change in IRPV and change in RO size or GFR was tested using a Spearman coefficient.

RESULTS

With median follow-up of 37 months, there was no significant change between initial vs. last eGFR (median 71.0 vs. 70.5 ml/min/1.73 m2, P = 0.50; median change -3.0 ml/min/1.73 m2). Among patients (n = 17) with RO growth >+10 cm3 during AS (median growth +28.6 cm3, IQR +16.9- + 46.5 cm3), IRPV generally remained stable (median change +0.5%, IQR -1.2%- + 1.2%), with only 2 cases surpassing 5% loss. No IRPV loss was detected among any patient within the top tertile of RO growth magnitude. RO growth magnitude did not correlate with loss of either IRPV (ρ = -0.30, P = 0.24) or eGFR (ρ = -0.16, P = 0.40), including among patient subsets with lower initial eGFR. Study limitations include a lack of long-term follow-up.

CONCLUSIONS

Volumetry is a promising novel tool to measure kidney and tumor tissue changes during AS. Our study using volumetry indicates that clinically significant loss of IRPV or eGFR is uncommon and unrelated to tumor growth among untreated RO patients with intermediate follow-up. These findings support that AS is in general functionally safe for RO patients, however longer study is needed to determine safety durability, particularly among uncommon ≥cT2 RO variants.

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.

CT radiomics for differentiating oncocytoma from renal cell carcinomas: Systematic review and meta-analysis

BACKGROUND

Radiomics is a type of quantitative analysis that provides a more objective approach to detecting tumor subtypes using medical imaging. The goal of this paper is to conduct a comprehensive assessment of the literature on computed tomography (CT) radiomics for distinguishing renal cell carcinomas (RCCs) from oncocytoma.

METHODS

From February 15th 2012 to 2022, we conducted a broad search of the current literature using the PubMed/MEDLINE, Google scholar, Cochrane Library, Embase, and Web of Science. A meta-analysis of radiomics studies concentrating on discriminating between oncocytoma and RCCs was performed, and the risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies method. The pooled sensitivity, specificity, and diagnostic odds ratio were evaluated via a random-effects model, which was applied for the meta-analysis. This study is registered with PROSPERO (CRD42022311575).

RESULTS

After screening the search results, we identified 6 studies that utilized radiomics to distinguish oncocytoma from other renal tumors; there were a total of 1064 lesions in 1049 patients (288 oncocytoma lesions vs 776 RCCs lesions). The meta-analysis found substantial heterogeneity among the included studies, with pooled sensitivity and specificity of 0.818 [0.619-0.926] and 0.808 [0.537-0.938], for detecting different subtypes of RCCs (clear cell RCC, chromophobe RCC, and papillary RCC) from oncocytoma. Also, a pooled sensitivity and specificity of 0.83 [0.498-0.960] and 0.92 [0.825-0.965], respectively, was found in detecting oncocytoma from chromophobe RCC specifically.

CONCLUSIONS

According to this study, CT radiomics has a high degree of accuracy in distinguishing RCCs from RO, including chromophobe RCCs from RO. Radiomics algorithms have the potential to improve diagnosis in scenarios that have traditionally been ambiguous. However, in order for this modality to be implemented in the clinical setting, standardization of image acquisition and segmentation protocols as well as inter-institutional sharing of software is warranted.

Protocol for a MULTI-centre feasibility study to assess the use of 99mTc-sestaMIBI SPECT/CT in the diagnosis of kidney tumours (MULTI-MIBI study)

INTRODUCTION

The incidence of renal tumours is increasing and anatomic imaging cannot reliably distinguish benign tumours from renal cell carcinoma. Up to 30% of renal tumours are benign, with oncocytomas the most common type. Biopsy has not been routinely adopted in many centres due to concerns surrounding non-diagnostic rate, bleeding and tumour seeding. As a result, benign masses are often unnecessarily surgically resected. ^99mTc-sestamibi SPECT/CT has shown high diagnostic accuracy for benign renal oncocytomas and other oncocytic renal neoplasms of low malignant potential in single-centre studies. The primary aim of MULTI-MIBI is to assess feasibility of a multicentre study of ^99mTc-sestamibi SPECT/CT against a reference standard of histopathology from surgical resection or biopsy. Secondary aims of the study include obtaining estimates of ^99mTc-sestamibi SPECT/CT sensitivity and specificity and to inform the design and conduct of a future definitive trial.

METHODS AND ANALYSIS

A feasibility prospective multicentre study of participants with indeterminate, clinical T1 renal tumours to undergo ^99mTc-sestamibi SPECT/CT (index test) compared with histopathology from biopsy or surgical resection (reference test). Interpretation of the index and reference tests will be blinded to the results of the other. Recruitment rate as well as estimates of sensitivity, specificity, positive and negative predictive value will be reported. Semistructured interviews with patients and clinicians will provide qualitative data to inform onward trial design and delivery. Training materials for ^99mTc-sestamibi SPECT/CT interpretation will be developed, assessed and optimised. Early health economic modelling using a decision analytic approach for different diagnostic strategies will be performed to understand the potential cost-effectiveness of ^99mTc-sestamibi SPECT/CT.

ETHICS AND DISSEMINATION

Ethical approval has been granted (UK HRA REC 20/YH/0279) protocol V.5.0 dated 21/6/2022. Study outputs will be presented and published nationally and internationally.

TRIAL REGISTRATION NUMBER

ISRCTN12572202.

Reliability and Management Outcomes Following a Percutaneous Biopsy Diagnosis of Oncocytoma: A 15-year Retrospective Analysis

Background There is uncertainty in the management of renal masses diagnosed as oncocytomas with image-guided percutaneous biopsy. Purpose To assess the reliability of a diagnosis of oncocytoma based on image-guided percutaneous renal mass biopsy and evaluate patient outcomes following different management strategies. Materials and Methods In this retrospective study, image-guided percutaneous biopsy pathology reports from April 2004 to April 2019 were searched for keywords "oncocytoma" and "oncocytic neoplasm" and compared with surgical pathology or repeat biopsy results. Patients with at least 12 months of clinical follow-up and known cause of death were grouped according to management strategies, and disease-specific survival and metastatic renal cell carcinoma (RCC)-free survival were compared. Mass growth rates were calculated with use of a normal linear mixed model. Results The database yielded 160 biopsy reports of 149 renal masses in 139 patients; 149 masses were categorized as oncocytoma (n = 107), likely oncocytoma (n = 12), oncocytic neoplasm (n = 28), and indeterminate with oncocytoma in differential (n = 2). Biopsied masses categorized as oncocytoma or likely oncocytoma were oncocytomas in 16 of 17 masses (94%) based on surgical pathology or repeat biopsy; four of eight masses (50%) categorized as oncocytic neoplasms were low-grade RCCs. Outcome analysis included 121 patients (mean age ± SD, 68 years ± 9.1; 82 men); 80 patients initially underwent active surveillance (11 were later treated), 33 underwent ablation, and eight underwent surgery. Disease-specific survival and metastatic-free survival were 100% after each management strategy (median follow-up, 86.6 months; range, 14.2-207.9 months). Mass growth rate (mean, 1.7 mm per year) showed no evidence of a significant difference among biopsy result categories (P = .37) or initial (P = .84) or final management strategies (P = .11). Conclusion Image-guided percutaneous biopsy diagnosis of renal oncocytoma was reliable. Although some masses diagnosed as oncocytic neoplasms were low-grade renal cell carcinomas (RCCs) at final diagnosis, no patients died of RCC, including those managed with active surveillance. © RSNA, 2023 See also the editorial by Lockhart in this issue.

A triple-classification for differentiating renal oncocytoma from renal cell carcinoma subtypes and CK7 expression evaluation: a radiomics analysis

Background

To investigate the value of computed tomography (CT)-based radiomics model analysis in differentiating renal oncocytoma (RO) from renal cell carcinoma subtypes (chromophobe renal cell carcinoma, clear cell carcinoma) and predicting the expression of Cytokeratin 7 (CK7).

Methods

In this retrospective study, radiomics was applied for patients with RO, chRCC and ccRCC who underwent surgery between January 2013 and December 2019 comprised the training cohort, and the testing cohort was collected between January and October 2020. The corticomedullary (CMP) and nephrographic phases (NP) were manually segmented, and radiomics texture parameters were extracted. Support vector machine was generated from CMP and NP after feature selection. Shapley additive explanations were applied to interpret the radiomics features. A radiomics signature was built using the selected features from the two phases, and the radiomics nomogram was constructed by incorporating the radiomics features and clinical factors. Receiver operating characteristic curve was calculated to evaluate the above models in the two sets. Furthermore, Rad-score was used for correlation analysis with CK7.

Results

A total of 123 patients with RO, chRCC and ccRCC were analyzed in the training cohort and 57 patients in the testing cohort. Subsequently, 396 radiomics features were selected from each phase. The radiomics features combining two phases yielded the highest area under the curve values of 0.941 and 0.935 in the training and testing sets, respectively. The Pearson’s correlation coefficient was statistically significant between Rad-score and CK7.

Conclusion

We proposed a non-invasive and individualized CT-based radiomics nomogram to differentiation among RO, chRCC and ccRCC preoperatively and predict the immunohistochemical protein expression for accurate clinical diagnosis and treatment decision.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-022-01099-0.

Diagnosing Oncocytoma by Core Needle Biopsy: A Single-Center Experience

Background

Oncocytoma is one of the most common benign kidney tumors, accounting for 3–7% of all solid renal masses. Diagnosing oncocytomas using renal biopsy remains a controversy in the uro-pathologic community. With the increasing use of biopsies for assessment of renal lesions, reaching this pathologically benign diagnosis may prevent further surgical measures and have significant clinical benefit.

Objective

To demonstrate our center's results using renal biopsy to diagnose oncocytomas and to suggest that this diagnosis can be made with high success rates.

Design

, Setting, and Participants. From our center's database, we retrospectively identified and retrieved all cases of oncocytoma diagnosed between the years 2011 and 2020 by renal biopsy. Medical records of those patients were then reviewed to view follow-up meetings and imaging of the lesions biopsied. Outcome Measurements and Statistical Analysis. In 21 biopsies performed on 19 patients, diagnosis was supported by subsequent follow-up averaging at 3.44 years per patient. Results and Limitations. The lesions exhibited benign behavior during follow-up after biopsy, consistent with the diagnosis of oncocytoma.

Conclusions

Our study demonstrates that with good patient selection and proficient cooperation between urologists, radiologists and dedicated uro-pathologists, correctly diagnosing oncocytomas using RCB is a viable task. Patient Summary. Oncocytomas are benign lesions of the kidney. In our study, we reviewed all cases of oncocytomas pathologically diagnosed using renal biopsy from our center's database. We found that in subsequent follow-up later to biopsy, the lesions displayed benign behavior consistent with oncocytoma. The use of percutaneous biopsies to reach this diagnosis could save patients more extensive surgeries.

Clinical utility of histopathology data: urological cancers

Cancer datasets recommend standardised reporting of histopathological data items with elements categorised as either core (required) or non-core (recommended), irrespective of the clinical scenario. However, the clinical significance of a data item in an individual case would depend on the clinicopathological setting as well as local management guidelines. A data item that is critical for patient management in one clinical scenario may be largely irrelevant in another patient. Pathologists must understand how their data are used in clinical practice so that they can focus their limited resources appropriately. We briefly review the use of histopathological data in the management of urological cancers, highlighting scenarios where a data item may be of limited clinical utility.

Benefit and Harm of Active Surveillance for Biopsy-proven Renal Oncocytoma: A Systematic Review and Pooled Analysis

Context

Active surveillance (AS) of biopsy-proven renal oncocytomas may reduce overtreatment. However, on biopsy, the risk of misdiagnosis owing principally to entities with peculiar hybrids and overlap morphology, and phenotypes argues for early intervention.

Objective

To assess the benefit and harm of AS in biopsy-proven renal oncocytoma.

Evidence acquisition

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). We systematically searched PubMed, Scopus, and Web of Science databases from September 26 up to October 2021, for studies that analyzed the outcomes of AS in patients with biopsy-proven renal oncocytoma.

Evidence synthesis

A total of ten studies with 633 patients met our inclusion criteria and were included for analysis. After a median follow-up of 34.5 mo (95% confidence interval [CI] 30.6–38.4), the overall definitive treatment rate from AS to definitive treatment was 17.3% (n = 75/433, six studies). The pooled pathological agreement between the initial renal mass biopsy and the surgical pathology report was 91.1%. The main indications for surgery during follow-up were rapid tumor growth and patient request. The pooled median growth rate was 1.55 mm/yr (95% CI 0.9–2.2). No metastasis or death related to renal oncocytoma was reported.

Conclusions

Annual tumor growth of biopsy-proven renal oncocytoma is low. AS is oncologically safe, with favorable compliance of patients. Crossover to definitive treatment revealed a strong concordance between biopsy and final pathology. Further studies on the long-term outcomes of AS are needed.

Patient summary

In this study, we examined the benefit and harm of active surveillance (AS) in biopsy-proven oncocytoma. Based on the available data, AS appears oncologically safe and may represent a promising alternative to immediate treatment. Patients should be included in AS decision discussions.

Real world outcomes of biopsy-proven oncocytic neoplasm of the kidney managed by surveillance

Objectives

To evaluate outcomes of patients diagnosed with oncocytic renal neoplasms on routine renal mass biopsy and to describe the natural history of these tumours when managed with surveillance as opposed to immediate intervention. To report disease-specific survival.

Patients and methods

Patients were identified from a retrospective review of pathology databases from three tertiary referral centres that utilise renal mass biopsy in routine clinical practice. All patients with biopsy-proven oncocytic tumours were included and a retrospective review of online patient records was undertaken.

Results

There were 184 biopsy-proven oncocytic renal neoplasms identified in 172 patients. There were two biopsy complications (both pneumothorax, Clavien-Dindo Grade I). Of these lesions, 135 were reported as oncocytomas or oncocytic renal neoplasms that were not further classified and 37 were reported as chromophobe carcinoma (ChRCC). The median age at diagnosis was 70 (33-88). The average tumour diameter at diagnosis was 33 mm. One hundred seven tumours were initially managed with surveillance (including 13 ChRCC) with a minimum follow-up of 6 months and a median of 39 months (6-144) whereas 49 patients underwent immediate treatment. The mean growth rate across all oncocytic renal neoplasms managed by surveillance was 3 mm/year. There was no statistically significant difference in growth rates between oncocytic renal neoplasms and ChRCC. Thirteen patients with oncocytic renal neoplasms initially managed by surveillance moved on to an active management strategy during follow-up. The clinical indication given for a change from surveillance was tumour growth in 12 cases and patient choice in 1 case. Where definitive pathology was available, there was 85% concordance with the biopsy. There were no cases of development of metastatic disease or disease-related morbidity or mortality during the study.

Conclusions

This multicentre retrospective cohort study supports the hypothesis that selected biopsy-proven oncocytic renal neoplasms can be safely managed with surveillance in the medium term. Routine renal mass biopsy may reduce surgery for benign or indolent renal tumours and the potential associated morbidity for these patients.

Clinical Benefits of Indocyanine Green Fluorescence in Robot-Assisted Partial Nephrectomy

Background: To compare the intraoperative and postoperative outcomes of indocyanine green (ICG) administration in robot-assisted partial nephrectomy (RAPN) and report the differences in the results between patients with benign and malignant renal tumors. Methods: From 2017 to 2020, 132 patients underwent RAPN at our institution, including 21 patients with ICG administration. Clinical data obtained from our institution’s RAPN database were retrospectively reviewed. Intraoperative, postoperative, pathological, and functional outcomes of RAPN were assessed. Results: The pathological results indicated that among the 127 patients, 38 and 89 had received diagnoses of benign and malignant tumors, respectively. A longer operative time (311 vs. 271 min; p = 0.006) but superior preservation of estimated glomerular filtration rate (eGFR) at 3-month follow-up (90% vs. 85%; p = 0.031) were observed in the ICG-RAPN group. Less estimated blood loss, shorter warm ischemia time, and superior preservation of eGFR at postoperative day 1 and 6-month follow-up were also noted, despite no significant differences. Among the patients with malignant tumors, less estimated blood loss (30 vs. 100 mL; p < 0.001) was reported in the ICG-RAPN subgroup. Conclusions: Patients with ICG-RAPN exhibited superior short-term renal function outcomes compared with the standard RAPN group. Of the patients with malignant tumors, ICG-RAPN was associated with less blood loss than standard RAPN without a more positive margin rate. Further studies with larger cohorts and prospective designs are necessary to verify the intraoperative and functional advantages of the green dye.

Updates in Grading of Renal Cell Carcinomas Beyond Clear Cell Renal Cell Carcinoma and Papillary Renal Cell Carcinoma

The World Health Organization (WHO) recommends grading of clear cell renal cell carcinoma (RCC) and papillary RCC using the WHO/International Society of Urological Pathology (ISUP) grade, which is primarily based on nuclear features. As the spectrum of RCC continues to evolve, with more recently described subtypes in the past decade, literature evidence on grading these subtypes is limited or not available for some tumor types. Herein, we outline a pragmatic approach to the topic of grading RCC, dividing the contemporarily described RCC subtypes into 7 categories based on the potential clinical applicability of grading as a useful prognostic parameter: (1) RCC subtypes that are reasonably validated and recommended for WHO/ISUP grading; (2) RCC subtypes where WHO/ISUP is not applicable; (3) RCC subtypes where WHO/ISUP grading is potentially clinically useful; (4) inherently aggressive RCC subtypes where histologic classification itself confers an aggressive biologic potential; (5) renal epithelial tumors where WHO/ISUP grading provides potentially misleading prognostic implication; (6) renal epithelial neoplasms where low WHO/ISUP grade features are a prerequisite for accurate histologic classification; and (7) renal epithelial neoplasms with no or limited data on grading or incomplete understanding of the biologic potential. Our aim in outlining this approach is 2-fold: (a) identify the gaps in understanding and application of grading in RCC subtypes so that researchers in the field may perform additional studies on the basis of which the important pathologic function of assignment of grade may be recommended to be performed as a meaningful exercise across a wider spectrum of RCC; and (b) to provide guidance in the interim to surgical pathologists in terms of providing clinically useful grading information in RCC based on currently available clinicopathologic information.

Application of Mass Spectrometry Imaging in Uro-Oncology: Discovering Potential Biomarkers

A growing need is emerging worldwide for new molecular markers which could enhance the accuracy of diagnostic and therapeutic methods for detecting urogenital cancers. Mass spectrometry imaging (MSI) is a very promising tool in this regard. In this review, we attempt to provide a subjective summary of the latest publications on potential biomarkers of renal, bladder, prostate, and testicular malignancies detected with MSI through the eyes of a clinical urologist.

Oncocytic renal neoplasms with diffuse keratin 7 immunohistochemistry harbor frequent alterations in the mammalian target of rapamycin pathway

Low-grade oncocytic tumor (LOT) has been recently proposed as a unique renal tumor. However, we have encountered tumors with more oncocytoma-like morphology that show diffuse keratin 7 reactivity, which we sought to characterize molecularly. Eighteen tumors with a diffuse keratin 7 positive and KIT negative pattern were identified from 184 with predominantly oncocytoma-like histology. These tumors were subjected to detailed immunohistochemical evaluation and 14 were evaluated using the Illumina^® HiSeq 4000 platform for 324 cancer-associated genes. Patients' ages ranged from 39 to 80 (median = 59.5 years) with a male to female ratio of 1.25:1. Morphology was predominantly oncocytoma-like with discrete nests, compared to the solid and edematous patterns described in LOT. Other than positive keratin 7 and negative KIT, the tumor cells were positive for PAX8, E-cadherin, AE1/AE3, Ber-EP4, AMACR, CD10, and MOC31, and were negative for other studied markers. FH and INI1 were normal. Eleven of 14 harbored genomic abnormalities, likely sporadic, primarily involving the MTOR pathway (73%). Overall, the alterations included MTOR activating mutation (n = 1), TSC1 inactivating mutation (n = 1), TSC2 mutation (p.X534 splice site, n = 1), STK11 (a negative regulator of the MTOR pathway) mutation (n = 1), both STK11 and TSC1 mutations (n = 1), biallelic loss of PTEN and TSC1 deletion (n = 1), and MET amplification and TSC1 inactivating mutation (n = 1). Amplification of FGFR3 was identified in one additional tumor. Other alterations included FOXP1 loss (n = 1), NF2 E427 homozygous loss (n = 1), and PI3KCA activating mutation (n = 1). At a median follow-up of 68 months (2-147 months) for 15 patients, all were alive without disease. Oncocytic renal tumors with diffuse keratin 7 labeling show frequent alterations in the TSC/MTOR pathway, despite more oncocytoma-like morphology than initially described in LOT, likely expanding the morphologic spectrum of the latter.

Renal Oncocytoma: The Diagnostic Challenge to Unmask the Double of Renal Cancer

Renal oncocytoma represents the most common type of benign neoplasm that is an increasing concern for urologists, oncologists, and nephrologists due to its difficult differential diagnosis and frequent overtreatment. It displays a variable neoplastic parenchymal and stromal architecture, and the defining cellular element is a large polygonal, granular, eosinophilic, mitochondria-rich cell known as an oncocyte. The real challenge in the oncocytoma treatment algorithm is related to the misdiagnosis due to its resemblance, at an initial radiological assessment, to malignant renal cancers with a completely different prognosis and medical treatment. Unfortunately, percutaneous renal biopsy is not frequently performed due to the possible side effects related to the procedure. Therefore, the majority of oncocytoma are diagnosed after the surgical operation via partial or radical nephrectomy. For this reason, new reliable strategies to solve this issue are needed. In our review, we will discuss the clinical implications of renal oncocytoma in daily clinical practice with a particular focus on the medical diagnosis and treatment and on the potential of novel promising molecular biomarkers such as circulating microRNAs to distinguish between a benign and a malignant lesion.

Bilateral Renal Oncocytoma: Active Surveillance Versus Partial Nephrectomy

Renal oncocytomas (ROs) are benign tumors comprising 16% of renal masses. Due to the overlapping phenotypes seen in RO and chromophobe renal cell carcinoma (RCC) and lack of specific clinical and laboratory characteristics of RO, physicians face a challenge when arriving at a definitive diagnosis of RO. ROs additionally appear indistinct from RCCs on CT scan, contributing further to the difficulty of arriving at a clear diagnosis of RO. 

This is a case report of a 66-year-old man who presented with flank pain found to be related to bilateral ROs and underwent bilateral partial nephrectomies.

ROs are benign small renal masses that often pose a diagnostic challenge since preoperative diagnosis can be difficult to achieve. Given advancements in technology, active surveillance with core renal biopsy is a promising approach to accurately diagnose and manage ROs conservatively. The application of these techniques has wide-reaching implications for patients and physicians by reducing the need for a potentially harmful surgery and creating a cost-effective way to manage a diagnosis.

Ultrasonography findings for the diagnosis of renal oncocytoma

Renal oncocytomas are rare benign epithelial tumors of the kidney. However, they are easily misdiagnosed as renal cancers, resulting in unnecessary radical nephrectomy. This review summarizes the use of ultrasound for the diagnosis of renal oncocytomas. On two-dimensional grayscale ultrasound, renal oncocytomas appear as solid, well-defined, round or oval, and relatively isoechoic or slightly hyperechoic masses. On color Doppler flow imaging, the "spoke-wheel" sign is evident. On power Doppler flow imaging, renal oncocytomas show mixed penetrating and peripheral patterns. Renal oncocytomas usually appear as highly enhanced on contrast-enhanced ultrasound images, and irregular nonenhanced areas in larger tumors. This review will help sonographers recognize renal oncocytomas.

[Dignity of Small Renal Masses: Implications for Diagnostics and Therapy]

Dignity of Small Renal Masses: Implications for Diagnostics and Therapy Abstract. The ubiquitous availability of radiological imaging has increased the diagnosis of renal incidentalomas with a diameter ≤4 cm. If malignancy is suspected, these are often treated surgically without prior biopsy. However, several studies demonstrate a relevant proportion of benign tumors, equating to a degree of overtreatment. There are no Swiss data available. Renal tumors resected in our center between 2006 and 2014 (n = 404) were retrospectively examined for size on cross-sectional imaging and their respective histology, identifying 221 (54.7 %) small renal masses with a diameter ≤4 cm. Of these, 62 (28 %) were benign and three (1.4 %) were of unclear or low malignant potential. Among the remaining 156 malignancies, 116 (74.4 %) were classified as prognostically favorable, allowing for active surveillance, if the patient's clinical context allows.

Active Surveillance for Biopsy Proven Renal Oncocytomas: Outcomes and Feasibility

OBJECTIVES

To report the outcomes and feasibility of active surveillance (AS) of biopsy-proven renal oncocytomas.

METHODS

Multicentric retrospective study (2010-2016) in 6 academic centers that included patients with biopsy-proven renal oncocytomas who were allocated to AS (imperative or elective indication) with a follow-up ≥1 year. Imaging was performed at least once a year, by CT-scan or ultrasound or MRI. Conversion to active treatment (surgical excision or ablative treatment) was at the discretion of the urologist. The primary endpoint was renal tumor growth (cm/year). Secondary outcomes included accuracy of biopsy, incidence, and reason to change AS to active treatment.

RESULTS

Eighty-nine patients were included: Median age 67 years (26-89) and median tumor size 26 mm [15-90] on diagnosis. During a mean follow-up of 43 months'' (median 36 [12-180]), mean tumor growth was 0.24 cm/year. No predictive factors (demographical, radiological or histologic) of tumor growth could be identified. Conversion from AS to active treatment occurred in 24 patients (27%) (13 surgical excisions, 11 ablative procedures), in a median time of 45 (12-76) months'' after diagnosis. Tumor growth was the main indication to convert AS to active treatment (58%) with 8% of the patients opting to discontinue AS. No patient had metastatic progression nor disease-specific death. The correlation between biopsy and surgical specimen was 92%.

CONCLUSION

Active surveillance for biopsy-proven renal oncocytomas was oncologically safe and patient adherence was high. No predictive factor for tumor growth could be identified but the tumor growth rate was low, and biopsy efficacy was high.

Surveillance for low-risk kidney cancer: a narrative review of contemporary worldwide practices

The management trend of low-risk kidney cancer over the last decade has been from treatment with radical nephrectomy, to use of nephron sparing procedures of partial nephrectomy and ablation, as well as the option of active surveillance (AS). This narrative review aims to summarise the available guidelines related to AS and review the published descriptions of regional practices on the management of low-risk kidney cancer worldwide. A search of PubMed, Google Scholar and Cochrane Library databases for studies published 2010 to June 2020 identified 15 studies, performed between 2000 and 2019, which investigated 13 different cohorts of low-risk kidney cancer patients on AS. Although international guidelines show a level of agreement in their recommendation on how AS is conducted, in terms of patient selection, surveillance strategy and triggers for intervention, cohort studies show distinct differences in worldwide practice of AS. Prospective studies showed general agreement in their predefined selection criteria for entry into AS. Retrospective studies showed that patients who were older, with greater comorbidities, worse performance status and smaller tumours were more likely to be managed with AS. The rate of percutaneous renal mass biopsy varied between studies from 2% to 56%. The surveillance protocol was different across all studies in terms of recommended modality and frequency of imaging. Of the 6 studies which had set indications for intervention, these were broadly in agreement. Despite clear criteria for intervention, patient or surgeon preference was still the reason in 11–71% of cases of delayed intervention across 5 studies. This review shows that AS is being applied in a variety of centres worldwide and that key areas of patient selection criteria and surveillance strategy have large similarities. However, the rate of renal mass biopsy and of delayed intervention varies significantly between studies, suggesting the process of diagnosing malignant SRM and decision making whilst on AS are varying in practice. Further research is needed on the diagnosis and characterisation of incidentally found small renal masses (SRM), using imaging and histology, and the natural history of these SRM in order to develop evidence-based active surveillance protocols.

Growth and renal function dynamics of renal oncocytomas in patients on active surveillance

OBJECTIVES

To study the natural history of renal oncocytomas and address indications for intervention by determining how growth is associated with renal function over time, the reasons for surgery and ablation, and disease-specific survival.

PATIENTS AND METHODS

The study was conducted in a retrospective cohort of consecutive patients with renal oncocytoma on active surveillance reviewed at the Specialist Centre for Kidney Cancer at the Royal Free London NHS Foundation Trust (2012 to 2019). Comparison between groups was performed using Mann-Whitney U-tests and chi-squared tests. A mixed-effects model with a random intercept for patient was used to study the longitudinal association between tumour size and estimated glomerular filtration rate (eGFR).

RESULTS

Longitudinal data from 98 patients with 101 lesions were analysed. Most patients were men (68.3%) and the median (interquartile range [IQR]) age was 69 (13) years. The median (IQR) follow-up was 29 (26) months. Most lesions were small renal masses, and 24% measured over 4 cm. Over half (64.4%) grew at a median (IQR) rate of 2 (4) mm per year. No association was observed between tumour size and eGFR over time (P = 0.871). Nine lesions (8.9%) were subsequently treated. Two deaths were reported, neither were related to the diagnosis of renal oncocytoma.

CONCLUSION

Natural history data from the largest active surveillance cohort of renal oncocytomas to date show that renal function does not seem to be negatively impacted by growing oncocytomas, and confirms clinical outcomes are excellent after a median follow-up of over 2 years. Active surveillance should be considered the 'gold standard' management of renal oncocytomas up to 7cm.

Targeted PET/CT imaging for clear cell renal cell carcinoma with radiolabeled antibodies: recent developments using girentuximab

PURPOSE OF REVIEW

Conventional imaging is unable to differentiate clear cell renal cell carcinoma (ccRCC) from other more indolent and benign renal tumors. Positron emission tomography/computed tomography (PET/CT) using radiolabeled antibodies may aid in detecting both localized and metastatic ccRCC. The purpose of this review is to summarize recent literature regarding the use of radiolabeled antibodies for imaging of ccRCC.

RECENT FINDINGS

Two recent studies evaluated the use of radiolabeled anticarbonic anhydrase IX antibody girentuximab for the imaging of ccRCC. PET/CT with 89zirconium-labeled girentuximab (89Zr-girentuximab PET/CT) was used to guide clinical decision making in 16 patients with localized disease. It had a high specificity for detecting ccRCC with 6/6 resected lesions with uptake proven to be ccRCC, all lesion without uptake showed to be indolent during follow-up. Clinical management was changed in 36% (5/14) of patients with the metastatic disease based on outcomes of the scan. Furthermore, in 42 patients 89Zr-girentuximab PET/CT combined with CT outperformed CT alone or combined with 18F fludeoxyglucose PET for detection of metastasis.

SUMMARY

89Zr-girentuximab PET/CT has the ability to diagnose ccRCC in localized disease. In metastatic disease, it enables the differentiation of ccRCC from non-ccRCC cancers and the evaluation of disease extent. 89Zr-girentuximab PET/CT diagnostic accuracy is currently evaluated in a multicenter phase III trial.

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.

The state of the art in kidney and kidney tumor segmentation in contrast-enhanced CT imaging: Results of the KiTS19 challenge

There is a large body of literature linking anatomic and geometric characteristics of kidney tumors to perioperative and oncologic outcomes. Semantic segmentation of these tumors and their host kidneys is a promising tool for quantitatively characterizing these lesions, but its adoption is limited due to the manual effort required to produce high-quality 3D segmentations of these structures. Recently, methods based on deep learning have shown excellent results in automatic 3D segmentation, but they require large datasets for training, and there remains little consensus on which methods perform best. The 2019 Kidney and Kidney Tumor Segmentation challenge (KiTS19) was a competition held in conjunction with the 2019 International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI) which sought to address these issues and stimulate progress on this automatic segmentation problem. A training set of 210 cross sectional CT images with kidney tumors was publicly released with corresponding semantic segmentation masks. 106 teams from five continents used this data to develop automated systems to predict the true segmentation masks on a test set of 90 CT images for which the corresponding ground truth segmentations were kept private. These predictions were scored and ranked according to their average Sørensen-Dice coefficient between the kidney and tumor across all 90 cases. The winning team achieved a Dice of 0.974 for kidney and 0.851 for tumor, approaching the inter-annotator performance on kidney (0.983) but falling short on tumor (0.923). This challenge has now entered an "open leaderboard" phase where it serves as a challenging benchmark in 3D semantic segmentation.

Active surveillance for bilateral renal oncocytomas already resected on one side: a case report

INTRODUCTION

To report our experience of active surveillance of new bilateral masses after left laparoscopic partial nephrectomy for oncocytoma.

METHOD

A 67-year old man underwent left laparoscopic partial nephrectomy for a renal mass and histology confirmed oncocytoma. At follow-up magnetic resonance imaging (MRI) showed new renal bilateral masses: hence, sonogram-guided percutaneous core renal biopsies were performed confirming the presence of oncocytoma in both kidneys. A re-biopsy was required because of an increasing of the left mass while a histological was also consistent with oncocytoma.

RESULT

At follow of 8 years the patient is well and shows a normal renal function.

CONCLUSION

Oncocytomas show minimal growth rate or progression. MRI has an important role in the appropriate follow-up of renal oncocytomas. Patients with biopsy proven oncocytoma may be managed conservatively by active surveillance (AS).

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.

The role of renal mass biopsy in the management of small renal masses – patterns of use and surgeon opinion

Aims:

Renal mass biopsy (RMB) is advocated to improve management of small renal masses, however there is concern about its clinical utility. This study aimed to elicit opinions about the role of RMB in small renal mass management from surgeons managing renal cell carcinomas (RCC), and examine the frequency of pre-treatment biopsy in those with RCC.

Methods:

All surgeons in two Australian states (Queensland: n = 59 and Victoria: n = 108) who performed nephrectomies for RCC in 2012/2013 were sent questionnaires to ascertain views about RMB. Response rates were 54% for Queensland surgeons and 38% for Victorian surgeons. We used medical records data from RCC patients to determine RMB frequency.

Results:

Most Queensland (81%) and Victorian (59%) surgeons indicated they rarely requested RMB; however 34% of Victorians reported often requesting RMB, compared with no Queensland surgeons. This was consistent with medical records data: 17.6% of Victorian patients with T1a tumours received RMB versus 6.7% of Queensland patients ( p < 0.001). Surgeons’ principal concerns regarding RMB related to sampling reliability (90%) and/or histopathological interpretation (76%).

Conclusions:

Most surgeons report infrequent use of RMB for small renal masses, however we observed practice variation. The principal reasons for infrequent use were concerns about sampling reliability and histopathological interpretation, which may be valid in regions with less access to interventional radiologists and uropathologists. Further evidence is required to define patient groups for whom biopsy results will alter management.

Level of evidence:

Not applicable for this multicentre audit.

Small Renal Mass Surveillance: Histology-specific Growth Rates in a Biopsy-characterized Cohort

BACKGROUND

Most reports of active surveillance (AS) of small renal masses (SRMs) lack biopsy confirmation, and therefore include benign tumors and different subtypes of renal cell carcinoma (RCC).

OBJECTIVE

We compared the growth rates and progression of different histologic subtypes of RCC SRMs (SRM^RCC) in the largest cohort of patients with biopsy-characterized SRMs on AS.

DESIGN, SETTING, AND PARTICIPANTS

Data from patients in a multicenter Canadian trial and a Princess Margaret cohort were combined to include 136 biopsy-proven SRM^RCC lesions managed by AS, with treatment deferred until progression or patient/surgeon decision.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Growth curves were estimated from serial tumor size measures. Tumor progression was defined by sustained size ≥4 cm or volume doubling within 1 yr.

RESULTS AND LIMITATIONS

Median follow-up for patients who remained on AS was 5.8 yr (interquartile range 3.4-7.5 yr). Clear cell RCC SRMs (SRM^ccRCC) grew faster than papillary type 1 SRMs (0.25 and 0.02 cm/yr on average, respectively, p =  0.0003). Overall, 60 SRM^RCC lesions progressed: 49 (82%) by rapid growth (volume doubling), seven (12%) increasing to ≥4 cm, and four (6.7%) by both criteria. Six patients developed metastases, and all were of clear cell RCC histology. Limitations include the use of different imaging modalities and a lack of central imaging review.

CONCLUSIONS

Tumor growth varies between histologic subtypes of SRM^RCC and among SRM^ccRCC, which likely reflects individual host and tumor biology. Without validated biomarkers that predict this variation, initial follow-up of histologically characterized SRMs can inform personalized treatment for patients on AS.

PATIENT SUMMARY

Many small kidney cancers are suitable for surveillance and can be monitored over time for change. We demonstrate that different types of kidney cancers grow at different rates and are at different risks of progression. These results may guide better personalized treatment.

Comparison of renal functional outcomes of active surveillance and partial nephrectomy in the management of oncocytoma

PURPOSE

To compare functional outcomes of partial nephrectomy (PN) and active surveillance (AS) in oncocytoma.

METHODS

Multicenter retrospective analysis of patients with oncocytoma managed with PN or AS (biopsy-confirmed). Primary outcome development of de novo chronic kidney disease (CKD) (eGFR < 60 mL/min/1.73m²). Cox regression Multivariable analysis (MVA) was carried out for predictors of de novo CKD. Linear regression was carried out for factors associated with increasing deltaGFR. Kaplan-Meier Analysis (KMA) was performed to analyze 5-year CKD-free survival.

RESULTS

295 patients were analyzed (224 PN/71 AS, median follow-up 37.4 months). No differences were noted for clinical tumor size (AS 2.6 vs. PN 2.9 cm, p = 0.108), and baseline eGFR (AS 79.6 vs. PN 77, p = 0.9670). Median change in tumor diameter for AS was 0.42 cm. Compared to PN, AS had deltaGFR (-15.3 vs. -6.4 mL/min/1.73m², p < 0.001) and de novo CKD (28.2% vs. 12.1%, p = 0.002). AS patients who developed CKD had higher RENAL score (p = 0.005) and lower baseline eGFR (73 vs. 91.2 mL/min/1.73m², p < 0.001) than AS patients who did not. MVA demonstrated increasing age (OR = 1.03, p = 0.025), tumor size (HR = 1.26, p = 0.032) and AS (HR = 4.91, p < 0.001) to be predictive for de novo CKD. Linear regression demonstrated AS was associated with larger decrease in deltaGFR (B = -0.219, p < 0.001). KMA revealed 5-year CKD survival was higher in PN (87%) vs. AS (62%, p < 0.001).

CONCLUSION

AS was associated with greater functional decline than PN in oncocytoma. PN may be considered to optimalize renal functional preservation in select circumstances. Further investigation into mechanisms of functional decline in oncocytoma is requisite.

Renal Oncocytoma: An Algorithm for Diagnosis and Management

Renal oncocytoma is an uncommon tumor that exhibits numerous features which are characteristic but not necessarily unique. Percutaneous biopsy is a safe method of diagnosis. However, differentiation from other tumor subtypes often requires sophisticated analysis and is not universally feasible. This is why, surgical management can be considered as a first-line treatment or after surveillance. Potential triggers for change in management are: tumor size >3 cm, stage progression, kinetics of size progression (>5 mm/y), and clinical change in patient or tumor factors. Long-term follow-up data are lacking and greater centralization should be considered to reach adequate management.

[Evolution of followed renal oncocytomas]

INTRODUCTION

Oncocytomas are primitive kidney tumours, considered benign but their evolution is not fully established. The local progression is generally admitted but few data explain what makes a oncocytoma to grow more or less quickly. The objective of our study is to analyse the evolution of followed renal oncocytomas after histologic confirmation and to identify factors that can influence their growth.

MATERIAL AND METHODS

This is a retrospective study in two centers (North Hospital and Hospital of the Conception of Marseille). All patients with renal oncocytoma diagnosed with percutaneous biopsy from September 2010 to April 2016 and followed for more than one year were included. Epidemiological, histological, and morphological data were collected at diagnosis, during follow-up and in case of strategy change (intervention). Statistical analysis of factors influencing oncocytomes growth was based on the Pearson correlation test.

RESULTS

Fifty-three patients were included. The median age for diagnosis was 65 years [39-85]. The sex ratio H/F was 6/5. The median follow-up was 34 months [12-180]. The average diagnosis size was 29 mm [12-90]. Thirteen patients (25%) were treated secondarily, including 70% by conservative treatment. The average growth was 0.25 (±0.23) cm/yr. The patients treated were younger and had a higher growth rate than the untreated (0.48±0.23cm/yr versus 0.18±0.18cm/yr, P<0,001). According to Pearson's analysis, there was a positive linear relationship (R=0.27, P=0.047) between velocity and initial size and a negative linear relationship (ρ=-0.44, P<0.001) between velocity and age at diagnosis. So tumor growth was faster if the patients were young and the tumor voluminous at diagnosis.

DISCUSSION

Rapid growth often leads to a cessation of surveillance in favour of an intervention strategy. For young patients, conservative treatment (partiel nephrectomy or ablative treatment) in the medium term is likely to be preferred, but for elderly patients or with important comorbidities follow-up is an alternative to an invasive attitude.

LEVEL OF EVIDENCE

3.

Roles for active surveillance in renal cancer

PURPOSE OF REVIEW

With this review, we describe the most recent advances in active surveillance as well as diagnosis and management of small renal masses (SRMs).

RECENT FINDINGS

We discuss diagnosis, differentiation of solid from cystic lesions, risk prediction and treatment of the SRM. A better understanding of the disease facilitates the use of more conservatory treatments, such as active surveillance. Active surveillance has been increasingly accepted not only for SRM, but also for larger tumors and even metastatic patients. Exiting advances in risk prediction will help us define which patients can be safely managed with active surveillance and which require immediate treatment. Meanwhile, the use of renal tumor biopsies is still an important tool for these cases.

SUMMARY

Active surveillance is an option for many patients with renal masses. Noninvasive methods for diagnosis and risk prediction are being developed, but meanwhile, renal tumor biopsy is a useful tool. A better understanding of the disease increases the number of patients who can undergo active surveillance fully certain of the safety of their management.

Current Management of Small Renal Masses, Including Patient Selection, Renal Tumor Biopsy, Active Surveillance, and Thermal Ablation

Renal cancer represents 2% to 3% of all cancers, and its incidence is rising. The increased use of ultrasonography and cross-sectional imaging has resulted in the clinical dilemma of incidentally detected small renal masses (SRMs). SRMs represent a heterogeneous group of tumors that span the full spectrum of metastatic potential, including benign, indolent, and more aggressive tumors. Currently, no composite model or biomarker exists that accurately predicts the diagnosis of kidney cancer before treatment selection, and the use of renal mass biopsy remains controversial. The management of SRMs has changed dramatically over the last two decades as our understanding of tumor biology and competing risks of mortality in this population has improved. In this review, we critically assess published consensus guidelines and recent literature on the diagnosis and management of SRMs, with a focus on patient treatment selection and use of renal mass biopsy, active surveillance, and thermal ablation. Finally, we highlight important opportunities for leveraging recent research discoveries to identify patients with SRMs at high risk for renal cell carcinoma-related mortality and minimize overtreatment and patient morbidity.

Caspase 3 as a Novel Marker to Distinguish Chromophobe Renal Cell Carcinoma from Oncocytoma

Despite advances in our understanding of the biology of chromophobe renal cell carcinoma (ChRCC) and renal oncocytoma (RO), the differential diagnosis among these tumors remains one of the most problematic in renal pathology. Today, CK7 is the most recommended marker to distinguish these entities, however it appears insufficiently accurate by itself. This study aimed to find an easily accessible IHC stain that might out-compete CK7 in this field. Expressions of CK7, cyclin D1, p16, survivin, CD138, Ki-67 and caspase 3 (CASP3) were analyzed in a total of 27 cases (20 ROs and 7 ChRCCs). Immunoreactivity was assessed based on a combined score of the extent and intensity of staining. Compared to RO, a higher percentage of the total ChRCCs stained positive for CK7 (67% vs. 22%, respectively) and CASP3 (86% vs. 25%) (P < 0.005). The differences in staining with cyclin D1, p16, survivin, CD138 and Ki-67 turned out to be statistically insignificant in differentiating ChRCC from RO. CASP3 is a promising marker in distinguishing ChRCC from RO and may represent an alternative for CK7. Cyclin D1, p16, survivin, CD138 and Ki-67 cannot be used to distinguish these neoplasms.