Diagnostic Accuracy and Risks of Biopsy in the Diagnosis of a Renal Mass Suspicious for Localized Renal Cell Carcinoma: Systematic Review of the Literature

Renal Cell Carcinoma Mimicking with Peritoneal Carcinomatosis and Krukenberg Tumor: Diagnosis Seen on Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography

Krukenberg tumor (KT) is a rare clinical entity with a mysterious origin. It originates most commonly from adenocarcinoma of the stomach. We present an interestingly rare case of this entity in renal cell carcinoma, revealed by ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) scan. Ovarian cancers with diffuse peritoneal metastasis were considered the differential diagnosis of the disease, based on PET/CT. The potential efficacy of this functional imaging for KT is still in the exploratory phase, but its applications in diagnosis, disease prognostication, therapeutic response monitoring, and follow-up recurrence detection are superior than other imaging modalities.

Artificial intelligence in urological oncology: An update and future applications

There continues to be rapid developments and research in the field of Artificial Intelligence (AI) in Urological Oncology worldwide. In this review we discuss the basics of AI, application of AI per tumour group (Renal, Prostate and Bladder Cancer) and application of AI in Robotic Urological Surgery. We also discuss future applications of AI being developed with the benefits to patients with Urological Oncology.

The added value of contrast-enhanced ultrasound in evaluation of indeterminate small solid renal masses and risk stratification of cystic renal lesions

OBJECTIVES

To investigate accuracy of contrast-enhanced ultrasound (CEUS) to characterize indeterminate small solid renal masses (sSRMs), excluding lipid-rich AMLs, and cystic renal masses (CRMs) according to the proposed Bosniak Classification 2019 MATERIALS AND METHODS: CEUS of pathology-proven CRMs and sSRMs (without definite enhancement or macroscopic fat on CT/MRI), and CRMs with ≥18 months follow-up were retrospectively reviewed. Two radiologists blindly categorized CRMs according to new Bosniak Classification on CT/MRI. On CEUS, two other radiologists evaluated arterial-phase enhancement of sSRMs relative to renal cortex and categorized CRMs following new Bosniak Classification. Fisher's exact/chi-squared test was used to compare categorical variables, and Cohen κ statistics for inter-observer agreement RESULTS: A total of 237 patients had 241 lesions: 161 pathology-proven sSRMs (122 malignant and 39 benign), 29 pathology-proven CRMs, 51 CRMs with adequate follow-up. Arterial-phase enhancement < renal cortex predicted malignancy with specificity of 97.4% (38/39) (CI 85.6-99.9%), and positive predictive value (PPV) of 98.2% (54/55) (CI 90.4-99.9%). Inter-observer kappa was 0.95. In pathology-proven CRMS, sensitivity of CEUS vs CT/MRI was 100% (15/15) (CI 79.6-100%) vs 60% (9/15) (CI 35.8-80.1%) (p value = .002) and negative predictive value (NPV) 100% (2/2) (CI 17.8-100%) vs 25% (2/8 ) (CI 4.4-59.1%) (p value < 0.0001), with similar specificity (50%) and PPV- 88.2% (15/17) (CI 65.7-97.9%) vs 81.8% (9/11) (CI 52.3-96.8%) ( p value = 0.586). Bosniak Classification inter-observer kappa was 0.92 for CEUS vs 0.68 for CT/MRI (p value = 0.009).

CONCLUSION

In our cohort, CEUS had high specificity and PPV to diagnose RCC in sSRMs excluding lipid-rich AML. CEUS had significantly higher sensitivity/NPV to diagnose malignancy in CRMs as compared to CT/MRI.

KEY POINTS

• Once lipid-rich AML is excluded by the other modalities, sSRM arterial phase hypo-enhancement relative to renal cortex on CEUS yielded high specificity (97.4%) and PPV (98.2%) to diagnose RCC. • When applying the proposed Bosniak Classification 2019, CEUS showed higher sensitivity compared to CT/MRI (100% vs 60%), p value=.0024, in the stratification of cystic renal masses to diagnose malignancy. • CEUS may reduce the number of CT/MRI Bosniak IIF lesions by assigning them to either II or III/IV categories.

Learnable image histograms-based deep radiomics for renal cell carcinoma grading and staging

Fuhrman cancer grading and tumor-node-metastasis (TNM) cancer staging systems are typically used by clinicians in the treatment planning of renal cell carcinoma (RCC), a common cancer in men and women worldwide. Pathologists typically use percutaneous renal biopsy for RCC grading, while staging is performed by volumetric medical image analysis before renal surgery. Recent studies suggest that clinicians can effectively perform these classification tasks non-invasively by analyzing image texture features of RCC from computed tomography (CT) data. However, image feature identification for RCC grading and staging often relies on laborious manual processes, which is error prone and time-intensive. To address this challenge, this paper proposes a learnable image histogram in the deep neural network framework that can learn task-specific image histograms with variable bin centers and widths. The proposed approach enables learning statistical context features from raw medical data, which cannot be performed by a conventional convolutional neural network (CNN). The linear basis function of our learnable image histogram is piece-wise differentiable, enabling back-propagating errors to update the variable bin centers and widths during training. This novel approach can segregate the CT textures of an RCC in different intensity spectra, which enables efficient Fuhrman low (I/II) and high (III/IV) grading as well as RCC low (I/II) and high (III/IV) staging. The proposed method is validated on a clinical CT dataset of 159 patients from The Cancer Imaging Archive (TCIA) database, and it demonstrates 80% and 83% accuracy in RCC grading and staging, respectively.

Metabolic imaging with hyperpolarized 13 C pyruvate magnetic resonance imaging in patients with renal tumors-Initial experience

BACKGROUND

Optimal treatment selection for localized renal tumors is challenging because of their variable biologic behavior and limitations in the preoperative assessment of tumor aggressiveness. The authors investigated the emerging hyperpolarized (HP) ¹³ C magnetic resonance imaging (MRI) technique to noninvasively assess tumor lactate production, which is strongly associated with tumor aggressiveness.

METHODS

Eleven patients with renal tumors underwent HP ¹³ C pyruvate MRI before surgical resection. Tumor ¹³ C pyruvate and ¹³ C lactate images were acquired dynamically. Five patients underwent 2 scans on the same day to assess the intrapatient reproducibility of HP ¹³ C pyruvate MRI. Tumor metabolic data were compared with histopathology findings.

RESULTS

Eight patients had tumors with a sufficient metabolite signal-to-noise ratio for analysis; an insufficient tumor signal-to-noise ratio was noted in 2 patients, likely caused by poor tumor perfusion and, in 1 patient, because of technical errors. Of the 8 patients, 3 had high-grade clear cell renal cell carcinoma (ccRCC), 3 had low-grade ccRCC, and 2 had chromophobe RCC. There was a trend toward a higher lactate-to-pyruvate ratio in high-grade ccRCCs compared with low-grade ccRCCs. Both chromophobe RCCs had relatively high lactate-to-pyruvate ratios. Good reproducibility was noted across the 5 patients who underwent 2 HP ¹³ C pyruvate MRI scans on the same day.

CONCLUSIONS

The current results demonstrate the feasibility of HP ¹³ C pyruvate MRI for investigating the metabolic phenotype of localized renal tumors. The initial data indicate good reproducibility of metabolite measurements. In addition, the metabolic data indicate a trend toward differentiating low-grade and high-grade ccRCCs, the most common subtype of renal cancer.

LAY SUMMARY

Renal tumors are frequently discovered incidentally because of the increased use of medical imaging, but it is challenging to identify which aggressive tumors should be treated. A new metabolic imaging technique was applied to noninvasively predict renal tumor aggressiveness. The imaging results were compared with tumor samples taken during surgery and showed a trend toward differentiating between low-grade and high-grade clear cell renal cell carcinomas, which are the most common type of renal cancers.

Diagnostic renal mass biopsy is associated with individual categories of PADUA and RENAL nephrometry scores: Analysis of diagnostic and concordance rates with surgical resection

BACKGROUND

Renal mass biopsy (RMB) is a safe and accurate method for diagnosis and clinical management of renal masses. However, the non-diagnostic rate is a limiting factor. We tested the hypothesis that imaging characteristics and anatomic complexity of the mass may impact RMB diagnostic outcome using the preoperative aspects and dimensions used for an anatomical (PADUA) classification and radius-exophytic/endophytic-nearness-anterior/posterior-location (RENAL) score.

MATERIAL AND METHODS

Single institution, retrospective study of 490 renal masses from 443 patients collected from 2001 to 2018. Outcome measurements include (1) diagnostic and concordance rates amongst RMB types and RMB with surgical resection specimens; (2) association between diagnostic RMB and anatomical complexity of renal masses. The analysis was conducted in unselected masses and small renal masses (SRMs).

RESULTS

RMB was performed by fine needle aspiration (FNA), core needle biopsy (CNB), or both (FNA+CNB). Non-diagnostic rate was significantly higher for FNA compared to CNB and FNA+CNB in both unselected and SRMs. Subset analysis in the FNA+CNB group showed similar diagnostic rates for FNA and CNB. In unselected masses, specificity for FNA, CNB, and FNA+CNB was 100%. Sensitivity was higher for CNB (90.1%, P = 0.002) and FNA+CNB (96.3%, P = 0.004) compared to FNA (66.7%). For unselected masses, endophytic growth predicted a non-diagnostic CNB. R.E.N.A.L location entirely between the polar lines (central) and entirely above the upper polar line predicted a diagnostic CNB. Sonography-guidance predicted a diagnostic FNA. For SRMs, non-diagnostic CNB was associated with endophytic growth, while diagnostic CNB was associated with renal sinus invasion and operator experience. More cystic masses were sampled by FNA, but diagnostic results were similar for FNA and CNB.

CONCLUSIONS

Endophytic growth consistently predicted a non-diagnostic CNB in unselected and SRMs, whereas sonography-guidance predicted a diagnostic FNA. Cystic masses could be adequately sampled by FNA.

Magnetic Resonance Imaging Radiomics Analyses for Prediction of High-Grade Histology and Necrosis in Clear Cell Renal Cell Carcinoma: Preliminary Experience

INTRODUCTION

Percutaneous renal mass biopsy results can accurately diagnose clear cell renal cell carcinoma (ccRCC); however, their reliability to determine nuclear grade in larger, heterogeneous tumors is limited. We assessed the ability of radiomics analyses of magnetic resonance imaging (MRI) to predict high-grade (HG) histology in ccRCC.

PATIENTS AND METHODS

Seventy patients with a renal mass underwent 3 T MRI before surgery between August 2012 and August 2017. Tumor length, first-order statistics, and Haralick texture features were calculated on T2-weighted and dynamic contrast-enhanced (DCE) MRI after manual tumor segmentation. After a variable clustering algorithm was applied, tumor length, washout, and all cluster features were evaluated univariably by receiver operating characteristic curves. Three logistic regression models were constructed to assess the predictability of HG ccRCC and then cross-validated.

RESULTS

At univariate analysis, area under the curve values of length, and DCE texture cluster 1 and cluster 3 for diagnosis of HG ccRCC were 0.7 (95% confidence interval [CI], 0.58-0.82, false discovery rate P = .008), 0.72 (95% CI, 0.59-0.84, false discovery rate P = .004), and 0.75 (95% CI, 0.63-0.87, false discovery rate P = .0009), respectively. At multivariable analysis, area under the curve for model 1 (tumor length only), model 2 (length + DCE clusters 3 and 4), and model 3 (DCE cluster 1 and 3) for diagnosis of HG ccRCC were 0.67 (95% CI, 0.54-0.79), 0.82 (95% CI, 0.71-0.92), and 0.81 (95% CI, 0.70-0.91), respectively.

CONCLUSION

Radiomics analysis of MRI images was superior to tumor size for the prediction of HG histology in ccRCC in our cohort.

Asian Conference on Tumor Ablation guidelines for renal cell carcinoma

Thermal ablation has been established as an alternative treatment for renal cell carcinoma (RCC) in patients who are poor candidates for surgery. However, while American and European guidelines have been established for American and European patients, respectively, no ablation guidelines for Asian patients with RCCs have been established many years after the Asian Conference on Tumor Ablation (ACTA) had been held. Given that Western guidelines are difficult to apply to Asian patients due to differences in body habitus, economic status, and insurance systems, the current review sought to establish the first version of the ACTA guidelines for treating a RCC with thermal ablation.

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.

Endoscopic ultrasound-guided fine-needle aspiration of renal lesions: experience in a tertiary center

INTRODUCTION

endoscopic ultrasound (EUS) allows the histological diagnosis of radiologically undetermined renal lesions, although few series have been described.

OBJECTIVES

to describe the procedure, yield and complications of EUS-guided renal fine-needle aspiration (FNA).

MATERIAL AND METHODS

a retrospective case series in a prospective database was used that consecutively included EUS procedures from March 2014 to August 2018. Data on complications, outcome and follow-up were collected. A successful FNA was defined as any FNA that allowed a histological diagnosis. Lesions were considered as malignant when surgically confirmed as such (the histological diagnosis was used for non-surgical patients) and benign when radiographically stable for ≥ 12 months.

RESULTS

eight patients were identified with a median age of 61.6 years (57.3-71.9), and five (62.5 %) were female. Five FNA procedures involved the right kidney and three involved the left kidney. 22G cytology needles were used. Renal FNA was diagnostic in all cases, with no complications.

CONCLUSIONS

EUS-guided FNA may represent an effective, safe procedure for the diagnosis of renal lesions of an uncertain origin.

The highest Fuhrman and WHO/ISUP grade influences the Ki-67 labeling index of those of grades 1 and 2 in clear cell renal cell carcinoma

Nuclear grade is one of the most important prognostic factors in clear cell renal cell carcinoma (CCRCC). Although CCRCCs usually have intratumoral heterogeneity with various nuclear atypia including nucleolar prominence, it is unclear whether a similar degree of nuclear grade component demonstrates the same proliferative activity. We aimed to reveal whether the presence of a higher nuclear grade has an effect on proliferative activity among each assigned nuclear grade in CCRCCs. We enrolled 129 CCRCC patients containing at least two different nuclear grades. We separately assessed nuclear grade using the Fuhrman and World Health Organization and International Society of Urologic Pathologists (WHO/ISUP) grading systems. In addition, we selected blocks containing different nuclear grade and assessed the Ki-67 labeling index (LI) for each using a computer-based analysis system. Ki-67 LIs significantly correlated with both Fuhrman and WHO/ISUP grades (P < 0.001 and P < 0.001). Of note, the LIs among Fuhrman and WHO/ISUP grades 1 and 2 were also statistically significant according to the highest nuclear grade (P < 0.01 for both grades 1 and 2). Our data suggests that the highest nuclear grade influences the proliferative activity in tumor components regardless of the morphologically assigned nuclear grades. The exact evaluation of Ki-67 LI in CCRCC can provide a more precise information of the malignant potential.

Contemporary Results and Clinical Utility of Renal Mass Biopsies in the Setting of Ablative Therapy: A single center experience

PURPOSE

Clinical guidelines have recently included renal mass biopsy (RMB) in management algorithms, especially in the setting of small renal masses ≤ 4 cm (SRM) and ablative therapy. We sought to evaluate the diagnostic rates of RMB, factors associated with a non-diagnostic biopsy, its clinical utility, and its safety profile in the setting of ablative therapy.

MATERIALS AND METHODS

A total of 174 RMB from 167 patients, performed in a tertiary academic center from 01/2015 to 01/2019, were included. Patient demographics, radiographic mass size, RMB diagnoses, subsequent clinical management, and complications were retrospectively reviewed. RMBs were classified as diagnostic or non-diagnostic based on set criteria.

RESULTS

The mean mass size was 3.0 cm (range: 0.5-15.3 cm) and 140 biopsies (80%) were SRM. Among all RMB, 159 (91%) were diagnostic and 15 (9%) were non-diagnostic. Non-diagnostic biopsies were associated with small mass size, the presence of a cystic component (p < 0.00001) and fewer number of cores submitted (p = 0.0046). All non-diagnostic biopsies occurred in SRMs, where the mean mass size was significantly smaller than diagnostic biopsies (1.3 versus 3.2 cm, p = 0.001). RMB with concurrent ablation yielded non-diagnostic results more frequently than isolated RMBs (15% vs 2%, respectively).

CONCLUSIONS

RMB is useful for definitive diagnosis and clinical management in the setting of ablative therapy. Small mass size, cystic lesions, and fewer number of passes obtained are associated with non-diagnostic biopsies. When a renal mass diagnosis is particularly critical, a separate biopsy procedure prior to ablative therapy is recommended.

CT and MR imaging surveillance of stage 1 renal cell carcinoma after microwave ablation

OBJECTIVE

To describe the CT and MR imaging findings after microwave ablation of clinical stage 1 renal cell carcinoma (RCC).

METHODS

This single-center retrospective study was performed under a waiver of informed consent. 49 patients (38 M/11F, mean age 66 ± 9.0) with 52 cT1a RCC and 19 patients (10M/9F, mean age 67 ± 9.7) with 19 cT1b RCC were treated with percutaneous microwave ablation between January 2012 and June 2014. The size and volume of the RCC and ablation zone were measured and the kidney, ablation zones and retroperitoneum were assessed at immediate post-procedure CT and surveillance CT and MRI.

RESULTS

Median imaging follow-up was 18 months (IQR 12-28). Ablation zones were heterogeneously hyperintense on T1W and hypointense on T2W MRI and hyperdense at CT. Thin peripheral, but no internal enhancement after contrast administration signified successful ablation zones. Ablation zones decreased in size, but did not resolve during surveillance. Immediate post-procedure subcapsular gas and hematoma (5/71, 7%) resolved prior to first follow-up. Focal, enhancing soft tissue within the ablation zone, invariably along the renal margin, signified local recurrence. Local recurrence rates were higher for T1b (2/19, 11%) compared to T1a (1/52, 2%). Urinomas (4/71, 6%) decreased in size and resolved during surveillance. Retroperitoneal fat necrosis (6/71, 9%), with opposed-phase loss of T1W MRI signal, was confirmed at histology after percutaneous biopsy.

CONCLUSION

CT and MR imaging features after microwave ablation of renal cell carcinoma are predictable and reliably demonstrate treatment success, early and delayed complications, and local recurrences that can guide patient management.

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.

Diagnostic accuracy and safety of percutaneous MRI-guided biopsy of solid renal masses: single-center results after 4.5 years

OBJECTIVES

To retrospectively evaluate diagnostic accuracy and complications of magnetic resonance imaging (MRI)-guided biopsy of radiologically indeterminate solid renal masses (RM).

METHODS

Electronic records of all consecutive patients undergoing MRI-guided biopsy of solid RM (using free-breathing T2-BLADE and BEAT-IRTTT sequences) between April 2014 and October 2018 were reviewed; 101 patients (69 men, 32 women; median age 68 years; range 32-76) were included. Patient and RM characteristics, procedural details/complications, pathologic diagnosis, and clinical management were recorded. Diagnostic accuracy was calculated on an intention-to-diagnose basis. Diagnostic yield was also evaluated. Multi-variable analysis was performed for variables with p < .20, including patient age/sex; RM size/location/contact with vascular pedicle, RENAL score, number and total length of biopsy samples, and biopsy tract embolization, to determine factors associated with diagnostic samples, diagnostic accuracy, and complications.

RESULTS

Median RM size was 2.4 cm (range 1-8.4 cm). There were 86 (85%; 95%CI 77-91%) diagnostic and 15 (15%; 95%CI 9-23%) non-diagnostic samples; 6/15 (40%) non-diagnostic biopsies were repeated with 50% malignancy rate. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 96% (95%CI 89-99%), 100% (95%CI 77-100%), 100% (95%CI 95-100%), 82% (95%CI 57-96%), and 97% (95%CI 90-99%), respectively. Primary and secondary diagnostic yields were 85% (95%CI 77-91%) and 91% (95%CI 84-96%), respectively. Seven (7%; 95%CI 1-10%) complications were observed. No tested variables were associated with diagnostic samples, diagnostic accuracy, or complications.

CONCLUSIONS

MRI-guided biopsy of solid RM is associated with high diagnostic accuracy and low complication rate. The technique might be helpful for inaccessible tumors.

KEY POINTS

• MRI-guided biopsy of radiologically indeterminate solid renal masses (RM) appears safe, with a low rate of minor self-limiting hemorrhagic complications. • Diagnostic accuracy and primary/secondary diagnostic yield are high and appear similar to reported estimates for US- and CT-guided RM biopsy. • MRI guidance may be particularly useful for RM with poor conspicuity on US and CT, for relatively inaccessible tumors (e.g., tumors requiring double-oblique steep-angled approaches), and for young patients or those with renal failure.

The role of Tc-99m MIBI scintigraphy in clinical T1 renal mass assessment: Does it have a real benefit?

INTRODUCTION

Despite the increasing accuracy of imaging modalities, the rate of benign renal tumors misclassified as malignant before surgery still non-negligible. Tc-99m sestamibi was demonstrated to be a possible reliable agent in discriminating oncocytoma from renal cell carcinoma (RCC). We aimed to study the efficacy of Tc-99m MIBI tumor scintigraphy in evaluating clinical T1 renal masses.

METHODS AND MATERIALS

Between July 2017 and March 2019, patients with clinical T1 renal mass underwent preoperative Tc-99m sestamibi tumor scintigraphy. Tc-99m sestamibi tumor scintigraphy findings were correlated with the postoperative pathology results.

RESULTS

A total of 90 renal masses were included in the study. Male to female ratio was 67/23. The mean age and tumor size were 55.5 ± 11.4 years and 4 ± 1.4 cm, respectively. In pathological evaluation, 20% (18/90) of masses were reported as benign (10 oncocytomas, 4 angiomyolipomas (AML), 2 chronic sclerosis, 1 fibroma and 1 hydatid cyst). While Tc-99m sestamibi uptake was positive in all oncocytomas; 6 patients with chronic sclerosis, fibroma, hydatid cyst and angiomyolipoma pathologies had no uptake. Except for 5 chromophobe cell RCC and 3 oncocytic papillary RCC masses, malignant lesions had no uptake. In predicting benign pathology, Tc-99m sestamibi tumor scintigraphy had positive and negative predictive value of 60% and 91.3%, respectively. The mean Tc-99m 2-methoxy isobutyl isonitrile lesion/normal renal parenchyma ratio of benign and malignant lesions was 0.6 and 0.37, respectively. A relative uptake of 0.49 was an acceptable cutoff point to discriminate oncocytomas from all other pathologies.

CONCLUSION

Tc-99m sestamibi tumor scintigraphy has a beneficial role in the assessment of clinical T1 renal mass. Masses with negative uptake harbor high probability of being malignant. While evaluating masses with positive uptake, it should be kept in mind that some malignant pathologies may demonstrate similar results.

Prospective performance of clear cell likelihood scores (ccLS) in renal masses evaluated with multiparametric magnetic resonance imaging

OBJECTIVES

Solid renal masses have unknown malignant potential with commonly utilized imaging. Biopsy can offer a diagnosis of cancer but has a high non-diagnostic rate and complications. Reported use of multiparametric magnetic resonance imaging (mpMRI) to diagnose aggressive histology (i.e., clear cell renal cell carcinoma (ccRCC)) via a clear cell likelihood score (ccLS) was based on retrospective review of cT1a tumors. We aim to retrospectively assess the diagnostic performance of ccLS prospectively assigned to renal masses of all stages evaluated with mpMRI prior to histopathologic evaluation.

METHODS

In this retrospective cohort study from June 2016 to November 2019, 434 patients with 454 renal masses from 2 institutions with heterogenous patient populations underwent mpMRI with prospective ccLS assignment and had pathologic diagnosis. ccLS performance was assessed by contingency table analysis. The association between ccLS and ccRCC was assessed with logistic regression.

RESULTS

Mean age and tumor size were 60 ± 13 years and 5.4 ± 3.8 cm. Characteristics were similar between institutions except for patient age and race (both p < 0.001) and lesion laterality and histology (both p = 0.04). The PPV of ccLS increased with each increment in ccLS (ccLS1 5% [3/55], ccLS2 6% [3/47], ccLS3 35% [20/57], ccLS4 78% [85/109], ccLS5 93% [173/186]). Pooled analysis for ccRCC diagnosis revealed sensitivity 91% (258/284), PPV 87% (258/295) for ccLS ≥ 4, and specificity 56% (96/170), NPV 94% (96/102) for ccLS ≤ 2. Diagnostic performance was similar between institutions.

CONCLUSIONS

We confirm the optimal diagnostic performance of mpMRI to identify ccRCC in all clinical stages. High PPV and NPV of ccLS can help inform clinical management decision-making.

KEY POINTS

• The positive predictive value of the clear cell likelihood score (ccLS) for detecting clear cell renal cell carcinoma was 5% (ccLS1), 6% (ccLS2), 35% (ccLS3), 78% (ccLS4), and 93% (ccLS5). Sensitivity of ccLS ≥ 4 and specificity of ccLS ≤ 2 were 91% and 56%, respectively. • When controlling for confounding variables, ccLS is an independent risk factor for identifying clear cell renal cell carcinoma. • Utilization of the ccLS can help guide clinical care, including the decision for renal mass biopsy, reducing the morbidity and risk to patients.

Comprehensive assessment of the morbidity of renal mass biopsy: A population-based assessment of biopsy-related complications

INTRODUCTION

We sought to assess seven-day and 30-day complications following renal mass biopsy (RMB), including mortality, hospitalizations, emergency department (ED) visits, and operative and non-operative complications and compare these to rates in population-matched controls.

METHODS

We performed a population-based, matched, retrospective cohort study of patients undergoing RMB following consultation with a urologist and axial imaging from 2003-2015 in Ontario, Canada. Data on seven-day and 30-day rates of mortality, as well as operative and non operative complications after RMB were reported. The seven-day and 30-day rates of mortality, operative and non-operative interventions, hospitalizations, and ED visits were compared to matched controls using multivariable logistic regression.

RESULTS

Among 6840 patients who underwent RMB in the study period, 24 (0.4%) and 159 (2.3%) died within seven and 30 days of their biopsy, respectively. Seven- and 30-day operative intervention rates were 79 (1.2%) and 236 (3.4%), respectively. Seven- and 30-day non-operative intervention rates were 227 (3.3%) and 529 (7.7%), respectively. Thirty-day mortality (odds ratio [OR] 8.1, 95% confidence interval [CI] 5.1-13.0), hospitalizations (OR 12.6, 95% CI 10.6-15.2), and ED visits (OR 3.8, 95% CI 3.4-4.3) were more common among patients who underwent RMB than the matched controls (p<0.001 for each).

CONCLUSIONS

Patients undergoing RMB may have a small but non-negligible increased risk of mortality, hospital readmission, and ED visits compared to matched controls. However, limitations in the granularity of the dataset limits the strength of these conclusions. Further studies are needed to confirm our results. These risks should be discussed with patients for shared decision-making and considered in the risk/benefit tradeoff for the management of small renal masses.

Development and Validation of a Deep-learning Model to Assist With Renal Cell Carcinoma Histopathologic Interpretation

OBJECTIVE

To develop and test the ability of a convolutional neural network (CNN) to accurately identify the presence of renal cell carcinoma (RCC) on histopathology specimens, as well as differentiate RCC histologic subtype and grade.

MATERIALS AND METHODS

Digital hematoxylin and eosin stained biopsy images were downloaded from The Cancer Genome Atlas. A CNN model was trained on 100 um2 samples of either normal (3000 samples) or RCC (12,168 samples) tissue samples from 42 patients. RCC specimens included clear cell, chromophobe, and papillary histiotypes, as well as tissue of Fuhrman grades 1 through 4. Model testing was performed on an additional held-out cohort of benign and RCC specimens. Model performance was assessed on the basis of diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value.

RESULTS

The CNN model achieved an overall accuracy of 99.1% in the testing cohort for distinguishing normal parenchyma from RCC (sensitivity 100%, specificity 97.1%). Accuracy for distinguishing between clear cell, papillary, and chromophobehistiotypes was 97.5%. Accuracy for predicting Fuhrman grade was 98.4%.

CONCLUSION

CNNs are able to rapidly and accurately identify the presence of RCC, distinguish RCC histologic subtypes, and identify tumor grade by analyzing histopathology specimens.

Does renal tumor biopsies for small renal carcinoma increase the risk of upstaging on final surgery pathology report and the risk of recurrence?

BACKGROUND

Renal tumor biopsies (RTB) have been proposed as a means to diminish overtreatment of small renal masses. A potential concern of RTB is tumor seeding along the biopsy tract leading to worse clinical outcomes.

OBJECTIVES

To evaluate whether RTB was associated with greater upstaging to pT3a compared to patients without a biopsy and to determine if pathologic upstaging affects the risk of recurrence.

DESIGN, SETTING AND PARTICIPANTS

The Canadian Kidney Cancer information system was used to identify patients who underwent radical or partial nephrectomy for malignant renal tumors ≤ 4cm (cT1a) between January 1, 2011 and July 2, 2019.

INTERVENTION

RTB prior to nephrectomy or nephrectomy without biopsy.

OUTCOMES MEASUREMENTS AND STATISTICAL ANALYSIS

Upstaging to pT3a and cancer recurrence were compared between subjects that had a RTB compared to those who did not. A multivariable analysis was used to evaluate factors associated with disease upstaging and recurrence.

RESULTS AND LIMITATIONS

The cohort consisted of 1993 cT1a patients, followed for a median of 17.5 months. Of these patients, 502 (25%) had a preoperative RTB. There was no difference in the proportion with tumor upstaging to pT3a between patients that had RTB compared to those who did not (7.2% vs. 6.3%; P = 0.5). On multivariable analysis, RTB was not associated with pathological upstaging (Odds Ratio 0.90; 95% Confidence Interval 0.61-1.34) or recurrence (Odds Ratio 1.04; 95% Confidence Interval 0.57-1.89). The main limitation is that the study is underpowered to detect small differences between groups.

CONCLUSIONS

In this large, multi-institution cohort, RTB was not associated with increased risk of tumor upstaging or recurrence. Hence, tumor tract seeding, although possible, should not be a clinical deterrent to using RTBs as a means of personalizing renal masses management and diminishing overtreatment.

PATIENT SUMMARY

Recent evidence suggests that tumor seeding following RTB may be more common than initially perceived. Our results have demonstrated that RTB was not associated with an increased risk of tumor upstaging or disease recurrence.

Imaging guided percutaneous renal biopsy: do it or not?

Since its first reported application, renal biopsy became an important part of the diagnostic algorithm, considered advantages and risks, to better manage therapeutic options. The biopsy can be performed with different techniques (open, laparoscopic, transjugular, transurethral and percutaneous). Currently, the percutaneous approach is the modality of choice. Percutaneous biopsy can be performed under CT or US guidance, but critical benefits and disadvantages have to be considered. Core needle biopsy is usually preferred to fine-needle aspiration because of the sample quality, usually obtaining multiple cores, especially in heterogeneous tumors. Principal complications are hematuria (1-10%), perinephric hematoma (10-90%), pneumothorax (0,6%), clinically significant pain (1,2%).

The role of percutaneous fine needle aspiration biopsy in the management of small renal masses without chance of nephron-sparing surgery

PURPOSE

We seek to confirm the safety and efficacy of percutaneous fine needle aspiration biopsy (FNAB) for small renal masses (SRMs) without chance of nephron-sparing surgery (NSS).

METHODS

Between 2015 and 2018, 169 consecutive patients with SRMs treated in two medical centers were enrolled in the study retrospectively. All patients were evaluated to be candidates of radical nephrectomy (RN) at the initial evaluation preoperatively and they would receive the second evaluation in operation to decide the ultimate surgical regimen. Patients were divided into two groups according to FNAB.

RESULTS

169 patients met inclusion criteria were enrolled in the finial study. The median follow-up of was 35 months (ranges from 23 to 49 months) from the first diagnosis. 83 patients received FNAB before surgery, and the other 86 patients underwent surgery immediately. The initial success rate of FNAB was 91.6% (76/83) and the rate of accuracy in identifying malignancies was 100%. 15 (18.1%) of 83 patients developed different levels of complications. 15 (18.1%) were diagnosed as benign tumors by FNAB. The initial success rate was just 50% for cystic SRMs. Complicated cystic SRMs account for 5.9% of all with a 50% benignity rate. The FNAB group had a significant lower ratio of RN than non-FNAB group (74.7% vs. 93%, p = 0.001, Pearson Chi-square test).

CONCLUSION

FNAB is safe and effective for SRMs without chance of NSS, and it could significantly reduce unnecessary RN.

Touch preparation for rapid onsite evaluations of renal mass biopsies: concordance rate, pearls, and pitfalls

INTRODUCTION

Core needle biopsy (CNB) of renal masses has not been commonly performed because of the perceived low sensitivity until recent years. Rapid onsite evaluation (ROSE) using touch preparations (TPs) has the potential to improve the yield of CNB, although it can be challenging because of the diverse morphology of various types of renal tumors and native cells.

MATERIALS AND METHODS

We retrospectively reviewed percutaneous CNBs of renal masses with ROSE using TPs. ROSE findings were correlated with diagnoses on CNBs.

RESULTS

Among the 165 cases identified between August 2016 and August 2019, CNB led to definitive diagnoses in 82.4% (136 of 165) cases. These included renal cell carcinomas (RCCs) (n = 113, 68.5%), benign neoplasms (n = 14, 8.5%), urothelial carcinomas (n = 6, 3.6%), metastatic carcinomas (n = 2, 1.2%) and 1 case of lymphoma (0.6%). Eight cases were indeterminate, including 2 cases positive for oncocytic neoplasm, 2 cases suspicious for RCC, and 4 cases with atypical features. Twenty-one (12.7%) CNBs were negative for tumor. ROSE interpretations for these cases were: malignant (n = 18, 10.8%); positive for neoplasm (n = 6, 3.6%); atypical/lesional/adequate not otherwise specified (n = 113, 68.5%); negative (n = 19, 11.5.0%); and unsatisfactory (n = 9, 5.5%). The overall concordance rate between ROSE and the final CNB diagnoses was 87.3%.

CONCLUSIONS

Renal mass CNBs revealed a subset of non-surgical conditions in addition to RCCs. ROSE using TPs showed a high concordance rate with CNB results. Proximal tubular cells, macrophages, and angiomyolipomas are common pitfalls, whereas vacuolated cytoplasm and background are helpful features to confirm low-grade RCCs.

Is percutaneous image-guided renal tumour ablation ready for prime time?

In the last few decades, thermal ablation (TA) techniques have been increasingly applied to treat small localised renal cell carcinomas. Despite this trend, there is still an underuse of TA compared to surgery and a substantial lack of high-quality evidence derived from large, prospective, randomised controlled trials comparing the long-term oncologic outcomes of TA and surgery. Therefore, in this narrative review, we assess published guidelines and recent literature concerning the diagnosis and management of kidney-confined renal cell carcinoma to understand whether percutaneous image-guided TA is ready to be proposed as a first-line treatment.

Renal biopsy under augmented reality guidance

Kidney biopsies are currently performed using preoperative imaging to identify the lesion of interest and intraoperative imaging used to guide the biopsy needle to the tissue of interest. Often, these are not the same modalities forcing the physician to perform a mental cross-modality fusion of the preoperative and intraoperative scans. This limits the accuracy and reproducibility of the biopsy procedure. In this study, we developed an augmented reality system to display holographic representations of lesions superimposed on a phantom. This system allows the integration of preoperative CT scans with intraoperative ultrasound scans to better determine the lesion's real-time location. An automated deformable registration algorithm was used to increase the accuracy of the holographic lesion locations, and a magnetic tracking system was developed to provide guidance for the biopsy procedure. Our method achieved a targeting accuracy of 2.9 ± 1.5 mm in a renal phantom study.

Radiomics Applications in Renal Tumor Assessment: A Comprehensive Review of the Literature

Radiomics texture analysis offers objective image information that could otherwise not be obtained by radiologists′ subjective radiological interpretation. We investigated radiomics applications in renal tumor assessment and provide a comprehensive review. A detailed search of original articles was performed using the PubMed-MEDLINE database until 20 March 2020 to identify English literature relevant to radiomics applications in renal tumor assessment. In total, 42 articles were included in the analysis and divided into four main categories: renal mass differentiation, nuclear grade prediction, gene expression-based molecular signatures, and patient outcome prediction. The main area of research involves accurately differentiating benign and malignant renal masses, specifically between renal cell carcinoma (RCC) subtypes and from angiomyolipoma without visible fat and oncocytoma. Nuclear grade prediction may enhance proper patient selection for risk-stratified treatment. Radiomics-predicted gene mutations may serve as surrogate biomarkers for high-risk disease, while predicting patients’ responses to targeted therapies and their outcomes will help develop personalized treatment algorithms. Studies generally reported the superiority of radiomics over expert radiological interpretation. Radiomics provides an alternative to subjective image interpretation for improving renal tumor diagnostic accuracy. Further incorporation of clinical and imaging data into radiomics algorithms will augment tumor prediction accuracy and enhance individualized medicine.

Identification of tumor size as the only factor associated with nondiagnostic biopsies in patients with small renal masses

INTRODUCTION

As greater numbers of small renal masses (SRMs) are discovered incidentally, renal tumor biopsy (RTB) is an increasingly recognized step for the management of these lesions, ideally for the prevention of surgical overtreatment for benign disease. While the diagnosis can often be obtained preoperatively by RTB, indeterminate results create greater difficulty for patients and clinicians. This study examines a series of RTBs, identifying the portion of these that were able to yield a diagnosis, and correlates patient factors, including RENAL and PADUA scoring, with the outcome of a non-diagnostic result.

METHODS

Patients were identified as having undergone RTB at the Princess Margaret Cancer Centre in Ontario, Canada, between January 2000 and December 2009. Data was compiled from these 423 patients and analyzed using CART methodology to determine the level of association between various patient and tumor factors and the outcome of a non-diagnostic biopsy. Tumor size was further used to develop a classification tree to describe the prediction of a non-diagnostic biopsy.

RESULTS

Of these 423 patients undergoing RTB, 66 (16%) resulted in a non-diagnostic biopsy. The only patient or tumor factor that was found to be associated with a non-diagnostic outcome was mass size, where small masses (<1.28 cm diameter) were found to have a 38% chance of being non-diagnostic, compared with a 13% chance in those tumors >1.28 cm diameter (86% accuracy, 95% confidence interval [CI] 0.82-0.89).

CONCLUSIONS

When evaluating SRMs for diagnostic workup, mass size is the only tumor or patient characteristic associated with a non-diagnostic RTB.

Tumour grade significantly correlates with total dysfunction of tumour tissue-infiltrating lymphocytes in renal cell carcinoma

It is important to evaluate the clinical importance of both CD8 T cells and CD4 T cells expression simultaneously because they have crucial networks in tumour targeting immune responses. In 97 RCC patients, RNA sequencing and gene set enrichment analysis of both CD8 and CD4 T cells based on the expression levels of PD-1 and TIM-3 implied that the populations of PD-1+TIM-3+ CD8 T cells and PD-1lowTIM-3 + CD4 T cells were characterized as exhausted CD8 T cells and regulatory CD4 T cells, respectively. These populations of CD4 and CD8 T cells were significantly upregulated in the patients with RCC of higher WHO/ISUP grade (grades 3, 4) (P < 0.001). Moreover, the cytokine productivities of each population in both CD4 and CD8 T cells of the higher-grade patients were significantly lower than those of the lower-grade patients (P < 0.05). Multivariate analysis showed the prognosis of patients with metastatic RCC of higher WHO/ISUP grade treated by nivolumab to be significantly worse than that of patients with lower grade (P = 0.026). This study showed that tumour grade significantly correlated with dysfunction of both CD4+ and CD8+ TILs and the efficacy of nivolumab treatment.

The role of renal biopsy to improve small renal mass diagnosis and management: are there predictive factors for a higher detection rate? The first Italian study of 100 cases

BACKGROUND

Incidence of small renal masses (SRMs) has increased over the last decade: in order to reduce overtreatment of benign lesions, renal tumor biopsy (RTB) has been advocated. The primary aim of this study were to establish the rate of diagnostic biopsies and the concordance rate between RTB and surgical pathology with regard to tumor histology. The secondary aim was to identify what predictive factors are associated with an initial diagnostic biopsy.

METHODS

We retrospectively analyzed RTB performed in our center in patients with SRMs between 2015 and 2017. We assessed patient demographics and clinical status, lesion characteristics and procedural factors. The categorical variables were tested with the chi-square test. We used univariate and multivariate analysis to identify what factors are indicative of non-diagnostic biopsies. We used the SPSS statistics v. 23.

RESULTS

We performed a total of 100 RTBs to management 94 patients. The initial biopsy was diagnostic in 88 patients (67 malignant and 21 benign lesion). The six remaining patients had repeat biopsies, of which four were diagnostic. Complications rate was 5% prevalently local hematoma treated with surveillance. Agreement between biopsy and surgical histology was found in 94% of cases. On contingency analysis and on univariate and multivariate analysis, these factors (age, tumor size, exophytic location, and type of imaging used) were not predictive with diagnostic biopsy.

CONCLUSIONS

RTB for SRMs helps establish pre-treatment diagnosis, reduce overtreatment, with a low risk of complications and high diagnostic rate. In our experience, we did not find predictive factors more likely associated with a diagnostic biopsy.

Texture analysis and machine learning algorithms accurately predict histologic grade in small (< 4 cm) clear cell renal cell carcinomas: a pilot study

PURPOSE

To predict the histologic grade of small clear cell renal cell carcinomas (ccRCCs) using texture analysis and machine learning algorithms.

METHODS

Fifty-two noncontrast (NC), 26 corticomedullary (CM) phase, and 35 nephrographic (NG) phase CTs of small (< 4 cm) surgically resected ccRCCs were retrospectively identified. Surgical pathology classified the tumors as low- or high-Fuhrman histologic grade. The axial image with the largest cross-sectional tumor area was exported and segmented. Six histogram and 31 texture (gray-level co-occurrences (GLC) and gray-level run-lengths (GLRL)) features were calculated for each tumor in each phase. T testing compared feature values in low- and high-grade ccRCCs, with a (Benjamini-Hochberg) false discovery rate of 10%. Area under the receiver operating curve (AUC) was calculated for each feature to assess prediction of low- and high-grade ccRCCs in each phase. Histogram, texture, and combined histogram and texture data sets were used to train and test four algorithms (k-nearest neighbor (KNN), support vector machine (SVM), random forests, and decision tree) with tenfold cross-validation; AUCs were calculated for each algorithm in each phase to assess prediction of low- and high-grade ccRCCs.

RESULTS

Zero, 23, and 0 features in the NC, CM, and NG phases had statistically significant differences between low and high-grade ccRCCs. CM histogram skewness and GLRL short run emphasis had the highest AUCs (0.82) in predicting histologic grade. All four algorithms had the highest AUCs (0.97) predicting histologic grade using CM histogram features. The algorithms' AUCs decreased using histogram or texture features from NC or NG phases.

CONCLUSION

The histologic grade of small ccRCCs can be accurately predicted with machine learning algorithms using CM histogram features, which outperform NC and NG phase image data.

Histotype predicts the rate of lymph node invasion at nephrectomy in patients with nonmetastatic renal cell carcinoma

BACKGROUND

Lymph node invasion (LNI) at nephrectomy is one of the most important predictors of mortality in patients with nonmetastatic renal cell carcinoma (RCC). We analyzed the effect of histology on lymph node metastases at nephrectomy and its effect on survival in a contemporary cohort of patients with nonmetastatic RCC.

METHODS

Within the Surveillance, Epidemiology, and End Results database (2004-2015), we identified 100,060 patients with clear-cell, papillary, chromophobe, sarcomatoid, and collecting duct RCC, who underwent nephrectomy with or without lymph node dissection for nonmetastatic RCC. Logistic regression models, cumulative incidence plots, and competing-risks regression models were performed.

RESULTS

Overall, 10,590 patients underwent lymph node dissection for nonmetastatic RCC. Of these, LNI was recorded in 52 (7.0%), 615 (8.7%), 282 (13.9%), 316 (25.1%), 129 (38.3%), 45 (71.4%) patients with chromophobe, clear-cell, nonotherwise specified RCC, papillary, sarcomatoid, and collecting duct RCC histological subtypes, respectively. In logistic regression models, relative to clear-cell, papillary Odds ratio (OR 3.9), sarcomatoid (OR 6.3), collecting duct (OR 14.6) but not chromophobe RCC (OR 0.9; P = 0.5) independently predicted LNI at surgery. Moreover, in competing-risks regression models, LNI increased the risk of CSM 1.8-fold for sarcomatoid, 3.6-fold for clear-cell, 4.1-fold for papillary, and 6.7-fold for chromophobe histological subtype.

CONCLUSIONS

Histology is an independent predictor of increased risk of LNI at nephrectomy. Moreover, the effect of pathological nodal stage on survival differs according to different histology.

Active Surveillance for Small Renal Masses

Active surveillance (AS) is a safe and reasonable management strategy for many patients with small renal masses (SRM) suspicious for a clinical T1a renal cell carcinoma based on excellent metastasis-free and cancer-specific survival. However, the expansion of robotic extirpation of SRM has outpaced the adoption of AS, resulting in the possibility of overtreatment for select patients with SRM, especially the elderly and comorbid. In this review of AS for SRM, with a focus on the Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) Registry, we detail the rationale behind AS, review lessons learned from the past decades of literature, and offer suggestions for appropriate patient selection and follow-up. An improved understanding of the data supporting AS will empower physicians and patients to more comfortably pursue AS to avoid over-treatment and provide individualized care to patients with SRM.

Current management of small renal masses

One of the consequences of the growing use of diagnostic imaging techniques is the notable growth in the detection of small renal masses presumably corresponding to localized tumors that are potentially curable with surgical treatment. When faced with the finding of a small renal mass, radiologists must determine whether it is benign or malignant, and if it is malignant, what subtype it belong to, and whether it should be managed with surgical treatment, with ablative techniques, or with watchful waiting with active surveillance. Small renal masses are now a clinical entity that require management different from the approaches used for classical renal cell carcinomas. In this scenario, radiologists are key because they are involved in all aspects of the management of these tumors, including in their diagnosis, treatment, and follow-up.

Management of Renal Cell Carcinoma-Current Practice in Sub-Saharan Africa

There is a global variation in the incidence of renal masses with the developed nations having a greater incidence. About 80–90% of renal malignancies are renal cell carcinomas (RCC) which account for 2–4% of all cancers. In Africa and the Middle East, the age-standardized incidence for RCC is 1.8–4.8/100,000 for males and 1.2–2.2/100,000 for females. The management of renal cell cancer is challenging. A multidisciplinary approach is effective for diagnosis, staging, and treatment. Guidelines recommend active surveillance, thermal ablation, partial nephrectomy, radical nephrectomy, cytoreductive nephrectomy and immunotherapy as various modalities for various stages of RCC. However, open radical nephrectomy is most widely adopted as an option for treatment at various stages of the disease in sub-Saharan Africa due to its cost-effectiveness, applicability at various stages, and the reduced cost of follow-up. Nevertheless, most patients in the region present with the disease in the advanced stage and despite surgery the prognosis is poor.

Utilization and Operative Influence of Renal Mass Biopsy in the Small Renal Mass: Analysis from the Clinical Research Office of the Endourological Society Small Renal Mass registry

Introduction and Objective: Definitive inclusion of renal mass biopsy (RMB) in small renal mass (SRM) diagnostic algorithm remains controversial. We assessed incidence and accuracy of RMB in SRMs in the CROES Renal Mass registry and the influence of preoperative RMB on perioperative complications after SRM nephron-sparing surgery (NSS). Materials and Methods: "ad hoc" description of incidence of preoperative RMB and characteristics of SRM cases with and without RMB. Accuracy of RMB was calculated in the SRM subcohort that received extirpative treatment and complication rate after NSS compared to between the two groups. Continuous variables were compared using t-test; categorical variables were compared using the chi-square test. K-statistics was used to analyze agreement between the biopsy histology and surgical pathology. Logistic regression was used to assess the association between RMB and NSS complications. All tests were two sided, and p-values <0.05 were considered statistically significant. Results: The rate of preoperative RMB in SRMs was 11.6% (175/1597) in Europe and the United States. RMB patients were more likely to have hypertension (p < 0.04), be on dialysis (p < 0.024), or smokers (p = 0.005), with multiple/bilateral tumors (0.008 and 0.010) and previous other malignancy (p = 0.021). They underwent radical nephrectomy more frequently than non-RMB group (p = 0.034). RMB was nondiagnostic in 16 cases (9%). Accuracy of RMB in distinguishing malignant from benign was 89.5%. Agreement between biopsy and final surgical pathology was 93% for malignant vs benign tumors (kappa = 0.655). Upstaging to pT3a occurred more frequently in the RMB group (12.6% vs 6.25% [p = 0.022]). Complication rate in renal mass-NSS subcohort was 15.8%, not statistically different between RMB and non-RMB groups. On logistic regression analysis, RMB was not associated with increased risk of postoperative complication after NSS (OR: 0.9, 95% CI: 0.43-1.89). Conclusion: The practice of RMB in SRM is still scarce despite high accuracy and concordance with final pathology. RMB does not seem to increase complication rate after NSS.

Development and validation of CT imaging-based preoperative nomogram in the prediction of unfavorable high-grade small renal masses

PURPOSE

In recent years, there has been an increase in the incidence of small renal masses (SRMs) and nephrectomy was the standard management of this disease in the past. Currently, the use of active surveillance has been recommended as an alternative option in the case of some patients with SRMs due to its heterogenicity. However, limited studies focused on the regarding risk stratification. Therefore, in the current study, we developed a nomogram for the purpose of predicting the presence of high-grade SRMs on the basis of the patient information provided (clinical information, hematological indicators, and CT imaging data).

PATIENTS AND METHODS

A total of 329 patients (consisting of development and validation cohort) who had undergone nephrectomy for SRMs between January 2013 and May 2016 retrospectively were recruited for the present study. All preoperative information, including clinical predictors, hematological indicators, and CT predictors, were obtained. Lasso regression model was used for data dimension reduction and feature selection. Multivariable logistic regression analysis was applied for the establishment of the predicting model. The performance of the nomogram was assessed with respect to its calibration and discrimination properties and externally validated.

RESULTS

The predictors used in the assessment of the nomogram included tumor size, CT tumor contour, CT necrosis, CT tumor exophytic properties, and CT collecting system oppression. Based on these parameters, the nomogram was evaluated to have an effective discrimination and calibration ability, and the C-index was found to be 0.883 after internal validation and 0.887 following external validation.

CONCLUSION

Based on the aforementioned findings, it can be concluded that CT imaging-based preoperative nomogram is an effective predictor of SRMs and hence can be used in the preoperative evaluation of SRMs, due to its calibration and discrimination abilities.

Diagnostic performance of prospectively assigned clear cell Likelihood scores (ccLS) in small renal masses at multiparametric magnetic resonance imaging

INTRODUCTION

Detection of small renal masses (SRM) is increasing with the use of cross-sectional imaging, although many incidental lesions have negligible metastatic potential. A method to identify this subtype would aid in risk stratification. A previously reported clear cell likelihood score (ccLS; 1-very unlikely, 2-unlikely, 3-equivocal, 4-likely, and 5-very likely), based on retrospective review of multiparametric magnetic resonance imaging (mpMRI), predicted the likelihood of encountering clear cell renal cell carcinoma (ccRCC) at surgery. Here, we assess the performance of ccLS prospectively assigned for prediction of ccRCC.

METHODS

Patients with a known renal mass who underwent mpMRI at a single institution between June 2016 and April 2018 were prospectively assigned a ccLS as part of the clinical MRI report. These patients were retrospectively reviewed, and those with a cT1a lesion and available pathological tissue diagnosis (diagnostic biopsy or extirpative surgery) were selected for analysis.

RESULTS

In total, 57 patients (mean age 61.7 ± 14.9 years) with 63 cT1a renal masses were identified. Mean tumor size was 2.7 ± 0.7 cm. Defining ccLS 4-5 lesions as positive demonstrated an overall accuracy of 84%, sensitivity of 89%, specificity of 79%, positive predictive value of 84%, and negative predictive value of 86%. A ccLS of 1-2 demonstrates an 86% accuracy and 100% sensitivity/positive predictive value of identifying non-ccRCC histology.

CONCLUSIONS

Utilizing prospectively assigned ccLS, we confirm that mpMRI can reasonably identify ccRCC histology in cT1a renal masses. Standardization of imaging protocols and reporting criteria such as the ccLS can be used to aid in the diagnosis and management of small renal masses.

Renal Mass Biopsy is Associated with Reduction in Surgery for Early-Stage Kidney Cancer

OBJECTIVE

To determine whether use of renal mass biopsy may be associated with a reduction in surgery for patients with small, localized renal cell carcinoma (cT1aN0M0), especially among older patients and patients with greater comorbidity burden.

METHODS

A total of 106,258 patients with cT1aN0M0 renal cell carcinoma from 2004 to 2015 were analyzed in the National Cancer Data Base. Multivariable logistic regression identified independent associations with nonsurgical management, receipt of biopsy, and pathologic upstaging. Marginal effects were derived by age and comorbidity. A sensitivity analysis was conducted in years identifying patients undergoing active surveillance (2010-2015).

RESULTS

There was increased use of biopsy (8.0%-15.3%) and nonsurgical management (11.7%-15.6%) over time. Biopsy was significantly associated with use of nonsurgical management (OR 4.80 [95%CI 4.58-5.02], P <.001) as well as active surveillance (OR 1.87 [1.69-2.07], P <.001) in the sensitivity analysis. Individual predicted probability of undergoing nonsurgical management ranged from 3% to 92% (median 31.4% with use of biopsy) and increased with age and comorbidity. Pathologic tumor upstaging (≥pT3a) occurred more frequently for patients receiving biopsy compared to no biopsy (5.8% vs 3.3%, P <.001). After adjustment, biopsy remained a statistically significant predictor of upstaging (OR 1.31 [95%CI 1.24-1.38], P <.001).

CONCLUSION

Overall, biopsy demonstrated a strong, independent association with reduced use of surgery for cT1aN0M0 kidney cancer, especially with increasing age and comorbidity. The potential association of renal mass biopsy with upstaging warrants caution, but it is uncertain whether it impacts prognosis relative to true perinephric fat invasion.

Renal cell cancer treatment: an expert panel recommendation from the Latin American cooperative group-genitourinary and the Latin American renal cancer group: focus on surgery

Background:

Renal cell cancer (RCC) is one of the 10 most common cancers in the world, and its incidence is increasing, whereas mortality is declining only in developed countries. Therefore, two collaborative groups, The Latin American Oncology Cooperative Group-Genitourinary Section (LACOG-GU) and the Latin American Renal Cancer Group (LARCG), held a consensus meeting to develop this guideline.

Methods:

Issues (134) related to the treatment of RCC were previously formulated by a panel of experts. The voting panel comprised 26 specialists (urologists and medical oncologists) from the LACOG-GU/LARCG. A consensus was reached if 75% agreement was achieved. If there was less concordance, a new discussion was undertaken, and a consensus was determined by the most votes after a second voting session.

Results:

The expert meeting provided recommendations that were in line with the global literature; 75.0% of the recommendations made by the panel of experts were evidence-based level A, 22.5% of the recommendations were level B, and 2.5% of the recommendations were level D.

Conclusions:

This review suggests recommendations for the surgical treatment of RCC according to the LACOG-GU/LARCG experts.

Percutaneous renal biopsy: approach, diagnostic accuracy and risks

PURPOSE OF REVIEW

This article provides a review of recent advances and issues regarding the controversial topic of renal mass biopsy (RMB). The purpose of this review is to provide an update on the current status of renal biopsy based on recently published literature. Here, we particularly focus on articles that have been published within the last 12 months.

RECENT FINDINGS

The main topics covered in this review are the approach, diagnostic accuracy and risks related to RMB.

SUMMARY

Current literature suggests that improvements in both technique and technological advancements of RMB have led to greater diagnostic accuracy and low risks to the patient. Newer technologies are leading toward innovative and harmless ways to diagnose kidney cancer, including liquid and image-based biopsy. However, it appears that the question of whether or not to instate renal biopsy as standard clinical practice has remained a highly debated controversy.