Advances of multidetector computed tomography in the characterization and staging of renal cell carcinoma

Oncological Safety and Diagnostic Yield of Percutaneous Needle-core Biopsies in Upper Tract Urothelial Carcinoma: The UPERCUT Study

BACKGROUND AND OBJECTIVE

A percutaneous biopsy of suspected upper tract urothelial carcinoma (UTUC) is considered contraindicated due to potential safety concerns. This study evaluated the risk of tumor seeding along the needle track following a percutaneous needle-core biopsy for UTUC, along with diagnostic yield and oncological outcomes.

METHODS

We conducted a retrospective multicenter study involving 53 patients who underwent a percutaneous biopsy for upper urinary tract urothelial carcinoma between 2012 and 2022. The primary endpoint was tumor recurrence along the biopsy needle track, assessed through a centralized review of follow-up cross-sectional imaging. The secondary endpoints included biopsy yield, histological concordance in tumor stage and grade compared with final histology in cases of nephroureterectomy, complication rates, and overall oncological outcomes.

KEY FINDINGS AND LIMITATIONS

The cohort consisted of 60% male patients with a mean age of 69 yr. At diagnosis, 32% had metastatic disease. A biopsy was performed due to diagnostic uncertainty regarding renal cell carcinoma or other diseases, distant metastases, or failed endoscopic biopsy. The median follow-up imaging time was 8.3 mo. Tumor track seeding occurred in one case (1.9%) 5 mo after the procedure. Biopsy yield was 94%, with histological concordance rates of 78% for tumor stage and 100% for grade. Complications occurred in 14.8% of cases, including two (3.7%) cases of obstructive pyelonephritis requiring endoscopic management.

CONCLUSIONS AND CLINICAL IMPLICATIONS

A percutaneous biopsy is a useful diagnostic tool for high-grade invasive upper urinary tract urothelial carcinoma, with a low risk of tumor track seeding. It provides critical histological confirmation, facilitating future research on neoadjuvant systemic therapies.

Diagnostic performance of CT for extrarenal fat invasion in renal cell carcinoma: a meta-analysis and systematic review

OBJECTIVES

Renal cell carcinoma (RCC) with extrarenal fat (perinephric or renal sinus fat) invasion is the main evidence for the T3a stage. Currently, computed tomography (CT) is still the primary modality for staging RCC. This study aims to determine the diagnostic performance of CT in RCC patients with extrarenal fat invasion.

METHODS

The PubMed, Web of Science, Cochrane Library, and EMBASE databases were systematically searched up to October 11, 2023. Study quality was assessed by the QUADAS-2 tool. Standard methods recommended for meta-analyses of diagnostic evaluation were used. Heterogeneity was analyzed through meta-regression analysis.

RESULTS

Fifteen studies were included in this meta-analysis. Among them, six studies focused on perinephric fat invasion (PFI) only, four on renal sinus fat invasion (RSFI) only, and five on both. Pooled weighted estimates of sensitivity, specificity, area of SROC curve, PLR, and negative likelihood ratio (NLR) of CT for PFI were 0.69 (95% CI: 0.55-0.79), 0.82 (95% CI: 0.69-0.90), 0.81 (95% CI: 0.77-0.84), 3.85 (95% CI: 2.22-6.67), and 0.38 (95% CI: 0.27-0.55). Pooled weighted estimates of sensitivity, specificity, area of SROC curve, PLR, and NLR of CT for RSFI were 0.81 (95% CI: 0.76-0.85), 0.79 (95% CI: 0.66-0.88), 0.82 (95% CI: 0.78-0.85), 3.91 (95% CI: 2.26-6.77), and 0.24 (95% CI: 0.18-0.31).

CONCLUSION

CT has the ability to detect the PFI and RSFI in patients with RCC. However, the diagnostic performance of CT has suffered from the limitation of slightly lower accuracy, resulting from the low positive sample in the current studies. Additionally, the current PLR is low.

CRITICAL RELEVANCE STATEMENT

This study provides radiologists and urologists with a systematic and comprehensive summary of CT and CT-related morphological features in assessing extrarenal fat invasion in patients with RCC.

KEY POINTS

CT can detect extrarenal fat invasion in patients with RCC, but the diagnostic performance is inconsistent. The diagnostic performance of CT is acceptable, but primarily affected by the low positive rate of included patients. Further large-scale trials are necessary to determine the true diagnostic capabilities of CT for extrarenal fat invasion.

Role of collateral vessels on contrast-enhanced computed tomography in predicting metastatic potential for small renal cell carcinoma

BACKGROUND

The presence of collateral vessels (CVs) on contrast-enhanced computed tomography is a poor prognostic factor in renal cell carcinoma (RCC), but its value in small RCC (sRCC; < 4 cm) remains unknown. In this study, we investigated whether presence of CVs is a predictor of high potential for metastasis in sRCC.

METHODS

We retrospectively reviewed clinical and imaging data of patients with pathologically confirmed sRCC evaluated at our institution between 2011 and 2021. All sRCCs were pathologically diagnosed by biopsy, metastasectomy, partial nephrectomy, or radical nephrectomy. CVs were defined as blood vessels of any diameter connecting the tumor with the surrounding perirenal tissues on contrast-enhanced computed tomography. The rate of metastasis-free survival (MFS), defined as the time from pathological diagnosis to confirmed metastasis, was compared among patients without CVs, those with one CV, and those with two or more CVs.

RESULTS

Of 141 patients, 4 (2.8%) had metastatic sRCC at initial diagnosis. In the 137 patients with nonmetastatic sRCC, the diagnosis was pathologically confirmed following radical surgery. The median follow-up period from pathological diagnosis was 73.9 months, and the overall 5-year MFS was 93.5%. The 5-year MFS was significantly poorer in patients with two or more CVs than in those with one CV (63.8% vs. 96.3%; p = 0.0003) and those without CVs (63.8% vs. 100%; p < 0.0001).

CONCLUSIONS

sRCCs with two or more CVs might have high potential for metastasis. Conversely, sRCCs without CVs might not be aggressive and be suitable for active surveillance.

Validation of the updated Bosniak classification (2019) in pathologically confirmed CT-categorised cysts

INTRODUCTION

The updated Bosniak classification in 2019 (v2019) addresses vague imaging terms and revises the criteria with the intent to categorise a higher proportion of cysts in lower-risk groups and reduce benign cyst resections. The aim of the present study was to compare the diagnostic accuracy and inter-observer agreement rate of the original (v2005) and updated classifications (v2019).

METHOD

Resected/biopsied cysts were categorised according to Bosniak classifications (v2005 and v2019) and the diagnostic accuracy was assessed with reference to histopathological analysis. The inter-observer agreement of v2005 and v2019 was determined.

RESULTS

The malignancy rate of the cohort was 83.6% (51/61). Using v2019, a higher proportion of malignant cysts were categorised as Bosniak ≥ III (88.2% vs 84.3%) and a significantly higher percentage were categorised as Bosniak IV (68.9% vs 47.1%; p = 0.049) in comparison to v2005. v2019 would have resulted in less benign cyst resections (13.5% vs 15.7%). Calcified versus non-calcified cysts had lower rates of malignancy (57.1% vs 91.5%; RR,0.62; p = 0.002). The inter-observer agreement of v2005 was higher than that of v2019 (kappa, 0.70 vs kappa, 0.43).

DISCUSSION

The updated classification improves the categorisation of malignant cysts and reduces benign cyst resection. The low inter-observer agreement remains a challenge to the updated classification system.

Computer tomography-based shape of tumor contour and texture of tumor heterogeneity are independent prognostic indicators for clinical T1b-T2 renal cell carcinoma

PURPOSE

To evaluate association between computer tomography (CT)-based features of renal cell carcinoma (RCC) and survival outcomes.

METHODS

Data of 958 patients with clinical T1b-T2 RCC who underwent partial/radical nephrectomy from June 2003 to March 2022 were retrospectively evaluated. CT images of patients were reviewed by two radiologists for texture analysis of tumor heterogeneity and shape analysis of tumor contour. Patients were divided into three groups according to patterns of CT-based features: (1) favorable feature group (n = 117); (2) intermediate feature group (n = 606); and (3) unfavorable feature group (n = 235). Kaplan-Meier survival analysis and multivariate Cox regression analysis were performed to evaluate overall survival (OS), cancer-specific survival (CSS), and recurrence-free survival (RFS).

RESULTS

RCCs with unfavorable CT-based feature showed larger size on CT, higher nuclear grade, higher rate of histologic necrosis, and higher rate of capsular invasion than those in the other two groups (all p < 0.001). Unfavorable feature was associated with poorer OS (p = 0.001), CSS (p < 0.001), and RFS (p < 0.001) on Kaplan-Meier analysis. In multivariate analysis, intermediate and unfavorable features were independent predictors for recurrence (hazard ratio [HR] 2.51, 95% confidence interval [CI] 1.09-5.79, p = 0.031 and HR 3.71, 95% CI 1.58-8.73, p = 0.003, respectively), but not for overall death or RCC-specific death.

CONCLUSIONS

A combination of irregular tumor contour feature with heterogeneous tumor texture feature on CT is associated with poor RFS in clinical T1b-T2 RCC preoperatively.

Renal cell carcinoma T staging: Diagnostic accuracy of preoperative contrast-enhanced computed tomography

Renal cell carcinoma (RCC) accounts for 1-2% of all malignancies and is the most common renal tumor in adults. Imaging studies are used for diagnosis and staging. Tumor-Node-Metastasis staging strongly affects prognosis and management, while contrast-enhanced computed tomography (CECT) is regarded as a standard imaging technique for local and distant staging. The present study aimed to evaluate the accuracy of CECT for the preoperative staging of RCC by using surgical and pathological staging as the reference methods. This single-center prospective study was conducted between October 2019 and November 2021. The preoperative abdominal CT scans of patients suspected of having RCC were reviewed. Imaging data were collected, including tumor side and size, and perinephric fat invasion. Intraoperative notes were recorded, including the operation type, perinephric fat invasion, renal vein (RV) or inferior vena cava (IVC) tumor extension, and surrounding organ invasion. pathological data were collected on tumor size, RCC type, presence of clear margins, presence of renal capsule or perinephric fat invasion, renal sinus or pelvicalyceal system (PCS) invasion, segmental or main RV extension, and the involvement of Gerota's fascia and nearby organs. Preoperative CECT revealed that 42 out of 59 tumors had a greater maximum diameter than the pathological specimen, with an overall disparity of 0.25 cm. The specificity of CT for the detection of tumor invasion of the perinephric and renal sinus fat and PCS was 95%, and the sensitivity ranged from 80 to 88%. CT had an 83% sensitivity and a 95 specificity in detecting T4 stage cancer, with a 100% specificity for adrenal invasion. The concordance between radiographic and histological results for RV and IVC involvement was high, with specificities of 94 and 98%, and sensitivities of 80 and 100%, respectively. Overall accuracy for correct T staging was 80%. In conclusion, CECT is accurate in the local T staging of RCC, with high sensitivity and specificity for estimating tumor size and detecting extension to nearby structures and venous invasion.

Recent advances in imaging techniques of renal masses

Multiphasic multidetector computed tomography (CT) forms the mainstay for the characterization of renal masses whereas magnetic resonance imaging (MRI) acts as a problem-solving tool in some cases. However, a few of the renal masses remain indeterminate even after evaluation by conventional imaging methods. To overcome the deficiency in current imaging techniques, advanced imaging methods have been devised and are being tested. This review will cover the role of contrast-enhanced ultrasonography, shear wave elastography, dual-energy CT, perfusion CT, MR perfusion, diffusion-weighted MRI, blood oxygen level-dependent MRI, MR spectroscopy, positron emission tomography (PET)/prostate-specific membrane antigen-PET in the characterization of renal masses.

Circ_0005875 sponges miR-502-5p to promote renal cell carcinoma progression through upregulating E26 transformation specific-1

Increasing evidence has shown that circular RNAs (circRNAs) play critical roles in various cancers, including renal cell carcinoma (RCC). We aimed to explore the role and underlying mechanism of circ_0005875 in RCC. The expression levels of circ_0005875, microRNA-502-5p (miR-502-5p) and E26 transformation specific-1 (ETS1) mRNA were determined by quantitative real-time PCR. Cell proliferation was assessed by Cell Counting Kit-8, colony formation, and 5-Ethynyl-2'-deoxyuridine (EdU) assays. Cell migration and invasion were monitored by wound healing assay and transwell assay, respectively. Flow cytometry analysis was applied to determine cell apoptosis and cell cycle distribution. Western blot assay was performed to measure the protein expression of CyclinD1 and ETS1. The interaction between miR-502-5p and circ_0005875 or ETS1 was confirmed by dual-luciferase reporter and RNA immunoprecipitation assays. A xenograft tumor model was established to confirm the role of circ_0005875 in vivo. Circ_0005875 and ETS1 were upregulated and miR-502-5p was downregulated in RCC tissues and cells. Knockdown of circ_0005875 suppressed RCC cell proliferation, migration and invasion, and induced apoptosis and cell cycle arrest. MiR-502-5p was a target of circ_0005875, and miR-502-5p inhibition reversed the inhibitory effects of circ_0005875 knockdown on the malignant behaviors of RCC cells. ETS1 was a direct target of miR-502-5p, and miR-502-5p exerted its anti-tumor role in RCC cells by targeting ETS1. Moreover, circ_0005875 knockdown decreased ETS1 expression by sponging miR-502-5p. Additionally, circ_0005875 depletion suppressed tumor growth in vivo. Circ_0005875 knockdown suppressed RCC progression by regulating miR-502-5p/ETS1 axis, which might provide a promising therapeutic target for RCC.

Comparison of cortico-medullary phase contrast-enhanced MDCT and T2-weighted MR imaging in the histological subtype differentiation of renal cell carcinoma: radiology-pathology correlation

Purpose

Renal cell carcinoma (RCC) subtype differentiation is of crucial importance in the management and prognosis of these patients. In this study, we investigated the usefulness of unenhanced and cortico-medullary phase contrast-enhanced multidetector-row computed tomography (MDCT) and T2-weighted fast spin-echo (FSE) magnetic resonance imaging (MRI) modalities in the discrimination of the 3 main subtype RCC patients in correlation with their histopathological findings.

Material and methods

A total of 80 pathologically proven RCC patients who had undergone either partial or total nephrectomy were retrospectively investigated in this study. Their histological subtypes were 54 clear cell renal cell carcinoma (ccRCC), 15 papillary renal cell carcinoma (pRCC), and 11 chromophobe renal cell carcinoma (cRCC), based on pathological evaluation. There were 62 male (77.5%) and 18 female (22.5%) patients. Among the 54 ccRCC patients, 29 patients had both non-contrast and cortico-medullary phase CT, 1 had only non-contrast CT, 5 only had cortico-medullary phase CT, and 38 had MRI examination. In the pRCC group, 10 patients had both non-contrast and cortico-medullary phase CT, 1 had only non-contrast CT, 1 had only cortico-medullary phase CT, and 12 had MRI. Finally, in the remaining 11 cRCC patients, 9 had both non-contrast and cortico-medullary phase CT, and only 5 had MRI. We calculated both tumour attenuation values as HU (Hounsfield units) on unenhanced and cortico-medullary phase MDCT images and also tumour mean signal intensity values on FSE T2-weighted MRI images by using the region of interest (ROI) including normal renal cortex measurements. Besides quantitative evaluation, we also performed qualitative visual assessment of tumours on contrast-enhanced MDCT and FSE T2-weighted MRI.

Results

There was no statistically significant difference among the attenuation values of the 3 tumour subtypes on pre-contrast CT images. ccRCC demonstrated a prominent degree of contrast enhancement compared to the chromophobe and papillary ones on cortico-medullary phase MDCT. We found no statistically significant difference between chromophobe and papillary subtypes, although chromophobe tumours showed slightly higher attenuation values compared to papillary ones. ccRCCs usually demonstrated a heterogenous contrast enhancement on cortico-medullary phase CT images, while the papillary subtype usually had a homogenous appearance on visual assessment. On FSE T2-weighted MR images, the signal intensity values of ccRCC patients were found to be significantly higher than both chromophobe and papillary subtypes. Although cRCC patients had a prominently lower T2 signal intensity than clear cell subtype, there was no statistically significant signal intensity difference between chromophobe and papillary subtypes. Regarding visual assessment, papillary subtype tumours showed a mostly homogenous appearance on T2-weighted images and a statistically significant difference was present. On the other hand, there was no significant difference of visual assessment of the clear cell and chromophobe subtypes.

Conclusions

The measurement of the attenuation values on cortico-medullary phase MDCT and the mean signal intensity values on FSE T2-weighted MRI can provide useful information in the differentiation of RCC main subtypes. Also, visual assessment of tumours on both modalities can contribute to this issue by providing additional imaging properties.

CT-based radiomics stratification of tumor grade and TNM stage of clear cell renal cell carcinoma

OBJECTIVES

To evaluate the utility of CT-based radiomics signatures in discriminating low-grade (grades 1-2) clear cell renal cell carcinomas (ccRCC) from high-grade (grades 3-4) and low TNM stage (stages I-II) ccRCC from high TNM stage (stages III-IV).

METHODS

A total of 587 subjects (mean age 60.2 years ± 12.2; range 22-88.7 years) with ccRCC were included. A total of 255 tumors were high grade and 153 were high stage. For each subject, one dominant tumor was delineated as the region of interest (ROI). Our institutional radiomics pipeline was then used to extract 2824 radiomics features across 12 texture families from the manually segmented volumes of interest. Separate iterations of the machine learning models using all extracted features (full model) as well as only a subset of previously identified robust metrics (robust model) were developed. Variable of importance (VOI) analysis was performed using the out-of-bag Gini index to identify the top 10 radiomics metrics driving each classifier. Model performance was reported using area under the receiver operating curve (AUC).

RESULTS

The highest AUC to distinguish between low- and high-grade ccRCC was 0.70 (95% CI 0.62-0.78) and the highest AUC to distinguish between low- and high-stage ccRCC was 0.80 (95% CI 0.74-0.86). Comparable AUCs of 0.73 (95% CI 0.65-0.8) and 0.77 (95% CI 0.7-0.84) were reported using the robust model for grade and stage classification, respectively. VOI analysis revealed the importance of neighborhood operation-based methods, including GLCM, GLDM, and GLRLM, in driving the performance of the robust models for both grade and stage classification.

CONCLUSION

Post-validation, CT-based radiomics signatures may prove to be useful tools to assess ccRCC grade and stage and could potentially add to current prognostic models. Multiphase CT-based radiomics signatures have potential to serve as a non-invasive stratification schema for distinguishing between low- and high-grade as well as low- and high-stage ccRCC.

KEY POINTS

• Radiomics signatures derived from clinical multiphase CT images were able to stratify low- from high-grade ccRCC, with an AUC of 0.70 (95% CI 0.62-0.78). • Radiomics signatures derived from multiphase CT images yielded discriminative power to stratify low from high TNM stage in ccRCC, with an AUC of 0.80 (95% CI 0.74-0.86). • Models created using only robust radiomics features achieved comparable AUCs of 0.73 (95% CI 0.65-0.80) and 0.77 (95% CI 0.70-0.84) to the model with all radiomics features in classifying ccRCC grade and stage, respectively.

[Risk factors of renal sinus invasion in clinical T1 renal cell carcinoma patients undergoing nephrectomy]

OBJECTIVE

To summarize the clinicoradiological characteristics of clinical T1 renal cell carcinoma patients and to investigate the risk factors of renal sinus invasion in cT1 renal cell carcinoma patients undergoing nephrectomy.

METHODS

A retrospective study was conducted in cT1 renal cell carcinoma patients from January 2016 to August 2019 in Department of Urology, Peking University Third Hospital, who underwent partial or radical nephrectomy by analyzing clinicopathological and radiological data. The influencing factors of renal sinus invasion for cT1 renal cell carcinoma were determined by χ² test, Mann-Whitney U test and Logistic regression analysis.

RESULTS

A total of 507 patients were enrolled, including 354 males (69.8%) and 153 females (30.2%). The median age was 59 years and the median body mass index (BMI) was 25.5 kg/m². Eighteen patients (3.6%) had gross hematuria preoperatively. The median tumor diameter was 3.5 cm. Three hundred twenty-two patients (63.5%) were staged clinical T1a and 165 cases (36.5%) were staged clinical T1b. The median R.E.N.A.L. score was 8. Three hundred fifty-nine patients (70.8%) had regular tumor border and 148 (29.2%) irregular. All the patients underwent surgical treatment, including 186 (36.7%) partial nephrectomy and 321 (63.3%) radical nephrectomy. Postoperative pathology showed seventy-five patients (14.8%) had renal sinus invasion, including 18 in cT1a (5.6%) and 57 in cT1b (30.8%). Univariate analysis showed that age (P=0.020), R.E.N.A.L. score (R value, E value, N value, P < 0.001) and tumor border (P < 0.001) were associated risk factors for cT1 renal cell carcinoma with renal sinus invasion. On multivariate binary Logistic analysis, R.E.N.A.L. score (P≤0.020) and irregular tumor border (P=0.001) were independent risk factors.

CONCLUSION

For cT1 renal cell carcinoma patients undergoing nephrectomy, about 15% had renal sinus invasion postoperatively. High R.E.N.A.L. score and irre-gular tumor border help predicting cT1 renal cell carcinoma renal sinus invasion.

Tumor grade estımatıon of clear cell and papıllary renal cell carcınomas usıng contrast-enhanced MDCT and FSE T2 weıghted MR ımagıng: radıology-pathology correlatıon

BACKGROUND

Discrimination of low grade (grade 1-2) renal tumors from high grade (grade 3-4) ones carries crucial importance in terms of the management of these patients and also in the decision-making of appropriate treatment strategies. Our aim was to investigate whether contrast-enhanced multidetector computed tomography (MDCT) and T2 weighted fast spin echo (FSE) magnetic resonance imaging (MRI) could play a specific role in the discrimination of low grade versus high grade tumors in clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) patients.

METHODS

In this study, we retrospectively evaluated 66 RCC patients based on histopathologic findings who had underwent either partial or total nephrectomies. Our cohort consisted of 52 ccRCC and 14 pRCC patients, of whom 50 were male (%76) and 16 were female (%24). Among the 52 ccRCC patients, 18 had both cortico-medullary phase contrast-enhanced CT and MRI, 15 had only cortico-medullary phase CT and 19 had only MRI examination. In the pRCC group, 8 patients had both cortico-medullary phase contrast-enhanced CT and MRI, 3 had only cortico-medullary phase CT and 3 had only MRI. We both calculated mean tumor attenuation values on cortico-medullary phase MDCT images as HU (hounsfield unit) and also tumor mean signal intensity values on FSE T2 weighted MR images, using both region of interest and whole lesion measurements including normal renal cortex. The obtained values were compared with the grading results of the ccRCC and pRCC tumors according to the WHO/International Society of Urological Pathology grading system.

RESULTS

A significant positive correlation was found between the mean attenuation values of both tumor subtypes on cortico-medullary phase contrast-enhanced CT and their grades (p < 0.001). High grade tumors exhibited higher mean attenuation values (74.3 ± 22.3 HU) than the low grade tumors (55.2 ± 23.7 HU) in both subtypes. However, a statistically significant correlation was not found between the mean signal intensity values of the two tumor subtypes on FSE T2 weighted MR images and their grades (p > 0.05). Low grade tumors had a mean signal intensity value of 408.9 ± 44.6, while high grade tumors showed a value of 382.1 ± 44.2. The analysis of the ccRCC group patients, yielded a statistically significant correlation between the mean signal intensity values on T2 weighted images and tumor grading (p < 0.001). Low grade (grade 1-2) ccRCC patients exhibited higher mean signal intensity values (475.7 ± 51.3), as compared to those of high grade (grade 3-4) (418.5 ± 45.7) tumors. On the other hand, analysis of the pRCC group patients revealed that there was a significant correlation between the mean attenuation values of tumors on cortico-medullary phase contrast-enhanced CT and their grades (p < 0.001). High grade papillary subtype tumors (54.2 ± 25.2) showed higher mean attenuation values than the low grade (35.5 ± 18.8) ones.

CONCLUSIONS

Contrast-enhanced MDCT and T2 weighted FSE MRI can play a considerable role in the discrimination of low grade versus high grade tumors of both subtype RCC patients. Thus, these non-invasive evaluation techniques may have positive impact on the determination of the management and treatment strategies of these patients.

Effect of radiomics from different virtual monochromatic images in dual-energy spectral CT on the WHO/ISUP classification of clear cell renal cell carcinoma

AIM

To investigate the effect of radiomics obtained from different virtual monochromatic images (VMIs) in dual-energy spectral computed tomography (CT) on the World Health Organization/International Association for Urological Pathology (WHO/ISUP) classification of clear cell renal cell carcinoma (ccRCC).

MATERIALS AND METHODS

A retrospective study of 99 ccRCC patients who underwent contrast-enhanced dual-energy CT was undertaken. ccRCC was confirmed at surgery or biopsy and graded according to the WHO/ISUP pathological grading criteria as low grade (n=68, grade I and II) or high grade (n=31, grade III and IV). Radiomics risk scores (RRSs) for differentiating high and low grades of ccRCC were constructed from 11 sets of VMI in (40-140 keV, 10 keV interval) the cortical phase. Receiver operating characteristic (ROC) curves were drawn and the area under the curves (AUCs) was calculated to evaluate the discriminatory power of RRS for each VMI. The Hosmer-Lemeshow test was used to evaluate the goodness-of-fit of each model and the decision curve was used to analyse its net benefit to patients.

RESULTS

The AUC values for distinguishing low-from high-grade ccRCC with RRS of 40-140 keV VMIs were all >0.920. The Hosmer-Lemeshow test showed that the p-values of RRS of VMIs were >0.05, suggesting good fits. In the decision curve analysis, RRS from the 40-140 keV VMIs had similar decision curves and provided better net benefits than considering all patients either as high-grade or low-grade.

CONCLUSIONS

The RRS obtained from multiple VMIs in dual-energy spectral CT have high diagnostic efficiencies for distinguishing between low- and high-grade ccRCC with no significant differences between different VMIs.

Clinicopathological and radiological significance of the collateral vessels of renal cell carcinoma on preoperative computed tomography

This study aimed to investigate the clinicopathological and radiological significance of the collateral vessel of renal cell carcinoma (RCC) on preoperative computed tomography (CT). Preoperative contrast-enhanced CT of 236 consecutive patients with pathological documented RCC were retrospectively reviewed during the period of 2014. The associations of the presence of collateral vessels with perioperative clinicopathological and radiological features, as well as long term survival outcomes were analyzed. Totally, collateral vessels were detected by contrast-enhanced CT in 110 of 236 patients. The presence of collateral vessels was significantly associated with higher pathologic T stage, higher Fuhrman grade, higher overall RENAL scores, greater tumor size and enhancement, and more tumor necrosis (all P < 0.05). In patients with clear cell RCC, those harboring collateral vessels had significantly higher SSIGN scores (P < 0.001) and shorter overall survival (P = 0.01) than those without collateral vessel. The incidence of intraoperative blood loss, blood transfusion, radical nephrectomy (RN) and open surgery were also significantly higher in patients with collateral vessels (all P < 0.05). In multivariate analysis, the presence of collateral vessels was significantly associated with RN (P = 0.021) and open surgery (P = 0.012). The presence of collateral vessels was significantly associated with aggressive clinicopathological parameters and worse prognosis. It is worth paying attention to its association with the choice of RN and open surgery in clinical practice.

Circ_101341 Deteriorates the Progression of Clear Cell Renal Cell Carcinoma Through the miR- 411/EGLN3 Axis

Background

Clear cell renal cell carcinoma (ccRCC) is one of the main subtypes of renal cell carcinoma, with intense aggressiveness. The involvement of circular RNAs (circRNAs) in human cancers attracts much concern. The intention of this study was to investigate the expression of circ_101341 and explore its function in ccRCC.

Materials and Methods

The expression of circ_101341, miR-411 and Egl nine homolog 3 (EGLN3) was measured using quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was assessed by cell counting kit-8 (CCK-8) assay and colony formation assay. Cell migration and invasion were monitored by transwell assay. Xenograft model was established to explore the role of circ_101341 in vivo. The protein levels of E-cadherin (E-cad), N-cadherin (N-cad), matrix metalloprotein-9 (MMP9) and EGLN3 were detected by Western blot. Bioinformatic analysis was conducted using Circinteractome and starBase. The targeted relationship was verified using dual-luciferase reporter assay, RNA-binding protein immunoprecipitation (RIP) assay and RNA pull-down assay.

Results

The expression of circ_101341 was elevated in ccRCC tissues and cells. Functionally, circ_101341 knockdown depleted proliferation, migration and invasion of ccRCC cells in vitro and restricted tumor growth in vivo. Circ_101341 directly targeted miR-411, and miR-411 inhibition revised the inhibitory effects of circ_101341 knockdown on proliferation, migration and invasion in ccRCC cells. Moreover, miR-411 directly bound to EGLN3, and EGLN3 overexpression also rescued the effects of circ_101341 knockdown.

Conclusion

Circ_101341 functioned as a tumor promoter to strengthen proliferation, migration and invasion by regulating EGLN3 via sponging miR-411, indicating that circ_101341 was a potential diagnostic and therapeutic biomarker of ccRCC.

Prediction models for clear cell renal cell carcinoma ISUP/WHO grade: comparison between CT radiomics and conventional contrast-enhanced CT

OBJECTIVE

Comparing the prediction models for the ISUP/WHO grade of clear cell renal cell carcinoma (ccRCC) based on CT radiomics and conventional contrast-enhanced CT (CECT).

METHODS

The corticomedullary phase images of 119 cases of low-grade (I and II) and high-grade (III and IV) ccRCC based on 2016 ISUP/WHO pathological grading criteria were analyzed retrospectively. The patients were randomly divided into training and validation set by stratified sampling according to 7:3 ratio. Prediction models of ccRCC differentiation were constructed using CT radiomics and conventional CECT findings in the training setandwere validated using validation set. The discrimination, calibration, net reclassification index (NRI) and integrated discrimination improvement index (IDI) of the two prediction models were further compared. The decision curve was used to analyze the net benefit of patients under different probability thresholds of the two models.

RESULTS

In the training set, the C-statistics of radiomics prediction model was statistically higher than that of CECT (p < 0.05), with NRI of 9.52% and IDI of 21.6%, both with statistical significance (p < 0.01).In the validation set, the C-statistics of radiomics prediction model was also higher but did not show statistical significance (p = 0.07). The NRI and IDI was 14.29 and 33.7%, respectively, both statistically significant (p < 0.01). Validation set decision curve analysis showed the net benefit improvement of CT radiomics prediction model in the range of 3-81% over CECT.

CONCLUSION

The prediction model using CT radiomics in corticomedullary phase is more effective for ccRCC ISUP/WHO grade than conventional CECT.

ADVANCES IN KNOWLEDGE

As a non-invasive analysis method, radiomics can predict the ISUP/WHO grade of ccRCC more effectively than traditional enhanced CT.

Nephron-Sparing Surgery for Adult Xp11.2 Translocation Renal Cell Carcinoma at Clinical T1 Stage: A Multicenter Study in China

Purpose

To evaluate the oncologic efficacy and feasibility of nephron-sparing surgery (NSS) in adult Xp11.2 translocation renal cell carcinoma (RCC).

Patients and Methods

Seventy patients with Xp11.2 translocation RCC and 273 with conventional RCC from five institutions in Nanjing were retrospectively studied. All patients were older than 18 years and were categorized into clinical T1 (cT1) stage using preoperative imaging. Using the preoperative imaging and electronic medical records, anatomical and pathological features were collected and analyzed.

Results

Among patients with Xp11.2 translocation RCC, 18/36 (50.0%) with cT1a and 12/34 (35.3%) with cT1b tumors underwent NSS. The respective proportions in the conventional RCC group were 121/145 (83.4%) and 93/128 (72.7%). Among cT1a tumors, the Xp11.2 translocation RCCs tended to be adjacent to the collecting system, sinus, and axial renal midline compared with conventional RCCs. Patients with Xp11.2 translocation RCCs who underwent NSS had comparable progression-free survival (PFS) and overall survival to radical nephrectomy (RN) patients (P > 0.05). Among cT1b tumors, surgical margin positivity and pelvicalyceal, vascular, and region lymphatic involvement were more likely to occur in the Xp11.2 translocation RCCs (P < 0.05). Patients with Xp11.2 translocation RCC who underwent RN had a more favorable PFS than those who underwent NSS (P = 0.048). However, multivariate analysis of PFS did not identify surgical method as a risk factor (P = 0.089).

Conclusions

Among adults with Xp11.2 translocation RCC, NSS can be an alternative for patients with cT1a tumor but should be performed with more deliberation in patients with cT1b tumors.

Electronic supplementary material

The online version of this article (10.1245/s10434-020-08813-y) contains supplementary material, which is available to authorized users.

Components of Radiologic Progressive Disease Defined by RECIST 1.1 in Patients with Metastatic Clear Cell Renal Cell Carcinoma

Background Progression-free survival (PFS) determined by Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) is the reference standard to assess efficacy of treatments in patients with clear cell renal cell carcinoma. Purpose To assess the most common components of radiologic progressive disease as defined by RECIST 1.1 in patients with clear cell renal cell carcinoma and how the progression events impact PFS. Materials and Methods This secondary analysis of the phase III METEOR trial conducted between 2013 and 2014 included patients with metastatic clear cell renal cell carcinoma, with at least one target lesion at baseline and one follow-up time point, who were determined according to RECIST 1.1 to have progressive disease. A chest, abdominal, and pelvic scan were acquired at each time point. Kruskal-Wallis analysis was used to test differences in median PFS among the RECIST 1.1 progression events. The Holm-Bonferroni method was used to compare the median PFS of the progression events for the family-wise error rate of 5% to adjust P values for multiple comparisons. Results Of the 395 patients (296 men, 98 women, and one patient with sex not reported; mean age, 61 years ± 10), 73 (18.5%) had progression due to non-target disease, 105 (26.6%) had new lesions, and 126 (31.9%) had progression of target lesions (defined by an increase in the sum of diameters). Patients with progression of non-target disease and those with new lesions had shorter PFS than patients with progression defined by the target lesions (median PFS, 2.8 months [95% confidence interval {CI}: 1.9 months, 3.7 months] and 3.6 months [95% CI: 3.3 months, 3.7 months] vs 5.4 months [95% CI: 5.0 months, 5.5 months], respectively [P < .01]). Conclusion The most common causes for radiologic progression of renal cell carcinoma were based on non-target disease and new lesions rather than change in target lesions, despite this being considered uncommon in the Response Evaluation Criteria in Solid Tumors version 1.1 literature. © RSNA, 2019 See also the editorial by Kuhl in this issue.

Clear cell renal cell carcinoma: CT-based radiomics features for the prediction of Fuhrman grade

OBJECTIVES

To discriminate low grade (Fuhrman I/II) and high grade (Fuhrman III/IV) clear cell renal cell carcinoma (CCRCC) by using CT-based radiomic features.

METHODS

161 and 99 patients diagnosed with low and high grade CCRCCs from January 2011 to May 2018 were enrolled in this study. 1029 radiomic features were extracted from corticomedullary (CMP), and nephrographic phase (NP) CT images of all patients. We used interclass correlation coefficient (ICC) and the least absolute shrinkage and selection operator (LASSO) regression method to select features, then the selected features were constructed three classification models (CMP, NP and with their combination) to discriminate high and low grades CCRCC. These three models were built by logistic regression method using 5-fold cross validation strategy, evaluated with receiver operating characteristics curve (ROC) and compared using DeLong test.

RESULTS

We found 11 and 24 CMP and NP features were independently significantly associated with the Fuhrman grades. The model of CMP, NP and Combined model using radiomic feature set showed diagnostic accuracy of 0.719 (AUC [area under the curve], 0.766; 95% CI [confidence interval]: 0.709-0.816; sensitivity, 0.602; specificity, 0.838), 0.738 (AUC, 0.818; 95% CI:0.765-0.838; sensitivity, 0.693; specificity, 0.838), 0.777(AUC, 0.822; 95% CI: 0.769-0.866; sensitivity, 0.677; specificity, 0.839). There were significant differences in AUC between CMP model and Combined model (P = 0.0208), meanwhile, the differences between CMP model and NP model, NP model and Combined model reached no significant (P = 0.0844, 0.7915).

CONCLUSIONS

Radiomic features could be used as biomarker for the preoperative evaluation of the CCRCC Fuhrman grades.

Relative Computed Tomography (CT) Enhancement Value for the Assessment of Microvascular Architecture in Renal Cell Carcinoma

BACKGROUND To investigate the correlation between the relative computed tomography (CT) enhancement value and the microvascular architecture in different pathologic subtypes of renal cell carcinoma (RCC). MATERIAL AND METHODS This retrospective study included 55 patients with pathologically confirmed RCC. Immunohistochemistry for CD34 was performed for all surgical specimens. Microvascular architecture parameters (density, area, diameter, and perimeter) for the microvessels and the microvessels with lumen were determined. The CT scan was performed during arterial phase or venous phase. The correlation of parameters on CT and tumor angiogenesis was investigated. RESULTS Density of microvessels showed a positive correlation with CT values of tumors, ratios of tumor to cortex, and differences of tumor and medulla, but no correlation with CT value ratio of tumor to aorta or tumor to medulla. CT parameters were positively correlated with microvascular parameters. However, no CT parameter differences between hypo-vascular clear cell RCC and papillary RCC was observed. Strikingly, the density and area of the microvessels were significantly higher in hypo-vascular clear cell RCC than that in papillary RCC, while the density of the microvessels with lumen in the cyst-present RCC was significantly higher than that in the cyst-absent RCC. The values (especially those of microvessels with lumen) of area density, diameter, and perimeter were higher in the capsule-absent RCC than in the capsule-present RCC. CONCLUSIONS The relative CT enhancement value of RCC was associated with vascular architecture parameters including density, area, and perimeter. Quantitative and semi-quantitative parameters on enhanced CT may shed some light on tumor vasculature and function as indicators of the biological behavior of RCC.

[Focal therapy for small renal masses : Observation, ablation or surgery]

BACKGROUND

The rising incidence of renal cell carcinoma, its more frequent early detection (stage T1a) and the increasing prevalence of chronic renal failure with higher morbidity and shorter life expectancy underscore the need for multimodal focal nephron-sparing therapy.

DISCUSSION

During the past decade, the gold standard shifted from radical to partial nephrectomy. Depending on the surgeon's experience, the patient's constitution and the tumor's location, the intervention can be performed laparoscopically with the corresponding advantages of lower invasiveness. A treatment alternative can be advantageous for selected patients with high morbidity and/or an increased risk of complications associated with anesthesia or surgery. Corresponding risk stratification necessitates previous confirmation of the small renal mass (cT1a) by histological examination of biopsy samples. Active surveillance represents a controlled delay in the initiation of treatment.

RESULTS

Percutaneous radiofrequency ablation (RFA) and laparoscopic cryoablation are currently the most common treatment alternatives, although there are limitations particularly for renal tumors located centrally near the hilum. More recent ablation procedures such as high intensity focused ultrasound (HIFU), irreversible electroporation, microwave ablation, percutaneous stereotactic ablative radiotherapy and high-dose brachytherapy have high potential in some cases but are currently regarded as experimental for the treatment of renal cell carcinoma.

Quantitative computer-aided diagnostic algorithm for automated detection of peak lesion attenuation in differentiating clear cell from papillary and chromophobe renal cell carcinoma, oncocytoma, and fat-poor angiomyolipoma on multiphasic multidetector computed tomography

OBJECTIVE

To evaluate the performance of a novel, quantitative computer-aided diagnostic (CAD) algorithm on four-phase multidetector computed tomography (MDCT) to detect peak lesion attenuation to enable differentiation of clear cell renal cell carcinoma (ccRCC) from chromophobe RCC (chRCC), papillary RCC (pRCC), oncocytoma, and fat-poor angiomyolipoma (fp-AML).

MATERIALS AND METHODS

We queried our clinical databases to obtain a cohort of histologically proven renal masses with preoperative MDCT with four phases [unenhanced (U), corticomedullary (CM), nephrographic (NP), and excretory (E)]. A whole lesion 3D contour was obtained in all four phases. The CAD algorithm determined a region of interest (ROI) of peak lesion attenuation within the 3D lesion contour. For comparison, a manual ROI was separately placed in the most enhancing portion of the lesion by visual inspection for a reference standard, and in uninvolved renal cortex. Relative lesion attenuation for both CAD and manual methods was obtained by normalizing the CAD peak lesion attenuation ROI (and the reference standard manually placed ROI) to uninvolved renal cortex with the formula [(peak lesion attenuation ROI - cortex ROI)/cortex ROI] × 100%. ROC analysis and area under the curve (AUC) were used to assess diagnostic performance. Bland-Altman analysis was used to compare peak ROI between CAD and manual method.

RESULTS

The study cohort comprised 200 patients with 200 unique renal masses: 106 (53%) ccRCC, 32 (16%) oncocytomas, 18 (9%) chRCCs, 34 (17%) pRCCs, and 10 (5%) fp-AMLs. In the CM phase, CAD-derived ROI enabled characterization of ccRCC from chRCC, pRCC, oncocytoma, and fp-AML with AUCs of 0.850 (95% CI 0.732-0.968), 0.959 (95% CI 0.930-0.989), 0.792 (95% CI 0.716-0.869), and 0.825 (95% CI 0.703-0.948), respectively. On Bland-Altman analysis, there was excellent agreement of CAD and manual methods with mean differences between 14 and 26 HU in each phase.

CONCLUSION

A novel, quantitative CAD algorithm enabled robust peak HU lesion detection and discrimination of ccRCC from other renal lesions with similar performance compared to the manual method.

Clinical versus Pathologic staging of Renal Tumors: Role of Multi-Detector CT Urography

INTRODUCTION

Our ability to diagnose renal cell carcinoma (RCC) has increased in the past 30 years as a result of the extensive application of imaging techniques, such as ultrasonography, computed tomography, and magnetic resonance imaging. Multi-detector computed tomography (MDCT) remains the most appropriate imaging modality for the diagnosis and staging of RCC. The aim of this work was to compare the findings of MDCT with surgical pathology to determine the accuracy of delineating tumor size, localization, organ confinement, lymph node metastases, and the extent of tumor thrombus in the renal vein and inferior vena cava.

METHODS

The clinical, surgical, and anatomo-pathologic records of 99 patients treated by nephrectomy (radical or partial) for solid renal tumors at Theodor Bilharz Research Institute and Nasser Institute from 2005 to 2011 were reviewed retrospectively. All cases were staged pre-operatively with abdominal MDCT (pre- and post-contrast enhancement) in addition to the routine biochemical, hematological, and radiological work-up. The tumors' histologic types were determined according to the WHO classification of renal tumors in adults in 2004, and staging was updated to the TNM 2010 system. Data were analyzed using the t-test.

RESULTS

The mean age was 52 (range 21-73). Seventy-eight patients were males, and 21 patients were females (Male/Female ratio: 3.7:1). There were no significant differences in the mean tumor size between radiographic and pathologic assessments in different tumor stages. The overall incidence of lymph node invasion in surgical specimens was 76%, whereas MDCT showed a positive incidence in 68.4% of cases (false negative result in 7 cases, 7.6%).

CONCLUSION

Our findings indicated that MDCT urography is an accurate method to estimate renal tumor size, lymph node, vascular and visceral metastases preoperatively. Also, preoperative staging of renal tumors with MDCT represents a valuable and accurate tool.